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Articles containing the keyword 'tree'.

Category: Commentary

article id 475, category Commentary
Petteri Muukkonen, Raisa Mäkipää. (2006). Biomass equations for European trees: addendum. Silva Fennica vol. 40 no. 4 article id 475. https://doi.org/10.14214/sf.475
A review of stem volume and biomass equations for tree species growing in Europe (Zianis et al. 2005) resulted in suggestions for additional equations. The numbers of original equations, compiled from scientific articles were 607 for biomass and 230 for stem volume. On the basis of the suggestions and an updated literature search, some new equations were published after our review, but more equations were also available from earlier literature. In this addendum, an additional 188 biomass equations and 8 volume equations are presented. One new tree species (Pinus cembra) is included in the list of volume equations. Biomass equations for twelve new tree species are presented: Abies alba, Carbinus betulus, Larix decidua, P. cembra, P. nigra, Quercus robur, Salix caprea, S. ‘Aquatica’, S. dasyclados, S. phylicifolias, S. triandra and S. accuparia. The tree-level equations predict stem volume, whole tree biomass or biomass of certain components (e.g., foliage, roots, total above-ground) as a function of diameter or diameter and height of a tree. Biomass and volume equations with other independent variables have also been widely developed but they are excluded from this addendum because the variables selected may reflect locally valid dependencies that cannot be generalized to other geographical regions. Most of the equations presented here are developed for Sweden, Finland and Norway in northern Europe, for Austria in central Europe and for Italy in southern Europe. There are also few equations from Poland and Belgium. Most of the equations deal with above-ground components such as stem, branches and foliage, but some new equations are also available for root biomass. Zianis et al. (2005) and this addendum can be used together as guides to the original publications of these equations. Our updated database of the biomass and volume equations is available also from the website www.metla.fi/hanke/3306/tietokanta.htm.
  • Muukkonen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: petteri.muukkonen@metla.fi
  • Mäkipää, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: raisa.makipaa@metla.fi (email)
article id 475, category Commentary
Petteri Muukkonen, Raisa Mäkipää. (2006). Biomass equations for European trees: addendum. Silva Fennica vol. 40 no. 4 article id 475. https://doi.org/10.14214/sf.475
A review of stem volume and biomass equations for tree species growing in Europe (Zianis et al. 2005) resulted in suggestions for additional equations. The numbers of original equations, compiled from scientific articles were 607 for biomass and 230 for stem volume. On the basis of the suggestions and an updated literature search, some new equations were published after our review, but more equations were also available from earlier literature. In this addendum, an additional 188 biomass equations and 8 volume equations are presented. One new tree species (Pinus cembra) is included in the list of volume equations. Biomass equations for twelve new tree species are presented: Abies alba, Carbinus betulus, Larix decidua, P. cembra, P. nigra, Quercus robur, Salix caprea, S. ‘Aquatica’, S. dasyclados, S. phylicifolias, S. triandra and S. accuparia. The tree-level equations predict stem volume, whole tree biomass or biomass of certain components (e.g., foliage, roots, total above-ground) as a function of diameter or diameter and height of a tree. Biomass and volume equations with other independent variables have also been widely developed but they are excluded from this addendum because the variables selected may reflect locally valid dependencies that cannot be generalized to other geographical regions. Most of the equations presented here are developed for Sweden, Finland and Norway in northern Europe, for Austria in central Europe and for Italy in southern Europe. There are also few equations from Poland and Belgium. Most of the equations deal with above-ground components such as stem, branches and foliage, but some new equations are also available for root biomass. Zianis et al. (2005) and this addendum can be used together as guides to the original publications of these equations. Our updated database of the biomass and volume equations is available also from the website www.metla.fi/hanke/3306/tietokanta.htm.
  • Muukkonen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: petteri.muukkonen@metla.fi
  • Mäkipää, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: raisa.makipaa@metla.fi (email)

Category: Research article

article id 10179, category Research article
Lauri Korhonen, Jaakko Repola, Tomi Karjalainen, Petteri Packalen, Matti Maltamo. (2019). Transferability and calibration of airborne laser scanning based mixed-effects models to estimate the attributes of sawlog-sized Scots pines. Silva Fennica vol. 53 no. 3 article id 10179. https://doi.org/10.14214/sf.10179
Highlights: Attributes of individual sawlog-sized pines estimated by transferring ALS-based models between sites; Mixed effects models were more accurate than k-NN imputation tested earlier; Calibration with a small number of field measured trees improved the accuracy.

Airborne laser scanning (ALS) data is nowadays often available for forest inventory purposes, but adequate field data for constructing new forest attribute models for each area may be lacking. Thus there is a need to study the transferability of existing ALS-based models among different inventory areas. The objective of our study was to apply ALS-based mixed models to estimate the diameter, height and crown base height of individual sawlog sized Scots pines (Pinus sylvestris L.) at three different inventory sites in eastern Finland. Different ALS sensors and acquisition parameters were used at each site. Multivariate mixed-effects models were fitted at one site and the models were validated at two independent test sites. Validation was carried out by applying the fixed parts of the mixed models as such, and by calibrating them using 1–3 sample trees per plot. The results showed that the relative RMSEs of the predictions were 1.2–6.5 percent points larger at the test sites compared to the training site. Systematic errors of 2.4–6.2 percent points also emerged at the test sites. However, both the RMSEs and the systematic errors decreased with calibration. The results showed that mixed-effects models of individual tree attributes can be successfully transferred and calibrated to other ALS inventory areas in a level of accuracy that appears suitable for practical applications.

  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-9352-0114 E-mail: lauri.korhonen@uef.fi (email)
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomikar@uef.fi
  • Packalen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi
  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi
article id 10075, category Research article
Matti Maltamo, Marius Hauglin, Erik Naesset, Terje Gobakken. (2019). Estimating stand level stem diameter distribution utilizing harvester data and airborne laser scanning. Silva Fennica vol. 53 no. 3 article id 10075. https://doi.org/10.14214/sf.10075
Highlights: Tree level-positioned harvester data were successfully used as plot-level training data for k-nearest neighbor stem diameter distribution modelling applying airborne laser scanning information as predictor variables; Stand-level validation showed that merchantable volume of total tree stock could be estimated with RMSE value of about 9%; The fit of the stem diameter distribution assessed by a variant of Reynold’s error index showed values smaller than 0.2; The most accurate results were obtained for the training plot sizes of 200 m2 and 400 m2.

Accurately positioned single-tree data obtained from a cut-to-length harvester were used as training harvester plot data for k-nearest neighbor (k-nn) stem diameter distribution modelling applying airborne laser scanning (ALS) information as predictor variables. Part of the same harvester data were also used for stand-level validation where the validation units were stands including all the harvester plots on a systematic grid located within each individual stand. In the validation all harvester plots within a stand and also the neighboring stands located closer than 200 m were excluded from the training data when predicting for plots of a particular stand. We further compared different training harvester plot sizes, namely 200 m2, 400 m2, 900 m2 and 1600 m2. Due to this setup the number of considered stands and the areas within the stands varied between the different harvester plot sizes. Our data were from final fellings in Akershus County in Norway and consisted of altogether 47 stands dominated by Norway spruce. We also had ALS data from the area. We concentrated on estimating characteristics of Norway spruce but due to the k-nn approach, species-wise estimates and stand totals as a sum over species were considered as well. The results showed that in the most accurate cases stand-level merchantable total volume could be estimated with RMSE values smaller than 9% of the mean. This value can be considered as highly accurate. Also the fit of the stem diameter distribution assessed by a variant of Reynold’s error index showed values smaller than 0.2 which are superior to those found in the previous studies. The differences between harvester plot sizes were generally small, showing most accurate results for the training harvester plot sizes 200 m2 and 400 m2.

  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu ORCID ID:E-mail: matti.maltamo@uef.fi (email)
  • Hauglin, Norwegian Institute of Bioeconomy Research, Division of Forest and Forest Resources, P.O. Box 115, 1431 Ås, Norway ORCID ID:E-mail: marius.hauglin@nibio.no
  • Naesset, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, 1432 Ås, Norway ORCID ID:E-mail: erik.naesset@nmbu.no
  • Gobakken, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, 1432 Ås, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
article id 10076, category Research article
Tore Skrøppa, Arne Steffenrem. (2019). Genetic variation in phenology and growth among and within Norway spruce populations from two altitudinal transects in Mid-Norway. Silva Fennica vol. 53 no. 1 article id 10076. https://doi.org/10.14214/sf.10076
Highlights: Norway spruce populations distributed along each of two altitudinal transects showed strong clinal relationships between the annual mean temperatures of the sites of the populations and height and phenology traits in short term tests and height in field trials; Large variation was present among families within populations for height and phenology traits and with a wider range within than among populations; Correlation patterns among traits were different for provenances and families.

Progenies from open pollinated cones collected in natural populations of Norway spruce (Picea abies (L.) Karst.) distributed along two altitudinal transects in Mid-Norway were tested in the nursery, in short term tests and in long-term field trials. The populations showed clinal variation related to the mean annual temperatures of the populations, with the earliest bud flush and cessation of shoot elongation and lowest height at age nine years for the high altitude populations. Within population variation was considerable as the narrow sense heritability for these traits was 0.67, 0.31 and 0.09 in one transect and 0.55, 0.18 and 0.14 in the other transect, respectively. Lammas shoots occurred in the short term trials with large variation in frequency between years. There was significant family variation for this trait, but also interactions between populations and year. The variance within populations was considerably larger in the populations from low altitude compared to the high-altitude populations. Significant genetic correlations between height and phenology traits and damage scores indicate that families flushing early and ceasing growth late were taller. Taller families also had higher frequencies of damages. Selection of the top 20% families for height growth in short term tests at age nine years gave a simulated gain of 11% increased height growth at age 18 years in long term trials at altitudes similar to those of origin of the populations. The gain was negative when high altitude populations were selected based on testing in the lowland.

  • Skrøppa, Norwegian Institute of Bioeconomy Research, P.O. Box 115, 1431 Ås, Norway ORCID ID:E-mail: tore.skroppa@nibio.no (email)
  • Steffenrem, ORCID ID:E-mail:
article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 10055, category Research article
Jaakko Repola, Hannu Hökkä, Hannu Salminen. (2018). Models for diameter and height growth of Scots pine, Norway spruce and pubescent birch in drained peatland sites in Finland. Silva Fennica vol. 52 no. 5 article id 10055. https://doi.org/10.14214/sf.10055
Highlights: Tree growth strongly correlated with site drainage status; Between-tree competition had a higher impact on tree diameter growth than on height growth; Growth predicted by the constructed models were calibrated using NFI11 data to ensure generally applicable growth predictions level in whole country.

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.

  • Repola, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Natural resources, Paavo Havaksen tie 3, FI-90014 University OF Oulu, Finland ORCID ID:E-mail: hannu.hokka@luke.fi
  • Salminen, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.salminen@luke.fi
article id 10013, category Research article
Hardo Becker, Jürgen Aosaar, Mats Varik, Gunnar Morozov, Kristiina Aun, Ülo Mander, Kaido Soosaar, Veiko Uri. (2018). Annual net nitrogen mineralization and litter flux in well-drained downy birch, Norway spruce and Scots pine forest ecosystems. Silva Fennica vol. 52 no. 4 article id 10013. https://doi.org/10.14214/sf.10013
Highlights: The net nitrogen mineralization (NNM) flux in drained peat soils depends largely on the C/N ratio and tree species; The soil NNM process is affected by trees through organic litter input into soil; Pine stand in low-fertility drained transitional bog is dominated by net ammonification; Birch and spruce stands on the fertile drained peat soil with higher pH and N content are dominated by net nitrification.

The main aim of the current study was to estimate the annual net nitrogen mineralization (NNM) flux in stands of different tree species growing on drained peatlands, as well as to clarify the effect of tree species, soil properties and litter on annual NNM dynamics. Three study sites were set up in May 2014: a downy birch (Betula pubescens Ehrh.) stand and a Norway spruce (Picea abies (L.) Karst.) stand in Oxalis full-drained swamp (ODS) and a Scots pine (Pinus sylvestris L.) stand in Myrtillus full-drained swamp (MDS). The NNM flux was estimated using the in situ method with incubated polyethylene bags. The highest value of NNM was found in stands that were growing on fertile ODS: 127.5 kg N ha–1 yr–1 and 87.7 kg N ha–1 yr–1, in the downy birch stand and in the Norway spruce stand, respectively. A significantly lower annual NNM flux (11.8 kg N ha–1 yr–1) occurred in the Scots pine stand growing in MDS. Nitrification was highest at fertile ODS sites and ammonification was the highest at the low fertility MDS site. For all study sites, positive correlation was found between soil temperature and NNM intensity. The difference in annual NNM between the downy birch stand and the Norway spruce stand growing on similar drained fertile peatlands was due to litter quality. The annual N input into the soil through leaf litter was the highest at the downy birch site where also the C/N ratio of litter was the lowest. The second highest N input into the soil was found in the spruce stand and the lowest in the pine stand.

  • Becker, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: hardo.becker@emu.ee (email)
  • Aosaar, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: jyrgen.aosaar@emu.ee
  • Varik, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: mats.varik@emu.ee
  • Morozov, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: gunnar.morozov@emu.ee
  • Aun, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: kristiina.aun@emu.ee
  • Mander, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: ulo.mander@ut.ee
  • Soosaar, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: kaido.soosaar@ut.ee
  • Uri, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: veiko.uri@emu.ee
article id 9980, category Research article
Eino Levkoev, Lauri Mehtätalo, Katri Luostarinen, Pertti Pulkkinen, Anatoly Zhigunov, Heli Peltola. (2018). Development of height growth and frost hardiness for one-year-old Norway spruce seedlings in greenhouse conditions in response to elevated temperature and atmospheric CO2 concentration. Silva Fennica vol. 52 no. 3 article id 9980. https://doi.org/10.14214/sf.9980
Highlights: Elevated temperature resulted in increased height growth, delayed onset and shortened duration of autumn frost hardiness development in Norway spruce seedlings; Elevated temperature increased variation between genotypes in height growth and frost hardiness development; Elevated atmospheric CO2 concentration had no effect on the development of height or autumn frost hardiness in Norway spruce seedlings.

The mean temperature during the potential growing season (April–September) may increase by 1 °C by 2030, and by 4 °C, or even more, by 2100, accompanied by an increase in atmospheric CO2 concentrations of 536–807 ppm, compared to the current climate of 1981–2010, in which atmospheric CO2 is at about 350 ppm. This may affect both the growth and frost hardiness of boreal trees. In this work, we studied the responses of height and autumn frost hardiness development in 22 half-sib genotypes of one-year-old Norway spruce (Picea abies (L.) Karst.) seedlings to elevated temperatures and atmospheric CO2 concentration under greenhouse conditions. The three climate treatments used were: T+1 °C above ambient and ambient CO2; T+4 °C above ambient and ambient CO2; and T+4 °C above ambient and elevated CO2 (700 ppm). The height growth rate and final height were both higher under T+4 °C compared to T+1 °C. Temperature increase also delayed the onset, and shortened the duration, of autumn frost hardiness development. Elevated CO2 did not affect the development of height or frost hardiness, when compared to the results without CO2 elevation under the same temperature treatment. Higher temperatures resulted in greater variation in height and frost hardiness development among genotypes. Three genotypes with different genetic backgrounds showed superior height growth, regardless of climate treatment; however, none showed a superior development of autumn frost hardiness. In future studies, clonal or full-sib genetic material should be used to study the details of autumn frost hardiness development among different genotypes.

  • Levkoev, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: eino.levkoev@uef.fi (email)
  • Mehtätalo, University of Eastern Finland, Faculty of Science and Forestry, School of Computing, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.mehtatalo@uef.fi
  • Luostarinen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi
  • Pulkkinen,  Natural Resources Institute Finland (Luke), Production systems, Haapastensyrjä Breeding Station, FI-16200 Läyliäinen, Finland ORCID ID:E-mail: pertti.pulkkinen@luke.fi
  • Zhigunov, Saint-Petersburg State Forest Technical University, Forestry Faculty, RU-194021, Institutskiy per. 5, Saint-Petersburg, Russia ORCID ID:E-mail: a.zhigunov@bk.ru
  • Peltola, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@uef.fi
article id 9914, category Research article
Jun Tanabe, Futoshi Ishiguri, Akira Tamura, Yuya Takashima, Jyunichi Ohshima, Kazuya Iizuka, Shinso Yokota. (2018). Within-tree radial and among-family variations in wood density, microfibril angle, and mechanical properties in Picea glehnii. Silva Fennica vol. 52 no. 2 article id 9914. https://doi.org/10.14214/sf.9914
Highlights: The modulus of elasticity was affected by both microfibril angle and wood density, whereas the modulus of rupture was mainly affected by wood density in Picea glehnii; A larger degree of among-family variation in wood properties was detected in juvenile wood than in mature wood, indicating that genetic improvements in the mechanical properties may be more effective for juvenile wood.

Genetic improvements in the mechanical properties of wood are important in forestry species used for lumber, such as Picea. The within-tree radial and among-family variations for the modulus of elasticity (MOE), modulus of rupture (MOR), and their related traits [i.e., microfibril angle (MFA) of the S2 layer in latewood tracheid and air-dry density (AD)] were evaluated in nine open-pollinated families of Picea glehnii (F. Schmidt) Mast. The radial variation in MOR was mainly affected by AD, whereas MOE was affected by MFA and AD. Higher F-values obtained by analysis of variance and coefficient of variation were observed for all properties at the 6th–15th annual ring, except for AD at the 6th–10th annual ring. This result suggests that the contribution of genetic effect is larger in these highly variable regions. In addition, positive correlation coefficients were obtained between wood properties at the 6th–15th annual ring and mean values of these properties. Therefore, genetic improvements for MOE, MOR, and their related traits in P. glehnii is likely to be more effective in juvenile wood, specifically at the 6th–15th annual ring from the pith.

  • Tanabe, Faculty of Education, Chiba University, Chiba, 263-8522, Japan ORCID ID:E-mail: tanabe_j@chiba-u.jp (email)
  • Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: ishiguri@cc.utsunomiya-u.ac.jp
  • Tamura, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: akirat@affrc.go.jp
  • Takashima, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: ytakashima@ffpri.affrc.go.jp
  • Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: joshima@cc.utsunomiya-u.ac.jp
  • Iizuka, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: kiizuka@cc.utsunomiya-u.ac.jp
  • Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: yokotas@cc.utsunomiya-u.ac.jp
article id 7816, category Research article
Pentti Niemistö, Harri Kilpeläinen, Eero Poutiainen. (2018). Effect of first thinning type and age on growth, stem quality and financial performance of a Scots pine stand in Finland. Silva Fennica vol. 52 no. 2 article id 7816. https://doi.org/10.14214/sf.7816
Highlights: Early commercial first thinning at the top height of 11 m with tree selection targeting high quality of remaining stems was more profitable in a Scots pine stand than thinning from below at similar time or delayed thinning 10 years later; After early first thinning only one intermediate thinning was needed, but a late thinning at age of 60 years was feasible in connection with increased amount of high quality butt logs after artificial pruning; The optimal rotation period for a Scots pine stand using a lower interest rate of 1% was 80–85 years depending on the thinning pattern. With a higher rate of 4%, the optimal rotation took only 60 years.

The objective of the study was to ascertain the effects of tree selection (thinning from below, from above and according to stem quality) and timing of first commercial thinning (early and delayed) on the growth, yield and quality of trees in a Scots pine (Pinus sylvestris L.) stand. A long-term field experiment (25 years) was measured in 5-year periods and the further development was simulated with growth and yield models to final cuttings using alternative rotation periods of 55–85 years. The measurements included also the exact location and type of technical defects detected on all trees in the experimental plots. The measured volume increment per unit area during the study period, 25 years after the early thinning stage was the lowest in the plots thinned from below, and the highest in the plots thinned from above or in the delayed thinning plots. However, the largest volume of saw logs during the whole rotation of 80 years was yielded after early first thinning according to the quality. The largest volume of very high-quality butt logs was produced by pruning connected with early thinning from above, and a smaller volume after early thinning according to stem quality but no after thinning from below or delayed first thinning. Without pruning an early quality thinning with one intermediate thinning was the most profitable thinning treatment in the Scots pine stand regardless the rotation length or the interest rate used. By interest rates of 1% and 2%, the optimal rotations were 80–85 years and 70 years respectively. A late thinning at the age of 60 year with long rotation was profitable only for the pruned pine stands with a low interest rate.

  • Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland ORCID ID:E-mail: pentti.niemisto@luke.fi (email)
  • Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Poutiainen, Oulu ORCID ID:E-mail: eero1.poutiainen@dnainternet.net
article id 7740, category Research article
Jonas R. Coussement, Kathy Steppe, Peter Lootens, Isabel Roldán-Ruiz, Tom De Swaef. (2018). A flexible geometric model for leaf shape descriptions with high accuracy. Silva Fennica vol. 52 no. 2 article id 7740. https://doi.org/10.14214/sf.7740
Highlights: A method for assessing leaf shape for 3D plant models is proposed; The model is highly flexible and fits a large variety of shapes; It allows analysis of shape differences within and between leaf datasets.

Accurate assessment of canopy structure is crucial in studying plant-environment interactions. The advancement of functional-structural plant models (FSPM), which incorporate the 3D structure of individual plants, increases the need for a method for accurate mathematical descriptions of leaf shape. A model was developed as an improvement of an existing leaf shape algorithm to describe a large variety of leaf shapes. Modelling accuracy was evaluated using a spatial segmentation method and shape differences were assessed using principal component analysis (PCA) on the optimised parameters. Furthermore, a method is presented to calculate the mean shape of a dataset, intended for obtaining a representative shape for modelling purposes. The presented model is able to accurately capture a large range of single, entire leaf shapes. PCA illustrated the interpretability of the parameter values and allowed evaluation of shape differences. The model parameters allow straightforward digital reconstruction of leaf shapes for modelling purposes such as FSPMs.

  • Coussement, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium ORCID ID:E-mail: jonas.coussement@ilvo.vlaanderen.be
  • Steppe, Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium ORCID ID:E-mail: kathy.steppe@ugent.be
  • Lootens, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium ORCID ID:E-mail: peter.lootens@ilvo.vlaanderen.be
  • Roldán-Ruiz, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium; Department of Plant Biotechnology and Bioinformatics, Faculty of Sciences, Ghent University, Technologiepark Zwijnaarde 927, B-9052 Zwijnaarde, Belgium ORCID ID:E-mail: isabel.roldan-ruiz@ilvo.vlaanderen.be
  • De Swaef, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium ORCID ID:E-mail: tom.deswaef@ilvo.vlaanderen.be (email)
article id 6977, category Research article
Anett Schibalski, Aleksi Lehtonen, Thomas Hickler, Boris Schröder. (2017). Identifying important topics for model refinement in a widely used process-based model informed by correlative model analyses in a boreal forest. Silva Fennica vol. 51 no. 4 article id 6977. https://doi.org/10.14214/sf.6977
Highlights: Continental-scale model parameterization of widely used LPJ-GUESS experiences problems when applied on the regional level; Competition, disturbances and soil conditions are crucial for explaining treeline position in Finland, besides climatic limitation; Picea abies is overly dominant in LPJ-GUESS model, as key competitive mechanisms are not implemented in sufficient detail.

Models attempting to predict treeline shifts in changing climates must include the relevant ecological processes in sufficient detail. A previous correlative model study has pointed to nutrients, competition, and temperature as the most important factors shaping the treelines of Pinus sylvestris L., Picea abies (L.) H. Karst. and Betula pubescens Ehrh. in Finnish Lapland. Here, we applied a widely used process-based dynamic vegetation model (LPJ-GUESS) to (i) test its capability to simulate observed spatial and temporal patterns of the main tree species in Finnish Lapland, and (ii) to explore the model representation of important processes in order to guide further model development. A European parameterization of LPJ-GUESS overestimated especially P. abies biomass and the species’ northern range limit. We identified implemented processes to adjust (competition, disturbance) and crucial processes in boreal forests to include (nutrient limitation, forest management) which account for the model’s failure to (edaphically) restrict P. abies in Finnish Lapland and the resulting species imbalance. Key competitive mechanisms are shade and drought tolerance, nutrient limitation, fire resistance, and susceptibility to disturbances (storm, herbivory) which we discussed with respect to boreal ecology and promising model developments to provide a starting point for future model development.

  • Schibalski, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany ORCID ID:E-mail: a.schibalski@tu-braunschweig.de (email)
  • Lehtonen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: aleksi.lehtonen@luke.fi
  • Hickler, Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; Department of Physical Geography, Goethe University, Altenhöferallee 1, D-60438 Frankfurt am Main, Germany ORCID ID:E-mail: thomas.hickler@senckenberg.de
  • Schröder, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research BBIB, Altensteinstr. 6, D-14195 Berlin, Germany ORCID ID:E-mail: boris.schroeder@tu-bs.de
article id 5662, category Research article
Samuel Egbäck, Urban Nilsson, Kenneth Nyström, Karl-Anders Högberg, Nils Fahlvik. (2017). Modeling early height growth in trials of genetically improved Norway spruce and Scots pine in southern Sweden. Silva Fennica vol. 51 no. 3 article id 5662. https://doi.org/10.14214/sf.5662
Highlights: The developed height growth model based on unimproved material predicted the development relatively well for genetically improved Norway spruce; For genetically improved Scots pine, however, the model needed to be modified; By incorporating a genetic component into the Scots pine model, the prediction errors were reduced.

Genetically improved Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) are used extensively in operational Swedish forestry plantations to increase production. Depending on the genetic status of the plant material, the current estimated genetic gain in growth is in the range 10–20% for these species and this is expected to increase further in the near future. However, growth models derived solely from data relating to genetically improved material in Sweden are still lacking. In this study we investigated whether an individual tree growth model based on data from unimproved material could be used to predict the height increment in young trials of genetically improved Norway spruce and Scots pine. Data from 11 genetic experiments with large genetic variation, ranging from offspring of plus-trees selected in the late 1940s to highly improved clonal materials selected from well performing provenances were used. The data set included initial heights at the age of 7–15 years and 5-year increments for almost 2000 genetic entries and more than 20 000 trees. The evaluation indicated that the model based on unimproved trees predicted height development relatively well for genetically improved Norway spruce and there was no need to incorporate a genetic component. However, for Scots pine, the model needed to be modified. A genetic component was developed based on the genetic difference recorded within each trial, using mixed linear models and methods from quantitative genetics. By incorporating the genetic component, the prediction errors were significantly reduced for Scots pine. This study provides the first step to incorporate genetic gains into Swedish growth models and forest management planning systems.

  • Egbäck, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, 230 53 Alnarp, Sweden ORCID ID:E-mail: samuel.egback@slu.se (email)
  • Nilsson, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, 230 53 Alnarp, Sweden ORCID ID:E-mail: urban.nilsson@slu.se
  • Nyström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, 901 83 Umeå, Sweden ORCID ID:E-mail: kenneth.nystrom@slu.se
  • Högberg, Skogforsk, Ekebo, 268 90 Svalöv, Sweden ORCID ID:E-mail: karl-anders.hogberg@skogforsk.se
  • Fahlvik, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, 230 53 Alnarp, Sweden ORCID ID:E-mail: nils.fahlvik@slu.se
article id 1666, category Research article
Mareike Wieczorek, Alexei Kolmogorov, Stefan Kruse, Inga Jacobsen, Ingmar Nitze, Anatoly N. Nikolaev, Ingo Heinrich, Luidmila A. Pestryakova, Ulrike Herzschuh. (2017). Disturbance-effects on treeline larch-stands in the lower Kolyma River area (NE Siberia). Silva Fennica vol. 51 no. 3 article id 1666. https://doi.org/10.14214/sf.1666
Highlights: Disturbances are an important shaping factor of larch stands at lower Kolyma; Youngest larch stands have the highest population densities and highest growth rates; Saplings grow clustered, irrespective of the underlying disturbance regime; Mixed climate-disturbance signals make it difficult to infer future treeline processes.

Tree stands in the boreal treeline ecotone are, in addition to climate change, impacted by disturbances such as fire, water-related disturbances and logging. We aim to understand how these disturbances affect growth, age structure, and spatial patterns of larch stands in the north-eastern Siberian treeline ecotone (lower Kolyma River region), an insufficiently researched region. Stand structure of Larix cajanderi Mayr was studied at seven sites impacted by disturbances. Maximum tree age ranged from 44 to 300 years. Young to medium-aged stands had, independent of disturbance type, the highest stand densities with over 4000 larch trees per ha. These sites also had the highest growth rates for tree height and stem diameter. Overall lowest stand densities were found in a polygonal field at the northern end of the study area, with larches growing in distinct “tree islands”. At all sites, saplings are significantly clustered. Differences in fire severity led to contrasting stand structures with respect to tree, recruit, and overall stand densities. While a low severity fire resulted in low-density stands with high proportions of small and young larches, high severity fires resulted in high-density stands with high proportions of big trees. At water-disturbed sites, stand structure varied between waterlogged and drained sites and latitude. These mixed effects of climate and disturbance make it difficult to predict future stand characteristics and the treeline position.

  • Wieczorek, Periglacial Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany; Institute of Earth and Environmental Science, University of Potsdam, 14476 Potsdam, Germany ORCID ID:E-mail: mareike.wieczorek@awi.de
  • Kolmogorov, Institute of Natural Sciences, North-Eastern Federal University of Yakutsk, 677000 Yakutsk, Russia ORCID ID:E-mail: kilatroooon@gmail.com
  • Kruse, Periglacial Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany; Institute of Earth and Environmental Science, University of Potsdam, 14476 Potsdam, Germany ORCID ID:E-mail: Stefan.Kruse@awi.de
  • Jacobsen, Periglacial Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany; Institute of Earth and Environmental Science, University of Potsdam, 14476 Potsdam, Germany ORCID ID:E-mail: Inga.Jacobsen@awi.de
  • Nitze, Periglacial Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany; Institute of Geography, University of Potsdam, 14476 Potsdam, Germany ORCID ID:E-mail: Ingmar.Nitze@awi.de
  • Nikolaev, Institute of Natural Sciences, North-Eastern Federal University of Yakutsk, 677000 Yakutsk, Russia; Melnikov Permafrost Institute of the Siberian Branch of RAS, 677000 Yakutsk, Russia ORCID ID:E-mail: yktnan@rambler.ru
  • Heinrich, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany ORCID ID:E-mail: heinrich@gfz-potsdam.de
  • Pestryakova, Institute of Natural Sciences, North-Eastern Federal University of Yakutsk, 677000 Yakutsk, Russia ORCID ID:E-mail: lapest@mail.ru
  • Herzschuh, Periglacial Research Section, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany; Institute of Earth and Environmental Science, University of Potsdam, 14476 Potsdam, Germany ORCID ID:E-mail: Ulrike.Herzschuh@awi.de (email)
article id 1563, category Research article
Kristina Ahnlund Ulvcrona, Dan Bergström, Urban Bergsten. (2017). Stand structure after thinning in 1–2 m wide corridors in young dense stands. Silva Fennica vol. 51 no. 3 article id 1563. https://doi.org/10.14214/sf.1563
Highlights: Boom corridor thinning (BCT) results in more stand structure heterogeneity than conventional thinning or pre-commercial thinning (PCT), maintaining both smaller-diameter trees and deciduous species; Neither dominant height nor number of possible future crop trees is jeopardized, and boom corridor thinning results in higher values of stem volume and biomass; The technique is flexible as various corridor types give similar stand structure results.

Boom corridor thinning (BCT) has been proposed as a cost-effective technique for biomass thinning (BT) in young dense stands. The objective of this study was to determine how various BCT operations affect stand structure following biomass thinning and to compare the results with conventional selective thinning methods. Two series of field experiments were established; BCT 1-series: Three sites in south of Sweden (9 and 11 m in mean and dominating tree height) with five treatments, including a control, conventional selective thinning and three BCT treatments (1 m and 2 m wide corridors and selective BCT). The second BCT series: Three regions in Sweden (in the north, centre and in the south), with two stand sites in each region with different tree heights (4/9 m and 5/10 m in mean/dominating tree height). Treatments were control, pre-commercial thinning (PCT), conventional selective thinning and BCT (high and low thinning). Following the first biomass thinning, BCT regimes and selective thinning methods resulted in similar stand structures based on the number of possible future crop trees (>80 mm in diameter at breast height). However, BCT maintained a higher diversity of tree sizes as well as more stems per hectare, including deciduous species, than the selective thinning approaches. The stands after BCT should have more vertical complexity, especially when compared to pre-commercial thinning. The structural heterogeneity resulting from BCT may also increase stand biodiversity and ecosystem service values.

  • Ahnlund Ulvcrona, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kristina.ulvcrona@slu.se (email)
  • Bergström, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: dan.bergstrom@slu.se
  • Bergsten, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
article id 1781, category Research article
Petr Čermák, Michal Rybníček, Tomáš Žid, Kjell Andreassen, Isabella Børja, Tomáš Kolář. (2017). Impact of climate change on growth dynamics of Norway spruce in south-eastern Norway. Silva Fennica vol. 51 no. 2 article id 1781. https://doi.org/10.14214/sf.1781
Highlights: Correlations between tree-ring width and climate parameters showed temporal instability in their relationship during the period 1915–2012; A statistically significant positive correlation of April–May precipitation on tree-ring growth was identified since the mid-1970s; The concomitant temperature increase may have contributed to the changes of growth dynamics.

The ongoing climate change may have a distinct effect on Norway spruce growth, one of the most important tree species in European forest management. Therefore, the understanding and assessment of climate-growth relationship can help to reveal relevant patterns in temporal variability that may result in lower tree vitality and decline. The main objective of our study was to evaluate the long-term climate-growth variability of Norway spruce in south-eastern Norway, at the northern edge of the temperate zone. We sampled in total 270 dominant and co-dominant trees from 18 plots in south-eastern Norway. We analysed stem cores and evaluated crown condition parameters to assess the retrospective tree growth and vitality. Despite considerable differences in the crown parameters, high similarity among tree-ring width (TRW) series allowed compiling the regional tree-ring width chronology. Correlations between TRW and climate parameters showed temporal instability in their relationship during the period 1915–2012. While we did not detect any significant relationships between TRW and climate parameters in the first half of the study period (1915–1963), a significant correlation between TRW and spring precipitation was observed for the period 1964–2012. This shift appeared concurrent with temperatures reaching above-average values compared to the average of the climate normal period 1961–1990.

  • Čermák, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: cermacek@mendelu.cz (email)
  • Rybníček, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic ORCID ID:E-mail: michalryb@post.cz
  • Žid, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: tom.z@centrum.cz
  • Andreassen, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: Kjell.Andressen@nibio.no
  • Børja, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: Isabella.Borja@nibio.no
  • Kolář, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic ORCID ID:E-mail: koldatom@gmail.com
article id 1562, category Research article
Mats Erik Berlin, Torgny Persson, Gunnar Jansson, Matti Haapanen, Seppo Ruotsalainen, Lars Bärring, Bengt Andersson Gull. (2016). Scots pine transfer effect models for growth and survival in Sweden and Finland. Silva Fennica vol. 50 no. 3 article id 1562. https://doi.org/10.14214/sf.1562
Highlights: Scots pine transfer effect models for growth and survival, valid in both Sweden and Finland have been developed; The models use high-resolution gridded climate data and can predict performance in future climatic conditions; The models perform well both for unimproved and genetically improved material and can be used to develop deployment recommendations of contemporary forest regeneration material in Sweden and Finland.

In this study, we developed models of transfer effects for growth and survival of Scots pine (Pinus sylvestris L.) in Sweden and Finland using a general linear mixed-model approach. For model development, we used 378 provenance and progeny trials with a total of 276 unimproved genetic entries (provenances and stand seed check-lots) distributed over a wide variety of climatic conditions in both countries. In addition, we used 119 progeny trials with 3921 selected genetic entries (open- and control pollinated plus-tree families) for testing model performance. As explanatory variables, both climatic indices derived from high-resolution gridded climate datasets and geographical variables were used. For transfer, latitude (photoperiod) and, for describing the site, temperature sum were found to be main drivers for both survival and growth. In addition, interaction terms (between transfer in latitude and site altitude for survival, and transfer in latitude and temperature sum for growth) entail changed reaction patterns of the models depending on climatic conditions of the growing site. The new models behave in a way that corresponds well to previous studies and recommendations for both countries. The model performance was tested using selected plus-trees from open and control pollinated progeny tests. Results imply that the models are valid for both countries and perform well also for genetically improved material. These models are the first step in developing common deployment recommendations for genetically improved forest regeneration material in both Sweden and Finland.

  • Berlin, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail: mats.berlin@skogforsk.se (email)
  • Persson, Skogforsk, Box 3, SE-91821 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Jansson, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
  • Haapanen, Natural Resources Institute Finland (Luke), Green Technology, Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: matti.haapanen@luke.fi
  • Ruotsalainen, Natural Resources Institute Finland (Luke), Green Technology, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail: seppo.ruotsalainen@luke.fi
  • Bärring, Rossby Centre, Swedish Meteorological and Hydrological Institute, Folkborgsvägen 17, SE-60176 Norrköping, Sweden ORCID ID:E-mail: lars.barring@smhi.se
  • Andersson Gull, Skogforsk, Box 3, SE-91821 Sävar, Sweden ORCID ID:E-mail: bengt.andersson@skogforsk.se
article id 1560, category Research article
Marina Gurskaya, Pavel Moiseev, Martin Wilmking. (2016). Does slope exposure affect frost ring formation in Picea obovata growing at treeline in the Southern Urals? Silva Fennica vol. 50 no. 3 article id 1560. https://doi.org/10.14214/sf.1560
Highlights: Frost ring formation was ubiquitous from continuous forest cover to treeline, but, surprisingly, was not affected by slope exposure; Late frosts in spring were the main cause for frost ring formation; While mainly young trees (< 30 years) recorded frost events, at the climatically harshest site (highest elevation, northeastern exposure), frost events were recorded also in trees older than 70 years.

Topographic complexity in mountainous ecosystems strongly influences plant growth and as such also wood formation. This wood formation can possibly be used to understand topographic variation of the main climatic drivers, e.g. by modulating frost events. Here we test the influence of different slope exposures on the spatio-temporal distribution of frost rings in Siberian spruce (Picea obovata Ledeb.) in the Southern Urals, Russia. We sampled on two opposite slopes, northeast (NE) and southwest (SW), on three elevation levels from the highest single trees to closed canopy forest and analysed frost ring occurrence and their seasonal timing. Frost ring formation at all exposure-elevation combinations was common and mainly concentrated in the early part of the growing season. The age until trees record frost rings was equally similar (until about 35 years) on both slopes and different elevational levels with the exception of the climatically harshest site, the highest elevation on the NE slope. While we could not deduce a direct, easily identifiable climatic driver for the formation of frost rings, our analysis shows high potential to disentangle the complex interplay between climate, site condition and tree growth in mountainous ecosystems.

  • Gurskaya, Institute of Plant and Animal Ecology (IPAE), Ural Branch of Russian Academy of Sciences , 8 Marta St. 202, 620144 Ekaterinburg, Russia ORCID ID:E-mail: mgurskaya@yandex.ru (email)
  • Moiseev, Institute of Plant and Animal Ecology (IPAE), Ural Branch of Russian Academy of Sciences , 8 Marta St. 202, 620144 Ekaterinburg, Russia ORCID ID:E-mail: moiseev@ipae.uran.ru
  • Wilmking, Institute of Botany and Landscape Ecology, Soldmanstrasse 15, Ernst-Moritz-Arndt-University Greifswald, 17487 Greifswald, Germany ORCID ID:E-mail: wilmking@uni-greifswald.de
article id 1410, category Research article
Seppo Nevalainen, Juho Matala, Kari T. Korhonen, Antti Ihalainen, Ari Nikula. (2016). Moose damage in National Forest Inventories (1986–2008) in Finland. Silva Fennica vol. 50 no. 2 article id 1410. https://doi.org/10.14214/sf.1410
Highlights: Almost 100 000 stands were studied; The proportion of damage doubled during the study period; Tree species mixture had a clear effect on the damage frequency; The damage was more common in mineral soils than in peatlands, in artificially than in naturally regenerated stands and in stands that needed thinning or clearing or in which soil preparation was used.

The occurrence of moose damage was studied using data from three National Forest Inventories (NFIs) accomplished between 1986 and 2008 in Finland. The combined data included a total of 97 390 young stands. The proportion of moose damage increased from 3.6% to 8.6% between the 8th NFI (1986–1994) and the 10th NFI (2004–2008). The majority (75%) of the damage occurred in Scots pine-dominated stands. The proportion of damage was higher in aspen-dominated stands than in stands dominated by any other tree species. The tree species mixture also had a clear effect on the occurrence of damage. Pure Scots pine stands had less damage than mixed Scots pine stands, and moose damage decreased linearly with the increasing proportion of Scots pine. Stands on mineral soil had more frequent moose damage than stands on peatlands. The fertility class of the site had no straightforward effect on the damage frequency. Artificially regenerated stands had more damage than naturally regenerated stands. Accomplished soil preparation measures and the need for thinning or clearing operations increased moose damage. High proportions of moose damage in young stands were found around the country. In the 10th NFI, the largest concentration of damage was found in southwestern Finland. Our study shows the temporal and spatial changes in the occurrence of moose damage and pinpoints some important silvicultural factors affecting the relative risk of young stands over a large geographical area.

  • Nevalainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi (email)
  • Matala, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Korhonen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: kari.t.korhonen@luke.fi
  • Ihalainen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: antti.ihalainen@luke.fi
  • Nikula, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi
article id 1377, category Research article
Raul Fernandez-Lacruz, Fulvio Di Fulvio, Dimitris Athanassiadis, Dan Bergström, Tomas Nordfjell. (2015). Distribution, characteristics and potential of biomass-dense thinning forests in Sweden. Silva Fennica vol. 49 no. 5 article id 1377. https://doi.org/10.14214/sf.1377
Highlights: Biomass-dense thinning forests (BDTF) cover 2.1–9.8 M ha in Sweden, which represents 9–44% of the country’s productive forest land area, depending on the constraints applied; 65% of BDTF area is found in northern Sweden; Analyses revealed a yearly harvesting potential of at least 4.3 M OD t of undelimbed whole trees (3.0 M OD t of delimbed stemwood including tops).

Understanding the characteristics of unutilized biomass resources, such as small-diameter trees from biomass-dense thinning forests (BDTF) (non-commercially-thinned forests), can provide important information for developing a bio-based economy. The aim of this study was to describe the areal distribution, characteristics (biomass of growing stock, tree height, etc.) and harvesting potential of BDTF in Sweden. A national forest inventory plot dataset was imported into a geographical information system and plots containing BDTF were selected by applying increasingly stringent constraints. Results show that, depending on the constraints applied, BDTF covers 9–44% (2.1–9.8 M ha) of the productive forest land area, and contains 7–34% of the total growing stock (119–564 M OD t), with an average biomass density of 57 OD t ha–1. Of the total BDTF area, 65% is located in northern Sweden and 2% corresponds to set-aside farmlands. Comparisons with a study from 2008 indicate that BDTF area has increased by at least 4% (about 102 000 ha), in line with general trends for Sweden and Europe. Analyses revealed that the technical harvesting potential of delimbed stemwood (over bark, including tops) from BDTF ranges from 3.0 to 6.1 M OD t yr–1 (7.5 to 15.1 M m3 yr–1), while the potential of whole-tree harvesting ranges from 4.3 to 8.7 M OD t yr–1 (10.2 to 20.6 M m3 yr–1) depending on the scenario considered. However, further technological developments of the harvest and supply systems are needed to utilize the full potential of BDTF.

  • Fernandez-Lacruz, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-9284-8911 E-mail: raul.fernandez@slu.se (email)
  • Di Fulvio, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden; International Institute for Applied Systems Analysis (IIASA), Ecosystems Services and Management Program (ESM), Schlossplatz 1, A-2361 Laxenburg, Austria ORCID ID:E-mail: Fulvio.di.Fulvio@slu.se
  • Athanassiadis, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dimitris.Athanassiadis@slu.se
  • Bergström, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dan.Bergstrom@slu.se
  • Nordfjell, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Tomas.Nordfjell@slu.se
article id 1408, category Research article
Anna Katharina Franke, Pasi Aatsinki, Ville Hallikainen, Esa Huhta, Mikko Hyppönen, Vesa Juntunen, Kari Mikkola, Seppo Neuvonen, Pasi Rautio. (2015). Quantifying changes of the coniferous forest line in Finnish Lapland during 1983–2009. Silva Fennica vol. 49 no. 4 article id 1408. https://doi.org/10.14214/sf.1408
Highlights: Volume of the growing stock of spruce and pine has increased in forests and in timber lines during the past 26 years; Spruce stem numbers increased on average, while pine stem numbers remained stable and location-specific variation was observed; Presuming that the ongoing trend of increasing temperature will remain, the enhanced forest regeneration and growth may result in extension of forests in the future.

The boreal timber- and tree-line forests grow in harsh environmental conditions in their outermost distribution limit. Here even small environmental changes may cause dramatic changes in the distribution of tree species. We examined changes of the forest lines of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) in Finnish Lapland five times during 1983–2009. We monitored the number of stems and the volume of the growing stock in thirteen different locations in forest-line areas. The linear temporal trends and the variations of these response variables were used as indicators of a possible change during the study period. Spruce showed a significant increase both in the volume of the growing stock (up to 40% increase) and in the total stem number (up to 100% increase). A significant increase in the volume of the growing stock was observed in the pine data as well (up to 70% increase), whereas the stem number stagnated or even decreased. The results suggest that spruce needs favourable conditions to have an abundant regeneration, but after the establishment the seedlings seem to be more resistant against biotic and abiotic disturbances than pine seedlings. The increasing stand volume might result in a climate-related northward and upward extension of forests in the future. However, our results show that responses in the boreal forest line are species and location specific and a more favourable climate does not necessarily lead to an advance of the coniferous forest line.

  • Franke, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: anna.franke@fau.de (email)
  • Aatsinki, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.aatsinki@luke.fi
  • Hallikainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@luke.fi
  • Huhta, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: esa.huhta@luke.fi
  • Hyppönen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mikko.hypponen@luke.fi
  • Juntunen, The Sámi Education Institute, Menesjärventie 4, P.O. Box 50, FI-99871 Inari, Finland ORCID ID:E-mail: vesa.juntunen@sogsakk.fi
  • Mikkola, Natural Resources Institute Finland (Luke), Economics and society, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: kari.mikkola@luke.fi
  • Neuvonen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101, Joensuu, Finland ORCID ID:E-mail: seppo.neuvonen@luke.fi
  • Rautio, Natural Resources Institute Finland (Luke), Bio-based business and industry, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.rautio@luke.fi
article id 1155, category Research article
Feng Chen, Yujiang Yuan, Wenshou Wei, Tongwen Zhang, Huaming Shang, Shulong Yu. (2015). Divergent response of tree-ring width and maximum latewood density of Abies faxoniana to warming trends at the timberline of the western Qinling Mountains and northeastern Tibetan Plateau, China. Silva Fennica vol. 49 no. 4 article id 1155. https://doi.org/10.14214/sf.1155
Highlights: We describe new tree-ring width and maximum latewood density chronologies of Faxon fir; Temperature is the most important limiting factor for the radial growth of Faxon fir; The tree-ring width series captured the warming trends and allowed detecting the recent warming in a long-term context, while the maximum latewood density series showed no upward trend.

Tree-ring width (TRW) and maximum latewood density (MXD) data of Faxon fir (Abies faxoniana Rehd. et Wils.) were analyzed for five timberline sites in the western Qinling Mountains and northeastern Tibetan Plateau, to investigate their relationships to climate change, especially twentieth century warming. The cross-correlations among TRW chronologies at the low-frequency band were higher, while the higher correlations among MXD chronologies were found at the high-frequency band. Response analysis showed that the tree-ring formation of fir trees was significantly and positively affected by temperature variations, while it was also negatively affected by precipitation. The TRW series captured the warming trends and allowed detecting the recent warming in a long-term context, while the MXD series showed no upward trend. We also found the temperature sensitivity of the TRW series is unstable over space and time. The divergent response between TRW and MXD might be caused by the seasonal variations of warming trends.

  • Chen, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: feng653@163.com (email)
  • Yuan, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: yuanyuj5502@sina.com
  • Wei, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: cycfqq@sohu.com
  • Zhang, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: tongwenzhang19820705@hotmail.com
  • Shang, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: shang8632@163.com
  • Yu, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: yushl@idm.cn
article id 1141, category Research article
Isabel Miranda, Jorge Gominho, Helena Pereira. (2015). Heartwood, sapwood and bark variation in coppiced Eucalyptus globulus trees in 2nd rotation and comparison with the single-stem 1st rotation. Silva Fennica vol. 49 no. 1 article id 1141. https://doi.org/10.14214/sf.1141
Highlights: Coppiced E. globulus trees in the 2nd rotation have similar heartwood and sapwood development as single-stem trees in the 1st rotation; The initial tree planting density did not influence heartwood development of coppiced E. globulus trees; Heartwood diameter and height can be modelled with tree diameter and height respectively; Sapwood width is approximately constant within and between coppice and single-stem E. globulus trees.
Coppiced Eucalyptus globulus trees with 18 years in a 2nd rotation were analysed in relation to heartwood, sapwood and bark content taking into account the effect of the initial planting density by using a spacing trial. A total of 25 stumps, with a variable number of stems per stump from 1 to 3, were analysed. Comparison was made to the previous 1st rotation single stem trees, also harvested at 18 years. In the 2nd rotation, the stump density did not significantly affect stem height and diameter, in opposition to the 1st rotation where spacing significantly impacted on tree dimensions. The effect of the initial planting density is somewhat lost in the coppiced stand in relation with i.e. the number of stems per stump. Heartwood was present in all the coppiced trees up to 49.9% of the total tree height and heartwood volume amounted to 38.9–51.7% of the total tree volume. Within the tree, heartwood content decreased from the base upwards, representing, on average, 54.1% at the base and decreasing to 5.1% at 15.3 m. The sapwood width remained relatively constant with an average radial width of approximately 2 cm. The average stem bark content of coppiced trees was 17.4% of the total stem volume. The comparison of heartwood and sapwood development in the coppiced trees did not show significant differences to the 1st rotation trees, nor did the initial spacing. Heartwood diameter could be modelled using the tree diameter both for 1st and 2nd rotation trees.
  • Miranda, Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade Lisboa, 1349-017 Lisboa, Portugal ORCID ID:E-mail: Imiranda@isa.ulisboa.pt
  • Gominho, Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade Lisboa, 1349-017 Lisboa, Portugal ORCID ID:E-mail: Jgominho@isa.utl.pt (email)
  • Pereira, Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade Lisboa, 1349-017 Lisboa, Portugal ORCID ID:E-mail: Hpereira@isa.utl.pt
article id 1219, category Research article
Thomas P. Sullivan, Druscilla S. Sullivan. (2014). Diversifying clearcuts with green-tree retention and woody debris structures: conservation of mammals across forest ecological zones. Silva Fennica vol. 48 no. 5 article id 1219. https://doi.org/10.14214/sf.1219
Highlights: Species diversity of small mammals increased with structural complexity left on clearcut sites; Productivity of red-backed vole populations was higher in sites with green-tree retention (GTR) and windrows of woody debris; GTR and windrows may provide additive effect for providing habitat to conserve mammals on clearcuts.
We tested the hypotheses (H) that on newly clearcut-harvested sites, (H1) abundance and species diversity of the forest-floor small mammal community, and (H2) abundance, reproduction, and recruitment of red-backed voles (Myodes gapperi Vigors), would increase with higher levels of structural retention via green-tree retention (GTR) and woody debris (dispersed and constructed into windrows). Study areas were located in three forest ecological zones in southern British Columbia, Canada. For H1, mean total abundance did generally increase with the gradient of retained habitat structure. Mean species richness and diversity were similar among treatment sites but did show an increasing gradient with structural compexity. For H2, mean abundance, reproduction, and recruitment of M. gapperi were higher in GTR and windrow sites than those without retained structures. There was a positive relationship between mean abundance of M. gapperi and total volume of woody debris across treatments. This study is the first investigation of the responses of forest-floor small mammals to an increasing gradient of retained habitat structure via GTR and woody debris on clearcuts. Our assessment of a combination of these two interventions suggested a potentially strong additive effect that could be cautiously extrapolated across three forest ecological zones. With the advent of low levels of GTR on clearcuts, woody debris structures should help provide some habitat to conserve forest mammals on harvest openings.
  • Sullivan, Department of Forest and Conservation Sciences, Faculty of Forestry, University of BC, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 ORCID ID:E-mail: tom.sullivan@ubc.ca (email)
  • Sullivan, Applied Mammal Research Institute, 11010 Mitchell Avenue, Summerland, BC, Canada V0H 1Z8 ORCID ID:E-mail: dru.sullivan@appliedmammal.com
article id 1190, category Research article
Jaakko Repola, Kristina Ahnlund Ulvcrona. (2014). Modelling biomass of young and dense Scots pine (Pinus sylvestris L.) dominated mixed forests in northern Sweden. Silva Fennica vol. 48 no. 5 article id 1190. https://doi.org/10.14214/sf.1190
Highlights: The biomass allocation to tree components is different in unmanaged and managed young stands; Higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands; Models for trees from young and dense stands provide better estimates of biomass in such stands than those based on data from managed stands.
Biomass models for the biomass of above-ground tree components of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in young dense Scots pine dominated forest stands in northern Sweden were constructed. Destructive above-ground biomass sampling was conducted in naturally generated young, dense, Scots pine dominated mixed stands. Three sampling campaigns were undertaken, the first in 1997 and 1998. The second was six years later (2003), and the last 13 years after the first (2010). In total, 280 trees (126 Scots pine, 68 Norway spruce and 86 birches) were sampled from six different stands in northern Sweden. The sampled trees’ diameter at breast height (dbh) was in the range 1–22 cm (Scots pine), 1–21 cm (Norway spruce) and 1–11 cm (birch). Biomass predictions were tested using our models and the widely used biomass models originally constructed for managed stands. The results showed that the biomass allocation to tree components is different in unmanaged and managed young stands; higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands. The overall conclusion is that the biomass models for managed stands did not produce satisfactory biomass estimates in unthinned, dense, young stands.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
  • Ahnlund Ulvcrona, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kristina.ulvcrona@slu.se
article id 1124, category Research article
Āris Jansons, Mārtiņš Zeps, Juris Rieksts-Riekstiņš, Roberts Matisons, Oskars Krišāns. (2014). Height increment of hybrid aspen Populus tremuloides x P. tremula as a function of weather conditions in central part of Latvia. Silva Fennica vol. 48 no. 5 article id 1124. https://doi.org/10.14214/sf.1124
Highlights: Intra-annual height growth of hybrid aspen was monitored; Clones with early leaf flushing dates showed faster height growth; Height growth was generally controlled by temperature; Fast-growing hybrids were more robust to weather conditions than slow-growing ones; Potential evapotranspiration (moisture regime) negatively affected height growth of clones with delayed phenology.
Height growth of young hybrid aspen (Populus tremula L. × P. tremuloides Michx.) was studied in relation to weather conditions. Height of clones with different leaf flushing phenology (early, intermediate and late) was monitored during the growing periods of 2010 and 2011 in a plantation established on former agricultural land. Mean daily height increment (HI) was calculated. Multiple linear regression was used to determine which weather factors (variables) had significant effect on HI. Mean seasonal height growth (mean seasonal HI) between clones (groups) was compared by ANOVA. In both years, HI was significantly higher for clones with early and intermediate leaf flushing compared to clones with late leaf flushing. The effect of weather factors also differed between clones according to their leaf flushing phenology; it was the weakest for HI of clones with early leaf flushing compared to clones with intermediate and late leaf flushing. Mean temperature was the main factor, which positively affected HI of all clones, suggesting that warmer climate might be beneficial for height growth of young hybrid aspen in Latvia. Nevertheless, significant negative relationship between HI and potential evapotranspiration (PET) was observed for clones with delayed leaf flushing, suggesting negative effect of increasing variability of precipitation on growth. Thus, the differences in height growth intensity might be related to growth sensitivity to weather conditions. On the other hand, such differences in height growth between clones might be caused by competition (i.e. with herbs), as trees with early leaf flushing might conquer more resources and become more robust against the environmental fluctuation.
  • Jansons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Zeps, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: martins.zeps@silava.lv
  • Rieksts-Riekstiņš, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: Juris.Riekstins@silava.lv
  • Matisons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Krišāns, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: oskars.krisans@silava.lv
article id 1161, category Research article
Tiina Laine, Veli-Matti Saarinen. (2014). Comparative study of the Risutec Automatic Plant Container (APC) and Bracke planting devices. Silva Fennica vol. 48 no. 3 article id 1161. https://doi.org/10.14214/sf.1161
Highlights: As currently designed, the prototype Risutec APC fitted with an automatic feeding system offers no significant advantage over the Bracke planting device in terms of planting productivity or quality; Cost estimates suggest that an idealized automated feeding system could increase productivity and decrease unit costs.
The productivity of mechanized planting could be increased by minimizing the time spent manually reloading seedling cassettes. This study compared the work-time distribution, productivity and quality of the prototype Risutec APC fitted with an automatic feeding system and the commonly-used and manually-loaded Bracke P11.a. An approach of comparative time study was employed that compared performance of two operators using both machines in four sites where slash and stumps had been removed. Operating costs were estimated and compared for these two machines and an idealized machine with automatic feeding system (referred as AUT). AUT was assumed to be similar to the Bracke planting machine with the only difference being in automatic feeding. Productivity of the Risutec APC (196 seedlings per productive work hour [pl PWh0–1]) was lower than that of Bracke (244 pl PWh0–1), making the unit cost 35.7% higher. A large portion (17.6%) of the productive work time of Risutec APC was interrupted by malfunctions, so it cannot be considered robust and reliable yet. Quality of the planting work was reasonable for both machines. The results suggest that an idealized AUT could increase planting capacity (hectares per year [ha yr–1]) by 15.4% and lower the unit cost (Euro per seedling [€ pl–1]) by 4.7% compared to today’s machines. The importance of an automated feeding system increases with planting efficiency because relatively more time is spent reloading seedlings. Proper automatic feeding system could offer a cost-effective solution and could enhance productivity, but the Risutec APC has yet to meet the technical and economic standards required to be competitive.
  • Laine, Finnish Forest Research Institute (METLA), Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: tiina.laine@metla.fi (email)
  • Saarinen, Finnish Forest Research Institute (METLA), Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: veli-matti.saarinen@metla.fi
article id 1064, category Research article
Back Tomas Ersson, Urban Bergsten, Ola Lindroos. (2014). Reloading mechanized tree planting devices faster using a seedling tray carousel. Silva Fennica vol. 48 no. 2 article id 1064. https://doi.org/10.14214/sf.1064
Highlights: Seedling reloading onto the Bracke Planter crane-mounted planting device was twice as fast with the MagMat tray-wise-loaded carousel as today’s seedling-wise-loaded carousel; Tray-wise reloading combined with deplugging seedlings from suitable cultivation trays has the potential to be an efficient and robust way to feed seedlings on any type of tree planting machine.
On Nordic clearcuts, today’s tree planting machines produce high-quality but costly regenerations. Much of this high cost is attributable to the planting machines’ low productivity. One promising way of raising productivity is to lessen the time spent manually reloading seedlings onto the carousels of crane-mounted planting devices. Using MagMat, a carousel test-rig designed by engineering students, we studied how much faster tray-wise seedling reloading is on the Bracke Planter compared to reloading with today’s seedling-wise-loaded carousel. The MagMat test-rig held eight Hiko cultivation trays from which seedlings were deplugged individually and dropped into the planting tube. The time study confirmed that seedling reloading was on average twice as fast with MagMat compared to today’s seedling carousel, thereby increasing assumed planting machine productivity by 8–9% depending on the planting device used. MagMat’s cost-efficiency was analysed to be particularly reliant on its added investment cost, mechanical availability and how quickly trays can be switched automatically. Nevertheless, MagMat’s field performance illustrated the overall potential of tray-wise loading compared to piecewise seedling loading for increasing the productivity of crane-mounted planting devices. Also, deplugging proved to be a reliable method of extracting seedlings from the rigid, copper-painted Hiko cultivation trays even when performed at the excavator’s boom-tip during mounding work. We conclude that, rather than piecewise seedling loading, tray-wise loading combined with deplugging seedlings from suitable cultivation trays is a reliable and much more time-efficient method to feed seedlings on probably any type of tree planting machine.
  • Ersson, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden ORCID ID:E-mail: back.tomas.ersson@slu.se (email)
  • Bergsten, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
  • Lindroos, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@slu.se
article id 1071, category Research article
Ursula Kretschmer, Nadeschda Kirchner, Christopher Morhart, Heinrich Spiecker. (2013). A new approach to assessing tree stem quality characteristics using terrestrial laser scans. Silva Fennica vol. 47 no. 5 article id 1071. https://doi.org/10.14214/sf.1071
Highlights: Minimal deviations of the bark surface can be detected and visualized based on terrestrial laser scan data; Additionally the geometrical properties of bark scars and branched knots can be assessed; Two methods using two different approaches are presented: (1) a method using intensity data and (2) a method using bark surface models.
This paper presents an approach to assess and measure bark characteristics as indicators of wood quality using terrestrial laser scan data. In addition to the detection and measurement by use of the intensity information of the scan data a new approach was established. Bark surface models are calculated for each tree. They offer the representation of the bark as a height model. The reference is the tree stem approximated by a chain of cylinders. Minimal deviations of the bark surface can be detected and visualized and the geometrical properties of bark scars and branched knots can be assessed. Results of the measurement of 18 scars are presented using the two approaches: (1) a method using intensity data or (2) using bark surface models. The selection of the adequate approach depends on the stem characteristics. In a next step, methods for automatic measurement of bark scars will be developed.
  • Kretschmer, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: ursula.kretschmer@iww.uni-freiburg.de (email)
  • Kirchner, VOLKE Consulting Engineers GmbH, Schätzweg 7-9, 80935 München, Germany ORCID ID:E-mail: nadeschda.kirchner@volke.muc.de
  • Morhart, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: christopher.morhart@iww.uni-freiburg.de
  • Spiecker, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: instww@uni-freiburg.de
article id 993, category Research article
Jori Uusitalo, Jari Ala-Ilomäki. (2013). The significance of above-ground biomass, moisture content and mechanical properties of peat layer on the bearing capacity of ditched pine bogs. Silva Fennica vol. 47 no. 3 article id 993. https://doi.org/10.14214/sf.993
Intensive utilisation of peatland forests calls for logging activities to be increasingly carried out in conditions other than those in harsh winter. The low bearing capacity of peatlands forms a severe obstacle for the prevailing harvesting machinery. The aim of this study was to clarify and quantify the significance of above-ground biomass, brash mat, moisture content and mechanical properties of peat layer on the bearing capacity of pine bogs. In-situ driving tests were conducted in Western Finland on a pine bog covering a large variation of growing stock. Portable tools were tested for measuring strength properties of the top layer of peat. According to the results, shear modulus of top layer of peat, volume of trees and the existence of cutting debris are the most important factors affecting bearing capacity. Spiked shear vane was shown to be a promising tool in predicting the strength properties of peat soil.
  • Uusitalo, Finnish Forest Research Institute, Parkano Unit, Kaironiementie 15, FI-39700 Parkano, Finland ORCID ID:E-mail: jori.uusitalo@metla.fi (email)
  • Ala-Ilomäki, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: jari.ala-ilomaki@metla.fi
article id 935, category Research article
Loice M. A. Omoro, Mike Starr, Petri K. E. Pellikka. (2013). Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya. Silva Fennica vol. 47 no. 2 article id 935. https://doi.org/10.14214/sf.935
Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.
  • Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: loice.omoro@helsinki.fi
  • Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mike.starr@helsinki.fi (email)
  • Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: petri.pellikka@helsinki.fi
article id 933, category Research article
Per-Ola Hedwall, Harald Grip, Sune Linder, Lars Lövdahl, Urban Nilsson, Johan Bergh. (2013). Effects of clear-cutting and slash removal on soil water chemistry and forest-floor vegetation in a nutrient optimised Norway spruce stand. Silva Fennica vol. 47 no. 2 article id 933. https://doi.org/10.14214/sf.933
Fertilisation with nutrient optimisation has in Sweden resulted in large increases in volume growth in young stands of Norway spruce. There are, however, environmental concerns about repeated fertilisation and one is the risk of nutrient leakage to ground water resources and aquatic ecosystems after clear-cutting of such forests. The present study followed soil-water chemistry in optimised fertilised stands after clear-cutting, as well as effects of harvest of slash on nutrient leakage. Parts of a 30-year-old stand of Norway spruce, which had been subject to a nutrient optimisation experiment for 17 years, were clear-cut. A split-plot design with whole-tree harvesting as the sub-plot treatment was applied. Lysimeters were installed and soil-water sampled at nine occasions during the following four years. No significant effects of fertilisation on nitrate leaching were found, while harvest of slash reduced the concentration of Ca, DOC, DON, K, Mg, ammonium and nitrate, as well as pH in the soil solution. While no effects of fertilisation could be seen on the soil water concentration of N, the results indicate an interaction between fertilisation and harvest of slash on the concentration of nitrate in the soil solution. The results indicate that forest-floor vegetation plays an important role in the retention of N after clear-cutting of fertilised forests.
  • Hedwall, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se (email)
  • Grip, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail: harald@grip2.se
  • Linder, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: sune.linder@slu.se
  • Lövdahl, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nilsson, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: urban.nilsson@slu.se
  • Bergh, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: johan.bergh@slu.se
article id 892, category Research article
M. Carmen San José, Laura V. Janeiro, Elena Corredoira. (2013). Micropropagation of threatened black alder. Silva Fennica vol. 47 no. 1 article id 892. https://doi.org/10.14214/sf.892
Micropropagation techniques are valuable tools for propagating, conserving and restoring trees. An efficient micropropagation method involving axillary shoot proliferation of material obtained from mature European alder (Alnus glutinosa (L.) Gaertn.) trees was developed. Branch segments from trees aged 20–30 years were forced to flush, and explants derived from new shoots were cultured on Woody Plant Medium supplemented with 8.88 µM benzyladenine and 2.85µM indole-3-acetic-acid. In vitro establishment was achieved in all five genotypes evaluated. Shoot cultures were maintained by sequential subculture of explants on the same medium supplemented with 0.88–0.44 µM benzyladenine and 2.85 µM indole-3-acetic acid. Transfer to fresh medium every 3 weeks during a 9-week multiplication period and the inclusion of 2.28 µM zeatin during the last 3 weeks of culture improved the multiplication rate and shoot quality. Use of 2% glucose as the carbohydrate source produced better results than 3% sucrose for shoot proliferation. In vitro rooting of shoots was achieved with 2% glucose and 0.49 µM indole-3-butyric acid for 7 days, followed by in vitro culture on auxin-free medium for 21 days. Rooted plantlets were acclimatized to the greenhouse and were viable for reintroduction into the natural habitat.
  • San José, Instituto de Investigaciones Agrobiológicas de Galicia (IIAG), CSIC, Apartado 122, 15080 Santiago de Compostela, Spain ORCID ID:E-mail: sanjose@iiag.csic.es (email)
  • Janeiro, INLUDES, Diputación Provincial de Lugo, Ronda de la Muralla 140, 27004 Lugo, Spain ORCID ID:E-mail: lauravj68@hotmail.com
  • Corredoira, Instituto de Investigaciones Agrobiológicas de Galicia (IIAG), CSIC, Apartado 122, 15080 Santiago de Compostela, Spain ORCID ID:E-mail: elenac@iiag.csic.es
article id 916, category Research article
M. Carmen San José, Lourdes Romero, Laura V. Janeiro. (2012). Effect of indole-3-butyric acid on root formation in Alnus glutinosa microcuttings. Silva Fennica vol. 46 no. 5 article id 916. https://doi.org/10.14214/sf.916
A study of the in vitro rooting process in mature alder (Alnus glutinosa (L.) Gaertn.) shoots is described. Microcuttings from shoots cultured in vitro were transferred to a half-strength Woody Plant Medium containing 0 or 0.1 mg l–1 indole-3-butyric acid (IBA) for 0 to 7 days. The presence of IBA in the medium increased the rooting percentage, number of roots, percentage of lateral roots, and length of the shoots. Histological studies were carried out with shoots treated with 0 or 0.1 mg l–1 IBA for 7 days. According to these criteria, treatment with IBA for 2–3 days proved to be the most successful. In both treatments, substancial reactivation of cell division was observed at the base of the shoots after 1 day. Some cambial zone and adjacent phloem cells became dense cytoplasm, having nuclei with prominent nucleoli. The first cell divisions were also observed at this time. In the treatment with IBA (0.1 mg l–1 for 7 days), meristemoids became individualized, consisting of densely staining cells, by day 3. Identifiable conical shaped root primordia with several cell layers were visible after 4–5 days. Roots with an organized tissue system emerged from the stem after 6 days in the IBA-treated shoots. Meristemoid formation was delayed until the fourth day and root emergence until the eight day in the control treatment (no IBA).
  • San José, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain ORCID ID:E-mail: sanjose@iiag.csic.es (email)
  • Romero, CIFP Politécnico de Santiago, Santiago de Compostela, Spain ORCID ID:E-mail:
  • Janeiro, INLUDES, Diputación Provincial de Lugo, Lugo, Spain ORCID ID:E-mail: lauravj68@hotmail.com
article id 47, category Research article
Iulian Dragotescu, Daniel D. Kneeshaw. (2012). A comparison of residual forest following fires and harvesting in boreal forests in Quebec, Canada. Silva Fennica vol. 46 no. 3 article id 47. https://doi.org/10.14214/sf.47
Residual forests are a key component of post-burned areas creating structure within burns and providing habitat and seed sources. Yet, despite their importance to biodiversity and ecosystem processes there is little information on how similar or different residuals in burned landscape are to harvested landscapes. Our goal was to examine and compare the density, size, shape, and spatial arrangement of residual forest vegetation after fire and clearcutting. We evaluated residual forest in two locations within the boreal mixedwood region of Quebec, Canada using aerial photo interpretation and ArcGIS 9.1 software. We found residual stands to be larger and more abundant in harvested zones relative to sites affected by fire. Differences with respect to shape and spatial arrangement of residual forest were also observed among disturbance types. Factors such as proximity to watercourses, watercourse shape, and physiography affected residual abundance and spatial distribution. Residual forest in harvested zones tended to be more elongated with greater edge due to rules governing forest operations. Despite greater quantity of residual forest in harvested areas than fires, managers should still be prudent as the surrounding forest matrix is reduced in many managed landscapes.
  • Dragotescu, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail: idragot@hotmail.com (email)
  • Kneeshaw, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail:
article id 45, category Research article
Guolei Li, Yong Liu, Yan Zhu, Qing Mei Li, R. Karsten Dumroese. (2012). Effect of fall-applied nitrogen on growth, nitrogen storage and frost hardiness of bareroot Larix olgensis seedlings. Silva Fennica vol. 46 no. 3 article id 45. https://doi.org/10.14214/sf.45
Nursery response of evergreen trees to fall fertilization has been studied widely, but little attention has been given to deciduous trees. Bareroot Olga Bay larch (Larix olgensis Henry) seedlings were fertilized in the nursery with urea at four rates (0, 30, 60, 90 kg N ha–1), with half of each rate applied on two dates (September 16 and October 1, 2009). The seedlings were excavated for evaluation on October 15. In the unfertilized (control) treatment, root and shoot dry mass increased by 100% and 57% respectively, while N concentration in the roots and shoots increased by 43% and 40% during the 30 day period. This indicated that substantial biomass growth during this period did not lead to internal nutrient dilution. Root dry mass increased when fall fertilization rates were ≥ 60 kg N ha–1. Fall fertilization increased N concentrations in root tissue by 48–73%. Compared with the control, shoot tissues of fall fertilized seedlings had slightly higher N concentration and content and significantly higher frost hardiness.
  • Li, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing 100083, China ORCID ID:E-mail:
  • Liu, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing 100083, China ORCID ID:E-mail: lyong@bjfu.edu.cn (email)
  • Zhu, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing 100083, China ORCID ID:E-mail:
  • Li, Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Forest Silviculture of State Forestry Administration, Beijing 100091, China ORCID ID:E-mail:
  • Dumroese, US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Moscow, ID, USA ORCID ID:E-mail:
article id 44, category Research article
Anabel Aparecida de Mello, Leif Nutto, Karla Simone Weber, Carlos Eduardo Sanquetta, Jorge Luis Monteiro de Matos, Gero Becker. (2012). Individual biomass and carbon equations for Mimosa scabrella Benth. (bracatinga) in southern Brazil. Silva Fennica vol. 46 no. 3 article id 44. https://doi.org/10.14214/sf.44
Mimosa scabrella Benth. is an important native species of southern Brazil widely used for energy and promising for reforestation carbon offsets. Quantification of biomass and carbon stock is valuable for both purposes. From a forest inventory conducted in southern Brazil, data of M. scabrella were analyzed. Thirty sample trees were felled, excavated and weighed in the field and brought to laboratory for biomass and carbon determination. The total aboveground biomass represented 85% of the tree biomass, while roots corresponded to 15%. Correlation matrix of diameter at 1.3 m height (D), tree height (H) versus total and compartment biomass (P) indicated strong association between tree dimensions and biomasses. Five regression models were tested and equations were fitted to data of five biomass compartments and total tree biomass. The best fitting model for total biomass was P = –0.49361 + 0.034865 x D2H whereas for the partial biomass of the compartments was lnP = β0 + β1 x ln(D) + β2 lnH. Carbon concentration was statistically significantly different in foliage than in other compartments. Three approaches of calculating carbon stocks were evaluated and compared to actual data: 1) Estimated total biomass x weighted mean carbon concentration; 2) Estimated partial (compartment) biomass x compartment average carbon concentration; and 3) Carbon regression equations. No statistical difference was detected among them. It was concluded that biomass equations fitted in this study were accurate and useful for fuelwood and carbon estimations.
  • de Mello, Federal University of Sergipe, Brazil ORCID ID:E-mail:
  • Nutto, Federal University of Paraná, Brazil ORCID ID:E-mail: lnutto.ufpr@gmail.com (email)
  • Weber, Federal University of Paraná ORCID ID:E-mail:
  • Sanquetta, Carlos Eduardo Sanquetta ORCID ID:E-mail:
  • Monteiro de Matos, Jorge Luis Monteiro de Matos ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilization and Work Science, Germany ORCID ID:E-mail:
article id 56, category Research article
Johan Holmgren, Andreas Barth, Henrik Larsson, Håkan Olsson. (2012). Prediction of stem attributes by combining airborne laser scanning and measurements from harvesters. Silva Fennica vol. 46 no. 2 article id 56. https://doi.org/10.14214/sf.56
In this study, a new method was validated for the first time that predicts stem attributes for a forest area without any manual measurements of tree stems by combining harvester measurements and Airborne Laser Scanning (ALS) data. A new algorithm for automatic segmentation of tree crowns from ALS data based on tree crown models was developed. The test site was located in boreal forest (64°06’N, 19°10’E) dominated by Norway spruce (Picea abies) and Scots Pine (Pinus sylvestris).The trees were harvested on field plots, and each harvested tree was linked to the nearest tree crown segment derived from ALS data. In this way, a reference database was created with both stem data from the harvester and ALS derived features for linked tree crowns. To estimate stem attributes for a tree crown segment in parts of the forest where trees not yet have been harvested, tree stems are imputed from the most similar crown segment in the reference database according to features extracted from ALS data. The imputation of harvester data was validated on a sub-stand-level, i.e. 2–4 aggregated 10 m radius plots, and the obtained RMSE of stem volume, mean tree height, mean stem diameter, and stem density (stems per ha) estimates were 11%, 8%, 12%, and 19%, respectively. The imputation of stem data collected by harvesters could in the future be used for bucking simulations of not yet harvested forest stands in order to predict wood assortments.
  • Holmgren, Swedish University of Agricultural Sciences, Forest Resource Management, Umeå, Sweden ORCID ID:E-mail: johan.holmgren@slu.se (email)
  • Barth, The Forestry Research Institute of Sweden, Uppsala, Sweden ORCID ID:E-mail:
  • Larsson, Swedish University of Agricultural Sciences, Forest Resource Management, Umeå, Sweden ORCID ID:E-mail:
  • Olsson, Swedish University of Agricultural Sciences, Forest Resource Management, Umeå, Sweden ORCID ID:E-mail:
article id 80, category Research article
Mari T. Jönsson, Shawn Fraver, Bengt Gunnar Jonsson. (2011). Spatio-temporal variation of coarse woody debris input in woodland key habitats in central Sweden. Silva Fennica vol. 45 no. 5 article id 80. https://doi.org/10.14214/sf.80
The persistence of many saproxylic (wood-living) species depends on a readily available supply of coarse woody debris (CWD). Most studies of CWD inputs address stand-level patterns, despite the fact that many saproxylic species depend on landscape-level supplies of CWD. In the present study we used dated CWD inputs (tree mortality events) at each of 14 Norway spruce (Picea abies) dominated woodland key habitat sites to analyze the spatial and temporal patterns of CWD additions between 1950 and 2002 within a small landscape in central Sweden. We found that inputs were episodic within sites, where local windstorms created pulses in CWD input. Pulses occurred simultaneously in many sites, yielding landscape-level synchrony of CWD input. These synchronous pulses, and importantly, the breaks between pulses, may have negative implications for saproxylic species that are dependent on large volume inputs of freshly killed Norway spruce. In addition, the inherent small size and relative isolation of these sites may further increase extinction risks due to stochastic events. However, background CWD input rates occurring between pulses varied substantially among sites, presumably the result of the sites’ varied histories and structural characteristics. This finding suggests that the different sites have varied abilities to provide habitat for saproxylic species during periods with low landscape-level input of CWD.
  • Jönsson, Department of Ecology, SLU, P.O. Box 7044, SE-750 07 Uppsala, Sweden (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail: mari.jonsson@slu.se (email)
  • Fraver, U.S. Forest Service, Northern Research Station, Grand Rapids, Minnesota, USA (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
article id 78, category Research article
Kris Vandekerkhove, Luc De Keersmaeker, Ruben Walleyn, Frank Köhler, Luc Crevecoeur, Leen Govaere, Arno Thomaes, Kris Verheyen. (2011). Reappearance of old-growth elements in lowland woodlands in northern Belgium: Do the associated species follow? Silva Fennica vol. 45 no. 5 article id 78. https://doi.org/10.14214/sf.78
The forest cover of the western European lowland plain has been very low for centuries. Remaining forests were intensively managed, and old-growth elements like veteran trees and coarse woody debris became virtually absent. Only over the last decades have these old-growth elements progressively redeveloped in parks, lanes and forests, and have now reached their highest level over the last 500–1000 years. Biodiversity associated with these old-growth elements makes up an important part of overall forest biodiversity. The ability of species to recolonise the newly available habitat is strongly determined by limitations in their dispersal and establishment. We analyse the current status and development of old-growth elements in Flanders (northern Belgium) and the process of recolonisation by means of specific cases, focussing on saproxylic fungi and saproxylic beetles. Our results show that ‘hotspots’ of secondary old growth, even isolated small patches, may have more potential for specialised biodiversity than expected, and may provide important new strongholds for recovery and recolonisation of an important share of old-growth related species.
  • Vandekerkhove, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail: kris.vandekerkhove@inbo.be (email)
  • De Keersmaeker, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Walleyn, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Köhler, Koleopterologisches Forschungsbüro, Bornheim, Germany ORCID ID:E-mail:
  • Crevecoeur, Genk, Belgium ORCID ID:E-mail:
  • Govaere, Agency of Nature and Forests, Brussels, Belgium ORCID ID:E-mail:
  • Thomaes, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Verheyen, Ghent University, Laboratory of Forestry, Gontrode, Belgium ORCID ID:E-mail:
article id 100, category Research article
Annika Kangas, Lauri Mehtätalo, Antti Mäkinen, Kalle Vanhatalo. (2011). Sensitivity of harvest decisions to errors in stand characteristics. Silva Fennica vol. 45 no. 4 article id 100. https://doi.org/10.14214/sf.100
In forest planning, the decision maker chooses for each stand a treatment schedule for a predefined planning period. The choice is based either on optimization calculations or on silvicultural guidelines. Schedules for individual stands are obtained using a growth simulator, where measured stand characteristics such as the basal area, mean diameter, site class and mean height are used as input variables. These characteristics include errors, however, which may lead to incorrect decisions. In this study, the aim is to study the sensitivity of harvest decisions to errors in a dataset of 157 stands. Correct schedules according to silvicultural guidelines were first determined using error-free data. Different amounts of errors were then generated to the stand-specific characteristics, and the treatment schedule was selected again using the erroneous data. The decision was defined as correct, if the type of harvest in these two schedules were similar, and if the timings deviated at maximum ±2 for thinning and ±3 years for clear-cut. The dependency of probability of correct decisions on stand characteristics and the degree of errors was then modelled. The proposed model can be used to determine the required level of measurement accuracy for each characteristics in different kinds of stands, with a given accuracy requirement for the timing of treatments. This information can further be utilized in selecting the most appropriate inventory method.
  • Kangas, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: annika.kangas@helsinki.fi (email)
  • Mehtätalo, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Mäkinen, Simosol Oy, Riihimäki, Finland ORCID ID:E-mail:
  • Vanhatalo, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 113, category Research article
Jinsong Wang, Chunyu Zhang, Fucai Xia, Xiuhai Zhao, Lianhai Wu, Klaus von Gadow. (2011). Biomass structure and allometry of Abies nephrolepis (Maxim) in Northeast China. Silva Fennica vol. 45 no. 2 article id 113. https://doi.org/10.14214/sf.113
Above- and below-ground tree biomass structure and allometric relationships of Abies nephrolepis (Maxim) were assessed in an old secondary forest dominated by A. nephrolepis, Pinus koraiensis, Quercus mongolica, Tilia amurensis, Fraxinus mandshurica and Acer mono in northeast China. Based on the breast-height diameter (D), a total of 21 sample trees were divided into three tree size classes: the small trees (1 cm ≤ D < 10 cm), the medium trees (10 cm ≤ D < 20 cm) and the big trees (D ≥ 20 cm). The greatest amount of live branch biomass was located in the middle and bottom layers of the crown, while the largest foliage biomass was found in the middle layer in each tree size category. The relative contribution of canopy biomass components (live branches and foliage) decreased with increasing tree size, while that of coarse root biomass remained almost constant. The relationship between above- and belowground biomass was linear. D and tree height (H) decreased with increasing competition intensity. The small trees had lower average crown ratio and higher average height-to-diameter ratio than those of the medium and big trees. The big trees had higher average stem to foliage mass ratio than those of the small and medium trees. Crown ratio, height-to-diameter ratio and stem to foliage mass ratio were not correlated with competition intensity in the same tree size class. Root to shoot mass ratio was almost constant among tree sizes. Allometric equations based on D gave higher correlations compared to those with other stem diameters: at tree base, at 30-cm height and at crown base.
  • Wang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Zhang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Xia, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Zhao, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: zhaoxh@bjfu.edu.cn (email)
  • Wu, Rothamsted Research, Okehampton, Devon, UK ORCID ID:E-mail:
  • Gadow, Faculty of Forestry and Forest Ecology, Georg-August-University Göttingen, Göttingen, Germany ORCID ID:E-mail:
article id 451, category Research article
Thomas P. Sullivan, Druscilla S. Sullivan, Pontus M. F. Lindgren, Douglas B. Ransome. (2010). Green-tree retention and life after the beetle: stand structure and small mammals 30 years after salvage harvesting. Silva Fennica vol. 44 no. 5 article id 451. https://doi.org/10.14214/sf.451
We report on a retrospective investigation of the impacts of salvage harvesting of lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Wats.), killed by an outbreak of mountain pine beetle (Dendroctonus ponderosae Hopk.) in the 1970s, with variable retention of Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco). Our inference to biodiversity was coniferous stand structure and four mammal species: the southern red-backed vole (Myodes gapperi Vigors), common shrew (Sorex cinereus Kerr), red squirrel (Tamiasciurus hudsonicus Erxleben) and northern flying squirrel (Glaucomys sabrinus Shaw). We tested hypotheses that, at 30 years after salvage harvest of beetle-killed lodgepole pine trees, (1) abundance and diversity of stand structure, and (2) abundance of mammal species, will increase with higher levels of green-tree retention (GTR). Stand structure attributes and small mammals were sampled during 2005–2008 in young pine stands, with a range of GTR seed-trees (none, dispersed, and aggregated Douglas-fir), and uncut forest in south-central British Columbia, Canada. Diameters and heights of Douglas-fir and lodgepole pine and basal area of total conifers supported hypothesis (1). Mean abundance of the red-backed vole was consistently higher (2.3 to 6.4 times) in the uncut forest than other stands. Overall mean patterns of abundance for common shrews, red squirrels, and northern flying squirrels were similar among treatment stands. Mean abundance of the red-backed vole supported hypothesis (2), but numbers of the other three species did not. There is “life after the beetle” at 30 years after salvage harvesting, and this was enhanced by GTR.
  • Sullivan, Department of Forest Sciences, Faculty of Forestry, University of BC, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 ORCID ID:E-mail: tom.sullivan@ubc.ca (email)
  • Sullivan, Department of Forest Sciences, Faculty of Forestry, University of BC, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 ORCID ID:E-mail:
  • Lindgren, Applied Mammal Research Institute, 11010 Mitchell Avenue, Summerland, BC, Canada V0H 1Z8 ORCID ID:E-mail:
  • Ransome, Applied Mammal Research Institute, 11010 Mitchell Avenue, Summerland, BC, Canada V0H 1Z8 ORCID ID:E-mail:
article id 454, category Research article
Paula Jylhä, Olli Dahl, Juha Laitila, Kalle Kärhä. (2010). The effect of supply system on the wood paying capability of a kraft pulp mill using Scots pine harvested from first thinnings. Silva Fennica vol. 44 no. 4 article id 454. https://doi.org/10.14214/sf.454
The efficiencies of wood supply systems based on cut-to-length (CTL) harvesting, the harvesting of loose whole trees, and whole-tree bundling were compared using the relative wood paying capabilities (WPC) of a kraft pulp mill as decisive criteria. The WPCs from mill to stump were calculated for three first-thinning stands of Scots pine (Pinus sylvestris L.) with mean breast-height diameter of the removal of 6, 8, and 12 cm. Pulp price had a strong effect on the WPC, and the CTL system resulted in the highest WPC per m3 at stump. The savings in procurement costs and gains in energy generation from additional raw material acquired with the harvesting of loose whole trees did not compensate the losses in pulp production. Considering removal per hectare, loose whole trees gave the highest WPCs at stump in the two stands with the smallest trees and the highest proportion of additional raw material. Decrease in pulp price and increase in energy price improved the competitiveness of the whole-tree systems. In the case of whole-tree bundling, savings in transportation costs did not balance the high cutting and compaction costs, and the bundling system was the least competitive alternative.
  • Jylhä, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Dahl, Aalto University School of Science and Technology, Department of Forest Products Technology, Espoo, Finland ORCID ID:E-mail:
  • Laitila, Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
article id 454, category Research article
Paula Jylhä, Olli Dahl, Juha Laitila, Kalle Kärhä. (2010). The effect of supply system on the wood paying capability of a kraft pulp mill using Scots pine harvested from first thinnings. Silva Fennica vol. 44 no. 4 article id 454. https://doi.org/10.14214/sf.454
The efficiencies of wood supply systems based on cut-to-length (CTL) harvesting, the harvesting of loose whole trees, and whole-tree bundling were compared using the relative wood paying capabilities (WPC) of a kraft pulp mill as decisive criteria. The WPCs from mill to stump were calculated for three first-thinning stands of Scots pine (Pinus sylvestris L.) with mean breast-height diameter of the removal of 6, 8, and 12 cm. Pulp price had a strong effect on the WPC, and the CTL system resulted in the highest WPC per m3 at stump. The savings in procurement costs and gains in energy generation from additional raw material acquired with the harvesting of loose whole trees did not compensate the losses in pulp production. Considering removal per hectare, loose whole trees gave the highest WPCs at stump in the two stands with the smallest trees and the highest proportion of additional raw material. Decrease in pulp price and increase in energy price improved the competitiveness of the whole-tree systems. In the case of whole-tree bundling, savings in transportation costs did not balance the high cutting and compaction costs, and the bundling system was the least competitive alternative.
  • Jylhä, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Dahl, Aalto University School of Science and Technology, Department of Forest Products Technology, Espoo, Finland ORCID ID:E-mail:
  • Laitila, Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
article id 132, category Research article
Mats Berlin, Lars Lönnstedt, Gunnar Jansson, Öje Danell, Tore Ericsson. (2010). Developing a Scots pine breeding objective: a case study involving a Swedish sawmill. Silva Fennica vol. 44 no. 4 article id 132. https://doi.org/10.14214/sf.132
The aim of this study was to develop a Scots pine (Pinus sylvestris L.) breeding objective for a vertically integrated sawmill in northern Sweden. The production system was defined as comprising the sawmill and the forests supplying it. Volume per hectare, wood density, survival and straightness were used as objective traits and the related selection criteria were measurements, collected at young tree age, of height, diameter, pilodyn penetration, vitality and straightness. A bio-economic model was used to calculate economic weights for the objective traits identified. We also investigated the efficiency of different selection indices based on these economic weights, in combination with available data on genetic parameters. Furthermore, we studied the effect of different discount rates on the calculated economic weights. The results showed that, compared to the full index (which included all selection criteria), omitting either vitality or straightness had a negligible effect, reducing predicted profit gain per hectare by less than one per cent. Height or diameter each had a greater effect, with a loss of predicted profit gain per hectare of up to 6%. Excluding pilodyn penetration from the selection index caused the largest reduction in predicted profit gain per hectare, amounting to over 10%. However, when both height and diameter were removed the predicted profit gain per hectare dropped to one-third of that based on the full index. Finally, ranking and genetic selection for the developed breeding objective was insensitive to changes in the discount rate.
  • Berlin, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: mats.berlin@skogsforsk.se (email)
  • Lönnstedt, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Jansson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Danell, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Ericsson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
article id 143, category Research article
Juha Laitila, Jani Heikkilä, Perttu Anttila. (2010). Harvesting alternatives, accumulation and procurement cost of small-diameter thinning wood for fuel in Central Finland. Silva Fennica vol. 44 no. 3 article id 143. https://doi.org/10.14214/sf.143
This study compared harvesting alternatives, accumulation and procurement costs of small-diameter thinning wood chips for fuel, when trees were harvested either as delimbed stemwood or whole trees. The calculation was made for a hypothetical plant located in Central Finland and the radius of the procurement area was 100 km via the existing road network. Cutting was done with conventional harvester head equipped with multi-tree-handling (MTH) accessories, with the logged trees being chipped at the roadside storage. The cost of delimbed stemwood chips at heating plant was 24% higher compared to the cost of whole tree chips. The availability analysis attested that delimbing lowered the regional cutting removal by 42% compared to the whole tree harvesting, when the minimum accumulation for the fuel fraction at the stand was set at 25 m3/ha. Delimbing diminishes the recovery rate at the site, resulting in a diminishing number of potential recovery sites meeting the threshold volume. However, the study showed that the forest energy potential is increased and procurement costs are reduced, if delimbed stemwood is harvested from stands where the whole tree harvesting is not acceptable due to nutrient loss or for other ecological reasons. Intelligent selection of cutting methods for different stands enables minimization of transport distance and control of procurement cost.
  • Laitila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail: juha.laitila@metla.fi (email)
  • Heikkilä, L&T Biowatti Oy, Seinäjoki, Finland ORCID ID:E-mail:
  • Anttila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
article id 143, category Research article
Juha Laitila, Jani Heikkilä, Perttu Anttila. (2010). Harvesting alternatives, accumulation and procurement cost of small-diameter thinning wood for fuel in Central Finland. Silva Fennica vol. 44 no. 3 article id 143. https://doi.org/10.14214/sf.143
This study compared harvesting alternatives, accumulation and procurement costs of small-diameter thinning wood chips for fuel, when trees were harvested either as delimbed stemwood or whole trees. The calculation was made for a hypothetical plant located in Central Finland and the radius of the procurement area was 100 km via the existing road network. Cutting was done with conventional harvester head equipped with multi-tree-handling (MTH) accessories, with the logged trees being chipped at the roadside storage. The cost of delimbed stemwood chips at heating plant was 24% higher compared to the cost of whole tree chips. The availability analysis attested that delimbing lowered the regional cutting removal by 42% compared to the whole tree harvesting, when the minimum accumulation for the fuel fraction at the stand was set at 25 m3/ha. Delimbing diminishes the recovery rate at the site, resulting in a diminishing number of potential recovery sites meeting the threshold volume. However, the study showed that the forest energy potential is increased and procurement costs are reduced, if delimbed stemwood is harvested from stands where the whole tree harvesting is not acceptable due to nutrient loss or for other ecological reasons. Intelligent selection of cutting methods for different stands enables minimization of transport distance and control of procurement cost.
  • Laitila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail: juha.laitila@metla.fi (email)
  • Heikkilä, L&T Biowatti Oy, Seinäjoki, Finland ORCID ID:E-mail:
  • Anttila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
article id 142, category Research article
Helmer Belbo. (2010). Comparison of two working methods for small tree harvesting with a multi tree felling head mounted on farm tractor. Silva Fennica vol. 44 no. 3 article id 142. https://doi.org/10.14214/sf.142
In this study, the efficiency of a small multi-tree felling head, mounted on a farm tractor with a timber trailer was studied, when harvesting small trees for energy in thinnings. Both separate loading and direct loading of the felled trees was studied. Time studies were carried out in a mixed stand of Norway spruce (Picea abies (L.) Karst) and birch (Betula pubescens Ehrh.). The time consumption of the work elements in the different work methods was formulated by regression analysis, where the independent variables were tree size and degree of accumulation. The average size of the harvested trees was 0.035 m3. The time consumption for the harvesting and loading were similar for the two studied methods, 20 minutes per m3 at a tree size of 0.035 m3, but the two methods showed different characteristics for different tree sizes and level of accumulation. The direct loading method had the highest productivity when more than 0.1 m3 were collected in the felling cycle, whereas the separate loading method had the highest productivity when less than 0.05 m3 were collected in the felling cycle. The total effective time consumption for harvesting and forwarding the biomass 300 meters to roadside landing was 27 minutes per m3. The efficiency of the initial felling and collecting of the small trees was the main challenge. Both the harvesting technique and harvesting technology needs further development to provide a feasible production chain for woodfuel from energy thinning.
  • Belbo, Norwegian Forest and Landscape Institute, Box 115, 1431 Ås, Norway ORCID ID:E-mail: helmer.belbo@skogoglandskap.no (email)
article id 159, category Research article
Johan Stendahl, Maj-Britt Johansson, Erik Eriksson, Åke Nilsson, Ola Langvall. (2010). Soil organic carbon in Swedish spruce and pine forests – differences in stock levels and regional patterns. Silva Fennica vol. 44 no. 1 article id 159. https://doi.org/10.14214/sf.159
The selection of tree species is one factor to consider if we want to mitigate carbon dioxide emissions to the atmosphere through forest management. The objectives of this study were to estimate the differences in soil organic carbon (SOC) stocks under Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) forests and to examine causes of differences in the accumulation of carbon in the forest soil. Large-scale inventory data was used to quantify variations in SOC stock in relation to stand type and the accumulation of carbon for spruce and pine stands was analysed by simulation. Based on field data, the national mean SOC stock was 9.2 kg m–2 in spruce dominated stands and 5.7 kg m–2 in pine dominated stands. For both species, the SOC stock, measured in the field inventory, increased significantly with increasing temperature, although at different rates. The SOC stock was larger for spruce under all temperature conditions, but the difference between species diminished with increasing temperature. The simulations indicated that the build-up of SOC over several rotations was 22% higher in spruce stands than in pine stands under similar environmental conditions. The main difference was found to be the greater input of harvest residues for spruce. Further, the simulations showed that ground vegetation contributed considerably more to the litter production under pine than under spruce. On sites where both Scots pine and Norway spruce are considered suitable, the latter should be selected if the aim of the forest management policy is to maximize the accumulation of SOC in the forest. Further, spruce is more favourable for SOC accumulation in areas with cold temperatures and on sites with low productivity.
  • Stendahl, Department of Soil and Environment, P.O. Box 7001, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden ORCID ID:E-mail: johan.stendahl@mark.slu.se (email)
  • Johansson, Department of Soil and Environment, P.O. Box 7001, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Eriksson, Department of Energy and Technology, P.O. Box 7061, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Nilsson, Department of Soil and Environment, P.O. Box 7001, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Langvall, Unit for Field-based Forest Research, Asa Experimental Forest and Research Station, Swedish University of Agricultural Sciences, SE-36030 Lammhult, Sweden ORCID ID:E-mail:
article id 184, category Research article
Jaakko Repola. (2009). Biomass equations for Scots pine and Norway spruce in Finland. Silva Fennica vol. 43 no. 4 article id 184. https://doi.org/10.14214/sf.184
In this study, biomass equations for the above- and below-ground tree components of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies [L.] Karst.) were developed. The models were based on 908 pine trees and 613 spruce trees collected in 77 stands located on mineral soil, and represented a wide range of stand and site conditions in Finland. The whole data set consisted of three sub data sets: 33 temporary sample plots, five thinning experiments, and the control plots of 39 fertilization experiments. The biomass equations were estimated for the individual tree components: stem wood, stem bark, living and dead branches, needles, stump, and roots. In the data analysis, a multivariate procedure was applied in order to take into account the statistical dependence among the equations. Three multivariate models for above-ground biomass and one for below-ground biomass were constructed. The multivariate model (1) was mainly based on tree diameter and height, and additional commonly measured tree variables were used in the multivariate models (2) and (3). Despite the unbalanced data in terms of the response variables, the statistical method generated equations that enable more flexible application of the equations, and ensure better biomass additivity compared to the independently estimated equations. The equations provided logical biomass predictions for a number of tree components, and were comparable with other functions used in Finland and Sweden even though the study material was not an objective, representative sample of the tree stands in Finland.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
article id 183, category Research article
Stella Bogino, María José Fernández Nieto, Felipe Bravo. (2009). Climate effect on radial growth of Pinus sylvestris at its southern and western distribution limits. Silva Fennica vol. 43 no. 4 article id 183. https://doi.org/10.14214/sf.183
The associations between tree-ring width and climatic variables, the tree age effect on climate-growth relationship and the drought index impact on radial growth of Scots pine (Pinus sylvestris L.) were studied in Mediterranean environments in the Iberian Peninsula. Dendrochronological techniques were applied to construct six tree-ring width chronologies for P. sylvestris. The association between tree growth and climate was analysed with correlation coefficients and bootstrapped response functions. Drought index (DRI) was used to detect the effects of aridity. Tree-ring width was positively correlated with rainfall in the growing season but this association stated earlier at the lowest altitudinal sites. The effects of temperature varied according to the site. The response to climatic variables depended on the age of the trees: more of the variability was explained by climatic variables in young stands than in old stands. The significant association between radial growth and DRI suggests that drought is a determining factor in the radial growth of P. sylvestris. Climate forecast scenarios show an increase in rainfall irregularity in the Mediterranean region so the differential tree response to rainfall at different elevations can be used to predict tree growth for determining silvicultural treatments.
  • Bogino, Universidad de Valladolid, Departamento de Producción Vegetal y Recursos Forestales, Joint Unit UVa-INIA ‘Sustainable Forest Management’, Avda. de Madrid 44, 34004 Palencia, Spain ORCID ID:E-mail: sbogino@fices.unsl.edu.ar (email)
  • Fernández Nieto, Universidad de Valladolid, Departamento de Producción Vegetal y Recursos Forestales, Joint Unit UVa-INIA ‘Sustainable Forest Management’, Avda. de Madrid 44, 34004 Palencia, Spain ORCID ID:E-mail:
  • Bravo, Universidad de Valladolid, Departamento de Producción Vegetal y Recursos Forestales, Joint Unit UVa-INIA ‘Sustainable Forest Management’, Avda. de Madrid 44, 34004 Palencia, Spain ORCID ID:E-mail:
article id 200, category Research article
Peder Gjerdrum, Mauro Bernabei. (2009). Three-dimensional spiral grain pattern in five large Norway spruce stems. Silva Fennica vol. 43 no. 3 article id 200. https://doi.org/10.14214/sf.200
There is a great deal of interest involved in investigating and understanding grain angle in trees. The objective of the study presented in this paper has been to identify a joint, three-dimensional model for grain angle in stems of Norway spruce (Picea abies (L.) Karst.) Five large spruce trees were sampled. Transverse disks were extracted at regular intervals along the stem, split through the pith with a blunt knife, and observed for grain angle and cambial age along the north radius, setting pith observation to zero angle. The overall finding confirmed grain pattern congruent to distance from pith along the stem, a pattern that varies from tree to tree. Models expressing distance from the pith in cambial age performed slightly better than models in spatial distance. Grain pattern changed slightly along the stem, and this change was found to be consistent for the five stems: the left-handed grain angle in the juvenile wood was more pronounced upwards in the stem, and the angle changed faster towards right-handed spiralling. The model did not account for grain variation related to knots, undulating pith or other irregularities. Model residuals were normally distributed and seemingly homogeneous for all trees and for all height levels. The model is an extension of existing two-dimensional models for stem cross-cuts. After verification in a wider sample, the results should be applicable in tree and wood modelling.
  • Gjerdrum, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail: peder.gjerdrum@skogoglandskap.no (email)
  • Bernabei, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail:
article id 206, category Research article
Qiaoying Zhang, Yunchun Zhang, Shaolin Peng, Eshetu Yirdaw, Ning Wu. (2009). Spatial structure of alpine trees in Mountain Baima Xueshan on the southeast Tibetan Plateau. Silva Fennica vol. 43 no. 2 article id 206. https://doi.org/10.14214/sf.206
Most of the trees at treeline on the Tibetan Plateau are endemic to the Plateau. Yet little is known about these species. The study focused on the population structure, spatial patterns and associations of the treeline species Abies forestii var. georgei and Juniperus saltuaria at treeline and timberline in Mountain Baima Xueshan on the southeast Tibetan Plateau. These species form monodominant communities on the north- and south-facing slopes, respectively. Stem density, DBH-distribution, distribution pattern of different tree size classes, and intraspecific spatial association between different tree size classes of both species were analyzed. Spatial structure varied between A. forestii var. georgei and J. saltuaria, and for the same species, the spatial structures were also different from timberline to treeline. Stem density, mean tree height and young individuals of A. forestii var. georgei were significantly higher than those of J. saltuaria. For the same species, they were different from timberline to treeline, i.e., stem density and mean tree height of both species became lower. Size classes of both species were mainly clustered either at treeline or at timberline but at different scales, and spatial patterns of young J. saltuaria were mainly dominated by random patterns. Clumps of trees created more favorable microenvironments in harsh environments at treeline and timberline. Most tree size classes showed positive intraspecific spatial associations, but positive associations between size classes of J. saltuaria were not as significant as those of A. forestii var. georgei. The south-facing slope was usually subjected to varying intensities of pastoralism. Livestock disturbance greatly changed the microhabitat and reduced the number of young individuals. The potential of trees to regenerate was greatly inhibited, while A. forestii var. georgei showed greater regeneration potential. Spatial structures of J. saltuaria were also modified by this kind of human impact.
  • Zhang, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China; Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China ORCID ID:E-mail: lsspsl@mail.sysu.edu.cn (email)
  • Zhang, Shandong Institute of Light Industry, Jinan 250353, Shandong Province, China ORCID ID:E-mail:
  • Peng, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China ORCID ID:E-mail:
  • Yirdaw, Viikki Tropical Resources Institute (VITRI), P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Wu, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China ORCID ID:E-mail:
article id 221, category Research article
Glen Murphy, Rod Brownlie, Mark Kimberley, Peter Beets. (2009). Impacts of forest harvesting related soil disturbance on end-of-rotation wood quality and quantity in a New Zealand radiata pine forest. Silva Fennica vol. 43 no. 1 article id 221. https://doi.org/10.14214/sf.221
The long-term effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on wood quality and quantity of second-rotation Pinus radiata growing on a clay loam soil, was assessed at the end the rotation, 26 years after planting. Relative to Control plots, average tree and stand total volume at rotation end was not significantly affected by litter removal and nil or light compaction, but was significantly reduced by 28% by litter and topsoil removal and moderate subsoil compaction, and further reduced by 38% by heavy compaction. Wood density at breast height in the inner rings of trees in the most disturbed treatments was elevated by up to 30 kg m–3. This occurred because these treatments were more N deficient as reflected by foliar N levels during the first 11 years of growth relative to the Control. However, no treatment differences in wood density were evident in outer rings, and by rotation age overall mean density did not differ significantly between treatments. Neither acoustic velocity of standing trees, nor acoustic velocity of logs, was significantly affected by soil disturbance, indicating that stiffness of lumber cut from trees in the trial was likely to be similar for all treatments. Economic impacts of soil disturbance and compaction on this soil type will therefore result largely from the considerable negative impacts on final tree size, with little or no compensation from improved wood properties.
  • Murphy, Forest Engineering, Resources and Management Department, Oregon State University, Corvallis, Oregon, USA ORCID ID:E-mail: glen.murphy@oregonstate.edu (email)
  • Brownlie, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
  • Kimberley, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
  • Beets, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
article id 218, category Research article
Md. Nurul Islam, Mikko Kurttila, Lauri Mehtätalo, Arto Haara. (2009). Analyzing the effects of inventory errors on holding-level forest plans: the case of measurement error in the basal area of the dominated tree species. Silva Fennica vol. 43 no. 1 article id 218. https://doi.org/10.14214/sf.218
Accurate inventory data are required for ensuring optimal net return on investment from the forest. Erroneous data can lead to the formulation of a non-optimal plan that can cause inoptimality losses. Little is known of the effect of using erroneous stand inventory data in preparing holding-level forest plans. This study reports on an approach for analyzing such inoptimality losses. Furthermore, inoptimality losses caused by measurement errors in the basal area of the dominated tree species were investigated in a case study. Based on the inventory data including routine measurements by 67 measurers, four measurer groups were created with different measurement error profiles for the basal area of the dominated tree species. This was followed by measurement error simulations for each group and by adding these to the accurate control inventory data to create erroneous data of different error profiles. Three different forest plans were then constructed by using erroneous data of each group. The plans were then analyzed and compared with plans based on correct data. The effect of measurement errors on the net present value from the whole planning period, and on the amount of remaining growing stock at the end of planning period, were analyzed and utilized in calculating the inoptimality losses. It was concluded that even errors involving dominated tree species can cause significant changes in the holding-level forest plans.
  • Islam, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: nurul.islam@joensuu.fi (email)
  • Kurttila, Finnish Forest Research Institute, Joensuu Research Unit, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Mehtätalo, University of Helsinki, Dept. of Forest Resource Management, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Haara, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 236, category Research article
Jaakko Repola. (2008). Biomass equations for birch in Finland. Silva Fennica vol. 42 no. 4 article id 236. https://doi.org/10.14214/sf.236
Biomass equations were compiled for the above- and below-ground tree components of birch (Betula pendula Roth and Betula pubescens Ehrh.). The equations were based on 127 sample trees in 24 birch stands located on mineral soil sites. The study material consisted of 20 temporary plots and ten plots from four thinning experiments with different thinning intensities (unthinned, moderately and heavily thinned plots). The equations were estimated for the following individual tree components: stem wood, stem bark, living and dead branches, foliage, stump, and roots. In the data analysis, a multivariate procedure was applied in order to take into account the statistical dependency among the equations. Three multivariate variance component models were constructed for the above-ground biomass components, and one for the below-ground biomass components. The multivariate model (1) was mainly based on tree diameter and height, and in the multivariate models (2) and (3) additional commonly measured tree variables were used. The equations provided logical biomass predictions for a number of tree components, and were comparable with other functions used in Finland and Sweden. The applied statistical method generated equations that gave more reliable biomass estimates than the equations presented earlier. Furthermore, the structure of the multivariate models enables more flexible application of the equations, especially for research purposes.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
article id 236, category Research article
Jaakko Repola. (2008). Biomass equations for birch in Finland. Silva Fennica vol. 42 no. 4 article id 236. https://doi.org/10.14214/sf.236
Biomass equations were compiled for the above- and below-ground tree components of birch (Betula pendula Roth and Betula pubescens Ehrh.). The equations were based on 127 sample trees in 24 birch stands located on mineral soil sites. The study material consisted of 20 temporary plots and ten plots from four thinning experiments with different thinning intensities (unthinned, moderately and heavily thinned plots). The equations were estimated for the following individual tree components: stem wood, stem bark, living and dead branches, foliage, stump, and roots. In the data analysis, a multivariate procedure was applied in order to take into account the statistical dependency among the equations. Three multivariate variance component models were constructed for the above-ground biomass components, and one for the below-ground biomass components. The multivariate model (1) was mainly based on tree diameter and height, and in the multivariate models (2) and (3) additional commonly measured tree variables were used. The equations provided logical biomass predictions for a number of tree components, and were comparable with other functions used in Finland and Sweden. The applied statistical method generated equations that gave more reliable biomass estimates than the equations presented earlier. Furthermore, the structure of the multivariate models enables more flexible application of the equations, especially for research purposes.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
article id 230, category Research article
Risto Jalkanen, Sheila Hicks, Tarmo Aalto, Hannu Salminen. (2008). Past pollen production reconstructed from needle production in Pinus sylvestris at the northern timberline: a tool for evaluating palaeoclimate reconstructions. Silva Fennica vol. 42 no. 4 article id 230. https://doi.org/10.14214/sf.230
Annual needle production (PROD) of Scots pine (Pinus sylvestris L.) and pine pollen accumulation rates (PAR) are compared along a 5-site transect from the Arctic Circle to the northern timberline. PROD is calculated using the Needle Trace Method (NTM). PAR is monitored by two series of pollen traps, located in the centres of mires and within forests, respectively. There is a strong year-to-year agreement in PAR and PROD between the sites for the common 19-year period for which both proxies are available. Mean July temperature of the previous year (TJUL–1) correlates statistically significantly with PROD at all five sites and with PAR in the four northernmost sites. There is also a significant relationship between TJUN–1 and PROD at all sites, and TJUN and PAR at the two northernmost sites. PROD and PAR correlate most strongly in the three near tree line sites, where PROD explains up to 51% of the variation in PAR. On the basis of the calibration between PROD, PAR and TJUL–1, PROD and TJUL–1 are used to reconstruct past PAR. That such a reconstruction is realistic is supported by its agreement with the pollen record for 1982–2000 and with records of male flowering for the period 1956–1973. The use of PROD in reconstructing past PAR can help in interpreting the fossil pollen signal in terms of climate rather than vegetation change and in evaluating the high-resolution dating of peat profiles and calculations of the rate of peat accumulation.
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi (email)
  • Hicks, Institute of Geosciences, P.O. Box 3000, FI-90014 University of Oulu, Finland ORCID ID:E-mail:
  • Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Salminen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 283, category Research article
Ilkka Korpela, Tuukka Tuomola, Esko Välimäki. (2007). Mapping forest plots: an efficient method combining photogrammetry and field triangulation. Silva Fennica vol. 41 no. 3 article id 283. https://doi.org/10.14214/sf.283
Intra stand spatial information is often collected in ecological investigations, when functioning or interactions in the ecosystem are studied. Local relative accuracy is often given priority in such cases. Forest maps with accurate absolute positions in a global coordinate system are needed in remote-sensing applications for validation and calibration purposes. Establishing the absolute position is particularly difficult under a canopy as is creating undistorted coordinate systems for large plots in the forest. We present a method that can be used for the absolute mapping of point features under a canopy that is efficient for large forest plots. In this method, an undistorted network of control points is established in the forest using photogrammetric observations of treetops. These points are used for the positioning of other points, using redundant observations of interpoint distances and azimuths and a least squares adjustment. The method provides decimetre-level accuracy and only one person is required to conduct the work. An estimate of the positioning accuracy of each point is readily available in the field. We present the method, a simulation study that explores the potential of the method and results from an experiment in a mixed boreal stand in southern Finland.
  • Korpela, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: ilkka.korpela@helsinki.fi (email)
  • Tuomola, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Välimäki, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 308, category Research article
Ville Hallikainen, Mikko Hyppönen, Juha Hyvönen, Juhani Niemelä. (2007). Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland. Silva Fennica vol. 41 no. 1 article id 308. https://doi.org/10.14214/sf.308
Researchers and professionals in practical forestry have faced problems concerning the regeneration success of Scots pine in natural regeneration near the timberline in North-East Lapland. The aim of the study was to analyze the seedling establishment and seedling height development of Scots pine in seed-tree stands in the area. The average number of living pine seedlings in the study stands was about 1000 ha–1, but there was considerable variation between the stands. The seedling density was modelled using a multinomial logistic regression with a random factor. Forest site type and the time since seed-tree cutting were the most significant explanatory variables in the model. The probability of reaching the acceptable seedling density was higher on dry site types than on the more fertile ones. The probability increased with the time elapsed since the regeneration activities. Effective temperature sum and the number of intermediate pines also positively affected the probability, but the presence of residual trees negatively. On northern and eastern slopes the probability was lower than on southern and western ones. Seedling height was modelled using a linear mixed model. The age of a dominant seedling was the most positively effective explanatory variable in the height development model. Other positively affecting significant predictors were time since seed-tree cutting, number of intermediate birches, and distance between a seedling and the nearest seed tree. Degree of paludification had a negative effect. The study suggests that the regeneration of Scots pine in North-East Lapland is a relatively slow process.
  • Hallikainen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@metla.fi (email)
  • Hyppönen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mikko.hypponen@metla.fi
  • Hyvönen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: juha.hyvonen@metla.fi
  • Niemelä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 307, category Research article
Jacqueline C. Bolli, Andreas Rigling, Harald Bugmann. (2007). The influence of changes in climate and land-use on regeneration dynamics of Norway spruce at the treeline in the Swiss Alps. Silva Fennica vol. 41 no. 1 article id 307. https://doi.org/10.14214/sf.307
Recent changes of climate and land-use are often regarded to affect the European Alpine region substantially and to trigger an increase in the elevation of the upper treeline. The patterns of tree invasion on a subalpine meadow at 1900 m a.s.l. in Sedrun, Canton Grisons, Switzerland, were studied in order 1) to reconstruct the process of tree establishment and tree–growth dynamics in space and time, and 2) to evaluate the influence of site properties, land-use change and climate on these processes. Dendroecological analysis of 105 Norway spruce combined with an assessment of 48 vegetation plots and 17 soil profiles revealed that the trees were established in one main period (1965–1980s), starting 15 years after the abandonment of the agricultural use of the meadow, and that there is a pronounced environmental gradient along the forest-meadow ecotone. Tree establishment and height growth were favoured close to the former forest edge, but all saplings irrespective of their distance to the forest edge and their age showed increased radial growth since 1990, coinciding with a period of higher summer temperatures in the region. Therefore, we conclude that the observed tree-line dynamics in Sedrun are the result of both land-use and climate change: Tree establishment was triggered by the abandonment of the agricultural use of the meadow, and strongly favoured by particularly good growing conditions in a warm decade, which illustrates the sensitivity of conifers near the alpine tree-line to temperature fluctuations.
  • Bolli, Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland ORCID ID:E-mail: jacqueline.bolli@wsl.ch (email)
  • Rigling, Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland ORCID ID:E-mail:
  • Bugmann, Swiss Federal Institute of Technology (ETH) Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland ORCID ID:E-mail:
article id 307, category Research article
Jacqueline C. Bolli, Andreas Rigling, Harald Bugmann. (2007). The influence of changes in climate and land-use on regeneration dynamics of Norway spruce at the treeline in the Swiss Alps. Silva Fennica vol. 41 no. 1 article id 307. https://doi.org/10.14214/sf.307
Recent changes of climate and land-use are often regarded to affect the European Alpine region substantially and to trigger an increase in the elevation of the upper treeline. The patterns of tree invasion on a subalpine meadow at 1900 m a.s.l. in Sedrun, Canton Grisons, Switzerland, were studied in order 1) to reconstruct the process of tree establishment and tree–growth dynamics in space and time, and 2) to evaluate the influence of site properties, land-use change and climate on these processes. Dendroecological analysis of 105 Norway spruce combined with an assessment of 48 vegetation plots and 17 soil profiles revealed that the trees were established in one main period (1965–1980s), starting 15 years after the abandonment of the agricultural use of the meadow, and that there is a pronounced environmental gradient along the forest-meadow ecotone. Tree establishment and height growth were favoured close to the former forest edge, but all saplings irrespective of their distance to the forest edge and their age showed increased radial growth since 1990, coinciding with a period of higher summer temperatures in the region. Therefore, we conclude that the observed tree-line dynamics in Sedrun are the result of both land-use and climate change: Tree establishment was triggered by the abandonment of the agricultural use of the meadow, and strongly favoured by particularly good growing conditions in a warm decade, which illustrates the sensitivity of conifers near the alpine tree-line to temperature fluctuations.
  • Bolli, Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland ORCID ID:E-mail: jacqueline.bolli@wsl.ch (email)
  • Rigling, Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland ORCID ID:E-mail:
  • Bugmann, Swiss Federal Institute of Technology (ETH) Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland ORCID ID:E-mail:
article id 305, category Research article
Anna-Maria Veijalainen, Marja-Liisa Juntunen, Arja Lilja, Helvi Heinonen-Tanski, Leo Tervo. (2007). Forest nursery waste composting in windrows with or without horse manure or urea – the composting process and nutrient leaching. Silva Fennica vol. 41 no. 1 article id 305. https://doi.org/10.14214/sf.305
In order to find the best management practices for forest nursery waste composting, organic waste was composted without or with horse manure or urea in six windrows for two years. The windrows were built in four consecutive years during 1999–2002. In 1999, no extra-nutrients were added to the windrow (N99). In 2000, urea fertilizer was used as a nitrogen source (U00). Despite this, the process did not function properly. In 2001, two windrows were built, one (H01) with and the other (N01) without horse manure. Horse manure slightly accelerated the heating process. Consequently, two windrows with more horse manure were built in 2002. One was aerated passively (H02) as earlier windrows, and the other was aerated forcedly (HA02). Horse manure and forced aeration were needed to keep the temperature above 55°C for long enough to ensure microbial hygiene of the material. The degradation of cellulose was greater during the curing stage. Nutrient leaching was low, although the additives increased leaching in conjunction with the inefficient process. The results showed that forest nursery waste alone is ineffective at raising the temperature of the compost, and degrades slowly due to its low nutrient and easily available carbon content. The best management practice for forest nursery waste composting is to use horse manure and aeration to ensure the heating process. Environmental contamination can be avoided by collecting the leachates. Further research is needed to evaluate the usability of the compost.
  • Veijalainen, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Juntunen, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Lilja, Finnish Forest Research Institute, PO Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Heinonen-Tanski, Univ. of Kuopio, Dept. of Environm. Sc., PO Box 1627, FI-70211 Kuopio, Finland ORCID ID:E-mail:
  • Tervo, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 321, category Research article
Jori Uusitalo, Anne Puustelli, Veli-Pekka Kivinen, Tapio Nummi, Bikas K. Sinha. (2006). Bayesian estimation of diameter distribution during harvesting. Silva Fennica vol. 40 no. 4 article id 321. https://doi.org/10.14214/sf.321
This research aims to combine two different data sets with Bayesian statistics in order to predict the diameter distribution of trees at harvest. The parameters of prior distribution are derived from the forest management plans supplemented by additional ocular information. We derive the parameters for the sample data from the first trees harvested, and then create the posterior distribution within the Bayesian framework. We apply the standard normal distribution to construct diameter (dbh) distributions, although many other theoretical distributions have been proved better with dbh data available. The methodology developed is then tested on nine mature spruce (Picea abies) dominated stands, on which the normal distribution seems to work well in mature spruce stands. The tests indicate that prediction of diameter distribution for the whole stand based on the first trees harvested is not wise, since it tends to give inaccurate predictions. Combining the first trees harvested with prior information seems to increase the reliability of predictions.
  • Uusitalo, The Finnish Forest Research Institute, Parkano unit, FI-39700 Parkano, Finland ORCID ID:E-mail: jori.uusitalo@metla.fi (email)
  • Puustelli, University of Tampere, Department of Mathematics, Statistics and Philosophy, FI-33014 University of Tampere, Finland ORCID ID:E-mail:
  • Kivinen, University of Helsinki, Department of Forest Resource Management, Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Nummi, University of Tampere, Department of Mathematics, Statistics and Philosophy, FI-33014 University of Tampere, Finland ORCID ID:E-mail:
  • Sinha, Stat-Math Division, Indian Statistical Institute, 203 B.T. Road, Kolkata - 700 108, India ORCID ID:E-mail:
article id 317, category Research article
Erik Eriksson, Tord Johansson. (2006). Effects of rotation period on biomass production and atmospheric CO2 emissions from broadleaved stands growing on abandoned farmland. Silva Fennica vol. 40 no. 4 article id 317. https://doi.org/10.14214/sf.317
The growth rates and carbon stocks of unthinned young and mature stands of broadleaved trees growing on abandoned farmland were determined to assess whether their management regimes should involve short (15-year) or long (45-year) rotations to maximize biomass production and reductions of CO2 emissions. Dry mass production and mean annual increment (MAI) were calculated for 28 young stands and 65 mature stands of European aspen (Populus tremula L.), common alder (Alnus glutinosa (L.) Gaertn.), grey alder (Alnus incana (L.) Moench.), silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.) ranging in latitude from 57° to 63° N in Sweden. The potential for using biomass from the stands to replace coal as a fuel and to store carbon was then evaluated both in short and long rotation scenarios. The results indicate that long rotations are beneficial if the objective is to maximize the average carbon stock in biomass. If, on the other hand, the intention is to optimize reductions in atmospheric CO2 emissions, rotations should be short for aspen, silver birch and grey alder stands. For downy birch and common alder, the MAI was higher for the mature stands than the young stands, indicating that in these species the mature stands are superior for both storing carbon and replacing fossil fuel. Stands of broadleaved trees grown to produce biofuel on abandoned farmland should be established on fertile soils to promote high MAI. If the MAI is low, the rotation period should be long to maximize the average carbon stock.
  • Eriksson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
  • Johansson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 329, category Research article
Vesa Juntunen, Seppo Neuvonen. (2006). Natural regeneration of Scots pine and Norway spruce close to the timberline in northern Finland. Silva Fennica vol. 40 no. 3 article id 329. https://doi.org/10.14214/sf.329
Two different datasets were analyzed in order to clarify the factors that affect regeneration success of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) in the climatically extreme areas in northern Finland. First, pine seed maturity and the number of cones in the trees were investigated at five pairs of study sites during the period 1997–2003. Secondly, the rate of seedling establishment and seedling survival of Scots pine and Norway spruce were monitored and compared among three different timberline zones (forest zone, timberline, tree line) in 13 localities during the period 1983–1999. The first study showed that both cone production (bud formation) and seed maturity may be limiting factors for successful reproduction in the climatically marginal habitats. Seed maturity correlated well with the temperature sum of the summer, but variation in the number of cones had a periodic component rather than strictly following the temperature sum of the summer of bud formation. Monitoring surveys since 1983 showed that pine and spruce regenerated more or less regularly in all the zones during 1983–1999. However, seedling mortality of pines was much higher compared to spruce. In general, initially small sized seedlings showed higher mortality compared with larger ones. The results suggest that besides restrictions in reproduction, stand dynamics in the timberline habitats are strongly controlled by seedling mortality due to a variety of causes.
  • Juntunen, Finnish Forest Research Institute, Kolari Research Unit, Muoniontie 21, FI-95900 Kolari, Finland ORCID ID:E-mail: vesa.juntunen@metla.fi (email)
  • Neuvonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 338, category Research article
Andrea Vajda, Ari Venäläinen, Pekka Hänninen, Raimo Sutinen. (2006). Effect of vegetation on snow cover at the northern timberline: a case study in Finnish Lapland. Silva Fennica vol. 40 no. 2 article id 338. https://doi.org/10.14214/sf.338
The presence of permanent snow cover for 200–220 days of the year has a determining role in the energy, hydrological and ecological processes at the climate-driven spruce (Picea abies) timberline in Lapland. Disturbances, such as forest fires or forest harvesting change the vegetation pattern and influence the spatial variation of snow cover. This variability in altered snow conditions (in subarctic Fennoscandia) is still poorly understood. We studied the influence of vegetation on the small-scale spatial variation of snow cover and wind climate in the Tuntsa area that was disturbed by a widespread forest fire in 1960. Radar was applied to measure snow thickness over two vegetation types, the spruce-dominant fire refuge and post-fire treeless tundra. Wind modelling was used to estimate the spatial variation of wind speed and direction. Due to the altered surface roughness and the increased wind velocity, snow drifting was more vigorous on the open tundra, resulting in a 30-cm thinner snow cover and almost half the water equivalent compared to the forest values. The changes in local climate after the fire, particularly in snow cover, may have played an important role in the poor recovery of vegetation: a substantial area is still unforested 40 years after the fire.
  • Vajda, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: andrea.vajda@fmi.fi (email)
  • Venäläinen, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail:
  • Hänninen, Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland ORCID ID:E-mail:
  • Sutinen, Geological Survey of Finland, P.O. Box 77, FI-96101 Rovaniemi, Finland ORCID ID:E-mail:
article id 350, category Research article
Ehsan Sayyad, Seyed Mohsen Hosseini, Jamshid Mokhtari, Reza Mahdavi, Seyed Gholamali Jalali, Moslem Akbarinia, Masoud Tabari. (2006). Comparison of growth, nutrition and soil properties of pure and mixed stands of Populus deltoides and Alnus subcordata. Silva Fennica vol. 40 no. 1 article id 350. https://doi.org/10.14214/sf.350
Concerns about decline in soil fertility and long-term productivity of fast-growing plantations have promoted interest in using nitrogen-fixing trees in mixed species plantations. Populus deltoides and Alnus subcordata were planted in five proportions (100P, 67P:33A, 50P:50A, 33P:67A, 100A) in Noor, Iran. After 7 years, the effects of species interactions on tree growth and nutrient concentration in live and senescent leaves and soil properties were assessed. Diameter at breast height and total height of individual Populus trees were positively affected by the presence of Alnus. Nitrogen concentrations in fully expanded and senescent leaves of Populus were higher in mixed plantations than monoculture plantations. The results of nutrition and nutrient return and growth indicated that mixed plantations of these two species were more productive and sustainable than their monoculture plantations. Within the framework of this experiment, it appeared that production was maximized when these two species were grown together in the relative proportions of 50% Populus and 50% Alnus.
  • Sayyad, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
  • Hosseini, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail: hosseini@europe.com (email)
  • Mokhtari, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
  • Mahdavi, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
  • Jalali, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
  • Akbarinia, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
  • Tabari, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran ORCID ID:E-mail:
article id 479, category Research article
Ken Olaf Storaunet, Jørund Rolstad, Ivar Gjerde, Vegard S. Gundersen. (2005). Historical logging, productivity, and structural characteristics of boreal coniferous forests in Norway. Silva Fennica vol. 39 no. 3 article id 479. https://doi.org/10.14214/sf.479
Conservation of forest biodiversity has brought about an interest in evaluating the naturalness of forests, and to locate and protect semi-natural and old-growth forests in the Fennoscandian countries. However, it is not always clear how natural these forests really are, and how the past management history has affected their present structural composition. We studied the relationships between cut stumps from historical logging activity (50–100 years ago) and forest structural characteristics of today in a total of 385 0.25 ha plots in three boreal coniferous forests which are parts of National Nature Reserves in Norway. We also studied how forest productivity influenced these relationships. In plots with negligible logging impact we found the amount of living trees, dead wood, and size of the oldest trees mainly to increase with increasing productivity, whereas the age of the oldest trees decreased. The amount of deciduous trees was generally low irrespective of productivity. The intensity of logging did not consistently influence most of these forest structural variables, neither at low- nor at high-productive sites. The only consistent relationship in all study areas was a decreasing amount of dead wood with increasing logging intensity at high-productive sites. Also, the decay class distribution of dead wood was more right-skewed (indicating on-going accumulation of dead wood) the more logging had occurred at high-productive sites. Except from the effects on dead wood, previous logging does not show up as a major determinant of other stand structures of today.
  • Storaunet, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway ORCID ID:E-mail: ken.storaunet@skogforsk.no (email)
  • Rolstad, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway ORCID ID:E-mail:
  • Gjerde, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway ORCID ID:E-mail:
  • Gundersen, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway ORCID ID:E-mail:
article id 408, category Research article
Sakari Sarkkola, Hannu Hökkä, Timo Penttilä. (2004). Natural development of stand structure in peatland Scots pine following drainage: results based on long-term monitoring of permanent sample plots. Silva Fennica vol. 38 no. 4 article id 408. https://doi.org/10.14214/sf.408
We studied the dynamics of stand structure on drained peatland sites in Scots pine dominated stands untreated with thinnings. The data consisted of consecutive stand measurements in 10 permanent sample plots where the monitoring periods varied from 29 to 66 years. We assumed that the stand’s structural development was driven by the natural processes of regeneration, growth, and mortality, all related to inter-tree competition within the stand. The DBH distributions of live and dead trees at different times of post-drainage stand development – smoothed by Weibull function – were analysed to characterise the change in stand structure. The initial uneven-sized structure of the natural, widely-spaced stands became more uneven during the first decades following drainage due to enhanced regeneration. Later, as stand density and mean tree size continuously increased, the DBH distributions approached bell-shaped distributions. Accordingly, the suppressed trees showed their highest mortality rate during the first decades, but the peak of the mortality distribution shifted to larger trees along stand succession. The change in structure was faster in southern Finland than in northern Finland. We assumed the changes in stand dynamics reflected increased inter-tree competition, initiated by enhanced site productivity and increased stand stocking resulting from the ditching operation.
  • Sarkkola, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: sakari.sarkkola@helsinki.fi (email)
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 417, category Research article
Jori Uusitalo, Sampsa Kokko, Veli-Pekka Kivinen. (2004). The effect of two bucking methods on Scots pine lumber quality. Silva Fennica vol. 38 no. 3 article id 417. https://doi.org/10.14214/sf.417
Modern harvesters are equipped with measurement and bucking optimization systems able not only to continuously measure the length and diameter of the stem but also to predict the profile of the unknown part of a stem and to calculate the optimal cross-cutting points for the whole stem. So far, tree-bucking optimization in the Nordic countries has been efficiently applied only with spruce because the quality of pine and birch varies much more both within a stem and between stems. Since limitations in the measuring equipment mean that the presence and position of grade limits as well as additional defects in the stem will normally have to be detected and estimated manually. Consequently, optimization works inefficiently because the harvester operator is continuously forced to disregard the cutting suggestions supplied by the harvester’s automatic system. This paper presents the outcome of research intended to define how change from the current quality bucking principle to automatic bucking affects lumber quality. The study is based on field experiments and test sawing data on 100 Scots pine (Pinus sylvestris) stems from southwestern Finland in 2001. Automatic bucking does not markedly lower the amount of good-quality lumber compared to quality bucking. Since automatic bucking inevitably leads to log distribution that matches the length requirements of customers better, it may be regarded as appropriate for these harvesting conditions.
  • Uusitalo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: jori.uusitalo@joensuu.fi (email)
  • Kokko, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kivinen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 416, category Research article
Glen Murphy, John G. Firth, Malcolm F. Skinner. (2004). Long-term impacts of forest harvesting related soil disturbance on log product yields and economic potential in a New Zealand forest. Silva Fennica vol. 38 no. 3 article id 416. https://doi.org/10.14214/sf.416
The effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on the productivity, log product yields and economic potential of second-rotation Pinus radiata growing on a clay loam soil, was assessed in a long-term trial 21 years after planting. The results are projected forward to the expected harvest age of 28 years. Relative to control plots, average tree volume at 21 years was reduced by 8% in the plots where the litter had been removed and the topsoil had been compacted, and by up to 42% in the plots where the topsoil had been removed and the subsoil compacted. The “degree of compaction” did not have a significant effect on average tree volume in the plots where litter had been removed but did have a significant effect where the topsoil had been removed. Per tree economic potential was reduced to a greater extent (up to 60% loss in value) than average tree volume was reduced. This was largely due to changes in log product yield distribution. Projecting tree growth forward to the end of the rotation at age 28 indicated that the impacts of soil disturbance on tree growth, economic potential and log product yields are likely to be similar in relative terms to those found at age 21.
  • Murphy, Forest Engineering Department, Oregon State University, Corvallis, OR 97331, USA ORCID ID:E-mail: glen.murphy@orst.edu (email)
  • Firth, Forest Research, Sala Street, Rotorua, New Zealand ORCID ID:E-mail:
  • Skinner, Forest Research, Sala Street, Rotorua, New Zealand ORCID ID:E-mail:
article id 413, category Research article
Mika Nieminen, Timo Penttilä. (2004). Inorganic and organic phosphorus fractions in peat from drained mires in northern Finland. Silva Fennica vol. 38 no. 3 article id 413. https://doi.org/10.14214/sf.413
Soil samples from 15 eutrophic, 26 herb-rich, 15 tall-sedge, and 11 low-sedge drained peatland sites were analysed for easily soluble and aluminum, iron, and calcium bound phosphorus (P) using the Chang and Jackson sequential fractionation method. Compared to earlier investigations, where only total and easily soluble P contents (e.g. NH4OAc or dilute H2SO4 extractable P) in peat have been analysed, significantly higher differences between sites were observed. The eutrophic sites were characterized by four to six-fold greater Ca-bound organic P and two to three-fold greater Ca-bound inorganic P contents than on the other three site type groups, whereas the average Al-bound inorganic P content of the eutrophic sites was only one-third of that at the other site types. Substantial differences between sites were also observed for Fe-bound inorganic P, i.e. two to four-fold greater Fe-P contents were measured at the herb-rich sites compared with the other three site type groups. The stand volume growth in the 67 studied drained peatland sites correlated significantly with Al-bound organic P and Fe-bound inorganic and organic P. The study showed that a detailed fractionation and discrimination of different forms of soil P is important in increasing the understanding of the relationship between P availability and vegetation community types and stand growth on drained peatlands.
  • Nieminen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mika.nieminen@metla.fi (email)
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 423, category Research article
Olle Rosenberg, Staffan Jacobson. (2004). Effects of repeated slash removal in thinned stands on soil chemistry and understorey vegetation. Silva Fennica vol. 38 no. 2 article id 423. https://doi.org/10.14214/sf.423
The increased interest in harvesting logging residues as a source of bio-energy has led to concerns about the potentially adverse long-term impact of the practice on site productivity. The aim of this study was to examine the effects on soil chemistry (pH, C, N and AL-extractable P, K, Ca and Mg) in three different soil layers (FH, 0–5 cm and 5–10 cm mineral soil) and understorey vegetation after the second removal of logging residues in whole-tree thinned stands. The study was performed at four different sites, established in the period 1984–87, representing a range of different climatic and soil conditions: a very fertile Norway spruce (Picea abies (L.) Karst.) site in south-western Sweden and three Scots pine (Pinus sylvestris L.) sites located in south, south-central and central Sweden. The effects of whole-tree thinning on soil chemistry and understorey vegetation were generally minor and variable. Across all sites the concentrations of Ca and Mg were significantly lower when slash was removed.
  • Rosenberg, Skogforsk – The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: olle.rosenberg@skogforsk.se (email)
  • Jacobson, Skogforsk – The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
article id 507, category Research article
Tysk Staffan Ericsson, Lars Östlund, Rikard Andersson. (2003). Destroying a path to the past – the loss of culturally scarred trees and change in forest structure along Allmunvägen, in mid-west boreal Sweden. Silva Fennica vol. 37 no. 2 article id 507. https://doi.org/10.14214/sf.507
The tradition to blaze trees to mark trails and boundaries is very old in northern Scandinavia. The disappearance of culturally modified trees (i.e. trees with trail blazes) and changes in forest structure along a section of an old bridle trail in boreal Sweden was analyzed using historical maps and forest surveys from the period 1876 to the year 2000. Remaining blazed trees were located during a field study and selected scars were dated. In total 104 scarred living and dead trees were found. The scars originated from the early 1500s to the early 1900s. Analysis of the forest surveys showed that the forest along the trail was dominated by older trees, and that the majority of the scarred trees probably were present, throughout the 19th century. By the mid 20th century logging had begun to affect the tree age along the trail and in 1974 no stands older than 180 years were present. A conservative estimate shows that around 90% of the original blazed trees have vanished. The trail was interpreted as have being lined for centuries with scarred trees which gradually have been destroyed during the 20th century. Culturally modified trees constitute an unique source of information for understanding pattern of old trails as well as of past human land use and movement in the landscape prior to the 20th century. This biological archive have to a large extent been destroyed by forestry activities and it is therefore very important to survey, recount and protect the trees that are still present.
  • Ericsson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail: staffan@delta.se (email)
  • Östlund, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Andersson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 507, category Research article
Tysk Staffan Ericsson, Lars Östlund, Rikard Andersson. (2003). Destroying a path to the past – the loss of culturally scarred trees and change in forest structure along Allmunvägen, in mid-west boreal Sweden. Silva Fennica vol. 37 no. 2 article id 507. https://doi.org/10.14214/sf.507
The tradition to blaze trees to mark trails and boundaries is very old in northern Scandinavia. The disappearance of culturally modified trees (i.e. trees with trail blazes) and changes in forest structure along a section of an old bridle trail in boreal Sweden was analyzed using historical maps and forest surveys from the period 1876 to the year 2000. Remaining blazed trees were located during a field study and selected scars were dated. In total 104 scarred living and dead trees were found. The scars originated from the early 1500s to the early 1900s. Analysis of the forest surveys showed that the forest along the trail was dominated by older trees, and that the majority of the scarred trees probably were present, throughout the 19th century. By the mid 20th century logging had begun to affect the tree age along the trail and in 1974 no stands older than 180 years were present. A conservative estimate shows that around 90% of the original blazed trees have vanished. The trail was interpreted as have being lined for centuries with scarred trees which gradually have been destroyed during the 20th century. Culturally modified trees constitute an unique source of information for understanding pattern of old trails as well as of past human land use and movement in the landscape prior to the 20th century. This biological archive have to a large extent been destroyed by forestry activities and it is therefore very important to survey, recount and protect the trees that are still present.
  • Ericsson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail: staffan@delta.se (email)
  • Östlund, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Andersson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 507, category Research article
Tysk Staffan Ericsson, Lars Östlund, Rikard Andersson. (2003). Destroying a path to the past – the loss of culturally scarred trees and change in forest structure along Allmunvägen, in mid-west boreal Sweden. Silva Fennica vol. 37 no. 2 article id 507. https://doi.org/10.14214/sf.507
The tradition to blaze trees to mark trails and boundaries is very old in northern Scandinavia. The disappearance of culturally modified trees (i.e. trees with trail blazes) and changes in forest structure along a section of an old bridle trail in boreal Sweden was analyzed using historical maps and forest surveys from the period 1876 to the year 2000. Remaining blazed trees were located during a field study and selected scars were dated. In total 104 scarred living and dead trees were found. The scars originated from the early 1500s to the early 1900s. Analysis of the forest surveys showed that the forest along the trail was dominated by older trees, and that the majority of the scarred trees probably were present, throughout the 19th century. By the mid 20th century logging had begun to affect the tree age along the trail and in 1974 no stands older than 180 years were present. A conservative estimate shows that around 90% of the original blazed trees have vanished. The trail was interpreted as have being lined for centuries with scarred trees which gradually have been destroyed during the 20th century. Culturally modified trees constitute an unique source of information for understanding pattern of old trails as well as of past human land use and movement in the landscape prior to the 20th century. This biological archive have to a large extent been destroyed by forestry activities and it is therefore very important to survey, recount and protect the trees that are still present.
  • Ericsson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail: staffan@delta.se (email)
  • Östlund, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Andersson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 502, category Research article
Janne Levula, Hannu Ilvesniemi, Carl Johan Westman. (2003). Relation between soil properties and tree species composition in a Scots pine–Norway spruce stand in southern Finland. Silva Fennica vol. 37 no. 2 article id 502. https://doi.org/10.14214/sf.502
It is commonly known in Finland that Scots pine (Pinus sylvestris L.) is a tree of dry soils and Norway spruce (Picea abies (L) Karst.) is a tree of fresh soils. However, the concepts of dry and fresh soils still lack a precise definition. Consequently, the discussion on which soil/site is a pine or spruce habitat has continued over several decades. Moreover, in forest regeneration, the practice of tree species selection between the pine and the spruce has varied. We investigated the relationship between soil properties and pine–spruce species composition in a mature, naturally regenerated stand in southern Finland. We applied spatial analysis to divide the stand area up into 3–7 classes based on selected soil properties and then investigated the variations in species composition among those classes. The pine–spruce basal area ratio (BA of pines / BA of spruces) increased along with increasing mean particle size and proportion of coarse sand and gravel particle size fraction (0.6–20 mm) of mineral soil, and was lowest in classes, with the highest proportions of fine texture fractions. The results suggest that in southern Finland on sorted soils, pine is more competitive in regeneration and growth than spruce when mean particle size is above 0.44 mm or percentage of coarse sand and gravel is higher than 50%.
  • Levula, University of Helsinki, Department of Forest Ecology, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: janne.levula@helsinki.fi (email)
  • Ilvesniemi, University of Helsinki, Department of Forest Ecology, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Westman, University of Helsinki, Department of Forest Ecology, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 510, category Research article
Helge Dzierzon, Risto Sievänen, Winfried Kurth, Jari Perttunen, Branislav Sloboda. (2003). Enhanced possibilities for analyzing tree structure as provided by an interface between different modelling systems. Silva Fennica vol. 37 no. 1 article id 510. https://doi.org/10.14214/sf.510
In recent years, many different advanced mathematical models and simulation systems for tree and forest growth have been developed. We show a possibility to extend analysis tools for measured and simulated plants using a data interface between the simulation model LIGNUM and the multifunctional software system GROGRA. Both systems were developed by different teams. To demonstrate the enhanced possibilities for analyzing a LIGNUM tree, several examples are given. In these examples three different approaches for analysis are applied to measured and simulated trees: Fractal dimension, deduction of tapering laws, and water potential patterns obtained from simulation of waterflow by the specialized software HYDRA. Conclusions for the interfacing and comparison of different modelling tools are drawn.
  • Dzierzon, Institut für Forstliche Biometrie und Informatik, Universität Göttingen, Büsgenweg 4, D-37077 Göttingen, Germany ORCID ID:E-mail: hdzierz@gwdg.de (email)
  • Sievänen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Kurth, Institut für Informatik, Brandenburgische Technische Universität Cottbus, P.O. Box 101344, D-03013 Cottbus, Germany ORCID ID:E-mail:
  • Perttunen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Sloboda, Institut für Forstliche Biometrie und Informatik, Universität Göttingen, Büsgenweg 4, D-37077 Göttingen, Germany ORCID ID:E-mail:
article id 566, category Research article
Philip J. Burton. (2002). Effects of clearcut edges on trees in the sub-boreal spruce zone of Northwest-Central British Columbia. Silva Fennica vol. 36 no. 1 article id 566. https://doi.org/10.14214/sf.566
Clearcut-forest boundaries were evaluated for their effects on mature and regenerating trees in the northern interior of British Columbia, Canada. Two hundred and eighteen rectangular plots measuring 200 m2 each were arrayed in transects across 12 cutblock edges created 9 to 21 years earlier, with the wall of standing timber facing either north or south. The density of canopy trees on the inner edge was found to be reduced by 19% (on north-facing edges) to 46% (on south-facing edges) from average densities found in forest interiors. This reduction was primarily due to windthrow after logging, which was elevated by 27% (over interior background levels) at north-facing edges, and by 216% at south-facing edges. Of the trees situated within 10 m of south-facing cutblock edges, 11% of the Pinus contorta, 18% of the Abies lasiocarpa, and 42% of the Picea engelmannii x glauca trees have apparently collapsed, primarily those having height-to-dbh ratios greater than 71:1. As a result, irradiance in the forest understory was elevated (over interior levels) at south-facing edges to distances of approximately 65 to 70 m into the forest. Increased irradiance from adjacent cutblocks enhanced the understory growth of Picea for approximately 60 m into the inner edge of forests, 75 m for Abies. Mature Pinus trees on south-facing edges showed an unexplained 48% decrease in radial growth compared to average growth rates in forest interiors, an effect that was detectable up to 45 m into the forest. Elevated densities of conifer seedlings were evident for up to approximately 70 m into clearcuts from north-facing forest edges. Seedling growth in clearcuts was largely unaffected by shade from stand edges. Though the extent of edge effects varies considerably with the statistical techniques used to detect them, it appears that opening effects on trees can extend between 40 and 120 m into this forest type, while canopy effects reach shorter distances into clearcuts.
  • Burton, Symbios Research and Restoration, P.O. Box 3398, 3868 13th Avenue, Smithers, British Columbia, Canada V0J 2N0 ORCID ID:E-mail: symbios@bulkley.net (email)
article id 558, category Research article
Tuomo Wallenius. (2002). Forest age distribution and traces of past fires in a natural boreal landscape dominated by Picea abies. Silva Fennica vol. 36 no. 1 article id 558. https://doi.org/10.14214/sf.558
Forest age distribution and occurrence of traces of past fires was studied in a natural Picea abies -dominated landscape in the Onega peninsula in north-west Russia. Forest age (maximum tree age) was determined and charcoal and fire scars were searched for in 43 randomly located study plots. In 70% of the study plots (30/43) trees older than 200 years existed. The largest 50-year age class consisted of plots with 251–300 year old forests. Traces of fires were found in all types of study plots, in forests on mineral soil as well as on peatlands. However, fire has been a rare disturbance factor, as traces of fires could not be found in 35% of the study plots (15/43). Estimated from the forest age class distribution, the fire rotation time for the whole area has been at least 300 years, but possibly considerably longer. This fire rotation time is much longer than fire history studies (largely based on examination of fire scars) commonly have reported for the average time between successive fires in Fennoscandia and Northwest Russia. The results suggest that the often stated generalisations about the importance and natural frequency of fire disturbance in boreal forests do not apply in landscapes dominated by Picea abies.
  • Wallenius, Department of Ecology and Systematics, University of Helsinki, P.O. Box 56, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tuomo.wallenius@helsinki.fi (email)
article id 555, category Research article
Leena Karjalainen, Timo Kuuluvainen. (2002). Amount and diversity of coarse woody debris within a boreal forest landscape dominated by Pinus sylvestris in Vienansalo wilderness, eastern Fennoscandia. Silva Fennica vol. 36 no. 1 article id 555. https://doi.org/10.14214/sf.555
The amount, variability, quality and spatial pattern of coarse woody debris (CWD) on mineral soil sites was studied within a natural Pinus sylvestris L. dominated boreal forest landscape in Russian Viena Karelia. Data on the total CWD was collected on 27 sample plots (20 m x 100 m) and data on large CWD was surveyed along four transects (40 m wide and up to 1000 m long). The mean volume of CWD (standing and down combined) was 69.5 m3 ha–1, ranging from 22.2 m3 ha–1 to 158.7 m3 ha–1 from plot to plot. On average, 26.9 m3 ha–1 (39%) of CWD was standing dead wood and 42.7 m3 ha–1 (61%) down dead wood. The CWD displayed a wide range of variation in tree species, tree size, stage of decay, dead tree type and structural characteristics, creating a high diversity of CWD habitats for saproxylic organisms. Large CWD was almost continuously present throughout the landscape and its overall spatial distribution was close to random, although a weak autocorrelation pattern was found at distances less than about 50 m. On small spatial scales total CWD showed wide variation up to a sample area of about 0.1 ha, beyond which the variation stabilized. The fire history variables of the sample plots were not related to the amount of CWD. This and the spatial pattern of CWD suggest that the CWD dynamics in this landscape was not driven by fire, but by more or less random mortality of trees due to autogenic causes of death.
  • Karjalainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi (email)
article id 580, category Research article
Susanna Sironen, Annika Kangas, Matti Maltamo, Jyrki Kangas. (2001). Estimating individual tree growth with the k-nearest neighbour and k-Most Similar Neighbour methods. Silva Fennica vol. 35 no. 4 article id 580. https://doi.org/10.14214/sf.580
The purpose of this study was to examine the use of non-parametric methods in estimating tree level growth models. In non-parametric methods the growth of a tree is predicted as a weighted average of the values of neighbouring observations. The selection of the nearest neighbours is based on the differences between tree and stand level characteristics of the target tree and the neighbours. The data for the models were collected from the areas owned by Kuusamo Common Forest in Northeast Finland. The whole data consisted of 4051 tally trees and 1308 Scots pines (Pinus sylvestris L.) and 367 Norway spruces (Picea abies Karst.). Models for 5-year diameter growth and bark thickness at the end of the growing period were constructed with two different non-parametric methods: the k-nearest neighbour regression and k-Most Similar Neighbour method. Diameter at breast height, tree height, mean age of the stand and basal area of the trees larger than the subject tree were found to predict the diameter growth most accurately. The non-parametric methods were compared to traditional regression growth models and were found to be quite competitive and reliable growth estimators.
  • Sironen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: susanna.sironen@forest.joensuu.fi (email)
  • Kangas, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland ORCID ID:E-mail:
  • Maltamo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kangas, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland ORCID ID:E-mail:
article id 574, category Research article
Hans W. Linderholm. (2001). Climatic influence on Scots pine growth on dry and wet soils in the central Scandinavian mountains, interpreted from tree-ring width. Silva Fennica vol. 35 no. 4 article id 574. https://doi.org/10.14214/sf.574
Tree rings are one of the most important proxy data sources for reconstructing past climate variability. In order to understand climate variability, it is necessary to get a spatial and temporal coverage of climate information. Summer temperatures mainly influence tree growth at the altitudinal tree line, while at lower altitudes additional factors affect growth. In addition, the nature of soil where trees grow may affect growth response to climate. To decide climate as well as growth-substrate influences on Scots pine (Pinus sylvestris L.) growing below the tree line, two tree-ring width chronologies, sampled at dry mineral soil and wet peat soil in a mountain valley in the central Scandinavian Mountains, were analysed for climate responses and spectral signals. Temperatures during growth season (May–August) showed the strongest influence on tree growth at both sites. Influence of precipitation in the growing season was low, indicating sufficient amounts of available water during growth. However, at the dry-soil site the influence of late winter/early spring precipitation was significant. Strength of the climate–tree–growth relationship at the dry site was similar to that of trees growing at the present tree line, while weaker at the wet site. Both site chronologies exhibited common spectral peaks at c. 3.5 and 13 years indicating a common growth forcing at those time scales. The wet-site chronology displayed low-frequency variations with a 19-year periodicity, where growth peaks coincided with the lunar tidal maxima indicating a possible influence of lunar forcing. At the dry-site, multi-decadal fluctuations displayed a periodicity of 66 years. Both 13- and 66-year periods can be linked to variations in sea surface temperatures of the North Atlantic Ocean, pointing to a maritime influence, on decadal scales, of pine growth in the area. These results suggest that Scots pine in this environment may be regarded as proxies of North Atlantic Ocean coupled climatic variability.
  • Linderholm, Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden ORCID ID:E-mail: hasse@natgeo.su.se (email)
article id 616, category Research article
Markus Lindholm, Hannu Lehtonen, Taneli Kolström, Jouko Meriläinen, Matti Eronen, Mauri Timonen. (2000). Climatic signals extracted from ring-width chronologies of Scots pines from the northern, middle and southern parts of the boreal forest belt in Finland. Silva Fennica vol. 34 no. 4 article id 616. https://doi.org/10.14214/sf.616
Climatic signals were extracted from ring-width chronologies of Scots pines (Pinus sylvestris L.) from natural stands of the northern, middle, and southern parts of the boreal forest belt in Finland. The strength of the common growth signals (forcing factors) were quantified as a function of time. This was achieved by mean inter-series correlations, calculated over a moving 30-year window, both within and between the regional chronologies. Strong regional signals and also evidence for common forcings were found, especially between northern and central, central and eastern, as well as central/eastern and southern chronologies. Response function analyses revealed that growing season temperatures govern the growth rates of northern pines, while towards south, pine growth becomes less affected by temperatures, and more affected by e.g. precipitation. During some periods, growing conditions seem to have been favorable in the south, while they have been unfavorable in the north (growth inversions). Going from the north to the south, the variability of radial growth clearly decreases, and the variance of ring-width series becomes smaller. Growth variability in the four regions was compared during the common interval of the chronologies, from 1806 to 1991. The spectral densities of the northern, central, eastern and southern chronologies were also compared as functions of frequency, viz. cycles per year. The variance is much greater and there is more periodic behavior in the north than in the south in high, medium, as well as lower frequencies.
  • Lindholm, Saima Centre for Environmental Sciences, University of Joensuu, Linnankatu 11, FIN-57130 Savonlinna, Finland ORCID ID:E-mail:
  • Lehtonen, Finnish Forest Research Institute, Joensuu Research Station, Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kolström, Finnish Forest Research Institute, Joensuu Research Station, Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Meriläinen, Saima Centre for Environmental Sciences, University of Joensuu, Linnankatu 11, FIN-57130 Savonlinna, Finland ORCID ID:E-mail:
  • Eronen, Department of Geology, Division of Geology and Palaeontology, Box 11, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Timonen, Finnish Forest Research Institute, Rovaniemi Research Station, Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 676, category Research article
Erik Sundström. (1998). Afforestation of low-productive peatlands in Sweden – a tree species comparison. Silva Fennica vol. 32 no. 4 article id 676. https://doi.org/10.14214/sf.676
In 1970, five low-productive treeless peatlands in Sweden, ranging from latitudes 56°N to 67°N, were drained and fertilized for afforestation. The aim of the study was to determine the effect of four ditch spacings, varying from 7.5 to 60 m, and five NPK-fertilizer combinations, on the survival and growth of planted Scots pine (Pinus sylvestris), lodgepole pine (Pinus contorta), Norway spruce (Picea abies), and silver birch (Betula pendula) seedlings. The assessments were carried out 18–22 years after planting. Neither silver birch, nor Norway spruce was regarded suitable for the site type. The mortality of silver birch was almost complete, and Norway spruce did not grow well in any of the study areas, however, better than Scots pine in the north. Lodgepole pine had better height and diameter growth but also higher mortality rates than Scots pine. In the two northernmost experimental areas no response to fertilization was found. In the other three areas, the response to fertilization did not differ between species. Phosphorus was the most effective of the added fertilizer elements, whereas nitrogen showed no positive effect. Broadcast fertilizer application, with three times higher amount of fertilizer per ha gave the same growth response as spot application.
  • Sundström, Swedish University of Agricultural Sciences, Dept. of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail: erik.sundstrom@ssko.slu.se (email)
article id 675, category Research article
Per Linder, Peter Jonsson, Mats Niklasson. (1998). Tree mortality after prescribed burning in an old-growth Scots pine forest in northern Sweden. Silva Fennica vol. 32 no. 4 article id 675. https://doi.org/10.14214/sf.675
Tree mortality and input of dead trees were studied after a prescribed burning in a forest reserve in northern Sweden. The stand was a multi-layered old-growth forest. The overstorey was dominated by Scots pine (Pinus sylvestris L.) and the understorey consisted of mixed Scots pine and Norway spruce (Picea abies L. Karst.). Ground vegetation was dominated by ericaceous dwarf-shrubs and feathermosses. The stand has been affected by six forest fires during the last 500 years. The prescribed burning was a low intensity surface fire that scorched almost 90% of the ground. Tree mortality for smaller pines and spruces (DBH < 10 cm) was over 80% in the burned parts of the reserve. For larger pines, 10–50 cm DBH, mortality showed a decreasing trend with increasing diameter, from 14% in class 10–20 cm DBH to 1.4% in class 40–50 cm DBH. However, pines with DBH ≥ 50 cm had a significantly higher mortality, 20%, since a high proportion of them had open fire scars containing cavities, caused by fungi and insects, which enabled the fire to burn inside the trunks and hollow them out. The fire-induced mortality resulted in a 21 m3 ha–1 input of dead trees, of which 12 m3 ha–1 consisted of trees with DBH ≥ 30 cm. An increased mortality among larger trees after low-intensity fires has not previously been described in Fennoscandian boreal forests, probably owing to a lack of recent fires in old-growth stands. However, since large pines with open fire scars were once a common feature in the natural boreal forest, we suggest that this type of tree mortality should be mimicked in forestry practices aiming to maintain and restore natural forest biodiversity.
  • Linder, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Jonsson, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Niklasson, Southern Swedish Forest Research Centre, SLU, Box 49, S-230 53 Alnarp, Sweden ORCID ID:E-mail:
article id 675, category Research article
Per Linder, Peter Jonsson, Mats Niklasson. (1998). Tree mortality after prescribed burning in an old-growth Scots pine forest in northern Sweden. Silva Fennica vol. 32 no. 4 article id 675. https://doi.org/10.14214/sf.675
Tree mortality and input of dead trees were studied after a prescribed burning in a forest reserve in northern Sweden. The stand was a multi-layered old-growth forest. The overstorey was dominated by Scots pine (Pinus sylvestris L.) and the understorey consisted of mixed Scots pine and Norway spruce (Picea abies L. Karst.). Ground vegetation was dominated by ericaceous dwarf-shrubs and feathermosses. The stand has been affected by six forest fires during the last 500 years. The prescribed burning was a low intensity surface fire that scorched almost 90% of the ground. Tree mortality for smaller pines and spruces (DBH < 10 cm) was over 80% in the burned parts of the reserve. For larger pines, 10–50 cm DBH, mortality showed a decreasing trend with increasing diameter, from 14% in class 10–20 cm DBH to 1.4% in class 40–50 cm DBH. However, pines with DBH ≥ 50 cm had a significantly higher mortality, 20%, since a high proportion of them had open fire scars containing cavities, caused by fungi and insects, which enabled the fire to burn inside the trunks and hollow them out. The fire-induced mortality resulted in a 21 m3 ha–1 input of dead trees, of which 12 m3 ha–1 consisted of trees with DBH ≥ 30 cm. An increased mortality among larger trees after low-intensity fires has not previously been described in Fennoscandian boreal forests, probably owing to a lack of recent fires in old-growth stands. However, since large pines with open fire scars were once a common feature in the natural boreal forest, we suggest that this type of tree mortality should be mimicked in forestry practices aiming to maintain and restore natural forest biodiversity.
  • Linder, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Jonsson, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Niklasson, Southern Swedish Forest Research Centre, SLU, Box 49, S-230 53 Alnarp, Sweden ORCID ID:E-mail:

Category: Review article

article id 1660, category Review article
Lars Rytter, Morten Ingerslev, Antti Kilpeläinen, Piritta Torssonen, Dagnija Lazdina, Magnus Löf, Palle Madsen, Peeter Muiste, Lars-Göran Stener. (2016). Increased forest biomass production in the Nordic and Baltic countries – a review on current and future opportunities. Silva Fennica vol. 50 no. 5 article id 1660. https://doi.org/10.14214/sf.1660
Highlights: Annual growth is 287 million m3 in the forests of the Nordic and Baltic countries; Growth can be increased by new tree species, tree breeding, high-productive management systems, fertilization and afforestation of abandoned agricultural land; We predict a forest growth increment of 50–100% is possible at the stand scale; 65% of annual growth is harvested today.

The Nordic and Baltic countries are in the frontline of replacing fossil fuel with renewables. An important question is how forest management of the productive parts of this region can support a sustainable development of our societies in reaching low or carbon neutral conditions by 2050. This may involve a 70% increased consumption of biomass and waste to meet the goals. The present review concludes that a 50–100% increase of forest growth at the stand scale, relative to today’s common level of forest productivity, is a realistic estimate within a stand rotation (~70 years). Change of tree species, including the use of non-native species, tree breeding, introduction of high-productive systems with the opportunity to use nurse crops, fertilization and afforestation are powerful elements in an implementation and utilization of the potential. The productive forests of the Nordic and Baltic countries cover in total 63 million hectares, which corresponds to an average 51% land cover. The annual growth is 287 million m3 and the annual average harvest is 189 million m3 (65% of the growth). A short-term increase of wood-based bioenergy by utilizing more of the growth is estimated to be between 236 and 416 TWh depending on legislative and operational restrictions. Balanced priorities of forest functions and management aims such as nature conservation, biodiversity, recreation, game management, ground water protection etc. all need consideration. We believe that these aims may be combined at the landscape level in ways that do not conflict with the goals of reaching higher forest productivity and biomass production.

  • Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se (email)
  • Ingerslev, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID:E-mail: moi@ign.ku.dk
  • Kilpeläinen, Finnish Environment Institute, Joensuu Office, P.O. Box 111, FI-80101 Joensuu, Finland; University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.kilpelainen@ymparisto.fi
  • Torssonen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: Piritta.Torssonen@uef.fi
  • Lazdina, Latvian State Forest Research Institute “Silava”, 111 Riga str, Salaspils, LV 2169 Latvia ORCID ID:E-mail: Dagnija.Lazdina@silava.lv
  • Löf, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49 SE-230 53 Alnarp, Sweden ORCID ID:E-mail: magnus.lof@slu.se
  • Madsen, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID:E-mail: pam@ign.ku.dk
  • Muiste, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Dept. Forest Industry, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: Peeter.Muiste@emu.ee
  • Stener, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID:E-mail: Lars-Goran.Stener@skogforsk.se
article id 1660, category Review article
Lars Rytter, Morten Ingerslev, Antti Kilpeläinen, Piritta Torssonen, Dagnija Lazdina, Magnus Löf, Palle Madsen, Peeter Muiste, Lars-Göran Stener. (2016). Increased forest biomass production in the Nordic and Baltic countries – a review on current and future opportunities. Silva Fennica vol. 50 no. 5 article id 1660. https://doi.org/10.14214/sf.1660
Highlights: Annual growth is 287 million m3 in the forests of the Nordic and Baltic countries; Growth can be increased by new tree species, tree breeding, high-productive management systems, fertilization and afforestation of abandoned agricultural land; We predict a forest growth increment of 50–100% is possible at the stand scale; 65% of annual growth is harvested today.

The Nordic and Baltic countries are in the frontline of replacing fossil fuel with renewables. An important question is how forest management of the productive parts of this region can support a sustainable development of our societies in reaching low or carbon neutral conditions by 2050. This may involve a 70% increased consumption of biomass and waste to meet the goals. The present review concludes that a 50–100% increase of forest growth at the stand scale, relative to today’s common level of forest productivity, is a realistic estimate within a stand rotation (~70 years). Change of tree species, including the use of non-native species, tree breeding, introduction of high-productive systems with the opportunity to use nurse crops, fertilization and afforestation are powerful elements in an implementation and utilization of the potential. The productive forests of the Nordic and Baltic countries cover in total 63 million hectares, which corresponds to an average 51% land cover. The annual growth is 287 million m3 and the annual average harvest is 189 million m3 (65% of the growth). A short-term increase of wood-based bioenergy by utilizing more of the growth is estimated to be between 236 and 416 TWh depending on legislative and operational restrictions. Balanced priorities of forest functions and management aims such as nature conservation, biodiversity, recreation, game management, ground water protection etc. all need consideration. We believe that these aims may be combined at the landscape level in ways that do not conflict with the goals of reaching higher forest productivity and biomass production.

  • Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se (email)
  • Ingerslev, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID:E-mail: moi@ign.ku.dk
  • Kilpeläinen, Finnish Environment Institute, Joensuu Office, P.O. Box 111, FI-80101 Joensuu, Finland; University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.kilpelainen@ymparisto.fi
  • Torssonen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: Piritta.Torssonen@uef.fi
  • Lazdina, Latvian State Forest Research Institute “Silava”, 111 Riga str, Salaspils, LV 2169 Latvia ORCID ID:E-mail: Dagnija.Lazdina@silava.lv
  • Löf, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49 SE-230 53 Alnarp, Sweden ORCID ID:E-mail: magnus.lof@slu.se
  • Madsen, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID:E-mail: pam@ign.ku.dk
  • Muiste, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Dept. Forest Industry, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: Peeter.Muiste@emu.ee
  • Stener, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID:E-mail: Lars-Goran.Stener@skogforsk.se
article id 1416, category Review article
Ulf Sikström, Hannu Hökkä. (2016). Interactions between soil water conditions and forest stands in boreal forests with implications for ditch network maintenance. Silva Fennica vol. 50 no. 1 article id 1416. https://doi.org/10.14214/sf.1416
Highlights: Ditch network maintenance (DNM) may influence soil water conditions less than initial ditching due to reduced hydraulic conductivity of the peat; Stand stocking and management substantially influence soil-water conditions; DNM can lower the GWL and increase tree growth; DNM growth responses of 0.5–1.8 m3 ha–1 yr–1 during 15–20-years in Scots pine peatland stands reported; Greatest need for DNM in the early phase of a stand rotation; Need for better understanding of the link between soil water and tree growth.

At sites with either peat or mineral soils in large areas of boreal forests, high soil-water contents hamper tree growth and drainage can significantly increase growth. Hence, areas covering about 15 × 106 ha of northern peatlands and wet mineral soils have been drained for forestry purposes. Usually ditches gradually deteriorate, thus reducing their functionality as drains, and ditch-network maintenance (DNM) might be needed to maintain stand growth rates enabled by the original ditching. This article reviews current knowledge on establishing the need for DNM in boreal forest stands, subsequent growth responses, and the financial outcome of the activity. The issues covered in the review are: (i) ditching, changes in ditches over time and the need for DNM; (ii) interactions between soil water and both stand properties and stand management; (iii) ground-water level (GWL) and tree growth responses to DNM; and (iv) financial viability of DNM. Conclusions about the current understanding of issues related to DNM are drawn and implications for DNM in practice are summarized. Finally, gaps in knowledge are identified and research needs are suggested.

  • Sikström, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: ulf.sikstrom@skogforsk.se (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@luke.fi
article id 463, category Review article
Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma, Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463
At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.
  • Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail: thomas.gschwantner@bfw.gv.at (email)
  • Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail:
  • Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy ORCID ID:E-mail:
  • Robert, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain ORCID ID:E-mail:
article id 463, category Review article
Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma, Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463
At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.
  • Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail: thomas.gschwantner@bfw.gv.at (email)
  • Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail:
  • Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy ORCID ID:E-mail:
  • Robert, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain ORCID ID:E-mail:
article id 463, category Review article
Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma, Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463
At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.
  • Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail: thomas.gschwantner@bfw.gv.at (email)
  • Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail:
  • Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy ORCID ID:E-mail:
  • Robert, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain ORCID ID:E-mail:
article id 463, category Review article
Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma, Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463
At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.
  • Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail: thomas.gschwantner@bfw.gv.at (email)
  • Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail:
  • Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy ORCID ID:E-mail:
  • Robert, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain ORCID ID:E-mail:
article id 535, category Review article
Thomas J. Givnish. (2002). Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox. Silva Fennica vol. 36 no. 3 article id 535. https://doi.org/10.14214/sf.535
Patterns in the dominance of evergreen vs. deciduous plants have long interested ecologists, biogeographers, and global modellers. But previous models to account for these patterns have significant weaknesses. Bottom-up, mechanistic models – based on physiology, competition, and natural selection – have often been non-quantitative or restricted to a small range of habitats, and almost all have ignored belowground costs and whole-plant integration. Top-down, ecosystem-based models have succeeded in quantitatively reproducing several patterns, but rely partly on empirically derived constants and thresholds that lack a mechanistic explanation. It is generally recognized that seasonal drought can favor deciduous leaves, and that infertile soils can favor long-lived evergreen leaves. But no model has yet explained three great paradoxes, involving dominance by 1) evergreens in highly seasonal, boreal forests, 2) deciduous larch in many nutrient-poor peatlands, and 3) evergreen leaf-exchangers in nutrient-poor subtropical forests, even though they shed their leaves just as frequently as deciduous species. This paper outlines a generalized optimality model to account for these and other patterns in leaf longevity and phenology, based on maximizing whole-plant carbon gain or height growth, and building on recent advances in our understanding of the quantitative relationships of leaf photosynthesis, nitrogen content, and mass per unit area to leaf life-span. Only a whole-plant approach can explain evergreen dominance under realistic ecological conditions, or account for the boreal paradox, the larch paradox, the leaf-exchanger paradox, and expected shifts in shade tolerance associated with leaf phenology. Poor soils favor evergreens not merely by increasing the costs of nutrient acquisition, but also by depressing the maximum rate of photosynthesis and thus the seasonal contrast in photosynthetic return between leaves adapted to favorable vs. unfavorable conditions. The dominance of evergreens in western North America beyond the coastal zone of mild winters and winter rainfall appears related to the unusually long photosynthetic season for evergreen vs. deciduous plants there. Future models for optimal leaf phenology must incorporate differences between evergreen and deciduous plants in allocation to photosynthetic vs. non-photosynthetic tissue, rooting depth, stem allometry, xylem anatomy, and exposure to herbivores and leaching, and analyze how these differences interact with the photosynthetic rate, transpiration, and nutrient demands of leaves with different life-spans to affect rates of height growth in specific microsites.
  • Givnish, Dept of Botany, University of Wisconsin, Madison, WI 53706, USA ORCID ID:E-mail: givnish@facstaff.wisc.edu (email)
article id 695, category Review article
Marja-Leena Päätalo. (1998). Factors influencing occurrence and impacts of fires in northern European forests. Silva Fennica vol. 32 no. 2 article id 695. https://doi.org/10.14214/sf.695
The return interval and number of fires vary, depending on the geographical location in interaction with climate, topography and amount of fuel. During recent decades, in northern Europe the number and severity of fires have been insignificant compared with Mediterranean region, in which fire return intervals may be 15–35 years, compared to the average of 60–120 years for boreal forests. This is partly due to the efficient system of fire protection in northern Europe, but is mainly due to the less favourable climate for fire and the smaller human impact on ignition of forest fires. The consequences of fire are related to both site and stand characteristics, site being the most important factor controlling the stability of stands. Dry sites being more flammable and likely to ignite are associated with high risk of fire. In northern Europe, due to the interaction between species and site, the role of species difference in risk of fire damage is not clear. In southern Europe, fire risk cannot be explained by differences between tree species. There, other vegetation (shrubs, etc.) is of major importance for the risk of fire. Management of forests can, to some degree, alter the risk and the occurrence of fire. In northern Europe, logging may have compensated for fire occurrence by decreasing the amount of fuel. In addition, forest roads act as fire-breaks and facilitate fire-fighting. On the contrary, in southern Europe the risk of fire has been found to increase because the traditional forest uses and management have decreased, which increases the accumulation of fuel. However, it is not yet possible to quantify and compare the effect of management in absolute terms. Currently, some tools, such as fire-risk indices, remote sensing and GIS-based techniques, are available for prediction of fire risk in some areas. For example, fire-risk indices are most suitable for areas, like northern Europe, which have a low fire risk. In high-risk areas, such as southern Europe, more sophisticated techniques are needed for assessment of the risk. In the future, assuming global warming at northern latitudes (2 x CO2 climate), the risk of fire damage could also increase in northern Europe. Therefore, to allow the various locational and silvicultural factors to be assessed on the European level, an integrated risk model is needed.
  • Päätalo, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:

Category: Research note

article id 1716, category Research note
Nelson Thiffault, Alain Paquette, Christian Messier. (2017). Early silvicultural guidelines for intensive management of hybrid larch plantations on fertile sub-boreal sites. Silva Fennica vol. 51 no. 2 article id 1716. https://doi.org/10.14214/sf.1716
Highlights: Satisfactory growth can be obtained using a wide range of site preparation intensities; There is a net advantage of performing two motor-manual release treatments over a single release; A second release treatment cannot be replaced by more intensive site preparation; Planting depth had no influence on planted seedling growth after 6 years.

Use of fast-growing tree plantations on dedicated areas is proposed as a means of reconciling fibre production with conservation objectives. Success of this approach however requires fine-tuning silvicultural scenarios so that survival and growth are optimized while management and environmental costs are minimized. This is particularly challenging for hybrid larch (Larix × marschlinsii Coaz), a shade-intolerant species planted on fertile sites in Quebec (Canada) where legislation prevents the use of chemical herbicides. In this context, multiple motor-manual release treatments are often required, with high impacts on costs and social issues related to the scarcity of a qualified workforce. We established a split-split-plot design on a recently harvested site to assess the main and interaction effects of mechanical site preparation (MSP) intensity (five modalities of trenching or mounding), motor-manual release scenario (one or two treatments) and planting depth (0–3 cm or 3–10 cm) on hybrid larch seedling growth and survival six years after planting. Mechanical site preparation intensity and planting depth did not influence seedling growth after 6 years. The lack of significant interaction between MSP and release scenarios indicates that these operations should be planned independently. A more intensive MSP treatment cannot replace a second motor-manual release on fertile sites, as proposed to reduce costs. Our results also show the significant advantage of performing two motor-manual release treatments two years apart (the first one early in the scenario), over performing a single treatment. Our study provides silvicultural guidelines for the establishment of high-yield exotic larch plantations.

  • Thiffault, Direction de la recherche forestière, Ministère des Forêts, de la Faune et des Parcs du Québec, 2700 rue Einstein, Québec, QC, Canada G1P 3W8; Centre d’étude de la forêt, CP 8888, Succursale Centre-ville, Montréal, QC, Canada H3C 3P8 ORCID ID: http://orcid.org/0000-0003-2017-6890 E-mail: nelson.thiffault@mffp.gouv.qc.ca (email)
  • Paquette, Centre d’étude de la forêt, CP 8888, Succursale Centre-ville, Montréal, QC, Canada H3C 3P8; Université du Québec à Montréal, Département des sciences biologiques, CP 8888, Succursale Centre-ville, Montréal, QC, Canada H3C 3P8 ORCID ID: http://orcid.org/0000-0003-1048-9674 E-mail: alain.paquette@gmail.com
  • Messier, Centre d’étude de la forêt, CP 8888, Succursale Centre-ville, Montréal, QC, Canada H3C 3P8; Université du Québec à Montréal, Département des sciences biologiques, CP 8888, Succursale Centre-ville, Montréal, QC, Canada H3C 3P8; Institut des Sciences de la Forêt tempérée (ISFORT), 58 rue Principale, Ripon, QC, Canada JOV 1V0 E-mail nelson.thiff ORCID ID:E-mail: christian.messier@uqo.ca
article id 1346, category Research note
Āris Jansons, Roberts Matisons, Oskars Krišāns, Baiba Džeriņa, Mārtiņš Zeps. (2016). Effect of initial fertilization on 34-year increment and wood properties of Norway spruce in Latvia. Silva Fennica vol. 50 no. 1 article id 1346. https://doi.org/10.14214/sf.1346
Highlights: The initial fertilization increased the productivity of Picea abies increasing stem volume by 17% at the age of 34 years; The tree-ring width was affected for up to15 years; The fertilization did not affect mean tree-ring density, although the latewood density was increased.

Initial fertilisation, when the fertilizer is supplied during the plantation, is applied to improve the competitive ability of the seedlings and hence to increase their growth and productivity; however, fertilization could also alter wood properties and timber quality. In this study, the dimensions and tree-ring parameters – width, proportion of latewood, maximum and mean density, mean earlywood and latewood density – of initially fertilized (by 14, 6 and 11 g of N, P and K per seedling, respectively) Norway spruce (Picea abies Karst.) growing in an experimental plantation in Kalsnava, Latvia (temperate climate region) were assessed. The fertilization significantly increased the dimensions of trees in long-term (ca. 17% increase of stemwood volume). The analysis of tree-ring width suggested that the duration of the effect was ca. 15 years. The maximum and latewood density were higher for the fertilized trees only in a few years. The mean and earlywood density of tree-rings were mainly similar for both treatments. Altogether, considering the one-time application of a limited amount of fertilizer, such treatment had notable and lasting effect on Norway spruce.

  • Jansons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Matisons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Krišāns, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: oskars.krisans@silava.lv
  • Džeriņa, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: baiba.dzerina@silava.lv
  • Zeps, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: martins.zeps@silava.lv
article id 1145, category Research note
Juha Siitonen. (2014). Ips acuminatus kills pines in southern Finland. Silva Fennica vol. 48 no. 4 article id 1145. https://doi.org/10.14214/sf.1145
Highlights: Recently dead pines colonized by Ips acuminatus were frequently found in southern Finland, in a region where the species was thought to be absent; Colonized trees were typically large (average DBH 30 cm), located at open spots in pine-dominated stands, often forming groups of several trees; The damages may be a consequence of dry and hot summers during the 2000s.
Recently dead Scots pines (Pinus sylvestris L.) apparently killed by Ips acuminatus (Gyllenhal) were observed in Sipoo, southern Finland, in summer 2013. This record was unexpected and in contradiction with what is currently known about the distribution and aggressiveness of the species in Finland. The aim of this study was to survey a larger area in Uusimaa region, to find out whether I. acuminatus occurs frequently in recently dead pines, and whether inhabited trees share some common tree- or site-level characteristics. Galleries of I. acuminatus were found in most of the studied trees. A total of 96 inhabited trees were found in 21 separate sites. Colonized pines were typically large (average DBH 30 ± 9 cm) trees located in relatively open pine-dominated heathland stands at half-open, sun-exposed spots. The whole upper part of the trunk with thin bark was usually occupied. Galleries of Tomicus piniperda L. or T. minor Hartig occurred only in few cases in the same trees, indicating that the trees had died later in the summer. Galleries of the jewel beetle Phaenops cyanea F. were found in 13 trees. Trees colonized by I. acuminatus often occurred as small groups, with generally 1­–12 trees (average 3 trees), but in one exceptional group there were no less than 35 trees. It is possible that the hot and dry summers during the 2000s have increased the susceptibility of pines to insect damage, and have contributed to a population growth of I. acuminatus.
  • Siitonen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: juha.siitonen@metla.fi (email)
article id 1125, category Research note
Anssi Krooks, Sanna Kaasalainen, Ville Kankare, Marianna Joensuu, Pasi Raumonen, Mikko Kaasalainen. (2014). Predicting tree structure from tree height using terrestrial laser scanning and quantitative structure models. Silva Fennica vol. 48 no. 2 article id 1125. https://doi.org/10.14214/sf.1125
Highlights: The analysis of tree structure suggests that trees of different height growing in similar conditions have similar branch size distributions; There is potential for using the tree height information in large-scale estimations of forest canopy structure.
We apply quantitative structure modelling to produce detailed information on branch-level metrics in trees. Particularly we are interested in the branch size distribution, by which we mean the total volume of branch parts distributed over the diameter classes of the parts. We investigate the possibility of predicting tree branch size distributions for trees in similar growing conditions. The quantitative structure model enables for the first time the comparisons of structure between a large number of trees. We found that the branch size distribution is similar for trees of different height in similar growing conditions. The results suggest that tree height could be used to estimate branch size distribution in areas with similar growing conditions and topography.
  • Krooks, Finnish Geodetic Institute, Geodeetinrinne 2, FI–02431 Masala, Finland ORCID ID:E-mail: Anssi.Krooks@fgi.fi
  • Kaasalainen, Finnish Geodetic Institute, Geodeetinrinne 2, FI–02431 Masala, Finland ORCID ID:E-mail: Sanna.Kaasalainen@fgi.fi (email)
  • Kankare, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland ORCID ID:E-mail: ville.kankare@helsinki.fi
  • Joensuu, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland ORCID ID:E-mail: marianna.joensuu@alumni.helsinki.fi
  • Raumonen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, Tampere, FI-33101, Finland ORCID ID:E-mail: Pasi.Raumonen@tut.fi
  • Kaasalainen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, Tampere, FI-33101, Finland ORCID ID:E-mail: Mikko.Kaasalainen@tut.fi
article id 1053, category Research note
Aleksey Fedorkov. (2014). Vitality and height growth of two Larix species and provenances in a field trial located in north-west Russia. Silva Fennica vol. 48 no. 1 article id 1053. https://doi.org/10.14214/sf.1053
Highlights: Differences in tree vitality among provenances were insignificant (p > 0.05) at an early age; The provenance effect was significant (p < 0.05) for total height; These findings were in agreement with those of Lukkarinen et al. (2010) using the same material at the same age for field trial located in Punkaharju (Finland).
Vitality and height of Larix species and provenances originating from Russia were estimated in a 5-yr field trial performed in the Komi Republic (north-west Russia) using a fully randomized single-tree plot design with 7–8 blocks. Tree provenance had no significant (p > 0.05) effect on tree vitality, though for Larix sukazcewii originating from the European part of Russia, trees from the northern regions were more vital than those from southern regions. Provenance was a significant (p < 0.05) factor for height, where the average height of 136 cm varied considerably (168 cm for trees from Nizhnij Novgorod and 111 cm for trees from Ufa). There were no significant correlations when vitality and height were compared to geographic and climatic variables for the locations.
  • Fedorkov, Institute of Biology, Komi Science Center, Russian Academy of Sciences, Syktyvkar, 167982, Kommunisticheskaya st., 28, Russia ORCID ID:E-mail: fedorkov@ib.komisc.ru (email)
article id 1053, category Research note
Aleksey Fedorkov. (2014). Vitality and height growth of two Larix species and provenances in a field trial located in north-west Russia. Silva Fennica vol. 48 no. 1 article id 1053. https://doi.org/10.14214/sf.1053
Highlights: Differences in tree vitality among provenances were insignificant (p > 0.05) at an early age; The provenance effect was significant (p < 0.05) for total height; These findings were in agreement with those of Lukkarinen et al. (2010) using the same material at the same age for field trial located in Punkaharju (Finland).
Vitality and height of Larix species and provenances originating from Russia were estimated in a 5-yr field trial performed in the Komi Republic (north-west Russia) using a fully randomized single-tree plot design with 7–8 blocks. Tree provenance had no significant (p > 0.05) effect on tree vitality, though for Larix sukazcewii originating from the European part of Russia, trees from the northern regions were more vital than those from southern regions. Provenance was a significant (p < 0.05) factor for height, where the average height of 136 cm varied considerably (168 cm for trees from Nizhnij Novgorod and 111 cm for trees from Ufa). There were no significant correlations when vitality and height were compared to geographic and climatic variables for the locations.
  • Fedorkov, Institute of Biology, Komi Science Center, Russian Academy of Sciences, Syktyvkar, 167982, Kommunisticheskaya st., 28, Russia ORCID ID:E-mail: fedorkov@ib.komisc.ru (email)
article id 897, category Research note
Lars Lundqvist, Susanne Spreer, Christer Karlsson. (2013). Volume production in different silvicultural systems for 85 years in a mixed Picea abies–Pinus sylvestris forest in central Sweden. Silva Fennica vol. 47 no. 1 article id 897. https://doi.org/10.14214/sf.897
A long-term comparison of different silvicultural systems was established in 1923 in central Sweden, in an uneven-aged mixed Norway spruce–Scots pine forest (Picea abies (L.) Karst. – Pinus sylvestris L.) with about 85% spruce and 15% pine. The five treatments consisted of two examples of even-aged management 1) clear-cutting followed by planting, and 2) seed tree regeneration, one uneven-aged management 3) selection system, one exploiting treatment 4) diameter limit cut, and 5) one untreated control plot. Each treatment plot was 1 ha, 100 m × 100 m. The plots were measured and managed at irregular intervals, ranging from 7 to 15 years. In 2007–2008 the even-aged treatments and the diameter limit cut were repeated and a new rotation started. Mean annual volume increment during the whole observation period differed widely between the treatments, partly because of differences in species composition over time, with treatment clear-cutting followed by planting at the top, and the control at the bottom. Treatment selection system gave only about 60% of planting, but this was probably largely an effect of too small growing stock during the first roughly 50 years. When the growing stock was increased, periodic annual volume increment increased to about 80% of the mean annual volume increment in the even-aged, planted plot.
  • Lundqvist, Deparment of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: lars.lundqvist@slu.se (email)
  • Spreer, Sveaskog Förvaltnings AB, Ljusdal, Sweden ORCID ID:E-mail: susanne.spreer@sveaskog.se
  • Karlsson, Field Research Unit, Swedish University of Agricultural Sciences, Siljansfors, Sweden ORCID ID:E-mail: christer.karlsson@slu.se
article id 897, category Research note
Lars Lundqvist, Susanne Spreer, Christer Karlsson. (2013). Volume production in different silvicultural systems for 85 years in a mixed Picea abies–Pinus sylvestris forest in central Sweden. Silva Fennica vol. 47 no. 1 article id 897. https://doi.org/10.14214/sf.897
A long-term comparison of different silvicultural systems was established in 1923 in central Sweden, in an uneven-aged mixed Norway spruce–Scots pine forest (Picea abies (L.) Karst. – Pinus sylvestris L.) with about 85% spruce and 15% pine. The five treatments consisted of two examples of even-aged management 1) clear-cutting followed by planting, and 2) seed tree regeneration, one uneven-aged management 3) selection system, one exploiting treatment 4) diameter limit cut, and 5) one untreated control plot. Each treatment plot was 1 ha, 100 m × 100 m. The plots were measured and managed at irregular intervals, ranging from 7 to 15 years. In 2007–2008 the even-aged treatments and the diameter limit cut were repeated and a new rotation started. Mean annual volume increment during the whole observation period differed widely between the treatments, partly because of differences in species composition over time, with treatment clear-cutting followed by planting at the top, and the control at the bottom. Treatment selection system gave only about 60% of planting, but this was probably largely an effect of too small growing stock during the first roughly 50 years. When the growing stock was increased, periodic annual volume increment increased to about 80% of the mean annual volume increment in the even-aged, planted plot.
  • Lundqvist, Deparment of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: lars.lundqvist@slu.se (email)
  • Spreer, Sveaskog Förvaltnings AB, Ljusdal, Sweden ORCID ID:E-mail: susanne.spreer@sveaskog.se
  • Karlsson, Field Research Unit, Swedish University of Agricultural Sciences, Siljansfors, Sweden ORCID ID:E-mail: christer.karlsson@slu.se

Category: Article

article id 7178, category Article
Matti Keltikangas, Pekka Tiililä. (1968). Koivun ja kuusen istutuksen keskinäinen edullisuusjärjestys käenkaali-mustikkatyypin metsämailla. Acta Forestalia Fennica vol. 82 no. 5 article id 7178. https://doi.org/10.14214/aff.7178
English title: The economic sequence of silver birch (Betula pendula) and Norway spruce (Picea abies) when planting Oxalis-Myrtillus type forest land.

The present study proposes to calculate the economic sequence of two of Finland’s three main tree species, Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) when planted on Oxalias-Myrtillus type sites where both species are equally suitable, on biological grounds. In addition, the accuracy and applicability of the present Finnish yield tables to an economic comparison is tested. Benefit/cost ratio was selected as criterion of profitableness. All future net incomes and costs were discounted into the planting time and added together. The ratio between the discounted net revenues and the discounted investment costs (later called profit ratio) was the criterion. There is no reliable method to forecast the future wood prices, therefore two price ratios, birch veneer timber to spruce pulpwood and birch cordwood to spruce pulpwood, were chosen as free variables. The economic sequence of the tree species was determined as the function of these variables.

The main conclusions are, first, that under the present price ratios spruce appears to be the better choice for the forest owner, and the most promising policy for changing the situation seems to decrease the production costs of plants in birch nurseries. Second, the present Finnish yield tables are not consistent or accurate enough to enable any sufficiently reliable economic comparisons of tree species in artificial regeneration. The possible error of difference between two rather uncertain estimates is big. More work is needed to construct a uniform system of yield tables covering all main tree species, all site types, all macro climate conditions and all types of regeneration.

The PDF includes a summary in English.

  • Keltikangas, ORCID ID:E-mail:
  • Tiililä, ORCID ID:E-mail:
article id 7176, category Article
Olli Makkonen. (1967). Ancient forestry : an historical study. 1. Facts and information on trees. Acta Forestalia Fennica vol. 82 no. 3 article id 7176. https://doi.org/10.14214/aff.7176

This paper presents a study on the works of ancient writers that deal with trees, forests and the use of forest before the time of actual forest sciences. The work describes the development of knowledge pertaining to the forest and trees and the progress made on utilizing them. This first part of a series of two articles is primarily concerned with biological information in ancient times. The article first describes the most important sources of information and concentrates then on the information on the structure of trees, on the vital functions of trees, on the factors affecting the growth of trees and tree species.

  • Makkonen, ORCID ID:E-mail:
article id 7166, category Article
J. E. Hårdh. (1966). Trials with carbon dioxide, light and growth substances on forest tree plants. Acta Forestalia Fennica vol. 81 no. 1 article id 7166. https://doi.org/10.14214/aff.7166

Growth-promoting effects of enhanced caron dioxide levels upon forest tree seedlings grown in plastic houses was studied in 1964 and 1965 in the Forest Breeding Foundation in Haapastensyrjä near Loppi in Southern Finland. In both years more vigorous height and weight growth, and development of root system was achieved when the CO2 concentration was increased to 0.2% than in the normal conditions (CO2 0.03%). The CO2 concentration was increased by burning propane in the plastic houses. Burning continued for four hours per day either at 8–10 and 14–16 a clock or 6–10 a clock. Growth was not affected by the time of the treatment, and it was equally high in 0.1% and 0.2% concentrations.

Treatment of the seedlings with 100–200 ppm gibberellic acid (GA) increased the height growth of healthy, well-rooted seedlings. Treatment with a concentrated (600 ppm) dosage, as well as treatment with a combination of GA and 1-naphtyl acetic acid (NAA) caused serious defects in grafts of Scots pine (Pinus sylvestris L.). GA treatments did not induce flower formation in pine. Red light during the night seemed to enhance growth of grafts of silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.).

The PDF includes a summary in Finnish.

  • Hårdh, ORCID ID:E-mail:
article id 7161, category Article
Olavi Laiho. (1965). Further studies on the ectendotrophic mycorrhiza. Acta Forestalia Fennica vol. 79 no. 3 article id 7161. https://doi.org/10.14214/aff.7161

There has not been complete agreement as to what is meant by ectendotrophic mycorrhizae, and there is a wide variety of opinion among authors on mycorrhizal terminology. In this paper ectendotrophic mycorrhizae are defined to be short roots with Hartig net and intracellular hyphae in the cortex. A mantle and digestion of intracellular hyphae may be found but are not necessary. In the study of Mikola (1965) ectendotrophic mycorrhiza was found to be common in Scots pine (Pinus sylvestris L.) seedlings in Finnish nurseries. The mycorrhizae had always similar structure and the mycelium isolated from the seedlings (E-strains) was similar. The aim of this study was to find out what kind of ectendotrophic mycorrhizae exist in forests and nurseries outside Finland, what kind of mycorrhizae do the E-strains isolated from Scots pine form with other tree species, and are these associations symbiotic.

Only one type of ectendotrophic mycorrhiza was found on the 600 short roots collected from the continents of Europa and America. The type was similar to the one described by Mikola: the mycelium is coarse and forms a strong Hartig net, and intracellular infection is heavy. Evidence is convincing that this structure was formed by the same fungus species. The species is unidentified. Mycorrhizae synthesized by E-strain with six spruce species, fir, hemloch and Douglas fir were all ectotrophic.

The E-type ectendotrophic mycorrhizae proved to be a balanced symbiosis. The seedlings of 13 tree species inoculated with the E-strain grew in the experiment better than the controls. The observation that ectendotrophic mycorrhizae dominates in the nurseries but is seldom found in forests, and then only in seedlings growing in the forest, was confirmed in the study. In synthesis experiments E-strain formed either ecto- or ectendotrophic mycorrhiza depending on the tree species.

  • Laiho, ORCID ID:E-mail:
article id 7161, category Article
Olavi Laiho. (1965). Further studies on the ectendotrophic mycorrhiza. Acta Forestalia Fennica vol. 79 no. 3 article id 7161. https://doi.org/10.14214/aff.7161

There has not been complete agreement as to what is meant by ectendotrophic mycorrhizae, and there is a wide variety of opinion among authors on mycorrhizal terminology. In this paper ectendotrophic mycorrhizae are defined to be short roots with Hartig net and intracellular hyphae in the cortex. A mantle and digestion of intracellular hyphae may be found but are not necessary. In the study of Mikola (1965) ectendotrophic mycorrhiza was found to be common in Scots pine (Pinus sylvestris L.) seedlings in Finnish nurseries. The mycorrhizae had always similar structure and the mycelium isolated from the seedlings (E-strains) was similar. The aim of this study was to find out what kind of ectendotrophic mycorrhizae exist in forests and nurseries outside Finland, what kind of mycorrhizae do the E-strains isolated from Scots pine form with other tree species, and are these associations symbiotic.

Only one type of ectendotrophic mycorrhiza was found on the 600 short roots collected from the continents of Europa and America. The type was similar to the one described by Mikola: the mycelium is coarse and forms a strong Hartig net, and intracellular infection is heavy. Evidence is convincing that this structure was formed by the same fungus species. The species is unidentified. Mycorrhizae synthesized by E-strain with six spruce species, fir, hemloch and Douglas fir were all ectotrophic.

The E-type ectendotrophic mycorrhizae proved to be a balanced symbiosis. The seedlings of 13 tree species inoculated with the E-strain grew in the experiment better than the controls. The observation that ectendotrophic mycorrhizae dominates in the nurseries but is seldom found in forests, and then only in seedlings growing in the forest, was confirmed in the study. In synthesis experiments E-strain formed either ecto- or ectendotrophic mycorrhiza depending on the tree species.

  • Laiho, ORCID ID:E-mail:
article id 7160, category Article
Peitsa Mikola. (1965). Studies on the ectendotrophic mycorrhiza of Scots pine in Finland. Acta Forestalia Fennica vol. 79 no. 2 article id 7160. https://doi.org/10.14214/aff.7160

The differences between different types of mycorrhiza; endomycorrhiza, ectomycorrhiza and ectendomycorrhiza, and the use of the terms have been variable in the earlier research. Studied of mycorrhiza in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedlings may suggest that the conditions affect which kind of mycorrhiza develops in the seedlings. This study is aimed mainly at finding out whether the difference of ectotrophic and ectendotrophic mycorrhizae depends on fungal symbionts or envirionmental conditions. Furthermore, the occurrence of ectendotrophic mycorrhiza in Finland under various conditions was studied, and experiments on the physiology and ecology of the mycorrhiza and the fungal partner were conducted.

The ectendotrophic mycorrhiza as described in this paper has proved to be very common on Scots pine in Finnish nurseries, but it was not found in Norway spruce seedlings. The results did not support the hypothesis presented in some earlier studies that ectendotrophic mycorrhiza is more parasitic than the other mycorrhizal fungi. The nursery survey showed that no correlation existed between the size and vigour of the seedlings and the presence of ectendotrophic mycorrhiza. Furthermore, greenhouse-grown seedlings with and without the fungus grew equally well. The type of mycorrhiza was, however, almost exclusively confined to young (1–3-years-old) seedlings and to nursery soils. The experiments indicates also that ectendomycorrhizal fungus has a very wide ecological amplitude in regard to light intensity, soil fertility, acidity, and humus content. It has, however, a weak competitive ability in natural forest soils against the indigenous fungal population. When the seedlings were transplanted from the nursery to forest soil, their mycorrhizal population was largely changed.

  • Mikola, ORCID ID:E-mail:
article id 7158, category Article
Olavi Huuri. (1965). Männyn- ja kuusenkäpyjen varastoinnin vaikutus niistä saatavan siemenen itävyyteen. Acta Forestalia Fennica vol. 78 no. 5 article id 7158. https://doi.org/10.14214/aff.7158
English title: The effects of storage in cones on the viability of pine and spruce seeds.

Seed storing experiments with cones of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) were conducted in Oitti seed extracting plant in Southern Finland from February to December 1955. The pine cones were stores for 267 and the spruce coned for 304 days. In four of the storage methods the cones were packed in sacks and another four in wooden boxes. Sample of cones were taken once a month, seeds were extracted and the germinative capacity was tested. The remaining extracted seeds were placed in storage, and in January 1956 moved to cold seed cellar until 1962, when the viability of the seeds was tested.

According to the results, cleaned pine cones can be stores for at least nine months using almost all methods of storage which are commonly used at our seed traction plants, without hazarding the usability of the seeds. The seeds in spruce cones, however, seemed to be more sensitive to conditions during the storage. The germinative capacity of the spruce seeds began to decrease after the beginning of May. Later the seeds were infected with mould, which increased towards the end of the experiment.

Thus, preservation of the germinative capacity of the seeds of pine and spruce requires storage in different conditions. The results suggest that extraction of spruce seeds should be finished during the cold winter months. It seems that seed in the cones of pine and spruce endure storage in piles of paper or cloth sacks at least as well as in wooden boxes. Occasional warming of the storage, snow and foreign material among the cones and an over meter thick cone layer decreased the germinative capacity of spruce seeds during spring and summer. Spruce seeds that had been extracted immediately after collecting of the cones preserved their germinative capacity well during an eight years storage period.

The PDF includes a summary in English.

  • Huuri, ORCID ID:E-mail:
article id 7150, category Article
Olavi Laiho, Peitsa Mikola. (1964). Studies on the effect of some eradicants on mycorrhizal development in forest nurseries. Acta Forestalia Fennica vol. 77 no. 2 article id 7150. https://doi.org/10.14214/aff.7150

Mycorrhizal association is a characteristic feature of the trees of the northern coniferous forests. The purpose of the present study was to determine what influence some fungicides and herbicides regularly used in Finnish nurseries have on formation and development mycorrhizal in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedlings. The results are based mainly on field experiments in nurseries. First the initiation of mycorrhiza was described in untreated seedlings.

In the first growing season mycorrhizal infection commences fairly late even under normal conditions, i.e. 6–7 weeks after seeding and 3–4 weeks after the formation of the first short roots. Soil disinfectants are commonly used in nurseries before seeding, and they are supposed to evaporate or disintegrate in a few days or 1–2 weeks. In pure culture experiments mycorrhizal fungi proved several times more sensitive than parasitic and indifferent soil moulds to herbicides and fungicides, but in field experiments the delay of mycorrhizal infection caused by them does not seem to harm the seedlings. In the second summer differences of mycorrhizal relations between treated and control plots disappeared. Accordingly, the influence of biocides on mycorrhizae, when applied in the customary concentrations, does not extend beyond the first growing season.

Methyl bromide and SMDC retarded mycorrhiza formation distinctly, while formaldehyde and allyl alcohol had no effect. Apart from not retarding mycorrhizae, formaldehyde and allyl alcohol promoted seedling growth and favoured Trichoderma viride in the soil. Trichoderma is known to be antagonistic to many fungi.

The PDF includes a summary in Finnish.

  • Laiho, ORCID ID:E-mail:
  • Mikola, ORCID ID:E-mail:
article id 7143, category Article
O. Meurman. (1963). Puutarhantutkimuslaitoksella Piikkiössä kokeilluista koristepuista ja -pensaista. Acta Forestalia Fennica vol. 76 no. 3 article id 7143. https://doi.org/10.14214/aff.7143
English title: Notes on ornamental trees and shrubs at the Department of horticulture (Piikkiö, Finland).

Trees and shrubs of foreign origin have been grown in Finland at least from the 1700th century. At the State Horticultural Institute in the neighbourhood of the town Turku in southwestern coast of the country, a number of ornamental trees and shrubs have been planted since 1927. During the first decade, weather conditions were quite favourable, but the winters in 1939–1940 were so severe, that only the hardiest plants survived.

It would be important to study hardiness and suitability of the various woody plants cultivated in the different parts of the country. This paper includes notes of the survival of the tree species and shrubs so far planted at the Institute.

The PDF includes a summary in English.

  • Meurman, ORCID ID:E-mail:
article id 7143, category Article
O. Meurman. (1963). Puutarhantutkimuslaitoksella Piikkiössä kokeilluista koristepuista ja -pensaista. Acta Forestalia Fennica vol. 76 no. 3 article id 7143. https://doi.org/10.14214/aff.7143
English title: Notes on ornamental trees and shrubs at the Department of horticulture (Piikkiö, Finland).

Trees and shrubs of foreign origin have been grown in Finland at least from the 1700th century. At the State Horticultural Institute in the neighbourhood of the town Turku in southwestern coast of the country, a number of ornamental trees and shrubs have been planted since 1927. During the first decade, weather conditions were quite favourable, but the winters in 1939–1940 were so severe, that only the hardiest plants survived.

It would be important to study hardiness and suitability of the various woody plants cultivated in the different parts of the country. This paper includes notes of the survival of the tree species and shrubs so far planted at the Institute.

The PDF includes a summary in English.

  • Meurman, ORCID ID:E-mail:
article id 7114, category Article
Paavo Yli-Vakkuri. (1960). Metsiköiden routa- ja lumisuhteista. Acta Forestalia Fennica vol. 71 no. 5 article id 7114. https://doi.org/10.14214/aff.7114
English title: Snow cover and ground frost in Finnish forests.

Snow cover and ground frost was studied in 29 forest stands in Southern and Central Finland in 1957–1959. The tree species influenced greatly accumulation of snow on the forest floor. Norway spruce (Picea abies (L.) Karst.) retains snow in its crown. In addition, snow and water falling from the branches compress the snow cover under the trees, and the ground freezes deeper because of the shallow snow cover. In the spring, the dense crown prevents rain and radiation reaching the ground, which remains cold longer. However, ground frost may protect spruce, which has a weak root system, from wind damages.

Scots pine (Pinus sylvestris L.) has similar, but milder, effects on snow cover within the forest. The crowns of pine seedlings and young trees pass snow easily, but later the crowns intercept it considerably. The lower branches are, however, high up and the snow is evenly spread on the ground. The deciduous trees intercept little snow and in the spring the snow smelts and the frozen soil thaws early. The snow conditions of deciduous forests are, however, changed by a spruce undergrowth.

It can be assumed that the unfavourable conditions in spruce forests can be alleviated by thinning. Also, mixture of pine and deciduous trees can transform the conditions more favourable in the spruce stands.

The PDF includes a summary in English.

  • Yli-Vakkuri, ORCID ID:E-mail:
article id 7486, category Article
Paavo Yli-Vakkuri. (1959). Siemensiipien hankaajista ja niiden vaikutuksesta siemenen itävyyteen. Acta Forestalia Fennica vol. 68 no. 4 article id 7486. https://doi.org/10.14214/aff.7486
English title: On machines for abrading seed wings and their influence on the germinative capacity of the seed.

This paper deals with two machines designed for abrading seed wings, and their influence on the germinative capacity of seed of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). Both machines are commonly used in Finland.

The results of the study indicate that the act of abrading may cause slight or even serious injuries to the seed. Slight injuries of about 3% are probably not easily avoided if mechanical abrading is resorted to. It must be noted, however, that even this reduction in germinative capacity causes significant yearly loss. If the reduction in germinative capacity is greater, which seems to be possible, it is advisable to test the mechanism of the machine and its method of abrading. As the clearance of the machines can affect the extent of injuries, all machines should be tested. If possible, a continual operation control should be arranged. It could, at the same time, to supply material for improving the abrading method and equipment.

The PDF includes a summary in English.

  • Yli-Vakkuri, ORCID ID:E-mail:
article id 7440, category Article
Erkki K. Kalela. (1954). Mäntysiemenpuiden ja -puustojen juurisuhteista. Acta Forestalia Fennica vol. 61 no. 28 article id 7440. https://doi.org/10.14214/aff.7440
English title: Root systems of Scots pine seed trees and stands.

Root systems of a Scots pine (Pinus sylvestris L.) stands of seed trees on a Vaccinium sites in Southern Finland were studied by taking soil samples around the seed trees. The results show that root system of an old Scots pine spreads relatively evenly around the tree up to at least 10 meters from the stem. The densest part of the root system is near the stem, which part is often acentric. This is probably due to root competition in the early stages of growth of the tree.

Root systems of the seed trees affect stocking of the site with seedlings and the growth of the seedlings. The root competition can cause, for instance, uneven grouping of the seedlings. It seems that the largest trees of a stand have the most even root system. It is therefore recommended to choose the strongest trees of the stand as seed trees, to ensure even distribution of seedlings.

The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.

The PDF includes a summary in German.

  • Kalela, ORCID ID:E-mail:
article id 7436, category Article
E. Salo. (1954). Puiden teknillinen vikaisuus ja sen vaikutus puuston arvoon. Acta Forestalia Fennica vol. 61 no. 24 article id 7436. https://doi.org/10.14214/aff.7436
English title: Technical defects of trees and their effect upon timber value.

In acquiring land for the population displaced by the Second World War, the forest had to be priced, according to the Land Reclamation Act of 1945, separately for land and timber. Technical defects in the growing stock were to be taken account in the form of a total reduction in the value of the stock. Generally, it was to be 5-15% of the total value. The present investigation aims at checking the reduction percentages.

When the reduction in the felling value of the growing stock caused by the defects is estimated, the reduction is defined for each timber assortment, and the total reduction is calculated from these values. The timber assortments have big variation in prices, therefore defects in the most valuable assortments can have big effect on the total value of the growing stock. According to the study, the decree implementing the Land Reclamation Act did not in some cases allow for price reductions for defects on a sufficiently small scale to correspond to real conditions.

The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The PDF includes a summary in English.

  • Salo, ORCID ID:E-mail:
article id 7421, category Article
Olli Heikinheimo. (1954). Taimitarhan maantieteellinen sijainti, siemenen alkuperä ja istutuskaudet. Acta Forestalia Fennica vol. 61 no. 9 article id 7421. https://doi.org/10.14214/aff.7421
English title: Geographical location of a tree nursery, seed origin and planting seasons.

Planning of large central tree nurseries, which has become topical in Finland, means that the seedlings will be used in a wide geographical area. The nursery must decide which proveniences of seeds of the different tree species it will use. This concerns also the customer that buys the seedlings. The planting and lifting of the seedlings in the nursery have to be timed so that the seedlings are in a right state of growth at the time of planting.

The growth of the seedlings can, under certain conditions, be promoted by using a slightly southerly seed provenience, and large-sized seeds. There are, however, limitations to how much the seeds can be transferred northwards. If the nursery lies much south of the planting site, the seedlings have started height growth at the time of planting. This applies especially larch (Larix sp.), Scots pine (Pinus sylvestris L.) and birch (Betula sp.), but affects less Norway spruce (Picea abies (L.) Karst.). The problem can be handled by using a cool storage space for the seedlings waiting for a delivery in the nursery.

According to an international study, seedlings grown from seeds collected in countries south from Finland usually die already during the first two years in the nursery. Within Finland the seeds can be transferred at least by two latitudes. Spruce seems to tolerate longer transfer. Seed orchards should be planted south of the seed’s origin to ensure better yield and better quality seeds.

The Silva Fennica issue 61 was published in honour of professor Eino Saari‘s 60th birthday.
The PDF includes a summary in German.

  • Heikinheimo, ORCID ID:E-mail:
article id 7408, category Article
Kullervo Kuusela. (1953). Zur Theorie der forstlichen Zuwachsberechnung auf Grund der periodischen Messung. Acta Forestalia Fennica vol. 60 no. 1 article id 7408. https://doi.org/10.14214/aff.7408
English title: On theory of forest increment calculation based on periodic measurements.

The article presents the background of increment calculations and periodic measurements of forests, as well the historical development of increment calculations in North-America, Middle-Europe, Scandinavia and Finland. The measurements and calculations are presented for individual trees, for a forest stand and for the total resource of a normal forest stand.   

The practice of increment calculations has still some problems regarding the measurements of standing and harvested trees. The article discusses some ways to overcome the problems. 

  • Kuusela, ORCID ID:E-mail:
article id 7397, category Article
Erkki K. Kalela. (1949). Ecological character of tree species and its relation to silviculture. Acta Forestalia Fennica vol. 57 no. 1 article id 7397. https://doi.org/10.14214/aff.7397

The tendency of successional development from young vegetation, rich in species and exposed to chance factors, towards regular plant communities, is found all around the world. Thee ecological groups of trees seem to be present in all forest regions in the world, namely the pioneer and the climax species, and a group of pre-climax species that can be ecologically either near the pioneer or the climax species. The succession of tree species in forest always leads to a climax stand, determined by climate, quality of soil and the mutual biotical strengths of the tree species in the region.

This division into ecological groups greatly facilitates choosing among different methods of treating stands and understanding the silvicultural methods of foreign regions. Stands formed by species of the same group must follow the same lines in their silvicultural treatment. For instance, mixed stand consisting of both pioneer and climax species represents a transition stage, in which the climax species strive for dominating position, and preservation of pioneer species is difficult. This indicates the broad lines for management of the stand. Also, regeneration methods of pioneer and climax species must be different. Studying the succession of natural forests can be used as a means to reach the highest possible silvicultural level. This is one reason why the preservation and study of virgin forests still in existence is indispensable.

The PDF includes a summary in Finnish.

  • Kalela, ORCID ID:E-mail:
article id 7370, category Article
Erkki K. Kalela. (1942). Männyn taimien juurien suhtautumisesta emäpuun juuriin. Acta Forestalia Fennica vol. 50 no. 17 article id 7370. https://doi.org/10.14214/aff.7370
English title: Roots of a seedling in relation to roots of the mother tree.

The study is based on observations in a Scots pine (Pinus sylvestris L.) stand on a dry upland forest site in Karhumäki, where a 10-15-year old seedling stand grew under a hold-overs of larger trees that had been left in the site in a previous felling. The root systems of 80-120 cm tall seedlings growing around single mother trees were unearthed. Root maps were drawn of the root systems of 120 seedlings.

No seedlings grew around old, large hold-overs. It seems that seedlings could not compete with their root system. If the hold-overs were stunted in their growth, seedlings grew also under the canopy of the mother tree. 90% of the seedlings had a tap root. Rest of the roots grew horisontally in the topsoil. Around a vigorous mother tree, the seedlings grew their roots away from the mother tree. Hold-overs that had belonged originally to the lower canopy layer of the old forest did not have similar effect on the root orientation of the seedlings. Their roots had been previously affected by trees of higher canopy layer, later removed in the felling.

The PDF includes a summary in German.

  • Kalela, ORCID ID:E-mail:
article id 7358, category Article
Arvo Ylinen. (1942). Über den Einfluss des Spätholzanteils und der Rohwichte auf die Festigkeits- und elastischen Eigenschaften des Nadelholzes. Acta Forestalia Fennica vol. 50 no. 5 article id 7358. https://doi.org/10.14214/aff.7358
English title: The effect of the amount of the summer wood on the elastic and tensile properties of coniferous trees.

The dependence of elastic and tensile properties of coniferous trees on the share of summer wood can be presented as linear functions, if the soft wood is considered as a statically indefinite structure. By eliminating the share of summer wood by a certain function presented in the article, the elastic and tensile properties are the linear functions of density.

The functions are proved right by conducting strength tests on pine. Practical implications of the derived functions in rating the quality of wood are also presented.

The PDF contains a summary in Finnish. 

  • Ylinen, ORCID ID:E-mail:
article id 7350, category Article
Ilmari Paasio. (1941). Zur Pflanzensoziologischen Grundlage der Weissmoortypen. Acta Forestalia Fennica vol. 49 no. 3 article id 7350. https://doi.org/10.14214/aff.7350
English title: Plant sociological principles of open bog types.

The plant populations of Finnish open bogs are typically formed of two layers. The layers normally consist of one or rarely two species. The structure of plant populations in open bogs is a consequence of the development where determining factors are different site requirements of the species, and the differences in the biotic vitality and capacity for reproduction.

Phytogenesis should be taken as a basic unit for describing the plant societies or vegetation of treeless bogs. However, acknowledging the sub-populations may be of advantage for describing the ecological, genetic and regional characters of open bogs.

The basic classification of open bogs must be done based on the ground layer. The more detailed classification follows mostly based on field layer, partly also based on the ground layer.

The PDF contains a summary in Finnish. 

  • Paasio, ORCID ID:E-mail:
article id 7338, category Article
Sakari Saarnijoki. (1937). Tampereen kaupungin ja sen lähiympäristön koristepuista ja -pensaista. Acta Forestalia Fennica vol. 46 no. 3 article id 7338. https://doi.org/10.14214/aff.7338
English title: Ornamental trees and shrubs in city of Tampere and the surrounding areas.
English keywords: park; garden; exotic species; shrub; fruit tree

The article is a report of the exotic tree and shrub species found in major parks and gardens in the city of Tampere, in Southern Finland, and the surrounding areas, including fruit trees and berry bushes. The survey of species was conducted in 1934-1935. There was a total of 221 tree and shrub species in the 245 parks and gardens of the city. Exotic species was found 193, of which 37 was introduced only recently. The frequency of 199 species in Tampere area and the condition of each species is listed. Most common are the native species of the genus Picea, Pinus, Betula, Acer, Prunus and Sorbus. Of the exotic species only Malus pumila (Mill.) is commonly cultivated. Relatively common are Ulmus montana (With.), Tilia cordata (Mill.) and Fraxinus excelsior (L.).

The PDF includes a summary in German.

  • Saarnijoki, ORCID ID:E-mail:
article id 7334, category Article
T. J. Hintikka. (1937). Über die Verbänderungen und Hexenbesen an der Traubenkirsche (Prunus Padus L.). Acta Forestalia Fennica vol. 45 no. 2 article id 7334. https://doi.org/10.14214/aff.7334
English title: On fasciations and witches‘ brooms on (European) bird cherry trees (Prunus padus L.).

The article presents six fasciations found in Finland on bird cherry trees. Based on the literature it seems that fasciations are the precondition for witches’ brooms. The witches’ brooms on bird cherry trees are rare, but they have been mentioned in literature. Some views on their occurrence and development are represented. Also the possible causes behind the developments are discussed based on literature.  

The PDF contains a summary in Finnish.  

  • Hintikka, ORCID ID:E-mail:
article id 7303, category Article
J. Keränen. (1934). Lämpöoloista puiden ja eräiden pensaiden kasvupaikkojen pohjoisilla rajoilla Suomessa. Acta Forestalia Fennica vol. 40 no. 26 article id 7303. https://doi.org/10.14214/aff.7303
English title: Thermal conditions in the northern limits of some tree species and bushes in Finland.

The article discusses the thermal conditions in the northern limits of trees and some bushes in Finland. Temperature is the most important limiting factor for distribution of plant species. Precipitation variations, however, are small in Finland. The article lists the main features of thermal conditions during the different seasons in different parts of Finland. The northern limits and the thermal condition of the area are described for the following species: Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.), mezereon, buckthorn, common alder, linden, elm, maple, hazel, ash, oak, hybrid mountain ash, yew and Swedish whitebeam.

The PDF includes a summary in English.

  • Keränen, ORCID ID:E-mail:
article id 7302, category Article
M. Lappi-Seppälä. (1934). Karsimisesta ja sen metsänhoidollisesta merkityksestä. Acta Forestalia Fennica vol. 40 no. 25 article id 7302. https://doi.org/10.14214/aff.7302
English title: The silvicultural influences of pruning.

Pruning growing trees influences tree growth and value of the wood and yield of timber of the stand. Pruning living branches create open wounds on the stems that can risk the growth of tree species that are vulnerable to injuries. For instance, pruning has been shown to cause decay in Norway spruce (Picea abies (L.) H. Karst.), while Scots pine (Pinus sylvestris L.) can quickly heal over the branch scars. Pruning of living branches reduces the crown, the effect of which remains small if only the lowest branches are pruned. Pruning of dry branches has little effect on the health of the tree. The main objective of pruning is to improve the quality of timber. Knottiness decreases strength and appearance of timber. Pruning increases the yield of knot-free sapwood, which is especially valuable in veneer timber. Pruning is, therefore, at present most suitable for birch and aspen which are used in veneer industry. In both species pruning should be directed mainly to dry branches.

The PDF includes a summary in German.

  • Lappi-Seppälä, ORCID ID:E-mail:
article id 7297, category Article
A. L. Backman. (1934). Om den Åländska skogens förhistoria. Acta Forestalia Fennica vol. 40 no. 20 article id 7297. https://doi.org/10.14214/aff.7297
English title: Early history of forests in Åland, Finland.

The paper presents preliminary results of paleobotanical studies on vegetation in Åland, south-west Finland. The investigations concentrated on studying arrival of tree species and stratigraphy of peatlands. According to the studies, some plant fossils found in the peat (Ceratophyllum submersum, Sparagnium neglectum, Najas flexilis) indicate that climate of the region has earlier been warmer than at the present. The present forests in Åland are dominated by coniferous species, but the pollen analysis of the peat indicate that Norway spruce (Picea abies (L.) H. Karst.) became a common species in the region about by the time of Christ’s birth. The species has reached its present distribution in Åland relatively late. The pollen analyses give relatively little information about the arrival of birch (Betula sp.) and Scots pine (Pinus sylvestris L.), but it seems obvious that occurrence of birch reached its culmination just before spruce. During the warm period common alder (Alnus glutinosa (L.) Gaertn.) was the most important species, and also pollen of oak (Quercus robur L.), kinden (Tilia cordata L.) and elm (Ulmus sp.) was relatively common in the peat of some of the studied peatlands. An interesting finding was the pollen of Carpinus betulus in many sites in Åland.

The PDF includes a Finnish and German summary.

  • Backman, ORCID ID:E-mail:
article id 7295, category Article
O. J. Lukkala. (1934). Lounais-Suomen metsien puulajihistoriasta. Acta Forestalia Fennica vol. 40 no. 18 article id 7295. https://doi.org/10.14214/aff.7295
English title: The history of tree species in southwest Finland.

Pollen analysis has given information on development of the tree species composition after the ice age, but this kind of studies have not been published in Finland. In this study, pollen analysis was performed in five peatlands in the southwest Finland. According to the analysis, the forests of the area have had similar tree species composition for many thousands of years. Scots pine (Pinus sylvestris L.) has been the dominant species as long as there has been Norway spruce (Picea abies (L.) H. Karst.) in the area. Norway spruce seems to have arrived about 4,500 years ago. It increased slowly in the beginning, and after reaching a maximum has been slowly decreasing. Before spruce arrived, Betula sp. was more abundant, and seemed to be the dominant tree species in some places. Traces of fire in the peat layers indicate that forest fires have been common before people arrived in the area, and may have beneficial to birch. Like Betula sp., also Alnus sp. were more common before spruce arrived. Also pollen of other broadleaved species, for example, Tilia sp., Ulmus sp. and Corylus could be found. However, Quercus pollen was not found. The paludification of the peatlands had begun at different times which indicates that there has not been a common cause for the development of the peatlands in the area.

The PDF includes a summary in German.

  • Lukkala, ORCID ID:E-mail:
article id 7228, category Article
Agnar Barth. (1929). Skjermforyngelsen i produksjonsökonomisk belysning. Acta Forestalia Fennica vol. 34 no. 15 article id 7228. https://doi.org/10.14214/aff.7228
English title: Natural regeneration from the production economic point of view.

Natural regeneration has been studied so far mostly on the perspective of regeneration, while the production capacity of the seed crop stand has been of little interest in the earlier studies. This paper studied volume growth of the seed trees and the economic impact of this regeneration method both in a literature review and measuring sample stands consisting of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) dominated stands and mixed forests in Norway.

It is concluded that in the most cases the seed tree stands give better pulpwood and timber yield than the stands in the average. The reason might be that the elite stems can better use their production capacity, and, thus, reach bigger and more valuable dimensions. Even though the growing stock diminishes in the seeding felling, the growth of the stand does not decrease or decreases only little. At the same time, the quality growth improves. In addition, the new tree regeneration is achieved usually without extra costs, and there is no unproductive time period in the stand.

  • Barth, ORCID ID:E-mail:
article id 7225, category Article
A. E. Osmaston. (1929). On the forest types in India. Acta Forestalia Fennica vol. 34 no. 12 article id 7225. https://doi.org/10.14214/aff.7225

Forest site type classification based on the vegetation has not been developed in India. The classifications made by forest officers have been based on the upper storeys of trees. Shrubs have been used to class such sites where grasses are the dominant species. However, some observers in India have used grass and bamboo species to identify sites suitable on unsuitable for certain valuable tree species. In Burma, some bamboo species have been noticed to be good indicators for sites suitable or unsuitable for teak (Tectona grandis L. f.). Studies in the western sub-Himalayan area suggest that certain grasses could be used as indicators for sites suitable for sal (Shorea robusta Gaertn.). Grasses have also been identified as indicators for certain kinds of forests and soils in the area between Ganges and the Jumna.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Osmaston, ORCID ID:E-mail:
article id 7218, category Article
John W. Harshberger. (1929). The forests of the Pacific coasts of British Columbia and Southeastern Alaska. Acta Forestalia Fennica vol. 34 no. 5 article id 7218. https://doi.org/10.14214/aff.7218

The vegetation in the Pacific coasts of British Columbia and Southeastern Alaska resemble the vegetation in the northern Fennoscandia. The national forests have been divided in two parts: Tongass and Chugach national forests. Both of the forests are fairly uniform in their vegetation. The forests have few coniferous tree species as the dominant species from south to north, Sitka spruce (Picea sitchensis (Bong.) Carrière) and western hemloch (Tsuga heterophylla (Raf.) Sarg.). It is difficult to distinguish forest site types, but it is probable that the forest lands in Alaska and British Columbia could be delimited to similar forest site types as professor Cajander established in Finland.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Harshberger, ORCID ID:E-mail:
article id 7217, category Article
Bunzo Hayata. (1929). Succession in the vegetation of Mt. Fuji. Acta Forestalia Fennica vol. 34 no. 4 article id 7217. https://doi.org/10.14214/aff.7217

­In different altitudes of the Mount Fuji in Japan occur succession of different tree species. For instance, at an altitude of 2,000 meters are pure stands of Tsuga diversifolia (Maxim.), under which is generally found young trees of Abies veitchii (Lindl.), but not of Tsuga. Abies veitchii is in its turn replaced perhaps with Larix sp. The succession of the forests of the volcano have reached maturity, which is not the case in the east–north-east flank of the mountain, where the Hōei eruption destroyed all vegetation in 1707. The vegetation had not revived even by the 1920s. The Hōei eruption site is compared to the much faster return of vegetation in mount Krakatau in the warmer tropical region. The succession of forests in the other parts of the mountain is described in detail. Finally, a succession theory is proposed that is opposed to the natural selection theory. The theory suggests that there is an Innermost Factor that controls the plant succession. According to the theory, every species, every formation, should die its natural death owing to the Innermost Factor.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Hayata, ORCID ID:E-mail:
article id 7216, category Article
L. Cockayne. (1929). Hybridism in the forests of New Zealand. Acta Forestalia Fennica vol. 34 no. 3 article id 7216. https://doi.org/10.14214/aff.7216

The article gives examples of hybridization of forest tree and shrub species in the forests of New Zealand. According to the article, many of the 498 vascular plant species in the forest communities of the New Zealand region must be excluded from the standpoint of hybridism, because they belong either to genera of one species or are unable to cross owing to geographical or biological isolation. The hybrids are in most cases jordanons which cross, and may be more or less distantly related or closely related. The hybrids occur usually in polymorphic groups. Most of the hybrids in New Zealand are fertile. The hybrids can affect the forest communities in two ways; by effecting their composition or their structure. The article includes a list of hybrid groups.

Jubileum publication of professor Aimo Kaarlo Cajander.

  • Cockayne, ORCID ID:E-mail:
article id 5629, category Article
Risto Sievänen, Eero Nikinmaa, Jari Perttunen. (1997). Evaluation of importance of sapwood senescence on tree growth using the model Lignum. Silva Fennica vol. 31 no. 3 article id 5629. https://doi.org/10.14214/sf.a8531

The effects of two alternative formulations of sapwood senescence on the behaviour of model LIGNUM (with parameter values adjusted for Scots pine (Pinus sylvestris L.) growing southern Finland) were studied. The two alternatives were autonomous sapwood senescence assuming a maximum age for the tree ring, and sapwood senescence that is controlled by the mortality of foliage. For the latter alternative two hypothetical further mechanisms were stipulated. All the formulations were implemented in LIGNUM. Simulations were made with all model variants for fertile and poor soil conditions using high, normal and low rates of foliage mortality. The simulation results were compared against of a data set consisting of 11 open grown Scots pine trees from southern Finland. Observations of heartwood proportion were used in this study. They show that heartwood starts to increase in trees from age of approximately 20 years onwards. The simulation results showed no differences between fertile and poor soil conditions as regards heartwood formation. Of the variants of foliage-controlled sapwood senescence the one where death of sapwood in a tree segment induces sapwood senescence in the tree parts below only slightly was the best. This and the autonomous sapwood senescence corresponded equally well to the observations. In order to make more refined conclusions additional data and simulations are necessary.

  • Sievänen, ORCID ID:E-mail:
  • Nikinmaa, ORCID ID:E-mail:
  • Perttunen, ORCID ID:E-mail:
article id 5626, category Article
Winfried Kurth, Branislav Sloboda. (1997). Growth grammars simulating trees – an extension of L-systems incorporating local variables and sensitivity. Silva Fennica vol. 31 no. 3 article id 5626. https://doi.org/10.14214/sf.a8527

The rule-based formal language of "stochastic sensitive growth grammars" was designed to describe algorithmically the changing morphology of forest trees during their lifetime under the impact of endogenous and exogenous factors, and to generate 3-D simulations of tree structures in a systematic manner. The description in the form of grammars allows the precise specification of structural models with functional components. These grammars (extended L-systems) can be interpreted by the software GROGRA (Growth grammar interpreter) yielding time series of attributed 3-D structures representing plants. With some recent extensions of the growth-grammar language (sensitive functions, local variables) it is possible to model environmental control of shoot growth and some simple allocation strategies, and to obtain typical competition effects in tree stands qualitatively in the model.

  • Kurth, ORCID ID:E-mail:
  • Sloboda, ORCID ID:E-mail:
article id 5626, category Article
Winfried Kurth, Branislav Sloboda. (1997). Growth grammars simulating trees – an extension of L-systems incorporating local variables and sensitivity. Silva Fennica vol. 31 no. 3 article id 5626. https://doi.org/10.14214/sf.a8527

The rule-based formal language of "stochastic sensitive growth grammars" was designed to describe algorithmically the changing morphology of forest trees during their lifetime under the impact of endogenous and exogenous factors, and to generate 3-D simulations of tree structures in a systematic manner. The description in the form of grammars allows the precise specification of structural models with functional components. These grammars (extended L-systems) can be interpreted by the software GROGRA (Growth grammar interpreter) yielding time series of attributed 3-D structures representing plants. With some recent extensions of the growth-grammar language (sensitive functions, local variables) it is possible to model environmental control of shoot growth and some simple allocation strategies, and to obtain typical competition effects in tree stands qualitatively in the model.

  • Kurth, ORCID ID:E-mail:
  • Sloboda, ORCID ID:E-mail:
article id 5626, category Article
Winfried Kurth, Branislav Sloboda. (1997). Growth grammars simulating trees – an extension of L-systems incorporating local variables and sensitivity. Silva Fennica vol. 31 no. 3 article id 5626. https://doi.org/10.14214/sf.a8527

The rule-based formal language of "stochastic sensitive growth grammars" was designed to describe algorithmically the changing morphology of forest trees during their lifetime under the impact of endogenous and exogenous factors, and to generate 3-D simulations of tree structures in a systematic manner. The description in the form of grammars allows the precise specification of structural models with functional components. These grammars (extended L-systems) can be interpreted by the software GROGRA (Growth grammar interpreter) yielding time series of attributed 3-D structures representing plants. With some recent extensions of the growth-grammar language (sensitive functions, local variables) it is possible to model environmental control of shoot growth and some simple allocation strategies, and to obtain typical competition effects in tree stands qualitatively in the model.

  • Kurth, ORCID ID:E-mail:
  • Sloboda, ORCID ID:E-mail:
article id 5625, category Article
Thomas Früh. (1997). Simulation of water flow in the branched tree architecture. Silva Fennica vol. 31 no. 3 article id 5625. https://doi.org/10.14214/sf.a8526

The model HYDRA, which simulates water flow in the branched tree architecture, is characterized. Empirical studies of the last decades give strong evidence for a close structure-function linkage in the case of tree water flow. Like stomatal regulation, spatial patterns of leaf specific conductivity can be regarded as a strategy counteracting conductivity losses, which may arise under drought. Branching-oriented water flow simulation may help to understand how damaging and compensating mechanisms interact within the hydraulic network of trees. Furthermore, a coupling of hydraulic to morphological modelling is a prerequisite if water flow shall be linked to other processes. Basic assumptions of the tree water flow model HYDRA are mass conservation, Darcy's law and the spatial homogeneity of capacitance and axial conductivity. Soil water potential is given as a one-sided border condition. Water flow is driven by transpiration. For unbranched regions these principles are condensed to a nonlinear diffusion equation, which serves as a continuous reference for the discrete method tailored to the specific features of the hydraulic network. The mathematical derivation and model tests indicate that the realization of the basic assumptions is reproducible and sufficiently exact. Moreover, structure and function are coupled in a flexible and computationally efficient manner. Thus, HYDRA may serve as a tool for the comparative study of different tree architectures in terms of hydraulic function.

  • Früh, ORCID ID:E-mail:
article id 5624, category Article
Hervé Sinoquet, Christophe Godin, Pierre Rivet. (1997). Assessment of the three-dimensional architecture of walnut trees using digitising. Silva Fennica vol. 31 no. 3 article id 5624. https://doi.org/10.14214/sf.a8525

A method for the measurement of the three-dimensional (3D) architecture of trees was applied to describe two 20-year-old walnut trees, one of them is a timber tree while the other is a fruit tree. The method works at the shoot level and simultaneously describes the plant topology, the plant geometry and the shoot morphology. The method uses a 3D digitiser (3SPACE® FASTRAK®, Polhemus Inc.) associated with software DiplAmi designed for digitiser control and data acquisition management. Plant images may be reconstructed from the data set by using the ray tracing software POV-Ray. Visual comparison between photographs of the walnut trees and images synthesised from digitising was satisfactory. Distribution of basal shoot diameter, as well as leaf area and fruit distributions for both the timber and the fruit tree were non-uniformly distributed in the crown volume. Gradients were likely to be related to the light distribution within the tree. This is in agreement with previous experimental results on several tree species, and also with the predictions of tree architecture models based on light-vegetation interactions.

  • Sinoquet, ORCID ID:E-mail:
  • Godin, ORCID ID:E-mail:
  • Rivet, ORCID ID:E-mail:
article id 5622, category Article
Christine Deleuze, François Houllier. (1997). A transport model for tree ring width. Silva Fennica vol. 31 no. 3 article id 5622. https://doi.org/10.14214/sf.a8523

Process-based tree growth models are recognized to be flexible tools which are valuable for investigating tree growth in relation to changing environment or silvicultural treatments. In the context of forestry, we address two key modelling problems: allocation of growth which determines total wood production, and distribution of wood along the stem which determines stem form and wood quality. Growth allocation and distribution are the outcome of carbon translocation, which may be described by the Munch theory. We propose a simpler gradient process to describe the carbon distribution in the phloem of conifers. This model is a reformulation of a carbon diffusion-like process proposed by Thornley in 1972. By taking into account the continuity of the cambium along the stem, we obtain a one-dimensional reaction-diffusion model which describes both growth allocation between foliage, stem and roots, and growth distribution along the stem. Distribution of wood along the stem is then regarded as an allocation process at a smaller scale. A preliminary sensitivity analysis is presented. The model predicts a strong relationship between morphology and foliage-root allocation. It also suggests how empirical data, such as stem analysis, could be used to calibrate and validate allocation rules in process-based growth models.

  • Deleuze, ORCID ID:E-mail:
  • Houllier, ORCID ID:E-mail:
article id 5608, category Article
Harri Mäkinen. (1997). Possibilities of competition indices to describe competitive differences between Scots pine families. Silva Fennica vol. 31 no. 1 article id 5608. https://doi.org/10.14214/sf.a8509

Possibilities of distance-independent and -dependent competition indices to describe the competition stress of an individual tree was studied in Southern Finland. Five half-sib open-pollinated families and one check lot of Scots pine (Pinus sylvestris L.) was used as study material in order to analyse competitive interactions of crown form and stand density variation. Almost all competition indices correlated strongly with radial increment. Thus distance-independent indices were adequate to describe competition in young row plantations, where distance effects between trees were implicitly eliminated. Correlations between indices and height increment were not significant. Along with the increase in competition, the width and length of the crown and the diameter increment of the stem of some narrow-crowned families decreased slowly compared to wide-crowned families.

  • Mäkinen, ORCID ID:E-mail:
article id 5608, category Article
Harri Mäkinen. (1997). Possibilities of competition indices to describe competitive differences between Scots pine families. Silva Fennica vol. 31 no. 1 article id 5608. https://doi.org/10.14214/sf.a8509

Possibilities of distance-independent and -dependent competition indices to describe the competition stress of an individual tree was studied in Southern Finland. Five half-sib open-pollinated families and one check lot of Scots pine (Pinus sylvestris L.) was used as study material in order to analyse competitive interactions of crown form and stand density variation. Almost all competition indices correlated strongly with radial increment. Thus distance-independent indices were adequate to describe competition in young row plantations, where distance effects between trees were implicitly eliminated. Correlations between indices and height increment were not significant. Along with the increase in competition, the width and length of the crown and the diameter increment of the stem of some narrow-crowned families decreased slowly compared to wide-crowned families.

  • Mäkinen, ORCID ID:E-mail:
article id 5600, category Article
Anton K. Chtchoukine. (1996). North European platyphyllous forests: biodiversity dynamics and climate changes in northwest European Russia. Silva Fennica vol. 30 no. 2–3 article id 5600. https://doi.org/10.14214/sf.a9245

Distribution, biodiversity and reforestation dynamics of the platyphyllous forests in the Northwest European Russia were investigated. Data assembled from 21 landscape regions (250–350 km2 each) show special features of small-leaved lime (Tilia cordata Mill., Norway maple (Acer platanoides L.), mountain elm (Ulmus glabra Mill.) and English oak (Qurecus robur L.) reforestation during the last two decades. New tendencies were found for the taiga areas with natural Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) vegetation. Natural platyphyllous reforestation in cut spruce areas poses as supposed a special question for forest management policy in the relationship to global climate changes. Feasible unsustainability of the common types of succession (Norway spruce - European birch (Betula pendula Roth); Norway spruce - European aspen (Populus tremula L.)) is discussed. Biodiversity of herbs, shrubs and tree species of platyphyllous forests is high and complex and is situated in 4–15 old-growth relics in each landscape region. Low-level genotype heterogeneity of nemoral flora species of such isolated populations is presumed. Special biodiversity conservation regulations are proposed.

  • Chtchoukine, ORCID ID:E-mail:
article id 7197, category Article
Erik Lönnroth. (1926). Der stereometrische Bestandesmittelstamm. Acta Forestalia Fennica vol. 30 no. 2 article id 7197. https://doi.org/10.14214/aff.7197
English title: The stereometric mean tree of the stand.

The mean has a great importance in statistics in general and also in forest statistical calculations. The meaning of the average tree and its characteristics is important also for the practical forest mensuration work. However, the question is how are the statistical numbers of a mean tree related to the statistical numbers of the stand.   

Study is based on the strip-wise survey of forests in southern Finland. From that information the 30 sample plots were chosen, 10 of each of most typical forest site types, MT, VT and CT. The stands are of different ages and development classes, varying from 14 to 159 years.

For the determination of the average tree are the statistical numbers of five characteristics needed: volume, basal area, diameter, height and form factor. The stereometric mean tree of the stand can be calculated with only one statistical method and that solution is absolute.

Theoretically and statistically absolute solution for the problem is the continuous solution by the mean that is weighted with the number of stems. This solution however is not very useful in practical sense.

A simple, practical and adequately exact solution for determining the average tree by approximation procedure of a certain arithmetic mean. 

  • Lönnroth, ORCID ID:E-mail:
article id 7197, category Article
Erik Lönnroth. (1926). Der stereometrische Bestandesmittelstamm. Acta Forestalia Fennica vol. 30 no. 2 article id 7197. https://doi.org/10.14214/aff.7197
English title: The stereometric mean tree of the stand.

The mean has a great importance in statistics in general and also in forest statistical calculations. The meaning of the average tree and its characteristics is important also for the practical forest mensuration work. However, the question is how are the statistical numbers of a mean tree related to the statistical numbers of the stand.   

Study is based on the strip-wise survey of forests in southern Finland. From that information the 30 sample plots were chosen, 10 of each of most typical forest site types, MT, VT and CT. The stands are of different ages and development classes, varying from 14 to 159 years.

For the determination of the average tree are the statistical numbers of five characteristics needed: volume, basal area, diameter, height and form factor. The stereometric mean tree of the stand can be calculated with only one statistical method and that solution is absolute.

Theoretically and statistically absolute solution for the problem is the continuous solution by the mean that is weighted with the number of stems. This solution however is not very useful in practical sense.

A simple, practical and adequately exact solution for determining the average tree by approximation procedure of a certain arithmetic mean. 

  • Lönnroth, ORCID ID:E-mail:
article id 5574, category Article
Jouni Vettenranta. (1996). Effect of species composition on economic return in a mixed stand of Norway spruce and Scots pine. Silva Fennica vol. 30 no. 1 article id 5574. https://doi.org/10.14214/sf.a9219

The effect of species mixture was studied in a mixed stand of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) by simulating around 100 different treatment schedules during the rotation in a naturally regenerated even-aged stand located on a site of medium fertility in North Karelia, Finland. Both thinning from below and thinning from above were applied. Optimum rotations were determined by maximising the net present value calculated to infinity and different treatment schedules were compared with the net present value over one rotation as per rotation applied. In the optimum treatment programme, the proportion of pines was decreased by half of the basal area in the first thinning stage and by the end of the rotation to about one third. In thinning from above, the proportion of pines can be maintained at a slightly higher level. It is economically profitable to maintain the growing stock capital at approximately the level recommended by Forest Centre Tapio, a semi-governmental forestry authority. With non-optimum species composition, the loss in net present value over one rotation can be about 10 % in thinning from below and about 20 % in thinning from above.

  • Vettenranta, ORCID ID:E-mail:
article id 5561, category Article
Jari Liski. (1995). Variation in soil organic carbon and thickness of soil horizons within a boreal forest stand – effect of trees and implications for sampling. Silva Fennica vol. 29 no. 4 article id 5561. https://doi.org/10.14214/sf.a9212

Spatial variation in the density of soil organic carbon (kg/m2) and the thickness of soil horizons (F/H, E) were investigated in a 6 m x 8 m area in Scots pine (Pinus sylvestris L.) stand in Southern Finland for designing an effective sampling for the C density and studying the effect of trees on the variation. The horizon thickness of the podzolized soil were measured on a total of 126 soil cores (50 cm deep) and the C density of the organic F/H and 0–10 cm, 10–20 cm and 20–40 cm mineral soil layers was analysed.

The C density varied 3–5 fold within the layers and the coefficients of variation ranged from 22 % to 40%. Considering the gain in confidence per sample, 8–10 samples were suggested for estimating the mean C density in the F/H and 0–40 cm layers, although about 30 samples are needed for 10% confidence in the mean. The C densities and horizon thicknesses were spatially dependent within the distances of 1–8 m, the spatial dependence accounting for 43–86% of the total variance. The F/H layer was thicker and contained more C within 1–3 m radius from trees. In the 10–20 cm and 20–40 cm layers (B horizon) the C density also increased towards the trees, but more pronouncedly in the immediate vicinity of the stems. Because the spatial patterning of the E horizon thickness was similar, the increase was attributed to stemflow and precipitation of organic compounds in the podzol B horizon.

  • Liski, ORCID ID:E-mail:
article id 5559, category Article
Jari Hynynen. (1995). Predicting the growth response to thinning for Scots pine stands using individual-tree growth models. Silva Fennica vol. 29 no. 3 article id 5559. https://doi.org/10.14214/sf.a9210

Individual tree-growth models for diameter and height, and a model for the cylindrical stem form factor are presented. The aims of the study were to examine modelling methods in predicting growth response to thinning, and to develop individual-tree, distance-independent growth models for predicting the development of thinned and unthinned stands of Scots pine (Pinus sylvestris L.). The models were constructed to be applicable in simulation systems used in practical forest management planning. The models were based on data obtained from eleven permanent thinning experiments located in even-aged Scots pine stands in Southern and Central Finland.

Two alternative models were developed to predict tree diameter growth in thinned and unthinned stands. In the first model, the effect of stand density was described using stand basal area. In the alternative model, an explicit variable was incorporated referring to the relative growth response due to thinning. The magnitude of the growth response was expressed as a function of thinning intensity. The Weibull function was employed to describe the temporal distribution of the thinning response. Both models resulted in unbiased predictions in unthinned and in moderately thinned stands. An explicit thinning variable was needed for unbiased growth prediction in heavily thinned stands, and in order to correctly predict the dynamics of the growth response.

In the height growth model, no explicit thinnning variable referring thinning was necessary for growth prediction in thinned stands. The stem form factor was predicted using the model that included tree diameter and tree height as regressor variables. According to the results obtained, the information on the changes in the diameter/height ratio following the thinning is sufficient to predict the change in stem form.

  • Hynynen, ORCID ID:E-mail:
article id 7191, category Article
V. T. Aaltonen. (1925). Allgemeines über die Einwirkung der Bäume auf einander. Acta Forestalia Fennica vol. 29 no. 1 article id 7191. https://doi.org/10.14214/aff.7191
English title: On the influence of trees to each other.
Original keywords: Wachstumsfaktor; Baum; Vechselwirkung
English keywords: growth factor; tree; interactions

The article discusses the growth factors, the influence of the seed tree to the seedlings and the relations of the trees within one age class in sense of growth of the trees and their effect for practical forest management.

The author concludes by noticing that there is a remarkable gap in knowledge about growth factors and more research is needed especially on the interactions of various growth factors. Earlier research on forests has not taken the characteristics of the site and its effect into account adequately. In addition to the observations in the nature, the individual growth factors and their interactions should be studied quantitatively.    

  • Aaltonen, ORCID ID:E-mail:
article id 5539, category Article
Tore Skrøppa. (1994). Impacts of tree improvement on genetic structure and diversity of planted forests. Silva Fennica vol. 28 no. 4 article id 5539. https://doi.org/10.14214/sf.a9179

After a presentation of basic biodiversity concepts, reviews are made of studies reporting genetic implications of tree improvement activities: seed treatments, seedling production, provenance transfers, plus tree selection, seed production in seed orchards and progeny testing.

Several of the activities may influence the genetic structure and diversity of the planted forests. The general conclusion is, however, that planted forests are at least as genetically diverse as the natural stands that they replace. The diversity in forest management and use is best assurance for the future adaptability of the forests.

  • Skrøppa, ORCID ID:E-mail:
article id 5539, category Article
Tore Skrøppa. (1994). Impacts of tree improvement on genetic structure and diversity of planted forests. Silva Fennica vol. 28 no. 4 article id 5539. https://doi.org/10.14214/sf.a9179

After a presentation of basic biodiversity concepts, reviews are made of studies reporting genetic implications of tree improvement activities: seed treatments, seedling production, provenance transfers, plus tree selection, seed production in seed orchards and progeny testing.

Several of the activities may influence the genetic structure and diversity of the planted forests. The general conclusion is, however, that planted forests are at least as genetically diverse as the natural stands that they replace. The diversity in forest management and use is best assurance for the future adaptability of the forests.

  • Skrøppa, ORCID ID:E-mail:
article id 5506, category Article
Risto Heikkilä, Sauli Härkönen. (1993). Moose (Alces alces L.) browsing in young Scots pine stands in relation to the characteristics of their winter habitats. Silva Fennica vol. 27 no. 2 article id 5506. https://doi.org/10.14214/sf.a15667

Moose (Alces alces L.) browsing was studied in young Scots pine (Pinus sylvestris L.) stands mixed with deciduous trees in high-density winter ranges. The proportional use of twig biomass decreased as the availability increased. The total as well as proportional biomass consumption were higher on the moist than on the dry type of forest. The per tree consumption of pine was higher on the moist type, where the availability of pine was lower. Deciduous trees were more consumed on the moist type, where their availability was relatively high. The consumption of pine saplings increased as the availability of birch increased. Pine stem breakages were most numerous when birch occurred as overgrowth above pine and at high birch densities. The availability of other deciduous tree species did not correlate with browsing intensity of Scots pine. Moose browsing had seriously inhibited the development of Scots pines in 6% of the stands, over 60% of available biomass having been removed. Rowan and aspen were commonly over-browsed and their height growth was inhibited, which occurred rarely by birch. There was no difference in the proportion of young stands in forest areas with high and low moose density. A high proportion of peatland forests was found to indicate relatively good feeding habitats in the high-density areas.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Härkönen, ORCID ID:E-mail:
article id 5466, category Article
Hely Häggman. (1991). Application of biotechnology to forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5466. https://doi.org/10.14214/sf.a15624

Forest tree breeding involves manipulation of genetic composition of populations and individuals, and biotechnology focuses on selected individuals. The new techniques cannot replace the conventional breeding techniques but both need effective cooperation of each other. Thus, the distinction between conventional breeding and biotechnology is artificial. The biotechnology methods are new and fast developing and the future with field and progeny testing will show which techniques will be permanently adopted into tree breeding. For instance, the earlier hope of the use of somaclonal variation as a new source of variability and a powerful tool for the breeder seem today quite the opposite. Somaclonal variation constituting a major problem in present-day micropropagation is due to the unpredictable variation. Based on knowledge of today, especially micropropagation via somatic embryos, transgenic trees and the identification of major genes seem to be good candidates to be permanently adopted into tree breeding.

  • Häggman, ORCID ID:E-mail:
article id 5465, category Article
Gösta Eriksson. (1991). Challenges for forest geneticists. Silva Fennica vol. 25 no. 4 article id 5465. https://doi.org/10.14214/sf.a15623

Studies of phenotypic as well as mixed population plasticities are urgently needed in a world that supposedly experiences a gradual change of its environment. It is important to understand that man creates his environment and silviculture. This is one of the reasons why for breeding it cannot be expected to find optimal phenotypes in nature. Other reasons are the phylogenetic constraints and migration of pollen and seeds.

Forest genetics up to now is characterized by the study of one trait at a time. There is an urgent need for simultaneous analysis of several traits by the aid of genetic correlations or multivariate analysis. Generally there is a need for inclusion of larger numbers of genetic entries in forest genetic investigations.

For the long-rotation-time species there is a need to determine the curves for degree of dormancy and hardiness during the annual cycle. Information of plasticity in two-dimensional environments like water availability and temperature is needed. Studies on nutrient utilization and acquisition will tell us whether or not we must have different breeding populations for different soil fertilities. An understanding of the phase changes between juvenile and adult opens up possible applications such as faster generation turn-over in the breeding population via early flowering and early testing as well as better plants for frost-prone and weedy sites.

  • Eriksson, ORCID ID:E-mail:
article id 5464, category Article
Donald I. Dickmann. (1991). Role of physiology in forest tree improvement. Silva Fennica vol. 25 no. 4 article id 5464. https://doi.org/10.14214/sf.a15622

The paper introduces different ways plant physiology research can avail the process of tree improvement. The breeding of tree cultivars that efficiently produce a particular wood product or amenity will be an important aspect of forest management. What physiologist can provide to breeders and genetic engineers is the opportunity to move their work from empirical level towards a more theoretical level, and help to make breeding more predictable and more precise in its objectives. The areas of research discussed in the paper are biotechnology, flowering, selection criteria, adaptability and application of ideotypes.

  • Dickmann, ORCID ID:E-mail:
article id 5464, category Article
Donald I. Dickmann. (1991). Role of physiology in forest tree improvement. Silva Fennica vol. 25 no. 4 article id 5464. https://doi.org/10.14214/sf.a15622

The paper introduces different ways plant physiology research can avail the process of tree improvement. The breeding of tree cultivars that efficiently produce a particular wood product or amenity will be an important aspect of forest management. What physiologist can provide to breeders and genetic engineers is the opportunity to move their work from empirical level towards a more theoretical level, and help to make breeding more predictable and more precise in its objectives. The areas of research discussed in the paper are biotechnology, flowering, selection criteria, adaptability and application of ideotypes.

  • Dickmann, ORCID ID:E-mail:
article id 5463, category Article
Öje Danell. (1991). Survey of past, current and future Swedish forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5463. https://doi.org/10.14214/sf.a15621

The paper gives an introduction of the tree breeding program of Sweden that started in 1936 by the establishment of an association for the tree breeding. In 1967 the Institute of Forest Improvement was founded and it replaced the earlier association. The main species in the programme have been Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), lately also birch (mainly Betula pendula Roth.) and lodgepole pine (Pinus contorta). In addition, limited breeding has been done also with hybrid aspen (Populus tremula x P. tremuloides), oak (Quercus), larch (Larix), black spruce (Picea mariana) and a few other native and exotic species. The dominating initial effort has been to select plustrees in natural stands and use them for production of reforestation material. In addition, a considerable body of tests was built. The paper lists the status of breeding material of the different tree species and introduces the medium and short-term breeding programmes.

  • Danell, ORCID ID:E-mail:
article id 5461, category Article
Run-Peng Wei, Dag Lindgren. (1991). Selection effects on diversity and genetic gain. Silva Fennica vol. 25 no. 4 article id 5461. https://doi.org/10.14214/sf.a15619

Four different methods of truncation selection were studied in a population consisting of a large number of unrelated full sib families of equal size: phenotype selection, family selection, within-family selection and combined index selection (optimal weighting of individual and family performance to get the best prediction of breeding value). Methods were developed for calculating diversity (”relative effective family number”) for the different selection methods. Numerical calculations were made for genetic gain and diversity. Model assumptions are additive gene control and normal distribution. Phenotypic was good at high heritabilities and between family at low heritabilities. Loss of diversity was strongly dependent on selection method and selection strength. Compared at the same diversity, genetic gain was lower for combined index compared to phenotypic. There is a need for methods combining the goals gain and diversity.

The PDF includes an abstract in Finnish.

  • Wei, ORCID ID:E-mail:
  • Lindgren, ORCID ID:E-mail:
article id 7075, category Article
A. F. Tigerstedt. (1922). Mustilan kotikunnas. Acta Forestalia Fennica vol. 24 no. 2 article id 7075. https://doi.org/10.14214/aff.7075
English title: The Mustila arboretum.

The article describes experiences in exotic tree and shrub species in Mustila arboretum in 1901-1921, situated in Southern Finland. Mustila is the first arboretum of the country, established in 1901. The tree species have mostly been planted as small stands or groups of trees. The objective has been to find species that suit the Finnish climate. The article describes experiences of cultivation trials of coniferous tree species from the genus of Taxus, Tsuga, Pseudotsuga, Abies, Picea, Larix, Pinus, Thyopsis, Thuya, Chamaecyparis and Juniperus, in total 100 different species. The climate of Finland ranges from maritime to semi-maritime and semi-continental, becoming more continental towards the eastern parts of the country. According to the experiments, in Mustila area most promising are the Western American species from regions that are suitable distance from the Pacific Ocean. The exact origin of the seeds in the America is important for the survival of the species in Finland.

The PDF includes a summary in English.

  • Tigerstedt, ORCID ID:E-mail:
article id 7075, category Article
A. F. Tigerstedt. (1922). Mustilan kotikunnas. Acta Forestalia Fennica vol. 24 no. 2 article id 7075. https://doi.org/10.14214/aff.7075
English title: The Mustila arboretum.

The article describes experiences in exotic tree and shrub species in Mustila arboretum in 1901-1921, situated in Southern Finland. Mustila is the first arboretum of the country, established in 1901. The tree species have mostly been planted as small stands or groups of trees. The objective has been to find species that suit the Finnish climate. The article describes experiences of cultivation trials of coniferous tree species from the genus of Taxus, Tsuga, Pseudotsuga, Abies, Picea, Larix, Pinus, Thyopsis, Thuya, Chamaecyparis and Juniperus, in total 100 different species. The climate of Finland ranges from maritime to semi-maritime and semi-continental, becoming more continental towards the eastern parts of the country. According to the experiments, in Mustila area most promising are the Western American species from regions that are suitable distance from the Pacific Ocean. The exact origin of the seeds in the America is important for the survival of the species in Finland.

The PDF includes a summary in English.

  • Tigerstedt, ORCID ID:E-mail:
article id 7074, category Article
Aimo Kaarlo Cajander. (1923). Der Anbau ausländischer Holzarten als forstliches und pflanzengeographisches Problem. Acta Forestalia Fennica vol. 24 no. 1 article id 7074. https://doi.org/10.14214/aff.7074
English title: Cultivation of exotic tree species as forestry and plant geographic problem.
Original keywords: ausländisch; Holzarten; Provenienz

The distribution and occurrence of plant species, including trees, in the nature show that living and splendor of them is constrained by climatic factors. They have their minimum, optimum and maximum for the temperatures they can survive in. The tree species, at least mostly are divided into different varieties in different areas of the world so that the species are most suitable for the climatic conditions of their site.

The article presents the main climatic zones with their tree species according L. Ilvessalo and they suitability to Finland. More accurate areas of suitable species are also listed. 

The referred results show that alongside the climatic conditions, the conditions of soil and relief must be taken into account when using exotic tree species for forestry purposes.  

  • Cajander, ORCID ID:E-mail:
article id 5412, category Article
Jari Parviainen. (1990). Metsäpuiden paakkutaimituotannon nykynäkymät. Silva Fennica vol. 24 no. 1 article id 5412. https://doi.org/10.14214/sf.a15564
English title: Future trends for containerized tree seedling production: A literature review.

Containerized tree seedlings will be used on an increasing scale in the future in different parts of the world. There are number of techniques for the production of small one-year-old seedlings but it has not been possible to develop a completely satisfactory methods for large containerized seedlings production. In the long-term development of pine plantations established with containerized seedlings the greatest problem has been deformation of the root system. With a new method, based on a sheet of peat and root pruning, it has been possible to produce conifer seedlings with a good root regeneration potential and favourable morphological root system development. The use of small containerized seedlings allows an increase in planting density without any marked increase in regeneration costs.

The PDF includes an abstract in English.

  • Parviainen, ORCID ID:E-mail:
article id 5411, category Article
Eero Paavilainen. (1990). Effect of refertilization of pine and birch stands on a drained fertile mire. Silva Fennica vol. 24 no. 1 article id 5411. https://doi.org/10.14214/sf.a15563

Refertilization with PK, about 15 years after the first fertilizer application, increased tree growth and the amount of nutrients in tree litter in Scots pine (Pinus sylvestris L.) and birch (mainly Betula pubescens Erhr.) stands on a drained fertile mire in Northern Finland (65°34 N’, 25°42’ E). The increase in growth and nutrient contents after refertilization was greatest in the mature pine stand where the application of nitrogen and micronutrients gave an additional response compared to the PK-application.

The PDF includes an abstract in Finnish.

  • Paavilainen, ORCID ID:E-mail:
article id 5404, category Article
Pentti Alho. (1990). Suomen metsittyminen jääkauden jälkeen. Silva Fennica vol. 24 no. 1 article id 5404. https://doi.org/10.14214/sf.a15556
English title: The history of forests in Finland after the last ice age.

Based on literature this paper describes the natural afforestation of Finland that took place after the last ice age and the changes which have taken place during the last 10,000 years. The origin and development of the vegetation and trees are related to the changes in the edaphic and climatic factors. The first tree species to arrive in Finland were the primary colonizing species, birch and Scots pine. The appearance of Norway spruce dates back to about 5000 B.P. There have been great changes in the species composition of Finnish forests during the last several thousands of years but some 2,000–3,000 years ago the various species reached their present balance. The epoch of naural forests, which had lasted some 9,500 years, came to a conclusion, however, when man started to have a marked effect on the forest’s development 300–400 years ago.

The PDF includes an abstract in English.

  • Alho, ORCID ID:E-mail:
article id 5385, category Article
Timo Kuuluvainen. (1989). Branching dynamics in young Scots pine. Silva Fennica vol. 23 no. 3 article id 5385. https://doi.org/10.14214/sf.a15542

The development of shoot number and shoot properties was examined in successive shoot cohorts of young widely-spaced Scots pine trees (Pinus sylvestris L.) growing in a progeny trial. This was accomplished by reconstructing the branching process of the trees over a period of five years, from tree age 4 to 8. During this time the number of shoots in successive shoot cohorts increased rapidly, while at the same time the mean shoot length decreased. The decrease in shoot lengths from older to younger shoots was accompanied by a decline in the bifuraction frequency of the shoots. In general, rapid changes occurred in the branching characteristics during the yearly development of the trees. The variation in the branching characteristics was reflected in the development of the architecture and biomass production of the trees.

The PDF includes an abstract in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
article id 5379, category Article
Timo Kuuluvainen, Timo Pukkala. (1989). Effect of Scots pine seed trees on the density of ground vegetation and tree seedlings. Silva Fennica vol. 23 no. 2 article id 5379. https://doi.org/10.14214/sf.a15536

The study uses the methodology of ecological field theory to model the effect of Scots pine (Pinus sylvestris L.) seed trees on the density of tree seedlings and other plants in the field layer. The seed trees had a clear effect on the expected value of the amount and distribution of the ground vegetation. The vicinity of seed trees had an adverse effect on the growth of grasses, herbs and seedlings, while mosses were most abundant near the trees. Models based on the ecological field approach were derived to describe the effect of seed trees on the ground vegetation.

The PDF includes an abstract in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
  • Pukkala, ORCID ID:E-mail:
article id 5376, category Article
Timo Pukkala. (1989). Predicting diameter growth in even-aged Scots pine stands with a spatial and non-spatial model. Silva Fennica vol. 23 no. 2 article id 5376. https://doi.org/10.14214/sf.a15533

The single tree growth models presented in this study were based on about 4,000 trees measured in 50 even-aged Scots pine (Pinus sylvestris L.) sample plots with varying density, spatial pattern of trees and stand age. Predictors that used information about tree locations decreased the relative standard error of estimate by 10 percentage points (15%), if past growth was not used as a predictor, and about 15 percentage points (30%) when past growth was one of the predictors. When ranked according to the degree of determination, the best growth models were obtained for the basal area increment, the next best for relative growth, and the poorest for diameter increment. The past growth decreased the relative standard error of estimate by 15–20 percentage points, but did not make the spatial predictors unnecessary. The degree of determination of the spatial basal area growth model was almost 80% if the past growth was unknown and almost 90% if the past growth was known. Variables that described the amount of removed competition did not improve the growth models.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
article id 5375, category Article
Timo Pukkala. (1989). Prediction of tree diameter and height in a Scots pine stand as a function of the spatial pattern of trees. Silva Fennica vol. 23 no. 2 article id 5375. https://doi.org/10.14214/sf.a15532

The study presents two methods of predicting tree dimensions in a Scots pine (Pinus sylvestris L.) stand if only the location of trees is known. The first method predicts the tree diameter from the spatial location of neighbours. In the second method the diameter distribution of a subarea is estimated from the local stand density. This distribution is then sampled to obtain diameters. In both methods the tree height is predicted with a spatial model on the basis of diameters and locations of trees. The main purpose of the presented models is to generate realistic stands for simulation studies.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
article id 5349, category Article
Raphael E. L. Ole-Meiludie, Goodseldah K. Pamba. (1988). Time study on different techniques for nursery pot filling operation. Silva Fennica vol. 22 no. 2 article id 5349. https://doi.org/10.14214/sf.a15506

Time study on different techniques in nursery pot filling operations at SUA Training Forest in Northern Tanzania was conducted. The results showed that improved tools and work place design significantly decreased the operation time, hence increased productivity. In addition, worker’s comfort was generally increased.

The PDF includes a summary in Finnish.

  • Ole-Meiludie, ORCID ID:E-mail:
  • Pamba, ORCID ID:E-mail:
article id 5347, category Article
Timo Kuuluvainen, Markku Kanninen, Juha-Pekka Salmi. (1988). Tree architecture in young Scots pine: properties, spatial distribution and relationships of components of tree architecture. Silva Fennica vol. 22 no. 2 article id 5347. https://doi.org/10.14214/sf.a15504

The architecture of Scots pine (Pinus sylvestris L.) was studied in an eight-year-old progeny test. The measurements included characteristics of crown structure, spatial distribution of shoots and yield components. The spatial distribution of shoots showed striking between-tree differences, and two extreme distribution patterns were detected. One represented a non-layered structure with a vertically relative even shoot distribution, and the other a layered structure with a vertically highly uneven shoot distribution.

Close correlations existed between several components of tree architecture and it is suggested that changes in the phenotypic architecture in Scots pine follow an epigenetic pattern, which enables the prediction of adaptational changes in structural components. The structural characteristics related to high above-ground biomass were a long crown, high total shoot length, high number of branches per whorl and big shoots of low needle density occupying a big share of the crown volume.

The PDF includes a summary in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Salmi, ORCID ID:E-mail:
article id 5328, category Article
Max Guignard. (1987). The tree in the Paris and Helsinki areas. Silva Fennica vol. 21 no. 4 article id 5328. https://doi.org/10.14214/sf.a15485

The paper describes some examples from Paris and Helsinki areas, where trees are essential landscape elements. It is typical in France to plant trees around town squares, market places and along streets and roads. In Finland trees are almost always kept close to the house, together with other vegetation protecting the entrance and windows. These traditional uses of trees should be studied to serve landscape management.

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in Finnish.

  • Guignard, ORCID ID:E-mail:
article id 7067, category Article
Aimo Kaarlo Cajander. (1921). Einige Reflexionen über die Entstehung der Arten inbesondere innerhalb der Gruppe der Holzwächse. Acta Forestalia Fennica vol. 21 no. 3 article id 7067. https://doi.org/10.14214/aff.7067
English title: Reflections on the evolution of the species, especially on arborescent plants.

The most abundant tree species occur in different variants in different geographical regions. They differ in their genetic, biological and partly also in morphological characters, however making clear difference between these subspecies is not possible. The different subspecies have developed according the respective areas' climatic and soil conditions, developing adaptive characters. These subspecies play a great role in practical forest management, since they differ in for forestry important characters, such as cold tolerance or stem form. 

The subspecies hybridize with each other in areas where their distribution areas overlap. In these areas the subspecies cannot be always clearly defined.   

  • Cajander, ORCID ID:E-mail:
article id 5316, category Article
Timo Pukkala, Timo Kuuluvainen. (1987). Effect of canopy structure on the diurnal interception of direct solar radiation and photosynthesis in a tree stand. Silva Fennica vol. 21 no. 3 article id 5316. https://doi.org/10.14214/sf.a15473

The utilization of direct radiation was studied in five model stands of Poisson-type tree distribution and cone-shaped crowns. The radiation extinction depended on the self-shading of the crown and the shading caused by other trees. The results indicate that at low sun elevation a stand populated by very narrow-crowned trees is most effective in light interception and photosynthesis. At high sun elevation a broad-crowned canopy is best illuminated and most favourable for photosynthesis. A stand with a two-storey canopy is effective in all latitudes when the crowns are moderately narrow. In two-storey canopies the foliage of the lower storey can be better illuminated than in the lower parts of the upper storey, because of the smaller self-shading in the small crowns of the lower storey. A canopy where the crown volume is concentrated on few big crowns is less effective than a canopy consisting of many small crowns.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kuuluvainen, ORCID ID:E-mail:
article id 5310, category Article
Petri Kärenlampi. (1987). Puun lahonkestävyys ja kosteusdynamiikka. Silva Fennica vol. 21 no. 2 article id 5310. https://doi.org/10.14214/sf.a15467
English title: The decay resistance and moisture dynamics of wood.

In laboratory studies the heartwood content seems to be the only natural property of a wood of different tree species influencing the decay resistance. Moistening and drying by diffusion happen quite slowly. Scots pine (Pinus sylvestris L.) sapwood takes moisture by capillary action quicker than pine heartwood and Norway spruce (Picea abies (L.) H. Karst.) wood. Swelling and shrinkage are also greatest in pine sapwood. Impregnation of pine sapwood can give it better hydrophobic and dimensional stability than that of pine heartwood.

The PDF includes an abstract in English.

  • Kärenlampi, ORCID ID:E-mail:
article id 5306, category Article
Timo Pukkala, Taneli Kolström. (1987). Competition indices and the prediction of radial growth in Scots pine. Silva Fennica vol. 21 no. 1 article id 5306. https://doi.org/10.14214/sf.a15463

The effect of competition on the radial growth of Scots pine (Pinus sylvestris L.) was studied in three naturally regenerated stands located in North Karelia, Finland. The competition situation of an individual tree was described with various competition indices which depended on the sizes and distances from the neighbouring trees. One competition index explained about 50% of the variation in 5-year radial growth in one stand. If all stands were combined, one index explained 43.5%, two indices 48.9% and three indices 51.2% of the variation. In one stand, the best competition indices accounted for about 20% of that variation which could not be explained by tree diameter. If all three stands were combined, the best index explained 11% of the residual variation. About 40% of the variation in 5-year radial growth could not be explained by the diameter and competition indices.
The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
article id 5302, category Article
Seppo Kellomäki, Heikki Hänninen, Taneli Kolström, Ahti Kotisaari, Timo Pukkala. (1987). A tentative model for describing the effects of some regenerative process on the properties of natural seedling stands. Silva Fennica vol. 21 no. 1 article id 5302. https://doi.org/10.14214/sf.a15459

The effect of the size of seed crop, dispersal of seeds and the early development of seedlings on the density and spatial distribution of young Scots pine (Pinus sylvestris L.) stands are evaluated on the basis of theoretical models. The models include (i) number and spatial distribution of parent trees on the regeneration area, (ii) size of annual seed crop, (iii) seed dispersal from a particular parent tree, (iv) germination of the seeds (germination percentage), (v) death of ageing seedlings after the establishment process, and (vi) height growth of the seedlings.

As expected, stand density and spatial distribution varied within a large range in relation to the density of the parent trees and the distance from them. The simulations also showed that natural seedling stands can be expected to be heterogenous due to the geometry of seed dispersal, emphasizing the frequency of young and small trees. The properties of the seedling stands were, however, greatly dependent on the density of the parent trees and the length of the regeneration period.

The PDF includes an abstract in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Hänninen, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
  • Kotisaari, ORCID ID:E-mail:
  • Pukkala, ORCID ID:E-mail:
article id 5256, category Article
Outi Muona, Raimo Hiltunen, Erkki Morén, D. V. Shaw. (1986). Analysis of monoterpene variation in natural stands and plustrees of Pinus sylvestris in Finland. Silva Fennica vol. 20 no. 1 article id 5256. https://doi.org/10.14214/sf.a15435

Variation of monoterpene composition of Pinus sylvestris L. was studied in Southern, Central and Northern Finland using data from both natural stands and plus trees. The natural stands were analysed using different techniques and for fewer terpenes than the plus trees.

There were large differences between areas in the proportion of 3-carene in trees from natural stands, as has been discussed by previous authors. The proportion of 3-carene is bimodally distributed and believed to be controlled by a single gene with large effect. For this reason, we stratified our samples into high carene (>10%) and low carene (<10%) groups. Univariate analysis did not reveal any additional differences between natural populations in different zones for components other than 3-carene. In plus trees, several components showed significant differences, but the proportion of 3-carene did not differ between areas. Multivariate discrimination analysis did not distinguish between areas for natural stands. However, for the plus trees discriminant analysis allowed us to discriminate between the zones relatively efficiently. The proportion of correct classification was greater than 64% using the best methods. The central zone was most distinct, and 80% of its trees were correctly classified. Broad generalizations are not possible due to the limitations imposed by our data. Our analysis of phenotypic variation does not support the suggestion that plus trees selected from the north represent a southern type.

The PDF includes an abstract in Finnish.

  • Muona, ORCID ID:E-mail:
  • Hiltunen, ORCID ID:E-mail:
  • Morén, ORCID ID:E-mail:
  • Shaw, ORCID ID:E-mail:
article id 5239, category Article
Jussi Kuusipalo. (1985). On the use of tree stand parameters in estimating light conditions below the canopy. Silva Fennica vol. 19 no. 2 article id 5239. https://doi.org/10.14214/sf.a15418

Especially in forest vegetation studies, the light climate below the canopy is of great interest. In extensive forest inventories, direct measurement of the light conditions is too time-consuming. Often only the standard tree stand parameters are available. The present study was undertaken with the aim to develop methods for estimation of the light climate on the basis of readily measurable tree stand characteristics. The study material includes 40 sample plots representing different kinds of more or less mature forest stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.).

In each forest stand, a set of hemipherical photographs was taken and standard tree stand measurements were performed. A regression approach was applied in order to elaborate linear models for predicting the canopy coverage. The total basal area of the stand explained 63% of variance in the canopy coverage computed from hemipherical photographs. A coefficient representing the relative proportion of Norway spruce in the stand increased the explanatory power into 75%. When either the stand density (stems/unit area) or dominant age of the stand was included into the model, increment of the explanatory power into 80% was achieved. By incorporating both of the preceding predictors, an explanatory power of 85% was reached.

The PDF includes a summary in Finnish.

  • Kuusipalo, ORCID ID:E-mail:
article id 5233, category Article
Leo Heikurainen. (1985). Verhopuuston vaikutus kuusitaimikon kehitykseen. Silva Fennica vol. 19 no. 1 article id 5233. https://doi.org/10.14214/sf.a15412
English title: The influence of birch nurse crop (Betula pubescens) on the growth of Norway spruce (Picea abies) seedling stands on drained peatlands.

Young Norway spruce (Picea abies (L.) H. Karst.) are susceptible to early summer frost damage. Birch (Betula pubescens Ehrh.) naturally colonize rich or fairly rich drained peatlands after clear cutting, and can provide protection for developing seedlings. The report describes the development of spruce stands after various types of handing of the birch nurse crops.

Different proportions of birch and spruces did not have any influence on the spruce stand production. In cases where the nurse crop stand is removed when the spruce stand age was 20 years and height 4 m the spruce suffered badly but recovered with time, reaching the spruce stand growing under a nurse stand within the next 20 years. The height growth of spruce depends on the density of the nurse stand, especially on fertile sites. The development of diameter growth also depends on the density of the nurse trees. Removal of the nurse stand in spruce stands on the sites concerned should be done when the spruce stand is 20 years old and at the height of 4 m.

The PDF includes a summary in English.

  • Heikurainen, ORCID ID:E-mail:
article id 5204, category Article
Pirkko Velling, P. M. A. Tigerstedt. (1984). Harvest index in a progeny test of Scots pine with reference to the model of selection. Silva Fennica vol. 18 no. 1 article id 5204. https://doi.org/10.14214/sf.a15383

Harvest index and number of associated traits were measured in a 16-year-old Scots pine (Pinus sylvestris L.) progeny test based on full-sib families. It was found that harvest index is a highly heritable trait and that a number of yield components are positively correlated with it. It is suggested that harvest index and tree ideotypes should be the basis of selection in cultivated trees. It is emphasized that an integrated approach to tree improvement including silviculture, soil science, industrial and economic constraints and tree breeding is a prerequisite for maximal response.

The PDF includes a summary in Finnish.

  • Velling, ORCID ID:E-mail:
  • Tigerstedt, ORCID ID:E-mail:
article id 5201, category Article
Jussi Kuusipalo. (1983). Distribution of vegetation on mesic forest sites in relation to some characteristics of the tree stand and soil fertility. Silva Fennica vol. 17 no. 4 article id 5201. https://doi.org/10.14214/sf.a15184

Vegetation data collected from a random sample of mature forest stands representing mesic upland forest sites in Southern Finland were analysed and classified using two-way indicator species analysis (TWINSPAN). The variation of some characteristics of the tree stand and soil fertility between the produced vegetation units were analysed statistically.

Both the species list and the sample list arranged by TWINSPAN reflects the overall site fertility considerably well. The results are in agreement with the main division of mesic forest sites in the Finnish forest site type classification: vegetation units which can be assigned to the Oxalis-Myrtillus site type are clearly separated from the remaining units, and the overall site fertility indicates a statistically significant difference. The within-type variation in the vegetation composition in the Oxalis-Myrtillus site type reflects the variation in site fertility, whereas the within-type variation in the Myrtillus site type is mainly caused by the tree stand factor.

The PDF includes a summary in Finnish.

  • Kuusipalo, ORCID ID:E-mail:
article id 5200, category Article
Seppo Kellomäki, Timo Nevalainen. (1983). Näkökohtia puuston tiheyden ja puiden koon välisestä suhteesta. Silva Fennica vol. 17 no. 4 article id 5200. https://doi.org/10.14214/sf.a15183
English title: Relationship between stand density on tree size.

Two Japanese models regarding the within-stand competition have been reviewed on the basis of relevant literature. Competition-density and 3/2 th power models seem to be applicable also into tree stands. The latter model has been applied into the material obtained from literature. Computations showed consistancy with the results obtained elsewhere in the world. It is concluded that also in Finnish conditions the 3/2 th power law may have great potentials in describing the effects of stand density on tree size.

The PDF includes a summary in English.

  • Kellomäki, ORCID ID:E-mail:
  • Nevalainen, ORCID ID:E-mail:
article id 7050, category Article
Lauri Ilvessalo. (1920). Ulkomaalaisten puulajien viljelymahdollisuudet Suomen oloja silmälläpitäen. Acta Forestalia Fennica vol. 17 no. 2 article id 7050. https://doi.org/10.14214/aff.7050
English title: Prospects of cultivating exotic tree species in Finland.

The article includes a dendrological review on the effect of climate to the success of cultivation of exotic tree species, based on literature and analysis of the existing Finnish field tests. The cultivation of an exotic tree species succeeds only if the seed has been procured from an area, which climate is similar to the place of cultivation. Climate is even more important than site quality.

Finnish climate is boreal and continental, and thus tree species of similar climate suit here best. In favorable site conditions it is possible to grow also species from boreal marine, and temperate climates. Finnish summers are not warm enough for species from temperate continental climate to get prepared for the winter, and the shoots can get frost damages. This may be compensated with a warm and sheltered site. If the species tolerates shading, it can be planted under sheltering trees. For species from maritime boreal climate, the Finnish summer tends to be too short, and the winters too cold. A suitable site is rich, warm and sheltered, and has preferably a protective sparse tree cover. Species from southern maritime climate cannot be grown in Finland. The provenance of the seeds is also very important. An important source of seeds are the successful plantations in Finland.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 5160, category Article
P. M. A. Tigerstedt. (1982). Metsäpuiden populaatiogenetiikka. Helsingissä 1981 pidetyn symposion tutkimusraportit. Silva Fennica vol. 16 no. 2 article id 5160. https://doi.org/10.14214/sf.a15075
English title: Population genetics of forest trees.

The publication comprises proceedings of a conference held in Helsinki in 1981. Forest tree populations are investigated for population genetic structure, mating systems, mechanisms of genetic adaptation and ecological adaptation. Methods and techniques used in population genetic research of forest trees are presented. Much concern is given to applications by means of forest tree breeding, particularly the seed orchard breeding technique. Generally, the application of population genetics in cultivated forests is discussed.

The PDF includes a preface and the presentations of the conference (25 short papers) in English, and a comprehensive summary of the themes of the conference in Finnish.

  • Tigerstedt, ORCID ID:E-mail:
article id 5140, category Article
Lars Westman. (1981). Monitoring of coniferous forest ecosystems in Sweden. Silva Fennica vol. 15 no. 4 article id 5140. https://doi.org/10.14214/sf.a15367

A monitoring program is planned for the terrestrial environment around industries in Sweden, which emit acid compounds and heavy metals. Directions for the County Government Boards are being prepared. The paper deals with the present pollution situation in Sweden, based on recent scientific results, the justifications for local monitoring, and the organizing of the monitoring including the parameters suggested.

Four examples from a case study at an oil power station illustrate reporting of the data and the difficulties in interpreting the results. The examples are the distribution of a lichen indicator, heavy metal content and phosphatase activity in the moor layer, soil respiration and tree growth.

  • Westman, ORCID ID:E-mail:
article id 5133, category Article
F. Scholz. (1981). Genecological aspects of air pollution effects on northern forests. Silva Fennica vol. 15 no. 4 article id 5133. https://doi.org/10.14214/sf.a15360

Natural forest tree populations are adapted to their natural environment. Forest tree species under northern conditions are at the edge of their range where the short growing season and the low winter temperatures are the two main factors limiting their ecological niche. Effects of air pollution on the ecological niche, designated as the environmental conditions that permit a population to survive permanently, are discussed according to G.E. Hutchinson’s concept of the ecological niche. Air pollution as an additional stress factor influences the ecological niche either by the direct influence as an additional dimension of the ecological niche or by interaction with the other dimensions. These interactions are especially important for low level long-term effects of air pollution which can result in reduced resistance to low winter temperature or, due to reduced net assimilation, reduced capability to survive the long period of winter dormancy. These effects influence the boundary of the ecological niche and reduce the area of the biotope of the respective species.

Within the remaining biotope genetic changes in forest tree species take place. Due to individual differences in exposure and susceptibility of trees to air pollution, higher and therefore more exposed trees as well as more susceptible trees will be reduced in reproduction or even be eliminated. This causes genetic changes in the tree population.

  • Scholz, ORCID ID:E-mail:
article id 7041, category Article
Yrjö Ilvessalo. (1920). Tutkimuksia metsätyyppien taksatoorisesta merkityksestä nojautuen etupäässä kotimaiseen kasvutaulujen laatimistyöhön. Acta Forestalia Fennica vol. 15 no. 3 article id 7041. https://doi.org/10.14214/aff.7041
English title: Studies on mensurational significance of forest site types as part of preparation of Finnish growth and yield tables.

New growth and yield tables were prepared for Southern Finland. To finalize the tables, it had to be determined whether the forest site types developed by Cajanus could be used in mensurational research.

Comparative study was performed in 1916-1919 to study the growth of the trees in different forest site types. Total of 467 sample sites were measured in Southern and Central Finland. All the forest site types were found to have a distinctive vegetation typical to the site. It can be concluded that the ground vegetation can be used to determine the forest site type. The growth of trees was different in different forest site types, yet similar within each site type. The forest site types are uniform, natural and easy to determine, and can thus be used to classify the forest stands and used in mensurational research and a basis to growth and yield tables.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 5114, category Article
Matti Kärkkäinen. (1981). Haapa- ja poppelilajien (Populus) käyttö. Silva Fennica vol. 15 no. 2 article id 5114. https://doi.org/10.14214/sf.a15055
English title: Utilization of aspen and poplars (genus Populus).
Original keywords: haapa; poppelit; viljely; puulajit; käyttö

The aim of this study was to establish from the literature the purposes and for which aspen (Populus tremula L.) and related poplar species are used and can be used.  According to the literature, numerous Populus species can be utilized in the industry with success instead of light softwood species in addition to them. The main emphasis is in the growing of large-sized timber, and there is no clear trend to changing to the short-rotation forestry of poplar. However, the utilization of the good sprouting properties of Populus species will probably increase as this regeneration method is cheap.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5078, category Article
Seppo Kellomäki, Pertti Hari. (1980). Eco-physiological studies on young Scots pine stands. I. Tree class as indicator of needle biomass, illumination and photosynthetic capacity of crown system. Silva Fennica vol. 14 no. 3 article id 5078. https://doi.org/10.14214/sf.a15019

The concept of tree class as indicated by dominant, codominant, intermediate and suppressed trees is analysed using empirical material representing 13 younger Scots pine (Pinus sylvestris L.) stands. The relative needle biomass, i.e. the needle biomass related to the maximum needle biomass in the stand, was closely related to the relative height of the tree and independent of the stand characteristics. Furthermore, the relative illumination of the crown system was related to the relative height of the trees as well as the relative photosynthetic capacity and tree-to-tree variation in growth. When calculated per needle biomass unit it appeared that height growth, radial growth, needle growth and other growth parameters were the highest in the suppressed trees. The suppressed trees thus appear to be more efficient in utilizing available resources than other tree classes. The ecologic significance of the results is discussed.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
article id 7034, category Article
V. T. Aaltonen. (1920). Über die Ausbreitung und den Reichtum der Baumwurzeln in den Heidewäldern Lapplands. Acta Forestalia Fennica vol. 14 no. 1 article id 7034. https://doi.org/10.14214/aff.7034
English title: The distribution and abundance of the tree roots in the heathy forests on Lapland.

The study presents and describes the abundance and distribution of tree roots in specific stands of heathy forest types in Lapland. The data was collected in the Sodankylä commune.  

Due to the shortcomings in the data, conclusions can be drawn only regarding pine forests. The result of study states that the root competition plays an important role in the development of the forests, and most of the other observed phenomena are linked with root competition. The more infertile the soil the vertically and horizontally wider and more abundant the root system. It seems that the abundance of the root system is similar in forest of same fertility class and same density and age.      

  • Aaltonen, ORCID ID:E-mail:
article id 5066, category Article
J. P. Efimov. (1980). Some results on the regularities of seed crops in Scots pine seed orchards. Silva Fennica vol. 14 no. 1 article id 5066. https://doi.org/10.14214/sf.a15007

Establishment of seed orchards to produce genetically improved seed started in the USSR in the 1960’s. The aim is that within 10–15 years the total seed production will reach 50% of the seed used. The paper describes seed production in seed orchards of Scots pine (Pinus sylvestris L.) in the forest-steppe of the European part of the USSR. The orchards have been established either by grafting or by planting of seedlings originating from plus trees. The grafts begin flowering relatively early, however, only at the age of 8–10 years seed crops become relatively regular and abundant. The cone yield in young seed orchards have great variability, and the yield of cones varies between clones. Cone yield does not always correlate with a good seed yield. One of the reasons for high amount of empty seeds is the difference in the periods of flowering between the clones.

The seed crops can be improved by establishing optimal conditions for the growth of the trees. Also, when a seed orchard is founded, the peculiarities of the generative activities of the clones and their reactions to changes in the environmental conditions must be taken account by taking an individual and selective measure approach to improvement measures. The orchards can be established with clones for their genetic combining ability and their requirements for the stimulation of seed-bearing.

The PDF includes a summary in Finnish.

  • Efimov, ORCID ID:E-mail:
article id 5064, category Article
E. P. Prokazin. (1980). Geographic variation in forest trees. Silva Fennica vol. 14 no. 1 article id 5064. https://doi.org/10.14214/sf.a15005

Planting of forest trees takes place in USSR on millions of hectares but without permanent forest seed bases having yet been established in every region of the country. Consequently, local seed does not suffice the need, and it is necessary to secure it from other geographical regions. To avoid negative consequences of seed transfer it is necessary to study geographic variation of the genetic characteristics of forest trees and construct scientifically based division into seed zones. Geographic transfer of seed can also be regarded as a breeding measure. A large research program is being carried out in the USSR on the subject. Most of the existing trials are provenience tests of Scots pine (Pinus sylvestris L.). Over 2,000 hectares of new provenience experiments is to be established in near future.

The PDF includes a summary in Finnish.

  • Prokazin, ORCID ID:E-mail:
article id 5062, category Article
I. Etverk. (1980). Geographical variability of the Norway spruce in the Estonian SSR. Silva Fennica vol. 14 no. 1 article id 5062. https://doi.org/10.14214/sf.a15003

The productivity and several morphological features of Estonian Norway spruce (Picea abies L. Karst.) show significant geographical variation. This is no doubt because of differences in the climatic and soil conditions, which in spite of the small area of the country is quite large. In order to check the possible geographical variability of the gene pool, preliminary experiments were carried out in 1969, when seeds from 93 spruce stands originating from 14 forest enterprises were sowed in a nursery. After two years, the seedlings originating from south-eastern Estonia were the tallest. The seedlings from northern origins were smallest. However, it cannot be maintained that spruces from Southern Estonia are of better genotype than genotype from Northern Estonia since the genotypes are evaluated on the basis of ecological conditions under which the experiments are carried out. Another study suggests that an average shift of 7° to the east of the territory for spruces are suitable for cultivation in Estonia.

The PDF includes a summary in Finnish.

  • Etverk, ORCID ID:E-mail:
article id 5061, category Article
Max Hagman. (1980). Experiences with Norway spruce provenances in Finland. Silva Fennica vol. 14 no. 1 article id 5061. https://doi.org/10.14214/sf.a15002

Ecological investigations have shown that Norway spruce (Picea abies (L.) H. Karst.) reached Western Finland about 1,500–1,000 years B.C. and did not reach Åland islands before around the year 0. The species spread into Finland from the east and north-east, having survived the glaciation somewhere in the central parts of the Asian continent. Geographical variation has provided foresters with provenances of better growth and higher economic yield. In Finland, provenances, for instance, from Austria, Eastern Germany, Romania, Southern Poland and Slovakia have been planted in experiments, mostly in various parts of Southern Finland. According to the results of the experiments, it seems that for the more northern parts of Finland and Sweden the best material was to be obtained from north-east Europe.

The Scandinavian countries decided in 1975 to make a common assessment of all the provenance experiments with Norway spruce. The synthesis confirms the earlier view that provenances from the most north-eastern parts of Central Europe are of the greatest value for Finland.

The PDF includes a summary in Finnish.

  • Hagman, ORCID ID:E-mail:
article id 5060, category Article
A. I. Novoselceva. (1980). On the application of forest genetics and forest tree breeding research to practical forest seed production. Silva Fennica vol. 14 no. 1 article id 5060. https://doi.org/10.14214/sf.a15001

The development of the scientific basis for the production of high-quality seed led to the introduction of a large part of the research findings in forest genetics and forest tree breeding into practical forest seed production in the USSR. Since 1971, work has begun in forest enterprises on the establishment of a permanent seed supply for the main tree species – Pinus sylvestris, Picea ssp., Larix ssp. Quercus robur, Haloxylon ssp. and nut trees.

The basis for forest tree improvement is a gene pool which is built up using mass and individual selection of valuable forms in natural populations. In accordance with a long-term programme up to 1990, an inventory of 13.2 million ha of the best high-productive stands has been carried out for breeding purposes in the state forests. About 7,000 ha of plus stands have been selected, and a total of 9,453 ha of seed orchards and 141,253 ha of seed collection stands have been established. The first stage of the programme is planned to be complete in 1980, and in the second stage clonal high-quality seed orchards will be established.

The PDF includes a summary in Finnish

  • Novoselceva, ORCID ID:E-mail:
article id 5060, category Article
A. I. Novoselceva. (1980). On the application of forest genetics and forest tree breeding research to practical forest seed production. Silva Fennica vol. 14 no. 1 article id 5060. https://doi.org/10.14214/sf.a15001

The development of the scientific basis for the production of high-quality seed led to the introduction of a large part of the research findings in forest genetics and forest tree breeding into practical forest seed production in the USSR. Since 1971, work has begun in forest enterprises on the establishment of a permanent seed supply for the main tree species – Pinus sylvestris, Picea ssp., Larix ssp. Quercus robur, Haloxylon ssp. and nut trees.

The basis for forest tree improvement is a gene pool which is built up using mass and individual selection of valuable forms in natural populations. In accordance with a long-term programme up to 1990, an inventory of 13.2 million ha of the best high-productive stands has been carried out for breeding purposes in the state forests. About 7,000 ha of plus stands have been selected, and a total of 9,453 ha of seed orchards and 141,253 ha of seed collection stands have been established. The first stage of the programme is planned to be complete in 1980, and in the second stage clonal high-quality seed orchards will be established.

The PDF includes a summary in Finnish

  • Novoselceva, ORCID ID:E-mail:
article id 5059, category Article
Pertti Harstela. (1980). Jäljelle jäävä puusto ja ajouralta toimivat harvennuspuun korjuukoneet. Silva Fennica vol. 14 no. 1 article id 5059. https://doi.org/10.14214/sf.a15000
English title: Remaining trees and machines working from the strip roads in thinning.

In the first part of the study the hindrance of the remaining trees when felling trees by machines working from the strip road in selective thinning was studied on the basis of the literature. In the second part there was geometrically studied the need of schematic thinning in some type stands when bundles are pre-skidded straight-lined to the strip road. In average only 0-1 trees per pre-skidding trail needs to be removed. It was concluded that trees removed from the pre-skidding trail do not significantly increase the need of schematic thinning. Remaining trees do not limit the length of machine booms if the pre-skidding trails are planned during the felling.

The PDF includes a summary in English.

  • Harstela, ORCID ID:E-mail:
article id 5058, category Article
Max Hagman. (1980). Suomalais-neuvostoliittolainen metsägenetiikan ja siemenhuollon symposiumi Punkaharjulla 17.–18.8.1978. Silva Fennica vol. 14 no. 1 article id 5058. https://doi.org/10.14214/sf.a14999
English title: Reports of the Finnish-Soviet symposium on forest genetics and forest tree seed production, Punkaharju, Finland, August 17-18. 1978.

As a part of the scientific and technical cooperation between Finland and the USSR a symposium and an excursion on forest genetics and seed production was organized in Finland in August 1978. The symposium paper presented at Punkaharju are published here in order to bring them available for a wider audience.

The 12 symposium reports deal with the following subjects: Practical application of forest genetic research (A.I. Novoselceva), geographical variability and provenance transfer (E.P. Prokazin, M. Hagman, I. Etverk), variation in wood density (P. Velling), variation of flowering and seed crops in seed orchards (Y.P. Efimov), and natural stands (V. Koski), vegetative propagation (J. Niiranen), seed size effects and early test problems (J. Mikola), quantitative analysis of genotypic and environmental effects (S.A. Petrov), hormonal induction of flowering (O. Luukkanen) and x-ray photography analysis of the ageing of seeds during storage (M. Ryynänen).

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  • Hagman, ORCID ID:E-mail:
article id 5052, category Article
Markku Nylund, Antti Haapanen, Seppo Kellomäki, Liisa Nylund. (1979). Deterioration of forest ground vegetation and decrease of radial growth of trees on camping sites. Silva Fennica vol. 13 no. 4 article id 5052. https://doi.org/10.14214/sf.a14909

The ground cover vegetation and tree growth at several camping sites in Southern Finland were investigated. The deterioration of ground vegetation appeared to be unavoidable in these areas, and only a few grass species were tolerant to heavy trampling. Only moderate deterioration was, however, detected when the trampling level was lower than 10,00015,000 user days. On the other hand, the ground cover was completely destroyed when the trampling level exceeded 100,000 user days. A considerable decrease in radial growth appeared to be associated with destruction of the ground vegetation. The decrease was abrupt and was found to continue throughout the whole period of use. After ten years’ use the growth in the trampled areas was 35% lower than that that of the untrampled areas. A further decrease in radial growth is expected in the future. 

The PDF includes a summary in Finnish. 

  • Nylund, ORCID ID:E-mail:
  • Haapanen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Nylund, ORCID ID:E-mail:
article id 5006, category Article
Seppo Kellomäki. (1978). Typpilannoituksen vaikutus havupuiden fotosynteesikapasiteettiin. Silva Fennica vol. 12 no. 3 article id 5006. https://doi.org/10.14214/sf.a14860
English title: Effects of nitrogen fertilization on photosynthetic capacity of coniferous trees.

The effect of nitrogen fertilizers on the photosynthetic capacity of conifers is assessed on the basis of literature. The review emphasizes the role of changes of needle mass as a factor affecting the result of nutrient application. In particular, the increase in needle mass results in a considerable increase in photosynthetic capacity. The effect of fertilization on the photosynthetic rate seems to be of minor importance. The effect on the photosynthetic rate is, however, poorly documented as is the case for the effect of fertilization on the respiration rate. There is evidence that proper application of nitrogen fertilizers may double the photosynthetic capacity of conifers, mainly as a result of increase in needle mass.

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  • Kellomäki, ORCID ID:E-mail:
article id 4970, category Article
Markku Mäkelä. (1977). Metsähakkeen tiheyden laskeminen. Silva Fennica vol. 11 no. 2 article id 4970. https://doi.org/10.14214/sf.a14821
English title: Calculating the basic density of whole tree- and logging residue chips.

A method is presented in this study for calculating the basic density of whole tree- and logging residue chips and the results of trial measurements on some commonly used chip sorts. The basic density of Scots pine whole tree chips was found to be 1–18 kg/m3 smaller than that of pine pulpwood of the same age. The basic density of Norway spruce whole tree chips was 4–22 kg/m3 greater than that of similar aged pulpwood. The basic density of birch whole tree chips was 4–16 kg/m3 and grey alder whole tree chips 7–24 kg/m3 greater than pulpwood of the same age. The basic density of conifer logging residue chips was considerably greater than that of pine and spruce whole tree ships.

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  • Mäkelä, ORCID ID:E-mail:
article id 4948, category Article
Matti Kärkkäinen. (1976). Puun ja kuoren tiheys ja kosteus sekä kuoren osuus koivun, kuusen ja männyn oksissa. Silva Fennica vol. 10 no. 3 article id 4948. https://doi.org/10.14214/sf.a14794
English title: Density and moisture content of wood and bark, and bark percentage in the branches of birch, Norway spruce and Scots pine.

In the study the proportion of branch samples of various diameter were studied. The branches were taken from small trees to be harvested by total tree chipping method. The material consisted of 1,056 branch samples of birch (Betula verrucosa, now B. pendula Roth, and Betula pubescens Erhr.), Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) at intervals of 20 cm along each branch.

With exception of the basic density of bark, there was a relation between all the other properties which were studied and the diameter. Even when the effect of diameter was eliminated, in many cases the effect of the distance of the samples from the stem became apparent.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 4944, category Article
Eino Mälkönen. (1976). Effect of whole-tree harvesting on soil fertility. Silva Fennica vol. 10 no. 3 article id 4944. https://doi.org/10.14214/sf.a14790

This paper analyses the nutrient loses caused by whole-tree harvesting on the basis of the literature data. It has been considered that traditional stemwood harvesting does not lead to impoverishment of the soil because the nutrient content of the wood is quite low. The nutrient loss occurring in connection with heavy thinnings and whole-tree harvesting has been considered so great that it has to be compensated by fertilizer application. In comparison with harvesting unbarked stem timber, whole-tree harvesting has been found to increase the nutrient loss at the stage of final cutting as follows: N2 to 4 times, P 2 to 5 times, K 1.5 to 3.5 times and Ca 1.5 to 2.5 times. Depending on the conditions prevailing on the site, any one of these nutrients may be the limiting factor for tree growth during the next tree generation

The PDF includes a summary in Finnish.

  • Mälkönen, ORCID ID:E-mail:
article id 4931, category Article
Olli Makkonen. (1976). Mitä vanhalla ajalla tiedettiin puiden kasvusta. Silva Fennica vol. 10 no. 1 article id 4931. https://doi.org/10.14214/sf.a14773
English title: What was known in ancient times about growth of trees?
Original keywords: historia; puiden kasvu
English keywords: history; growth of trees

In this article, information about tree growth which was familiar to the learned men in the old days is presented. The time when different tree species start growing, the different growth rate of various tree species, the age of trees, their resistance to injury etc. are discussed.

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  • Makkonen, ORCID ID:E-mail:
article id 4930, category Article
Tapio Lehtiniemi. (1976). Ionisoivan säteilyn vaikutus varastokuivien ja liotettujen metsäpuiden siementen idäntään ja taimien alkukehitykseen. Silva Fennica vol. 10 no. 1 article id 4930. https://doi.org/10.14214/sf.a14772
English title: Effect of ionizing radiation on the germination of storage-dry and soaked forest tree seeds and on the initial development of seedlings.

The study was carried out in order to find out the changes taking place in germination of seeds in certain tree species as a function of gamma irradiation, the height growth of the seedlings produced and the types of phenotypic mutants possibly found in the generation that had received radiation. The tree species studied were Pinus sylvestris L., Picea abies (L.) H. Karst., Betula verrucosa (Betula pendula Roth), B. Pubescens Ehrh., Alnus glutinosa (L.) Gaertn. and Alnus incana (L.) Moench.

Soaked seeds that had received a rather small dose of radiation germinated usually better than storage-dry seeds, B. pubescens being an exception. The damages observed in germination, height growth and the relative number of mutants were greater the higher the irradiation doses. The LD50 dose (germination, 28 days) was as follows in the case of the different tree species (storage dry/soaked): P. Sylvestris 1,500-2,000/2500-3,000, P. abies 1,000-1,500/4,000-4,500, B. pendula 9,500-10,000/7,000-7,500, B. pubescens >10,000/7,500-8,000 and A. Glutinosa 10,000/8,500-9,000 rad. Mass production of different mutants of deciduous trees for ornamental purposes, for example, appears to be easy using gamma-irradiation. On the other hand, the possibility of increasing tree growth remains open for further study.

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  • Lehtiniemi, ORCID ID:E-mail:
article id 4924, category Article
Teklé Kapustinskaité. (1975). Puuston kasvu ja turpeen tuhkapitoisuus ojitetuilla soilla. Silva Fennica vol. 9 no. 3 article id 4924. https://doi.org/10.14214/sf.a14766
English title: Ash content of peatland soils and stand growth in connection with drainage.

The ash content has been found to correlate with the fertility of peatlands. Relationship between height of 80-year-old stands and ash content of peat in topmost 30 cm layer was examined in Lithuanian conditions. On drained peatlands with ash content of peat from 3% to 8% pine stands increase in height. Ash content of peat being about 7% Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on drained sites are found to be of equal height. Ash content of peat more than 8–9% has no significant effect on growth of pine or spruce stands. Birch (Betula verrucosa (B. Pendula Roth.) and Betula pubescens Erhrh.), stands are less sensitive to ash content of peat compared with other species. Black alder (Alnus glutinosa L. Gaertn.) stands occurred in sites with ash content of peat more than 8–10%. The height of the stands become equal both in drained and undrained sites in the cases where ash content of peat is about 16–18%. Ash (Fraxinus exelsior L.) stands attain high productivity on drained sites with ash content of peat about 20%.

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  • Kapustinskaité, ORCID ID:E-mail:
article id 7020, category Article
S. E. Multamäki. (1919). Tutkimuksia metsien tilasta Savossa ja Karjalassa. Acta Forestalia Fennica vol. 9 no. 2 article id 7020. https://doi.org/10.14214/aff.7020
English title: Studies on state of forests in Savo and Karelia.

A strip survey was made to define the forest and peatland site class distribution and the condition of the forests in Savo and Karelia in central and eastern parts of Finland. According to the survey, 24% of the forested lands are peatlands. Fresh mineral soil sites (26%) were the most common mineral soil site type. Intermediately dry forest soil sites covered 22% of the area, forest sites with grass-herb vegetation 12,79%, rich grass-herb forest soil sites 3,16% and dry forest soil sites 9,59% of the forested area. The most common tree species were Scots pine (Pinus sylvestris L.), 39%, Betula sp., 26%, Norway spruce (Picea abies (L.) H. Karst.), 18%, and grey alder (Alnus incana (L.) Moench), 10% of the forest land. The article includes a review about the wood harvesting in the forests, and their present silvicultural state. According to the study, about 30% of the forested lands (not including peatlands) were unproductive; mostly mixed alder and birch stands of poor quality or open lands.

The PDF includes a summary in German.

  • Multamäki, ORCID ID:E-mail:
article id 4897, category Article
A. V. Chudnyi. (1974). Metsäpuiden populaatiorakenteen tutkimusmenetelmistä. Silva Fennica vol. 8 no. 1 article id 4897. https://doi.org/10.14214/sf.a14741
English title: Investigation methods in forest tree population studies.

From the tree breeder’s point of view, an investigation of the chemical compounds in a tree population is worthwhile, if sufficiently high correlations exist between the chemical composition and any economical important characteristics. In Scots pine (Pinus sylvestris L.) populations, such a correlation seems to exist between a high α-pinene and a low Δ3-carene content on the one hand, and the poor resistance to Fomitopsis annosa Fr. (now Heterobasidion annosum (Fr.) Bref.) but a rapid development during the first half of the life cycle on the other hand. Detailed investigation on the terpene contents in pine populations were conducted at 121 locations throughout the Soviet Union. As a result, the range of this species was divided into zones, each of which was characterized by a distinct terpene composition pattern. In continuing selection and breeding work, the terpene contents are being used as indicators when the variation of economically important characteristics of Scots pine populations is studied.

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  • Chudnyi, ORCID ID:E-mail:
article id 4888, category Article
Olavi Luukkanen. (1973). Havaintoja kuusen vapaapölytysjälkeläistöjen ja männyn metsikköalkuperien CO2-aineenvaihdunnasta. Silva Fennica vol. 7 no. 4 article id 4888. https://doi.org/10.14214/sf.a14726
English title: Observations on CO2 exchange in open pollinated progenies of Norway spruce and provenances of Scots pine.

Photosynthesis and dark respiration in five families of autochtonous Norway spruce (Picea abies (L.) H. Karst.) and in seedlings from twenty Finnish stands of Scots pine (Pinus sylvestris L.) were investigated in constant environmental conditions. Values of CO2 exchange were compared with the height growth and weight of seedlings in Norway spruce and with the weight alone in Scots pine. No statistically significant differences were found in CO2 exchange among progenies or stands. Photosynthetic efficiency and photosynthetic capacity showed a positive correlation both in spruce and in pine. Growth and net photosynthetic capacity were linearly and positively correlated in pine. Spruce and a higher light compensation point than pine. The use of an open IRGA system with several simultaneous measurements and the trap-type cuvette construction in genetic work are discussed.

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  • Luukkanen, ORCID ID:E-mail:
article id 4877, category Article
Pertti Laatikainen. (1973). Jyrsinturve ja kuorihumus männyn kylvötaimien kasvualustoina muovihuoneessa. Silva Fennica vol. 7 no. 1 article id 4877. https://doi.org/10.14214/sf.a14707
English title: Milled peat and milled bark as substrate for Scots pine seedlings in greenhouses.

The purpose of this study was to compare the development of Scots pine (Pinus sylvestris L.) seedlings sown on substrates off milled peat and milled bark. Mille peat, ordinary milled bark, milled inner bark waste, and a mixture of milled peat and milled bark in the ratio of 1:1, were all compared in the plastic greenhouse. In addition, two fertilization applications were used with milled park: ordinary surface fertilization and double surface fertilization. The germination and development were measured twice during the summer.

It is concluded that milled bark seems to be a rather useful substrate for use in plastic greenhouses, as long as its special requirements are taken into consideration. In the first measurement, there were no differences between the treatments, in the second measurements seedlings growing on a mixture of peat and bark were slightly more developed than the others. Growth of the seedlings was slightly better in ordinary milled bark. Double surface fertilization increased disease and mortality compared to ordinary fertilization.

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  • Laatikainen, ORCID ID:E-mail:
article id 4869, category Article
Ole Oskarsson, P. M. A. Tigerstedt. (1972). Metsänjalostuksen mahdollisuudet II. Silva Fennica vol. 6 no. 3 article id 4869. https://doi.org/10.14214/sf.a14672
English title: The possibilities in forest tree breeding II. Selection differences and genetic gains in selected seed stands of Scots pine.

The aim of this study was to estimate the genetic gain of volume growth in Scots pine (Pinus sylvestris L.) selected seed stands. To obtain highest possible accuracy, the estimations are based on a large statistical material comprising 197 separate seed stands. It is concluded that the genetic gain of volume growth ranges between 7.4–15.0%. Unwanted pollen contaminations may, however, in the worst case halve this genetic gain.

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  • Oskarsson, ORCID ID:E-mail:
  • Tigerstedt, ORCID ID:E-mail:
article id 4865, category Article
Tauno Kallio. (1972). Esimerkki kuusikon lahovikaisuuden Etelä-Suomessa aiheuttamasta taloudellisesta menetyksestä. Silva Fennica vol. 6 no. 2 article id 4865. https://doi.org/10.14214/sf.a14668
English title: An example on the economic loss caused by decay in growing Norway spruce timber in Southern Finland.

A growing stand of Norway spruce (Picea abies (L.) H. Karst.) marked for cutting was investigated in the winter of 1971–72 in Helsinki in Southern Finland in order to determine the economic loss caused by decay. Taking a sample from growing spruce trees with increment borer is not a reliable method of determining the frequency of decay. The decayed stems were twice measured for assortment cutting into lengths; the first time disregarding the decay and the second time doing the actual assortment cutting according to the grade of timber. The direct economic loss caused by decay was 13% of the price for standing timber. The indirect loss may be as great as the direct loss.

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  • Kallio, ORCID ID:E-mail:
article id 7011, category Article
Antti Tanttu. (1915). Tutkimuksia ojitettujen soiden metsittymisestä. Acta Forestalia Fennica vol. 5 no. 2 article id 7011. https://doi.org/10.14214/aff.7011
English title: Studies on forest growth of drained peatlands.
Original keywords: ojitus; räme; neva; korpi; turvekangas

Draining of peatlands to improve forest growth started to increase in Finland in the beginning of 1900s. The aim of the study was to find out which kind of peatlands are suitable for draining. The peatlands examined in this study had been drained earlier in 1800s for other purposes, and the original peatland type was deduced afterwards. When the peatland is drained, its vegetation changes gradually towards that of mineral soil sites, depending on the original peatland type. The article includes detailed description of the vegetation on different drained peatland sites. Best represented in the study were different types of pine swamps, which change towards Calluna or Vaccinium forest site type depending on the original peatland type. The Sphangnum species and brushwood disappear gradually and Cladina sp. become common in some drained pine swamp types. Scots pine (Pinus sylvestris L.) regenerates well on most drained pine swamps, and also Betula sp may grow as dominant species. The richer pine swamp types develop to Vaccinium-myrtillus forest site type, which may grow also Norway spruce (Picea abies (L.) H. Karst). Drained treeless bogs change first towards pine swamps. However, trees regenerate poorly on these sites and the growth is low. Flark-bogs develop typically to treeless lichen heaths. Drained spruce swamps develop to forest with grass-herb vegetation or Myrtillus site type.

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  • Tanttu, ORCID ID:E-mail:
article id 4836, category Article
Erkki Lähde. (1971). Anaerobisten olosuhteiden ja aerobisuusrajan esiintymisestä erilaisilla luonnontilaisilla turvemailla ja merkityksestä suotyypin kuvaajana. Silva Fennica vol. 5 no. 1 article id 4836. https://doi.org/10.14214/sf.a14625
English title: Anaerobic conditions in various virgin peat soils and the significance of the aerobic limit as an indicator of site quality.

The aim of the present study was to increase the knowledge of the anaerobic conditions prevailing in virgin peat soils of different kinds, and on the fluctuation of the aerobic limit. Silver rod method was used to indicate anaerobic conditions and to locate the aerobic limit. The material included 18 peatland sample plots on treeless bogs, in pine bogs and in spruce swamps in Southern Finland. Observations of the discoloration of the silver rods and measurements of ground water level were made from 8 June to 13 August 1968.

The results show that the location of the aerobic limit is dependent of the depth of the ground water table, and usually lies 5–15 cm above the ground water table. Down to 10–20 cm below the aerobic limit, where it reaches maximum, the rate of decomposition of sulfurous organic matter is positively correlated with the distance from the aerobic limit. Deeper it gradually decreases, and in the depth of 25–35 cm no hydrogen sulphide seems to be released.

In the forested peatland types the volume of the growing stock and the increment were dependent on the depth of the aerobic limit only when nutrient content and pH of the peat was more or less constant. Where the aerobic limit was close to the ground surface but the nutrient contents were relatively high, the volume of the growing stock may be comparatively high. Birch (Betula sp.), better than the conifers, is able to stand conditions poor in oxygen. The growing stock was poor in sites where the aerobic limit was near the ground surface, but the nitrogen and phosphorus contents were high, or vice versa. Consequently, aerobic limit is of great importance as an indicator of site quality.

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  • Lähde, ORCID ID:E-mail:
article id 4833, category Article
Eero Malmivaara, Jouni Mikola, Christel Palmberg. (1971). Pajujen mahdollisuudet metsäpuiden jalostuksessa. Silva Fennica vol. 5 no. 1 article id 4833. https://doi.org/10.14214/sf.a14622
English title: Potential of willows in forest tree breeding.
Original keywords: metsänjalostus; pajut; Suomi

A review is made into the experiences and possibilities of willow breeding, with a particular consideration of their application under Finnish conditions.

In comparison with other tree genera, Salix has many advantages in breeding. The great number of species, large genetic variation between and within species and frequent crossability offer good possibilities for improvement by hybridization. The dioecious flowering, plentiful seed production and short generation cycle are valuable properties for breeding by controlled pollination. Individuals with desirable characteristics can be easily propagated vegetatively from cuttings. The propertied stated above are also characteristic of poplars, the breeding of which has resulted in great success. Corresponding results can be therefore expected from willow breeding, which has recently been initiated in several countries.

Today willows have no practical significance for forestry in Finland. There are, however, some suitable Salix species, both indigenous and exotic, for starting material for breeding, and plenty of favourable sites for willows. Therefore, the beginning of breeding research with willows should be well justified also in Finland.

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  • Malmivaara, ORCID ID:E-mail:
  • Mikola, ORCID ID:E-mail:
  • Palmberg, ORCID ID:E-mail:
article id 4831, category Article
Lauri Mikkola. (1970). Kuusilajien risteytyvyydestä. Silva Fennica vol. 4 no. 4 article id 4831. https://doi.org/10.14214/sf.a14620
English title: On the crossability of Picea species.

Seed development was microscopically studied after controlled pollinations. In all the interspecific crosses incompatibility occured. In the following crosses the growth of all the pollen tubes stopped before they had penetrated through the nuclear cap: Picea abies (L.) Karst. x mariana, abies x jezoensis (and the reciprocal), abies x omorika (and the reciprocal), mariana x asperata, mariana x jezoensis and Picea abies x Pinus sylvestris L.

Some of the eggs were fertilized in the crosses Picea abies x glauca (and the reciprocal) abies x asperata, abies x koyamai, abies x obovata, mariana x omorika and jezoensis x omorika. Embryo degeneration was observed in all these crosses. All the embryos died in the crosses abies x glauca (and the reciprocal) as well as jezoensis x omorika. Adequate amounts of full seed for germination test was obtained from the crosses abies x asperata, abies x koyamai and abies x obovata. In all these crosses there were seeds which were able to germinate and the hybrids are now one growth season old.

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  • Mikkola, ORCID ID:E-mail:
article id 4823, category Article
Christel Palmberg. (1970). Heritabiliteetin arvioiminen eräässä männyn (Pinus silvestris L.) jälkeläiskokeessa. Silva Fennica vol. 4 no. 3 article id 4823. https://doi.org/10.14214/sf.a14612
English title: Estimation of heritability in open-pollinated plus tree progenies of Pinus sylvestris L.

Field experiments of Scots pine (Pinus sylvestris L.) was established by planting seedlings grown from seeds collected from open-pollinated plus trees throughout the country. The 36 progenies represented were planted in 4 blocks as 2+2 transplants in 1960. The main characteristics of the seedlings were measured in 1966 and 1968. Considerable damage had been caused to the stands by moose (Alces alces) and Melampsora pinitorqua Rostr., consequently, therefore, only normally developed seedlings were measured.

Highly significant differences between progenies were found in the number of branches in 1968 and in the ratio of height of tree to the length of the longest branch. In 1968, the differences in height between progenies were not significant, but there were significant differences between blocks both in tree height and length of terminal shoot. Obviously, the edaphic heterogeneity of the site has influenced mainly the juvenile growth of the plants, because in the length of the terminal shoot there could be seen also significant differences between the progenies. There were no significant differences between the progenies in the length of the longest branch, in the angles of the thickest branches, in stem taper and in the diameter of the thickest branch.

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  • Palmberg, ORCID ID:E-mail:
article id 4823, category Article
Christel Palmberg. (1970). Heritabiliteetin arvioiminen eräässä männyn (Pinus silvestris L.) jälkeläiskokeessa. Silva Fennica vol. 4 no. 3 article id 4823. https://doi.org/10.14214/sf.a14612
English title: Estimation of heritability in open-pollinated plus tree progenies of Pinus sylvestris L.

Field experiments of Scots pine (Pinus sylvestris L.) was established by planting seedlings grown from seeds collected from open-pollinated plus trees throughout the country. The 36 progenies represented were planted in 4 blocks as 2+2 transplants in 1960. The main characteristics of the seedlings were measured in 1966 and 1968. Considerable damage had been caused to the stands by moose (Alces alces) and Melampsora pinitorqua Rostr., consequently, therefore, only normally developed seedlings were measured.

Highly significant differences between progenies were found in the number of branches in 1968 and in the ratio of height of tree to the length of the longest branch. In 1968, the differences in height between progenies were not significant, but there were significant differences between blocks both in tree height and length of terminal shoot. Obviously, the edaphic heterogeneity of the site has influenced mainly the juvenile growth of the plants, because in the length of the terminal shoot there could be seen also significant differences between the progenies. There were no significant differences between the progenies in the length of the longest branch, in the angles of the thickest branches, in stem taper and in the diameter of the thickest branch.

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  • Palmberg, ORCID ID:E-mail:
article id 7534, category Article
Olli Heikinheimo. (1915). Kaskiviljelyksen vaikutus Suomen metsiin. Acta Forestalia Fennica vol. 4 no. 2 article id 7534. https://doi.org/10.14214/aff.7534
English title: The effect of shifting cultivation on forests in Finland.

The article is a review on shifting cultivation, its methods and use in Finland, and its effect on the condition of forests. Shifting cultivation decreases forest reserves not only by burning large amounts of wood. Of the area used for shifting cultivation, 10-50% can be open land. The older age classes of forests are often missing, and range of tree species shift towards deciduous trees. This causes lack of large timber. The shorter the rotation, the less well the most valuable trees survive on the area. One reason is lack of seed trees. Of the coniferous trees, Scots pine (Pinus sylvestris L.) is able to survive in the burnt-over lands better than Norway spruce (Picea abies (L.) H. Karst.), because it can produce seeds at a relatively young age. Betula sp. and especially grey alder (Alnus incana (L.) Moench) regenerate well on burnt-over lands. Also the frequency of good seed years determine which tree species become the dominant species on a burnt-over site.

When shifting cultivation is abandoned, deciduous trees keep their advantage over coniferous trees, because the wood of coniferous trees is used more in the surrounding villages. Pine and spruce spread to the burnt-over areas from the poorer sites that often had remained unburned. In densely populated areas in some counties in Savo in eastern Finland, where shifting cultivation was practiced intensively, Norway spruce became rare. Dominant tree species in the burnt-over areas became birch and pine.

The article is divided in two parts. A German summary is included in a separate PDF
  • Heikinheimo, ORCID ID:E-mail:
article id 4819, category Article
Matti Kärkkäinen. (1970). Hakkuutähteiden merkityksestä puuston vaurioitumisen ja raiteenmuodostuksen kannalta harvennusmetsissä. Silva Fennica vol. 4 no. 2 article id 4819. https://doi.org/10.14214/sf.a14608
English title: Significance of logging waste in thinnings as to scars and tracks in the terrain.

The purpose of this study was to explain whether it is possible to affect, in practical working site conditions, by means of logging waste on the strip road, the depth of the track which is formed in terrain transportation and the injuries of the growing stand. Five 20 m long investigation areas with logging waste and five similar areas without logging waste were arranged on one strip road at Teisko logging site in Southern Finland. The logging waste layer was mainly Norway spruce and 10–15 cm thick. A KL–836 B forwarder was used. The type of soil was loam.

The logging waste affected the depth of the track only by decreasing the wear of humus layer. Even decreasing effect of logging waste on the injuries in the growing stand was minor. At Kitee working site in Eastern Finland strip roads were studied. The type of soil was thick, rather mouldered peat. The thickness of logging waste was 3–4 times greater than in Teisko, mainly spruce. A Volvo Nalle SM 460 forwarder was used. The effect of the logging waste on the depth of the tracks was clearly to be noticed. On basis of the appearance of the tracks one could assume that the difference was due to different wear of the humus, and not so much due to the quantity of logging waste that improves the carrying capacity of terrain.

In some extent logging waste was also found to affect the amount and quality of tree injuries. In practical working conditions, the importance might be small, since in the experiments an unrealistically great amount of logging waste was used.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 4816, category Article
P. M. A. Tigerstedt, Eero Malmivaara. (1970). Metsänjalostuksen mahdollisuudet I.Pluspuiden valintaero ja siemenviljelysten valintahyöty. Silva Fennica vol. 4 no. 2 article id 4816. https://doi.org/10.14214/sf.a14605
English title: The possibilities in forest tree breeding. I Selection differential of plus trees and genetic gain in seed orchards in Finland.

An attempt was made to estimate critically the genetic gain in clonal seed orchards of Scots pine (Pinus sylvestris L.) in Finland. The selection differential of Scots pine and Norway spruce (Picea abies (L.) H. Karst.) is calculated on the basis of filed information on selected plus trees which has been kept by the genetic register at the Finnish Forest Research Institute. The differentials were computed as realized differences in height between plus-trees and normal stand characteristics on respectively site class and as a function of age.

The genetic gain in height growth of Pinus sylvestris was computed on the basis of information on selection differential and heritability. This genetic gain is between 2.6–4.4% provided there is no pollen contamination from unknown sources outside the seed orchard. The genetic gain of volume growth in Scots pine is about 7–15%, provided there is no pollen contamination in the seed orchard. However, according to investigations, there is invariably some pollen contamination in this kind of seed orchards. The contamination decreases to about 30–50% as the orchard matures and starts to produce endemic pollen. If the pollination would be entirely due to foreign pollen sources, the mathematically calculated genetic gain would be 3.5–7.5%.

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  • Tigerstedt, ORCID ID:E-mail:
  • Malmivaara, ORCID ID:E-mail:
article id 4807, category Article
J. G. Iyer, G. Chesters, S. A. Wilde. (1969). Recovery of growth potential of nursery stock produced on biocide-treated soils. Silva Fennica vol. 3 no. 4 article id 4807. https://doi.org/10.14214/sf.a14595

Certain biocides used in production of tree nursery stock exterminate undesirable organisms but cause an abnormal growth stimulation of plants. The reforestation material has decreased survival potential because of high degree of succulence, top:root and height:diameter ratios, and low specific gravity and root surface area. Some fumigants impede mycorrhizae development and arrest phosphorus uptake. Recovery of growth potential was achieved by aluminium sulphate and/or fermented compost inoculated with mycorrhiza-forming fungi.

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  • Iyer, ORCID ID:E-mail:
  • Chesters, ORCID ID:E-mail:
  • Wilde, ORCID ID:E-mail:
article id 4807, category Article
J. G. Iyer, G. Chesters, S. A. Wilde. (1969). Recovery of growth potential of nursery stock produced on biocide-treated soils. Silva Fennica vol. 3 no. 4 article id 4807. https://doi.org/10.14214/sf.a14595

Certain biocides used in production of tree nursery stock exterminate undesirable organisms but cause an abnormal growth stimulation of plants. The reforestation material has decreased survival potential because of high degree of succulence, top:root and height:diameter ratios, and low specific gravity and root surface area. Some fumigants impede mycorrhizae development and arrest phosphorus uptake. Recovery of growth potential was achieved by aluminium sulphate and/or fermented compost inoculated with mycorrhiza-forming fungi.

The PDF includes a summary in Finnish.

  • Iyer, ORCID ID:E-mail:
  • Chesters, ORCID ID:E-mail:
  • Wilde, ORCID ID:E-mail:
article id 4766, category Article
Olli Makkonen. (1968). Roomalaisten taimitarhat. Silva Fennica vol. 2 no. 2 article id 4766. https://doi.org/10.14214/sf.a14551
English title: The nurseries of the ancient romans.

The paper outlines the information about forest tree nurseries in the Roman Empire, found in ancient writings. According to the author, it cannot be stated that actual forest cultivation was practiced in the times of the Roman Empire, even if tree seedlings were used for a variety of purposes, such as embellishment of cities, parks and gardens, and raising supporting trees in forest vineyards. Nurseries were usually established on farms to fill the owner’s needs. For instance, Gato, Varro, Virgil, Pliny and Colulmella have given instructions about establishment and management of nurseries, and methods to sowing seeds of different tree species. Except for seeds, both root- and branch-cuttings were used in cultivation of trees. Also, grafting was known.

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  • Makkonen, ORCID ID:E-mail:
article id 4766, category Article
Olli Makkonen. (1968). Roomalaisten taimitarhat. Silva Fennica vol. 2 no. 2 article id 4766. https://doi.org/10.14214/sf.a14551
English title: The nurseries of the ancient romans.

The paper outlines the information about forest tree nurseries in the Roman Empire, found in ancient writings. According to the author, it cannot be stated that actual forest cultivation was practiced in the times of the Roman Empire, even if tree seedlings were used for a variety of purposes, such as embellishment of cities, parks and gardens, and raising supporting trees in forest vineyards. Nurseries were usually established on farms to fill the owner’s needs. For instance, Gato, Varro, Virgil, Pliny and Colulmella have given instructions about establishment and management of nurseries, and methods to sowing seeds of different tree species. Except for seeds, both root- and branch-cuttings were used in cultivation of trees. Also, grafting was known.

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  • Makkonen, ORCID ID:E-mail:
article id 7528, category Article
Einari Vuori. (1913). Die durch Brandkultur entstandenen Nadelholzbestände des Staatsforstes Vesijako. Acta Forestalia Fennica vol. 2 no. 1 article id 7528. https://doi.org/10.14214/aff.7528
English title: Coniferous tree stands of the state forest “Vesijako” reforested through controlled burning.

The study area is state owned forest of Vesijako in southern middle Finland that has earlier been intensively managed with slash-and-burn agriculture. Reforestation of broad-leaved forests into coniferous forest with controlled burning has been studied on 76 sample plots.

The article describes the practice of leasing forest stands to leaseholders who executed the controlled burning and forest regeneration and management according a leasing contract. The results of the reforestation with coniferous trees shows that sowed pine (Pinus silvestris) stands give good results but spruce (Picea abies) must be planted as a seedling.  For the state this method of forest improvement is cost effective  and should be used more widely. 

  • Vuori, ORCID ID:E-mail:
article id 4761, category Article
Pentti Nisula. (1968). Ehdotus metsikön kuution ja käyttöpuuosuuden määrittämiseksi. Silva Fennica vol. 2 no. 1 article id 4761. https://doi.org/10.14214/sf.a14545
English title: A proposal for the determination of total volume and utilization per cent of standing timber .

The present study gives an account of the dependence prevailing between the actual volume of timber crops, and, on one hand, the sum of cylindrical volume of individual trees, and on the other hand, the utilization per cent. This dependence is rectlinear if the volumes in question are calculated on a running-foot basis. The cylindrical volume of individual trees was calculated on the basis of cross-section area at breast height and the height of the trees. On the basis of the results, it seems that it is possible to simplify timber measurement.

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  • Nisula, ORCID ID:E-mail:
article id 4753, category Article
Helge Johnsson. (1967). Olika vägar för rasmässig förbättring av vårt skogsodlingsmaterial. Silva Fennica vol. 1 no. 3 article id 4753. https://doi.org/10.14214/sf.a14537
English title: Different ways of genetic improvement of forest trees in Scandinavia.

Transfer of southern provenances of trees to the north leads to an increased growth until the limit of hardiness is exceeded, which may be utilized in practical forestry. Selection from certain local provenances are important both for the immediate supply of seed and on a somewhat longer view. A certain degree of improvement can be achieved by avoiding minus regions and concentrating seed collection on better areas. Also, seeds can be collected from the best stands only, and by accepting only seed from the best trees of such stands. The selection can be strengthened considerably by production of seed orchards. The seed production is based on a small number of trees of particular superiority that are reproduced vegetatively. The clones are planted in an orchard, which pollinate each other.

Hybridization of two different provenances might result in an increased capacity of production. Such hybridized seed can be produced in orchards established, for instance, as a combination of selection and hybridization orchards. As regards the major Scandinavian tree species there are only small prospects of advancement through species hybridization. The method available at present for efficient racial improvement of our forest trees is individual selection in connection with seed production in orchards. In special cases, however, other methods such as transfer of provenances, provenance hybridization, species hybridization, and polyploidization will result in considerable progress.

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  • Johnsson, ORCID ID:E-mail:
article id 7527, category Article
August Renvall. (1913). Die periodischen Erscheinungen der Reproduktion der Kiefer an der polaren Waldgrenze. Acta Forestalia Fennica vol. 1 no. 2 article id 7527. https://doi.org/10.14214/aff.7527
English title: The periodic variation of the regeneration of pine (Pinus sylvestris) at the polar tree line.

The study deals with the preconditions for natural regeneration of the pine at the polar tree line in northern Finland and Sweden. The data has been collected in three summers from 1909 to 1911 in areas of Inari and Utsjoki in Finland and Kaaresuvanto, Jukkasjärvi und Pajala in Sweden. The yearly variation of seed production of pine is studied and compared with the age of the stand, site factors and weather conditions.

Intensity of reproduction is dependent on different preconditions for pistils and stamens and hence the total reproduction (formation of cones) can vary very much depending on the weather.

According the study, the formation of cones varies yearly and is particularly strong every three to four years.  Supposedly the same model applies to whole polar tree line of the Fennoscandia. There seem to be no difference between northern and southern parts of Scandinavia when it comes to frequency of good cone years though they not always occur in the same years.
  • Renvall, ORCID ID:E-mail:
article id 4744, category Article
Pekka Tiililä. (1967). Tutkimuksia eräiden ulkomaisten puulajien siemensadon laadusta Suomessa. Silva Fennica vol. 1 no. 2 article id 4744. https://doi.org/10.14214/sf.a14454
English title: Studies on the quality of seed yields in some foreign tree species in Finland.

The aim of this present study was to elucidate the quality of seed of foreign tree species grown in Finland, and the factors which have affected the quality of the seed yields. Due to the smallness of the material, however, no far-fetching conclusions can be drawn. The bulk of the seeds were collected in the fall of 1964. The samples of seeds were X-rayed and their classification to empty seeds and full seeds of four quality classes was done on the basis of the anatomical structures. The species studied (a total of 34 species) belonged to the following genera: Abies, Chamaecyparis, Larix, Picea, Pinus, Pseudotsuga, Thuja and Tsuga.

The percentage of empty seeds was throughout quite high. The reasons for the generation of empty seeds probably originate from the special nature of the stands from which the seeds were collected. As a rule, the stands were young and small in area, which may have caused weak pollination and self-pollination leading to embryo mortality. Also, insect damages were observed.

Seeds with albumen still discernible, although the embryo had died, occurred to some extent. In some Larix species, even the bulk of the seeds recorded as full belonged in this group.

The ripening of seeds with embryos was quite successful in spite of the fact that the temperature sum of the year of ripening was slightly below the average in Finland. For instance, all Abies species ripened almost completely.

According to the results, it can be expected that the tree species examined in this study are able to produce rich yields of good-quality seed in Finland, provided that the ovules are well pollinated and self-pollination does not take place to a large extent.

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  • Tiililä, ORCID ID:E-mail:
article id 4744, category Article
Pekka Tiililä. (1967). Tutkimuksia eräiden ulkomaisten puulajien siemensadon laadusta Suomessa. Silva Fennica vol. 1 no. 2 article id 4744. https://doi.org/10.14214/sf.a14454
English title: Studies on the quality of seed yields in some foreign tree species in Finland.

The aim of this present study was to elucidate the quality of seed of foreign tree species grown in Finland, and the factors which have affected the quality of the seed yields. Due to the smallness of the material, however, no far-fetching conclusions can be drawn. The bulk of the seeds were collected in the fall of 1964. The samples of seeds were X-rayed and their classification to empty seeds and full seeds of four quality classes was done on the basis of the anatomical structures. The species studied (a total of 34 species) belonged to the following genera: Abies, Chamaecyparis, Larix, Picea, Pinus, Pseudotsuga, Thuja and Tsuga.

The percentage of empty seeds was throughout quite high. The reasons for the generation of empty seeds probably originate from the special nature of the stands from which the seeds were collected. As a rule, the stands were young and small in area, which may have caused weak pollination and self-pollination leading to embryo mortality. Also, insect damages were observed.

Seeds with albumen still discernible, although the embryo had died, occurred to some extent. In some Larix species, even the bulk of the seeds recorded as full belonged in this group.

The ripening of seeds with embryos was quite successful in spite of the fact that the temperature sum of the year of ripening was slightly below the average in Finland. For instance, all Abies species ripened almost completely.

According to the results, it can be expected that the tree species examined in this study are able to produce rich yields of good-quality seed in Finland, provided that the ovules are well pollinated and self-pollination does not take place to a large extent.

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  • Tiililä, ORCID ID:E-mail:
article id 4740, category Article
Pentti Räsänen. (1967). Metsänviljelyksessä käytettävien taimien luokitteluperusteet. Silva Fennica vol. 1 no. 1 article id 4740. https://doi.org/10.14214/sf.a14450
English title: Book review: ’Wachstum und Qualität von Forstpflanzen'.

This article is a book review of a book ’Wachstum und Qualität von Forstpflanzen. Zweite Erweitrte Auflage von Die Gütebeurteilung von Forstpflanzen’ written by Helmut Scmidt-Vogt.

  • Räsänen, ORCID ID:E-mail:
article id 7517, category Article
Juha Nurmi. (1997). Heating values of mature trees. Acta Forestalia Fennica no. 256 article id 7517. https://doi.org/10.14214/aff.7517

The effective heating values of the above and below ground biomass components of mature Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), downy birch (Betula pubescens Ehrh), silver birch (B. pendula Roth), grey alder (Alnus incana (L.) Moench), black alder (A. glutinosa (L.) Gaertn.) and aspen (Populus tremula L.) were studied. Each sample tree was divided into wood, bark and foliage components. Bomb calorimetry was used to determine the calorimetric heating values.

The species is a significant factor in the heating value of individual tree components. The heating value of the wood proper is highest in conifers. Broadleaved species have a higher heating value of bark than conifers. The species factor diminishes when the weighted heating value of crown, whole stems or stump-root-system are considered. The crown material has a higher heating value per unit weight in comparison with fuelwood from small-sized stems or whole trees. The additional advantages of coniferous crown material are that it is non-industrial biomass resource and is readily available. The variability of both the chemical composition and the heating value is small in any given tree component of any species. However, lignin, carbohydrate and extractive content were found to vary from one part of the tree to another and to correlate with the heating value

  • Nurmi, ORCID ID:E-mail:
article id 7517, category Article
Juha Nurmi. (1997). Heating values of mature trees. Acta Forestalia Fennica no. 256 article id 7517. https://doi.org/10.14214/aff.7517

The effective heating values of the above and below ground biomass components of mature Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), downy birch (Betula pubescens Ehrh), silver birch (B. pendula Roth), grey alder (Alnus incana (L.) Moench), black alder (A. glutinosa (L.) Gaertn.) and aspen (Populus tremula L.) were studied. Each sample tree was divided into wood, bark and foliage components. Bomb calorimetry was used to determine the calorimetric heating values.

The species is a significant factor in the heating value of individual tree components. The heating value of the wood proper is highest in conifers. Broadleaved species have a higher heating value of bark than conifers. The species factor diminishes when the weighted heating value of crown, whole stems or stump-root-system are considered. The crown material has a higher heating value per unit weight in comparison with fuelwood from small-sized stems or whole trees. The additional advantages of coniferous crown material are that it is non-industrial biomass resource and is readily available. The variability of both the chemical composition and the heating value is small in any given tree component of any species. However, lignin, carbohydrate and extractive content were found to vary from one part of the tree to another and to correlate with the heating value

  • Nurmi, ORCID ID:E-mail:
article id 7503, category Article
Anssi Niskanen, Olavi Luukkanen, Olli Saastamoinen, Suree Bhumibhamon. (1993). Evaluation of the profitability of fast-growing tropical trees. Acta Forestalia Fennica no. 241 article id 7503. https://doi.org/10.14214/aff.7503

The profitability of fast-growing trees (Eucalyptus camaldulensis Dehnh., Acacia mangium Willd. and Melia azedarach L.) was investigated in the north-eastern and eastern provinces of Thailand. The financial, economic, and tentative environmental-economic profitability was determined separately for three fast-growing plantation tree species and for three categories of plantation managers: the private industry, the state (the Royal Forest Department) and the farmers. Fast-growing tree crops were also compared with teak (Tectona grandis L. f.), a traditional medium or long rotation species, and Para rubber (Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.) which presently is the most common cultivated tree in Thailand.

The optimal rotation for Eucalyptus camaldulensis pulpwood production was eight years. This was the most profitable species in pulpwood production. In sawlog production Acacia mangium and Melia azedarach showed a better financial profitability. Para rubber was more profitable and teak less profitable than the three fast-growing species. The economic profitability was higher than the financial one, and the tentative environmental-economic profitability was slightly higher than the economic profitability.

The profitability of tree growing is sensitive to plantation yields and labour cost changes and especially to wood prices. Management options which aim at pulpwood production are more sensitive to input or output changes than those options which include sawlog production. There is an urgent need to improve the growth and yield data and to study the environmental impacts of tree plantations for all species and plantation types.

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  • Niskanen, ORCID ID:E-mail:
  • Luukkanen, ORCID ID:E-mail:
  • Saastamoinen, ORCID ID:E-mail:
  • Bhumibhamon, ORCID ID:E-mail:
article id 7685, category Article
Risto Ojansuu. (1993). Prediction of Scots pine increment using a multivariate variance component model. Acta Forestalia Fennica no. 239 article id 7685. https://doi.org/10.14214/aff.7685

Diameter and volume increment as well as change in stem form of Scots pine (Pinus sylvestris L.) were analysed to predict tree increment variables. A stem curve set model is presented, based on prediction of the diameters at fixed angles in a polar coordinate system. This model consists of three elementary stem curves: 1) with bark, 2) without bark, and 3) without bark five years earlier. The differences between the elementary stem curves are the bark curve and the increment curve. The error variances at fixed angles and covariances between the fixed angles are divided into between-stand and within-stand components. Using principal components, the between-stand and within-stand covariance matrices are condensed separately for stem curve with bark, bark curve and increment curve. The two first principal components of the bark curve describe the vertical change in Scots pine bark type and the first principal component of the increment curve describes the increment rate. The elementary stem curves, bark curve and increment curve as well as corresponding stem volumes, bark volume and volume increment can be predicted for all trees in the stand with free choice of sample tree measurements. When only a few sample trees are measured, the stem curve set model gives significantly more accurate predictions of bark volume and volume increment for tally trees than does the volume method, which is based on the differences between two independent predictions of volume. The volume increment of tally trees can be predicted as reliably with as without measurement of sample tree height increment.

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  • Ojansuu, ORCID ID:E-mail:
article id 7682, category Article
Juha Nurmi. (1993). Heating values of the above ground biomass of small-sized trees. Acta Forestalia Fennica no. 236 article id 7682. https://doi.org/10.14214/aff.7682

The heating values of wood, inner and outer bark, and foliage components of seven small-size tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula pubescens Erhr., B. pendula Roth, Alnus incana (L.) Moench, A. glutinosa (L.) Gaertn., Populus tremula L.) were studied. Significant differences were found between species within each component. However, the differences between species for weighted stem, crown and whole-tree biomass are very small. The weighted heating value of the crown mass is slightly higher than that of the stem in all species. The heating value of stem, crown and whole-tree material was found to increase with increasing latitude.

The effective heating value of wood correlated best with the lignin content, inner bark with carbohydrate, and outer bark with carbohydrates and the extractives soluble in alkalic solvents. It is suggested that the determination of the heating value might be used as an indicator of the cellulose content of coniferous wood.

The PDF includes a summary in Finnish.

  • Nurmi, ORCID ID:E-mail:
article id 7682, category Article
Juha Nurmi. (1993). Heating values of the above ground biomass of small-sized trees. Acta Forestalia Fennica no. 236 article id 7682. https://doi.org/10.14214/aff.7682

The heating values of wood, inner and outer bark, and foliage components of seven small-size tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula pubescens Erhr., B. pendula Roth, Alnus incana (L.) Moench, A. glutinosa (L.) Gaertn., Populus tremula L.) were studied. Significant differences were found between species within each component. However, the differences between species for weighted stem, crown and whole-tree biomass are very small. The weighted heating value of the crown mass is slightly higher than that of the stem in all species. The heating value of stem, crown and whole-tree material was found to increase with increasing latitude.

The effective heating value of wood correlated best with the lignin content, inner bark with carbohydrate, and outer bark with carbohydrates and the extractives soluble in alkalic solvents. It is suggested that the determination of the heating value might be used as an indicator of the cellulose content of coniferous wood.

The PDF includes a summary in Finnish.

  • Nurmi, ORCID ID:E-mail:
article id 7678, category Article
Lauri. Valsta. (1992). An optimization model for Norway spruce management based on individual-tree growth models. Acta Forestalia Fennica no. 232 article id 7678. https://doi.org/10.14214/aff.7678

A nonlinear programming algorithm was combined with two individual-tree growth simulators consisting of distance-independent diameter and height growth models and mortality models. Management questions that can be addressed by the optimization model include the timing, intensity and type of thinning, rotation age, and initial density. The results were calculated for Norway spruce (Picea abies (L.) H. Karst.) stands on Oxalis-Myrtillus site in Southern Finland, where the stand density after clearing of a seedling stand is about 2,000 trees/ha.

The optimum thinning programs were characterized by late first thinnings (at dominant height of 15–17 m) and relatively high growing stock levels. It was optimal to thin from above, unless mean annual increment was maximized instead of an economic objective. In most cases, the optimum number of thinnings was two or three. Compared to a no-thinning alternative, thinnings increased revenues by 15 –45% depending on the objective of stand management. Optimum rotation was strongly dependent on the interest rate.

Hooke and Jeeves’ direct search method was used for determining optimum solutions. The performance of the optimization algorithm was examined in terms of the number of functional evaluations and the equivalence of the objective function values of repeated optimizations.

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  • Valsta, ORCID ID:E-mail:
article id 7670, category Article
Risto Heikkilä. (1991). Moose browsing in a Scots pine plantation mixed with deciduous tree species. Acta Forestalia Fennica no. 224 article id 7670. https://doi.org/10.14214/aff.7670

The utilization of available food resources by the moose (Alces alces L.) was studied in a Scots pine (Pinus sylvestris L.) plantation containing an admixture of deciduous species. Rowan (Sorbus aucuparia L.) and aspen (Populus tremula L.) were highly utilized compared to pine and both silver birch (Betula pendula Roth) and downy birch (B. pubescens Ehrh.). However, they were not capable of withstanding continuous browsing by moose owing to their diminished biomass. In total, the browsing intensity (number of browsed twigs/tree) on pine and birch was about double of that on rowan and aspen.

The number of browsed twigs per tree increased as the amount of available main branches increased. The number of bites per available branch, as well as the maximum diameter of the bites, decreased as the density of the plantation increased. Silver birch was more used by moose than pubescent birch as well as planted silver birch compared with naturally regenerated trees.

Main stem breakage was especially common in winter 1988, the average height of the pine and birch trees being over two meters. The tops of broken stems were commonly utilized as food. The increase in moose density and the relatively deep snow cover evidently promoted the incidence of serious damage. The number of undamaged trees/ha was greater in dense than in sparse parts of the stand.

The PDF includes a summary in Finnish.

  • Heikkilä, ORCID ID:E-mail:
article id 7629, category Article
Pekka Kilkki. (1983). Sample trees in timber volume estimation. Acta Forestalia Fennica no. 182 article id 7629. https://doi.org/10.14214/aff.7629

Analysis of sample tree data showed that the major part of the residual variation of the stem volume estimates occurs within the forest stands. The division of the residual variation into the variation within and between populations is the basis for the mean-square error formulae of the volume estimators. Efficiency of different sample tree measurement combinations has been studied by comparing the errors of the volume estimates to the sampling costs. The measurement of the upper diameter (d6) is of less value than is generally suggested.

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  • Kilkki, ORCID ID:E-mail:
article id 7620, category Article
Min-Sup Chung. (1981). Biochemical methods for determining population structure in Pinus sylvestris L. Acta Forestalia Fennica no. 173 article id 7620. https://doi.org/10.14214/aff.7620

Studies on Finnish Scots pine (Pinus sylvestris L.) plus tree clones by monoterpene and isozyme analyses was undertaken to further investigate mating system, population structure and pollination. Six allozyme systems (3 GOT, 1 GDH and 2 LAP) were properly analysed on the basis of segregation. Monoterpenes were analysed from needle material and segregation in high and low 3-carene content was found to depend on two alleles C and c. Thus, six allozyme systems and one monoterpene system were used as markers in this study.

It was shown that the northern clonal group maintains a much genetic variation as the central or southern clonal groups. The conditional probability of self-fertilization in about 20-year old clones estimated by the multilocus model was 14.1%, of which 8% originate from mating between trees that carry the same alleles to one of the maternal parent at some loci and 6% through self-fertilization.

There was no prominent difference in allele frequency of male gametes that pollinated the very early or very late flowering clones. The northern clonal group has higher a lower frequency of alleles GOT B2 and B3 respectively than of the southern clonal groups. The artificial plus tree selection, particularly in northern Finland, appears to favour heterozygous genotypes for the alleles that control 3-carene content n Scots pine.

The PDF includes a summary in Finnish.

  • Chung, ORCID ID:E-mail:
article id 7620, category Article
Min-Sup Chung. (1981). Biochemical methods for determining population structure in Pinus sylvestris L. Acta Forestalia Fennica no. 173 article id 7620. https://doi.org/10.14214/aff.7620

Studies on Finnish Scots pine (Pinus sylvestris L.) plus tree clones by monoterpene and isozyme analyses was undertaken to further investigate mating system, population structure and pollination. Six allozyme systems (3 GOT, 1 GDH and 2 LAP) were properly analysed on the basis of segregation. Monoterpenes were analysed from needle material and segregation in high and low 3-carene content was found to depend on two alleles C and c. Thus, six allozyme systems and one monoterpene system were used as markers in this study.

It was shown that the northern clonal group maintains a much genetic variation as the central or southern clonal groups. The conditional probability of self-fertilization in about 20-year old clones estimated by the multilocus model was 14.1%, of which 8% originate from mating between trees that carry the same alleles to one of the maternal parent at some loci and 6% through self-fertilization.

There was no prominent difference in allele frequency of male gametes that pollinated the very early or very late flowering clones. The northern clonal group has higher a lower frequency of alleles GOT B2 and B3 respectively than of the southern clonal groups. The artificial plus tree selection, particularly in northern Finland, appears to favour heterozygous genotypes for the alleles that control 3-carene content n Scots pine.

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  • Chung, ORCID ID:E-mail:
article id 7590, category Article
Jukka Sarvas. (1977). Mathematical model for the physiological clock and growth. Acta Forestalia Fennica no. 156 article id 7590. https://doi.org/10.14214/aff.7590

In this paper a precise definition is given of the term physiological clock and the role of this clock in biological developmental and growth processes is mathematically studied. The heat sum method employed in the study of the annual cycle of development of forest trees has been used as the starting point. The mathematical principles of this method are analysed and it is shown that, on the same principles, a fairly general physiological clock can be constructed. Also, two growth models are presented in which this generalized physiological clock proves to play an important role.

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  • Sarvas, ORCID ID:E-mail:
article id 7580, category Article
Seppo Kellomäki. (1975). Forest stand preferences of recreationists. Acta Forestalia Fennica no. 146 article id 7580. https://doi.org/10.14214/aff.7580

The environmental preferences of recreationists were studied at the forest stand level in this study. The hypothesis which has been drawn up on the basis of the literature has been studied by attempting to elucidate the environmental preferences of groups using two recreation areas owned by the City of Helsinki using interviews and questionnaires. The material consisted of 1,323 interviews supplemented by questionnaires.

The replies to the questionnaires showed that recreationists consider birch and Scots pine to be more beautiful than Norway spruce, and stands made up of several tree species to be more beautiful than stands of single tree species. They also consider mature stands to be more beautiful than young stands.

During the interviews, the attention of the recreationists was directed at the view formed by the interview stand. The scenic preferences for the stands were measured using adjectives which the interviewee was asked to use in describing his or her impression of the view which was pointed out. First of all, the results clearly indicated that from the point of view of the scenic value of the stand, the way in which the stand is organised to form a scenic aspect or a stand view is more important than its ecological structure. However, it is obvious that stands containing large sized trees in particular are in many ways more preferred than stands which are younger in their development stage. This should therefore be the case when changes in the stand view resulting from management measures are insignificant or difficult to see. The main tree species in the stand does not seem to have from the point of view of scenic preference as much significance as would have been expected judging by the questionnaire material.

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article id 7579, category Article
Pekka Kilkki, Markku Siitonen. (1975). Metsikön puuston simulointimenetelmä ja simuloituun aineistoon perustuvien puustotunnusmallien laskenta. Acta Forestalia Fennica no. 145 article id 7579. https://doi.org/10.14214/aff.7579
English title: Simulation of artificial stands and derivation of growing stock models from this material.

The purpose of this study was that of providing a long-term timber production model (Kilkki and Pökkälä 1975) with growing stock models. The paper is divided into two parts; the first is concerned with generation of the stand data through Monte-Carlo simulation. The growing stock of each stand was described by a DBH-height distribution. The necessary information on the relationships between the stand characteristics was derived from sample plots measured in the national forest inventory of Finland. A total of 1,500 Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst), and birch (Betula sp.) stands, each comprising 100 trees were provided by simulation.

In the second part, models predicting the form factor, timber assortment distribution, and value of the growing stock were derived through regression analysis for each species of tree. The predicting variables included the form factor of the basal area median tree, basal area median diameter, and height in the form factor models. In the timber assortment and value models, the only predicting variable was the volume of the basal area median tree. The Matchcurve-technique (Jensen 1973) was employed in derivation of the regression models.

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  • Siitonen, ORCID ID:E-mail:
article id 7572, category Article
Tauno Kallio, Pekka Tamminen. (1974). Decay of spruce (Picea abies (L.) Karst.) in the Åland Islands. Acta Forestalia Fennica no. 138 article id 7572. https://doi.org/10.14214/aff.7572

In 1972, all Norway spruce (Picea abies (L.) H. Karst.) trees of a minimum 7 cm diameter at breast height growing in the sample plots of the Sixth National Forest Inventory were examined on the main island of Aland, Finland. The soundness of standing trees was estimated by means of external characteristics and increment borer chips. The trees were then felled and measured. They were cut into lengths, and the type and extent of decay were studied.

30% of the trees examined was affected by butt rot, ca. 3% by wound decay. A comparison of the results with those of the Sixth National Forest Inventory justifies the estimate that in Aland 23% of spruce trees exceeding 7 cm in diameter at 1.3 m had butt rot.

The proportion of decayed trees in the cubic volume was 31%. Decayed wood material accounted for 5% of the volume including bark. Butt rot increased towards the mature stands. The reduction in the number of timber trees due to decay was 14.5%, in their volume 21.5%, and in the volume of sulphite pulpwood 12%. The share of sulphate pulpwood increased from 1 to 10%. The total reduction in usable wood was 6.3%. The stumpage price of the trees fell by 10.3%. As the degree of decay increased the increment percentage of the trees decreased. The most common cause of butt rot was Fomes annosus (Heterobasidion annosum) found in 46% of the number of decayed trees. Armillaria mellea was found in 16%. Bacteria were found in 50% of the decayed trees.

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  • Tamminen, ORCID ID:E-mail:
article id 4704, category Article
V. A. Kolehmainen. (1960). Lehtikuusenviljelys Tuomarniemellä. Silva Fennica no. 108 article id 4704. https://doi.org/10.14214/sf.a9139
English title: Cultivation of larch in Tuomarniemi, Finland.

Foreign tree species have been planted in Finland since 1900s, the most famous being Larix sibirica plantations in Raivola in Karelia, which now belongs to Soviet Union. One of the largest larch plantations of Finland today is situated in Tuomarniemi, in Central Finland. Ten larch stands were established in Tuomarniemi between 1912 and 1937 mainly by planting. The stand established in 1937 was sown. The trees represent five larch species: Larix sibirica Ledeb. (5 stands), Larix gmelinii var. kurilensis (2 stands, current name probably Larix gmelinii var. gmelinii), Larix americana Michx. (1 stand, now Larix laricina), Larix decidua Mill. (1 stand) and Larix occidentalis Nutt. (1 stand). The total area of the larch stands is 82.5 ha. This paper reports the studies made in the plantations in 1958.

In Tuomarniemi larch grows well in many types of soil from Vaccinium type sites to fresh mineral soil sites. The age of the stands varies from 19 to 48, height from 12 to 24 metres and annual growth from 5 to 12 m3/ha. Larix sibirca has the best stem form of the species, followed by L. gmelinii var. kuriliensis. Easiest to split is the straight-grained L. gmelinii var. kuriliensis. L. sibirica is almost as easy to process. The wood of L. decidua, on the other hand, is often spiral-grained and tough. The trees are seldom infected with decay fungi.

The PDF includes a summary in German.

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article id 7609, category Article
Matti Kärkkäinen. (1969). Metsän vaurioituminen kesäaikaisessa puunkorjuussa. Acta Forestalia Fennica no. 100 article id 7609. https://doi.org/10.14214/aff.7609
English title: The amount of injuries caused by timber transportation in the summer.

The purpose of this study was to build a mathematic predictive model for the formation of injuries and to try its usability in predicting. The empirical data consisted of 24 thinning sites, which were situated mainly in forests owned by forestry companies. The timber was made by strip roads. The terrain transportation of timber was carried out by forwarders or by agricultural tractor-trailer combinations.

The model has been compiled by multiple regression analysis. The predictive model has been interpreted so that the formation of injuries is, for one part, dependent of the number of trees exposed to damages, and, on the other hand, on the factors influencing the probability of injuries, the possibility for this existing. The number of trees exposed to injuries is dependent on the density of strip roads and on the amount of standing timber left after logging. The probability of injuries is influenced by the