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Silva Fennica 1926-1997
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Articles containing the keyword 'growth'.

Category: Commentary

article id 461, category Commentary
Sari Palmroth. (2009). Boreal forest and climate change – from processes and transport to trees, ecosystems and atmosphere. Silva Fennica vol. 43 no. 4 article id 461. https://doi.org/10.14214/sf.461
Book review: Hari, P. & Kulmala, L. (eds.). 2008. Boreal Forest and Climate Change. Advances in Global Change Research 34. Springer. 582 p. ISBN 978-1-4020-8717-2.
  • Palmroth, Duke University, Nicholas School of the Environment, Box 90328 Duke University, Durham, USA ORCID ID:E-mail: sari.palmroth@duke.edu (email)

Category: Research article

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 10040, category Research article
Bengt Andersson Gull, Torgny Persson, Aleksey Fedorkov, Tim J. Mullin. (2018). Longitudinal differences in Scots pine shoot elongation. Silva Fennica vol. 52 no. 5 article id 10040. https://doi.org/10.14214/sf.10040
Highlights: More northerly Scots pine origins exhibit earlier onset and cessation of shoot growth; Continental origins show more northern phenological behaviour; Heat accumulation requirements for onset are not fixed and may be lower when accumulating slower; Scots pine may suffer from spring frost due to earlier growth onset in a warming climate; Phenological traits show potential to adapt to new climate conditions by breeding.

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine (Pinus sylvestris L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.

  • Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
  • Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia ORCID ID: https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
  • Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se (email)
article id 10040, category Research article
Bengt Andersson Gull, Torgny Persson, Aleksey Fedorkov, Tim J. Mullin. (2018). Longitudinal differences in Scots pine shoot elongation. Silva Fennica vol. 52 no. 5 article id 10040. https://doi.org/10.14214/sf.10040
Highlights: More northerly Scots pine origins exhibit earlier onset and cessation of shoot growth; Continental origins show more northern phenological behaviour; Heat accumulation requirements for onset are not fixed and may be lower when accumulating slower; Scots pine may suffer from spring frost due to earlier growth onset in a warming climate; Phenological traits show potential to adapt to new climate conditions by breeding.

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine (Pinus sylvestris L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.

  • Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
  • Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia ORCID ID: https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
  • Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se (email)
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 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 7813, category Research article
Jaana Luoranen. (2018). Autumn versus spring planting: the initiation of root growth and subsequent field performance of Scots pine and Norway spruce seedlings. Silva Fennica vol. 52 no. 2 article id 7813. https://doi.org/10.14214/sf.7813
Highlights: Conifer seedlings planted after mid-September generally have poor rooting, which causes poor root egress during the following spring; Although Scots pine and Norway spruce seedlings planted in late autumn may have a slightly reduced growth, it is possible to plant them if weather conditions are favorable in late-autumn, without increased mortality.

There is a need to extend the planting season of conifer regeneration into periods where the soil remains unfrozen due to a lack of available labor and the mechanization of planting. This study investigated how the summer- (August) and autumn-, especially late autumn (mid-September to mid-October) plantings affect the field performance of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) container seedlings. This study examined the timing of root growth just after planting, shoot flush and the start of root growth the following spring, and subsequent field performance. Seedlings of both species were planted in a nursery field trial, and in a clearcut reforestation site from August to October and the following May. The root growth of planted seedlings declined in September and ceased after mid-September. In the following spring, seedlings which were planted in early-autumn started their root growth faster than late-autumn-planted seedlings in both species. There was no difference in the timing of shoot flush for various planting dates. During the initial two years after planting, the shoot growth of spring-planted seedlings was lower, compared to autumn-planted seedlings. In conclusion, it is possible to plant conifer seedlings in the boreal forest zone up to October under non-limiting field conditions.

  • Luoranen, Natural Resources Institute Finland (Luke), Production systems, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@luke.fi (email)
article id 7813, category Research article
Jaana Luoranen. (2018). Autumn versus spring planting: the initiation of root growth and subsequent field performance of Scots pine and Norway spruce seedlings. Silva Fennica vol. 52 no. 2 article id 7813. https://doi.org/10.14214/sf.7813
Highlights: Conifer seedlings planted after mid-September generally have poor rooting, which causes poor root egress during the following spring; Although Scots pine and Norway spruce seedlings planted in late autumn may have a slightly reduced growth, it is possible to plant them if weather conditions are favorable in late-autumn, without increased mortality.

There is a need to extend the planting season of conifer regeneration into periods where the soil remains unfrozen due to a lack of available labor and the mechanization of planting. This study investigated how the summer- (August) and autumn-, especially late autumn (mid-September to mid-October) plantings affect the field performance of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) container seedlings. This study examined the timing of root growth just after planting, shoot flush and the start of root growth the following spring, and subsequent field performance. Seedlings of both species were planted in a nursery field trial, and in a clearcut reforestation site from August to October and the following May. The root growth of planted seedlings declined in September and ceased after mid-September. In the following spring, seedlings which were planted in early-autumn started their root growth faster than late-autumn-planted seedlings in both species. There was no difference in the timing of shoot flush for various planting dates. During the initial two years after planting, the shoot growth of spring-planted seedlings was lower, compared to autumn-planted seedlings. In conclusion, it is possible to plant conifer seedlings in the boreal forest zone up to October under non-limiting field conditions.

  • Luoranen, Natural Resources Institute Finland (Luke), Production systems, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@luke.fi (email)
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 1734, category Research article
Jyrki Hytönen, Paula Jylhä, Keith Little. (2017). Positive effects of wood ash fertilization and weed control on the growth of Scots pine on former peat-based agricultural land – a 21-year study. Silva Fennica vol. 51 no. 3 article id 1734. https://doi.org/10.14214/sf.1734
Highlights: Weed control decreased and fertilization increased vegetation height and shading of seedlings; Weed control decreased mortality, but fertilization had no effect; Despite improved foliar K concentration though ash fertilization, all trees in the trial had severe K deficiency after 21 years; Weed control increased growth by 20 m3 ha–1 and fertilization by 35 m3 ha–1 in 21 years.

The impacts of weed control, ash fertilization and their interaction were tested for the afforestation of former agricultural peat-based soil with Scots pine (Pinus sylvestris L.) in northern Finland in a factorial arrangement of four treatments. Weed control with herbicides was carried out in July 1 and 2 years from planting, and wood ash (5 Mg ha–1) was applied in the spring of the 2nd year. Various vegetation, tree growth and nutrient assessments were made over the 21-year study period. Weed control decreased the weed cover by 36–56 percentage points, vegetation height by 4–26 cm and thus shading of seedlings by vegetation for at least 4 years after planting. For the same period, ash fertilization increased vegetation height by 6–15 cm and shading of seedlings. Weed control reduced seedling mortality by 27 percentage points in 21 years, but ash fertilization had no significant effect. Ash fertilization increased foliar potassium and boron concentrations, but its effect declined, and severe K-deficiency was recorded 21 years after planting. Up to the 9th year, weed control had a greater influence on growth than fertilization. Later the significance of fertilization increased due to an aggravated K-deficiency. Stand volume at year 21 for the untreated control plots was 8 m3 ha–1. Weed control and fertilization increased stand volume by 20 and 35 m3 ha–1, with a combined effect of 55 m3 ha–1. The effects of weed control and fertilization were additive and no significant interactions were found. Due to severe K-deficiencies, re-fertilization of all treatments would be necessary for the continued survival and growth of Scots pine.

  • Hytönen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID: http://orcid.org/0000-0001-8475-3568 E-mail: jyrki.hytonen@luke.fi (email)
  • Jylhä, Natural Resources Institute Finland (Luke), Green technology, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: paula.jylha@luke.fi
  • Little, Nelson Mandela Metropolitan University, George Campus, Western Cape, South Africa ORCID ID:E-mail: keith.little@nmmu.ac.za
article id 1607, category Research article
Yanlin Fu, Juan A. Oliet, Guolei Li, Jiaxi Wang. (2017). Effect of controlled release fertilizer type and rate on mineral nutrients, non-structural carbohydrates, and field performance of Chinese pine container-grown seedlings. Silva Fennica vol. 51 no. 2 article id 1607. https://doi.org/10.14214/sf.1607
Highlights: We demonstrated that Chinese pine container-grown seedling nutrient status and non-structural carbohydrate content were sufficient over a wide range of fertilization rates; Fertilization at 80 mg N seedling–1 was optimal for seedling responses in the nursery and field; Nursery fertilization using controlled release fertilizer (CRF) with a single coating layer yielded better seedling nursery performance than CRF with multiple coatings.

Although controlled release fertilizer (CRF) with single and multiple-layer coatings are extensively used in tree seedlings, studies that compare the impact of CRF type and application rate on seedling growth, nutrient storage, and, most importantly, outplanting performance, are lacking. In the current study, container-grown Pinus tabulaeformis Carr. (Chinese pine) seedlings were fertilized with commercial CRF with either one or multiple coating layers with equivalent formulation and longevity, at six rates ranging from 40 to 240 mg N seedling–1. Seedlings were sampled for dry mass, non-structural carbohydrate (NSC) content, and mineral nutrient status at the end of the growing season in the nursery, and subsequently outplanted for one season. Compared to Chinese pine seedlings fertilized with single-layer CRF treatments, seedlings treated with multiple-layer CRF had higher starch concentrations but reduced dry mass and N, P, K concentrations in the nursery, and reduced diameter growth in the field. Fertilization rates of 80 and 120 mg N seedling–1 generally yielded maximal plant dry mass and mineral nutrient content. Field survival peaked at 80 mg N seedling–1. Seedling growth, soluble sugar content, and starch concentration in the nursery and survival in the field consistently decreased at rates of 200 and 240 mg N seedling–1. In our study, optimal nursery and field performance of P. tabulaeformis were observed using single layer CRF at 80 mg N seedling–1 (3.3 g CRF l–1 media).

  • Fu, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University; Beijing Laboratory of Urban and Rural Ecological Environment; 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: bjfu_fu@163.com
  • Oliet, Department of Natural Systems and Resources, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: juan.oliet@upm.es
  • Li, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University; Beijing Laboratory of Urban and Rural Ecological Environment; 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: glli226@163.com (email)
  • Wang, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University; Beijing Laboratory of Urban and Rural Ecological Environment; 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: wjx198979@163.com
article id 1692, category Research article
Aleksey Fedorkov, Ludmila Gutiy. (2017). Performance of lodgepole pine and Scots pine in field trials located in north-west Russia. Silva Fennica vol. 51 no. 1 article id 1692. https://doi.org/10.14214/sf.1692
Highlights: Stem volume was bigger for lodgepole pine in comparison to local Scots pine except for the southernmost origin; The proportion of stems with no defects was lower for all lodgepole pine seed sources than for local Scots pine; Lodgepole pine stem growth traits were significantly related to latitude of seed origin.

Mortality, stem growth and quality of lodgepole pine (Pinus contorta var. latifolia) originating from the six Swedish seed orchards and local Scots pine (Pinus sylvestris L.) were estimated in four field trials established in the Komi Republic (north-west Russia). A randomized row-plot design with 6–12 replicates of each entry was used. The tree mortality was slightly higher for Scots pine than that for lodgepole pine, except for the lodgepole pine seed sources of the southern origins with lower survival. Scots pine stem quality was better than that of lodgepole pine, but the lodgepole pine stem growth was faster except the seed source of the southernmost origin. The lodgepole pine seed sources of northern origins had better stem growth (height, diameter at breast height and volume), while the effect of latitude on the quality traits was insignificant.

  • Fedorkov, Institute of Biology, Komi Science Center, Russian Academy of Sciences, 28 Kommunisticheskaya st., Syktyvkar 167982, Russia ORCID ID: http://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru (email)
  • Gutiy, Syktyvkar Forest Institute (branch), Saint-Petersburg State Forest Technical University, 39 Lenin st., Syktyvkar 167000, Russia ORCID ID:E-mail: lguti@mail.ru
article id 1680, category Research article
Liisa Kulmala, Indre Žliobaitė, Eero Nikinmaa, Pekka Nöjd, Pasi Kolari, Kourosh Kabiri Koupaei, Jaakko Hollmén, Harri Mäkinen. (2016). Environmental control of growth variation in a boreal Scots pine stand – a data-driven approach. Silva Fennica vol. 50 no. 5 article id 1680. https://doi.org/10.14214/sf.1680
Highlights: High water potential and carbon gain during bud forming favoured height growth; High water potential during the elongation period favoured height growth; A spring with high carbon gain favoured diameter growth; The obtained regression models had generally low generalization performance.

Despite the numerous studies on year-to-year variation of tree growth, the physiological mechanisms controlling annual variation in growth are still not understood in detail. We studied the applicability of data-driven approach i.e. different regression models in analysing high-dimensional data set including continuous and comprehensive measurements over meteorology, ecosystem-scale water and carbon fluxes and the annual variation in the growth of app. 50-year-old Scots pine stand in southern Finland. Even though our dataset covered only 16 years, it is the most extensive collection of interactions between a Scots pine ecosystem and atmosphere. The analysis revealed that height growth was favoured by high water potential of the tree and carbon gain during the bud forming period and high water potential during the elongation period. Diameter growth seemed to be favoured by a winter with high precipitation and deep snow cover and a spring with high carbon gain. The obtained models had low generalization performance and they would require more evaluation and iterative validation to achieve credibility perhaps as a mixture of data-driven and first principle modeling approaches.

  • Kulmala, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: liisa.kulmala@helsinki.fi (email)
  • Žliobaitė, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: zliobaite@gmail.com
  • Nikinmaa, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: eero.nikinmaa@helsinki.fi
  • Nöjd, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: pekka.nojd@luke.fi
  • Kolari, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland; University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: pasi.kolari@helsinki.fi
  • Kabiri Koupaei, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kourosh.kabiri@helsinki.fi
  • Hollmén, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: jaakko.hollmen@aalto.fi
  • Mäkinen, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: harri.makinen@luke.fi
article id 1680, category Research article
Liisa Kulmala, Indre Žliobaitė, Eero Nikinmaa, Pekka Nöjd, Pasi Kolari, Kourosh Kabiri Koupaei, Jaakko Hollmén, Harri Mäkinen. (2016). Environmental control of growth variation in a boreal Scots pine stand – a data-driven approach. Silva Fennica vol. 50 no. 5 article id 1680. https://doi.org/10.14214/sf.1680
Highlights: High water potential and carbon gain during bud forming favoured height growth; High water potential during the elongation period favoured height growth; A spring with high carbon gain favoured diameter growth; The obtained regression models had generally low generalization performance.

Despite the numerous studies on year-to-year variation of tree growth, the physiological mechanisms controlling annual variation in growth are still not understood in detail. We studied the applicability of data-driven approach i.e. different regression models in analysing high-dimensional data set including continuous and comprehensive measurements over meteorology, ecosystem-scale water and carbon fluxes and the annual variation in the growth of app. 50-year-old Scots pine stand in southern Finland. Even though our dataset covered only 16 years, it is the most extensive collection of interactions between a Scots pine ecosystem and atmosphere. The analysis revealed that height growth was favoured by high water potential of the tree and carbon gain during the bud forming period and high water potential during the elongation period. Diameter growth seemed to be favoured by a winter with high precipitation and deep snow cover and a spring with high carbon gain. The obtained models had low generalization performance and they would require more evaluation and iterative validation to achieve credibility perhaps as a mixture of data-driven and first principle modeling approaches.

  • Kulmala, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: liisa.kulmala@helsinki.fi (email)
  • Žliobaitė, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: zliobaite@gmail.com
  • Nikinmaa, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: eero.nikinmaa@helsinki.fi
  • Nöjd, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: pekka.nojd@luke.fi
  • Kolari, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland; University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: pasi.kolari@helsinki.fi
  • Kabiri Koupaei, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kourosh.kabiri@helsinki.fi
  • Hollmén, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: jaakko.hollmen@aalto.fi
  • Mäkinen, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: harri.makinen@luke.fi
article id 1406, category Research article
Tatiana V. Stankova. (2016). A dynamic whole-stand growth model, derived from allometric relationships. Silva Fennica vol. 50 no. 1 article id 1406. https://doi.org/10.14214/sf.1406
Highlights: A dynamic whole-stand model was derived from simple allometries and biological rationale; The state-space modelling approach was applied, suggesting several novelties to overcome scarcity of longitudinal data; The model consists of a three-dimensional state vector, defined by dominant stand height, stand density and mean stem volume, and three transition functions; It was tested with data from Scots pine plantations.

Growth and yield tables are constrained by a standard production regime and the stand-level dynamic models are an attractive alternative for the even-aged monospecific stands. The objective of this study is to derive a parsimonious and biologically sound whole-stand dynamic growth model and to validate its consistency and relevance for prediction of stand growth and yield. The state-space modelling approach was employed, introducing several novelties in comparison with its current usage. The model consists of a three-dimensional state vector, defined by dominant stand height, number of trees per hectare and mean stem volume, and three transition functions. A site index model was incorporated for height growth projection and transition functions for stand density and mean stem volume with respect to dominant height increase were derived from simple allometries and biological rationale. The model was examined with data from 79 permanent sample plots in Scots pine plantations. Nonlinear Seemingly Unrelated Regression was used to account for cross-equation correlations, and the Base-Height-Invariant dummy variable method was employed to estimate dynamic-form equations. Model consistency was validated in terms of accuracy of predictions and applicability to both thinned and unthinned stands. The new dynamic growth model is a parsimonious biometric whole-stand model that simulates the expected stand development for a broad spectrum of potential management alternatives and can be incorporated in a computer program for further use. It may be especially useful for application when a scarcity of longitudinal data prevents the use of more complicated modelling approaches.

  • Stankova, Forest Research Institute of Bulgarian Academy of Sciences, Department of Forest Genetics, Physiology and Plantations, 132 “St. Kliment Ohridski” Blvd., 1756 Sofia, Bulgaria ORCID ID: http://orcid.org/0000-0002-9932-7286 E-mail: tatianastankova@yahoo.com (email)
article id 1391, category Research article
Roberts Matisons, Jānis Jansons, Juris Katrevičs, Āris Jansons. (2015). Relation of tree-ring width and earlywood vessel size of alien Quercus rubra L. with climatic factors in Latvia. Silva Fennica vol. 49 no. 4 article id 1391. https://doi.org/10.14214/sf.1391
Highlights: Climate-growth relationships of red oak from three sites in Latvia were studied; Tree-ring width was mainly affected by temperature and precipitation in late summer; Vessel size was correlated with temperature parameters in autumn–spring; Sets of climatic factors significant for growth of red oak differed between sites; Changes in climate-growth relationships occurred during 20th century.

The effect of climatic factors on wood anatomy of the alien red oak (Quercus rubra L.) growing in three experimental plantations in Latvia was assessed by classical dendrochronological techniques. Two tree-ring proxies – tree-ring width (TRW) and mean area of earlywood vessel lumen (VLA) – were studied on 33 trees. Annual variation of TRW amongst trees was similar (mean r = 0.46), but there was more individuality in VLA (mean r = 0.26); nevertheless, chronologies of both proxies had rather synchronous variation amongst the sites. Annual variation of TRW was affected by factors related to water deficit in late summer, as suggested by the negative effect of temperature and positive effect of precipitation that have intensified during the 20th century, likely due to warming. Although weather conditions during the dormant period did not directly affect TRW, temperature during the autumn-spring period has been the main climatic determinant of VLA likely via influence on overwintering and hence vigour of tree. This suggests that conductive properties of wood and hence the susceptibility to water deficit have been affected by weather conditions before the formation of tree rings. During the 20th century, sensitivity of VLA has shifted from temperature in winter to temperature in autumn likely due to climate change. Still, the positive effect of these factors suggests that warming of climate would increase VLA and hence the risk of embolism and xylem disfunction. Therefore, the importance of availability of water for growth of red oak in Latvia is increasing.

  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Jansons, Latvian Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV 1006 ORCID ID:E-mail: janis.jansons@silava.lv
  • Katrevičs, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.katrevics@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
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 1302, category Research article
Nils Fahlvik, Per Magnus Ekö, Nils Petersson. (2015). Effects of precommercial thinning strategies on stand structure and growth in a mixed even-aged stand of Scots pine, Norway spruce and birch in southern Sweden. Silva Fennica vol. 49 no. 3 article id 1302. https://doi.org/10.14214/sf.1302
Highlights: Precommercial thinning (PCT) was a useful tool to influence the stand structure in accordance to silvicultural goals; PCT had a great impact on tree species composition; The seemingly great potential to influence the structure of a heterogeneous, mixed stand was restrained by natural settings and unconditional considerations at PCT (e.g. tree vitality, stem quality, regular spacing).
Four different management strategies were applied to a young mixed stand of Scots pine (Pinus sylvestris L.), Norway spruce (Pices abies (L.) Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in southern Sweden. All strategies included an initial precommercial thinning to ca. 2400 stems ha–1. The different aims were: (i) a conifer-dominated stand with focus on high productivity; (ii) a conifer-dominated stand with high quality timber; (iii) keeping a stem-wise species mixture; (iv) a mosaic-wise species mixture. Stem selection according to the different strategies were simulated with a starting point from plots with a 5 m radius. All strategies were applied to all of the plots. A growth simulator was used to simulate the stand development up to final felling. This study illustrates the possibilities for influencing the structure of a mixed stand through precommercial thinning. The study also illustrates the long-term effects on stand structure and volume yield by consequently applying a management strategy from precommercial thinning until final felling. Precommercial thinning was found to be a useful tool to influence the stand structure in accordance to the aims set. However, the opportunities for influencing the stand by precommercial thinning were restricted by natural settings and unconditional considerations (e.g. tree vitality, stem quality, regular spacing), beyond what could be judged from stand average data. The stem volume production during a rotation was 6% lower for (iii) and (iv) compared to (i) and (ii), mainly due to a greater proportion of birch in the former strategies.
  • Fahlvik, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: nils.fahlvik@slu.se (email)
  • Ekö, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per.magnus.eko@slu.se
  • Petersson, StoraEnso Skog AB, Åsgatan 22, SE-791 80 Falun, Sweden ORCID ID:E-mail: nils.petersson@storaenso.com
article id 1301, category Research article
Mikko Moilanen, Jyrki Hytönen, Hannu Hökkä, Anssi Ahtikoski. (2015). Fertilization increased growth of Scots pine and financial performance of forest management in a drained peatland in Finland. Silva Fennica vol. 49 no. 3 article id 1301. https://doi.org/10.14214/sf.1301
Highlights: All fertilizers containing phosphorus and potassium improved the P and K status and the stem growth of Scots pine still 26 years from application; Wood ash, containing more nutrients than other fertilizers, gave the strongest stand growth response and the highest net present value; Ash fertilizer treatment outperformed other fertilizer treatments and control in net present value, regardless of the applied discount rate, 3%, 4% or 5%.

The long-term effects of fertilization on the needle nutrient concentrations, growth and financial performance of a Scots pine (Pinus sylvestris L.) stand was examined in a thick-peated drained peatland forest located in Central Finland. At the trial establishment in 1985, the trees were suffering from P and K deficiencies, but their N status was good. The fertilizer treatments were Control, PK (rock phosphate + potassium chloride), ApaBio (apatite phosphorus + biotite) and wood ash, applied both with and without N and replicated six times. All treatments containing phosphorus and potassium increased foliar P and K concentrations above the deficiency limits up to the end of the study period of 26 years. The effect of the fertilization on stand volume growth of Scots pine was strong and continued still at the end of the study period. The trees on ApaBio and PK plots grew nearly two-fold and those on Ash plots over two-fold compared with the control plots. In a thinning made at the end of the study period the total logging removal on fertilized plots was 1.5–2.2 times greater and included more saw logs than on the control plots. Ash fertilizer treatment outperformed other fertilizer treatments as well as the control. With a 5% discounted equivalent annual income (EAI) of Ash fertilizer treatment was statistically significantly (p=0.009) almost three times higher than that of control. As a conclusion, fertilization (either using PK fertilizers or Ash) in N-rich drained peatlands is a financially feasible method of management.

  • Moilanen, Natural Resources Institute Finland, Natural resources and bioproduction, Paavo Havaksen tie 3, FI-90014 Oulu, Finland ORCID ID:E-mail: mikko.moilanen@luke.fi (email)
  • Hytönen, Natural Resources Institute Finland, Natural resources and bioproduction, Silmäjärventie 2, FI-69100 Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@luke.fi
  • Hökkä, Natural Resources Institute Finland, Natural resources and bioproduction, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@luke.fi
  • Ahtikoski, Natural Resources Institute Finland, Natural resources and bioproduction, Paavo Havaksen tie 3, FI-90014 Oulu, Finland ORCID ID:E-mail: anssi.ahtikoski@luke.fi
article id 1262, category Research article
Āris Jansons, Roberts Matisons, Māra Zadiņa, Linards Sisenis, Jānis Jansons. (2015). The effect of climatic factors on height increment of Scots pine in sites differing by continentality in Latvia. Silva Fennica vol. 49 no. 3 article id 1262. https://doi.org/10.14214/sf.1262
Highlights: Height increment-climate relationships of Scots pine were assessed using dendrochronological techniques; Annual height increment was significantly affected by climatic factors; In western Latvia, temperature in preceding summer mainly affected height increment; In eastern Latvia height increment was affected by previous autumn temperature; During the 20th century, the effect of climatic factors has altered likely dues to climate change.
Height growth of trees is a crucial parameter that influences the composition and productivity of forest stands and quality of timber; however, the relationships between annual height increment (HI) and climatic factors have been poorly studied. In this study, the effect of monthly mean temperature and precipitation sums on the HI of Scots pine in two sites in Latvia have been determined using dendrochronological techniques. Correlation and response function analyses were conducted for entire chronologies of HI and for 50-year intervals within them. Climatic factors significantly affected the HI of Scots pine; however, not only did the suite of significant factors differ between the sites, but the influence of these factors changed during the 20th century. In the site in western Latvia where climate is milder, temperature in the preceding summer was the main climatic determinant of HI. The effect of temperature in the dormant period and spring was significant during the first part of the 20th century, while the effect of temperature in the previous September and November has become significant since the second half of the 20th century. In the site in eastern Latvia where summers are hotter, HI has been affected by both temperature and water deficit related factors in the summer. However, since the later part of the 20th century, the effect of temperature in the previous October has intensified and become the main climatic determinant of HI.
  • Jansons,  LSFRI “Silava”, Rīgas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Matisons,  LSFRI “Silava”, Rīgas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Zadiņa,  LSFRI “Silava”, Rīgas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: mara.zadina@silava.lv
  • Sisenis, LUA Forestry Faculty, Akadēmijas str. 11, Jelgava, Latvia ORCID ID:E-mail: linards.sisenis@llu.lv
  • Jansons, Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV1006 ORCID ID:E-mail: janis.jansons@silava.lv
article id 1274, category Research article
Juho Hautsalo, Paul Mathieu, Sakina Elshibli, Pekka Vakkari, Juha Raisio, Pertti Pulkkinen. (2015). Variation in height and survival among northern populations of pedunculate oak (Quercus robur L.): results of a 13-year field study. Silva Fennica vol. 49 no. 2 article id 1274. https://doi.org/10.14214/sf.1274
Highlights: A height-sum function allowed us to compare the combined growth and survival of northernmost stands of pedunculate oak; Individuals from Turku-Katariinanlaakso performed the best, although other families performed more consistently across trials, which should be considered in future conservation and breeding. Surprisingly, trees planted in a trial location beyond the natural northern limit of pedunculate oak showed the best performance.
We analysed the adaptive potential of pedunculate oak (Quercus robur L.) in terms of variation in height and survival in five field trials located in southern and central Finland. The trials were established with Finnish native material from six different seed origins. Thirteen years after planting, the number of living trees was counted and measured for height. Analysis of height and survival revealed a significant effect of origin, i.e., a genetic basis to individual tree performance. Two origins from the Turku region (Ruissalo and Katariinanlaakso) performed the best while trees originating from Parainen (Lenholmen) performed the worst. In order to study the effects due to tree origin, a comparison of families (half-sibling trees, i.e. those sharing the same ‘mother’ tree) was made by combining height and survival through a height-sum equation (i.e., the product of mean survival and height of each family in each trial) and used to calculate family- and origin-level ecovalences. Ecovalence is a metric for performance consistency, and indicates how much each variable contributes to the total variation; the higher the value, the lower the consistency of trees across the trials based on their origin or family. Analysis of consistency showed similar results to growth and survival, with Turku families performing the best and families from Parainen performing the worst. Families in the Katariinanlaakso stand (Turku) generally had more stable ecovalence values and more dispersed height-sums, while Ruissalo (Turku) families had higher mean height-sum but higher variability in ecovalence values. These results suggest that seed origins (i.e., genotypes) can be optimized in terms of their suitability for commercial or ecological forest management.
  • Hautsalo,  Natural Resources Institute Finland (Luke), Green technology, Antinniementie 1, FI-41330 Vihtavuori, Finland ORCID ID:E-mail: juho.hautsalo@luke.fi (email)
  • Mathieu, Agrocampus Ouest, 35000 Rennes, France ORCID ID:E-mail:
  • Elshibli, University of Helsinki, Helsinki, Finland ORCID ID:E-mail:
  • Vakkari, Natural Resources Institute Finland (Luke), Vantaa, Finland ORCID ID:E-mail: pekka.vakkari@luke.fi
  • Raisio, City of Helsinki, Helsinki, Finland ORCID ID:E-mail:
  • Pulkkinen, Natural Resources Institute Finland (Luke), Vantaa, Finland ORCID ID:E-mail: pertti.pulkkinen@luke.fi
article id 1300, category Research article
Jaana Luoranen, Risto Rikala. (2015). Post-planting effects of early-season short-day treatment and summer planting on Norway spruce seedlings. Silva Fennica vol. 49 no. 1 article id 1300. https://doi.org/10.14214/sf.1300
Highlights: Summer planting and short-day treatment advanced the bud burst and increased the height of Norway spruce seedlings after planting, compared to autumn and spring planted or untreated seedlings.
Effects of short-day (SD) treatment on bud burst, growth and survival of Norway spruce (Picea abies [L.] Karst.) container seedlings after summer planting were studied in an experiment established in Suonenjoki, Central Finland. One-year-old seedlings were SD-treated for three weeks starting on 18 June, 24 June and 8 July 2004 and then planted on 22 July, 5 August, 6 September 2004 and, as a normal spring planting, on 10 May, 2005. Untreated control seedlings were also planted on these dates. Second flush on the planting year and bud burst the following spring was monitored in planted seedlings, whereas seedling height and survival were determined at the end of growing seasons 2004–2006. We observed a non-significant risk of a second flush if seedlings were SD-treated on 18 June. Also, SD-treated seedlings planted in July or August showed advanced bud burst and increased height the following growing season without significant effects on survival, compared to autumn and spring planted seedlings. Planting in July or early August was associated with a significant increase in the incidence of multiple leaders in later years. Based on our results, to begin a three-week SD treatment in late June or early July and then plant seedlings in late July or early August could be a good practice.
  • Luoranen, Natural Resources Institute Finland (Luke), Natural resources and bioproduction, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@luke.fi (email)
  • Rikala, The Finnish Forest Research Institute, Suonenjoki Unit, Suonenjoki, Finland ORCID ID:E-mail: rikala@dnainternet.fi
article id 1192, category Research article
Hannu Hökkä, Hanna Mäkelä. (2014). Post-harvest height growth of Norway spruce seedlings in northern Finland peatland forest canopy gaps and comparison to partial and complete canopy removals and plantations. Silva Fennica vol. 48 no. 5 article id 1192. https://doi.org/10.14214/sf.1192
Highlights: Norway spruce seedlings’ height growth recovered within four years after the cutting of canopy gaps; Growth was linearly related to tree height, being highest for tallest seedlings; Seedlings in the 20 m diameter gap and in the central and northern parts in the 15 m diameter gap showed the best growth; In gaps early height growth was 60% of that in peatland spruce plantations but 2–3 times higher than in uneven-aged cut forests.
Recent studies have shown the establishment of Norway spruce (Picea abies (L.) Karst.) to be successful in small canopy gaps cut in drained spruce mire stands in northern Finland. The aim of this study was to quantify seedling height growth in gaps and compare it to that observed in other canopy cuttings and plantations. We sampled spruce crop seedlings (maximum density ca. 3000 ha–1) in the spring of 2013 in a field experiment in which canopy gaps of 10, 15 and 20 m in diameter had been cut in winter 2004. The total seedling height in 2013 and the length of annual shoots over the past five years (2012–2008) were recorded in the survey. Seedling height varied from 20 cm to 2.7 m, with an average of 65 cm. The average annual height growth was 7.1 cm. A mixed linear model analysis was carried out to investigate seedling height growth variation. Seedling height was linearly and positively related to growth. Height growth started to increase in the fifth growing season after cutting. Seedling height growth in the 20 m gap was slightly better than in the smaller ones. In the 15 m gap, both the centrally located seedlings and those located at the northern edge grew best. In the 20 m gap, southerly located seedlings grew more slowly than seedlings in all other locations. The average seedling height growth in this study was about 60% of that in peatland plantations, but comparable to that in mineral soil gaps, and 2–3 times higher than in uneven-age cut stands.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Mäkelä, Lapland University of Applied Sciences, Jokiväylä 11 C, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hanna.makela@edu.ramk.fi
article id 1192, category Research article
Hannu Hökkä, Hanna Mäkelä. (2014). Post-harvest height growth of Norway spruce seedlings in northern Finland peatland forest canopy gaps and comparison to partial and complete canopy removals and plantations. Silva Fennica vol. 48 no. 5 article id 1192. https://doi.org/10.14214/sf.1192
Highlights: Norway spruce seedlings’ height growth recovered within four years after the cutting of canopy gaps; Growth was linearly related to tree height, being highest for tallest seedlings; Seedlings in the 20 m diameter gap and in the central and northern parts in the 15 m diameter gap showed the best growth; In gaps early height growth was 60% of that in peatland spruce plantations but 2–3 times higher than in uneven-aged cut forests.
Recent studies have shown the establishment of Norway spruce (Picea abies (L.) Karst.) to be successful in small canopy gaps cut in drained spruce mire stands in northern Finland. The aim of this study was to quantify seedling height growth in gaps and compare it to that observed in other canopy cuttings and plantations. We sampled spruce crop seedlings (maximum density ca. 3000 ha–1) in the spring of 2013 in a field experiment in which canopy gaps of 10, 15 and 20 m in diameter had been cut in winter 2004. The total seedling height in 2013 and the length of annual shoots over the past five years (2012–2008) were recorded in the survey. Seedling height varied from 20 cm to 2.7 m, with an average of 65 cm. The average annual height growth was 7.1 cm. A mixed linear model analysis was carried out to investigate seedling height growth variation. Seedling height was linearly and positively related to growth. Height growth started to increase in the fifth growing season after cutting. Seedling height growth in the 20 m gap was slightly better than in the smaller ones. In the 15 m gap, both the centrally located seedlings and those located at the northern edge grew best. In the 20 m gap, southerly located seedlings grew more slowly than seedlings in all other locations. The average seedling height growth in this study was about 60% of that in peatland plantations, but comparable to that in mineral soil gaps, and 2–3 times higher than in uneven-age cut stands.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Mäkelä, Lapland University of Applied Sciences, Jokiväylä 11 C, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hanna.makela@edu.ramk.fi
article id 1192, category Research article
Hannu Hökkä, Hanna Mäkelä. (2014). Post-harvest height growth of Norway spruce seedlings in northern Finland peatland forest canopy gaps and comparison to partial and complete canopy removals and plantations. Silva Fennica vol. 48 no. 5 article id 1192. https://doi.org/10.14214/sf.1192
Highlights: Norway spruce seedlings’ height growth recovered within four years after the cutting of canopy gaps; Growth was linearly related to tree height, being highest for tallest seedlings; Seedlings in the 20 m diameter gap and in the central and northern parts in the 15 m diameter gap showed the best growth; In gaps early height growth was 60% of that in peatland spruce plantations but 2–3 times higher than in uneven-aged cut forests.
Recent studies have shown the establishment of Norway spruce (Picea abies (L.) Karst.) to be successful in small canopy gaps cut in drained spruce mire stands in northern Finland. The aim of this study was to quantify seedling height growth in gaps and compare it to that observed in other canopy cuttings and plantations. We sampled spruce crop seedlings (maximum density ca. 3000 ha–1) in the spring of 2013 in a field experiment in which canopy gaps of 10, 15 and 20 m in diameter had been cut in winter 2004. The total seedling height in 2013 and the length of annual shoots over the past five years (2012–2008) were recorded in the survey. Seedling height varied from 20 cm to 2.7 m, with an average of 65 cm. The average annual height growth was 7.1 cm. A mixed linear model analysis was carried out to investigate seedling height growth variation. Seedling height was linearly and positively related to growth. Height growth started to increase in the fifth growing season after cutting. Seedling height growth in the 20 m gap was slightly better than in the smaller ones. In the 15 m gap, both the centrally located seedlings and those located at the northern edge grew best. In the 20 m gap, southerly located seedlings grew more slowly than seedlings in all other locations. The average seedling height growth in this study was about 60% of that in peatland plantations, but comparable to that in mineral soil gaps, and 2–3 times higher than in uneven-age cut stands.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Mäkelä, Lapland University of Applied Sciences, Jokiväylä 11 C, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hanna.makela@edu.ramk.fi
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 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 1019, category Research article
Michael Henke, Stephan Huckemann, Winfried Kurth, Branislav Sloboda. (2014). Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle. Silva Fennica vol. 48 no. 2 article id 1019. https://doi.org/10.14214/sf.1019
Highlights: A complete pipeline for plant organ modelling (at the example of poplar leaves) is presented, from non-destructive data acquisition, over automated data extraction, to growth and shape modelling; Leaf contour models are compared; Resulting “organ” modules are ready for use in FSPMs.
A simple and efficient photometric methodology is presented, covering all steps from field data acquisition to binarization and allowing for leaf contour modelling. This method comprises the modelling of area and size (correlated and modelled with a Chapman-Richards growth function, using final length as one parameter), and four shape descriptors, from which the entire contour can be reconstructed rather well using a specific spline methodology. As an improvement of this contour modelling method, a set of parameterized polynomials was used. To model the temporal kinetics of the shape, geodesics in shape spaces were employed. Finally it is shown how this methodology is integrated into the 3D modelling platform GroIMP.
  • Henke, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: mhenke@uni-goettingen.de (email)
  • Huckemann, Institute of Mathematical Stochastics, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: huckeman@math.uni-goettingen.de
  • Kurth, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: wk@informatik.uni-goettingen.de
  • Sloboda, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: bslobod@web.de
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 903, category Research article
Mikko Hyppönen, Ville Hallikainen, Juhani Niemelä, Pasi Rautio. (2013). The contradictory role of understory vegetation on the success of Scots pine regeneration. Silva Fennica vol. 47 no. 1 article id 903. https://doi.org/10.14214/sf.903
In North-East Finland, severe problems have been encountered in the natural regeneration of Scots pine (Pinus sylvestris L.) on sites where regeneration through site preparation usually is quite successful. We hypothesized that in that area understory vegetation, especially heather (Calluna vulgaris), crowberry (Empetrum hermaphroditum), mosses and lichens, could play a key role in this pattern. We found that in general, ground- and field-layer vegetation tends to be in a negative relationship with the establishment, growth and survival of pine seedlings. Some positive relationships were also observed. Lingonberry (Vaccinium vitis-idea) tended to improve seedling height growth. Heather, instead, seemed to have a contradictory role. It was positively related to seedling establishment but negatively to seedling growth. This dual role raises further questions about the primary reasons for the regeneration problems in North-East Finland. All in all, our results suggest that conventional methods of forest regeneration in these kinds of areas are not always effective enough and additional measures are needed. These might include severe prescribed burning along with site preparation in order to decrease the impact of the dominant ground- and field-layer vegetation on the success of Scots pine regeneration.
  • Hyppönen, Finnish Forest Research Institute, Rovaniemi Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mikko.hypponen@metla.fi (email)
  • Hallikainen, Finnish Forest Research Institute, Rovaniemi Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@metla.fi
  • Niemelä, Finnish Forest Research Institute, Rovaniemi Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Rautio, Finnish Forest Research Institute, Rovaniemi Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.rautio@metla.fi
article id 83, category Research article
Inari Ylläsjärvi, Håkan Berglund, Timo Kuuluvainen. (2011). Relationships between wood-inhabiting fungal species richness and habitat variables in old-growth forest stands in the Pallas-Yllästunturi National Park, northern boreal Finland. Silva Fennica vol. 45 no. 5 article id 83. https://doi.org/10.14214/sf.83
Indicators for biodiversity are needed for efficient prioritization of forests selected for conservation. We analyzed the relationships between 86 wood-inhabiting fungal (polypore) species richness and 35 habitat variables in 81 northern boreal old-growth forest stands in Finland. Species richness and the number of red-listed species were analyzed separately using generalized linear models. Most species were infrequent in the studied landscape and no species was encountered in all stands. The species richness increased with 1) the volume of coarse woody debris (CWD), 2) the mean DBH of CWD and 3) the basal area of living trees. The number of red-listed species increased along the same gradients, but the effect of basal area was not significant. Polypore species richness was significantly lower on western slopes than on flat topography. On average, species richness was higher on northern and eastern slopes than on western and southern slopes. The results suggest that a combination of habitat variables used as indicators may be useful in selecting forest stands to be set aside for polypore species conservation.
  • Ylläsjärvi, Rovaniemi University of Applied Sciences, School of Forestry and Rural Industries, Jokiväylä 11 c, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: inari.yllasjarvi@ramk.fi (email)
  • Berglund, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 82, category Research article
Nicole J. Fenton, Yves Bergeron. (2011). Dynamic old-growth forests? A case study of boreal black spruce forest bryophytes. Silva Fennica vol. 45 no. 5 article id 82. https://doi.org/10.14214/sf.82
Old-growth forests have sparked significant interest over the last twenty years and definitions have evolved from structure based to process based, acknowledging the diversity of forests that could be considered old growth. However studies frequently group all forests over a certain age into a single type, negating the dynamic processes that create old growth. In this study we examine a 2350-year chronosequence in boreal black spruce forests in northwestern Quebec to determine whether continued community change can be observed in the bryophyte layer. Bryophytes dominate the understory of boreal forests and influence ecosystem functioning, particularly in paludified forests where production exceeds decomposition in the organic layer. Community composition and richness changed throughout the chronosequence with no evidence of a steady state associated with an old-growth phase. In contrast the bryophyte community continued to evolve with multiple phases being evident. These results suggest that old-growth forests on the Clay Belt of northwestern Quebec and northeastern Ontario, Canada, should be regarded as part of the continuous gradient in forest development rather than a single state. This complicates conservation of these forests as multiple phases should be considered when planning forest reserves.
  • Fenton, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail: nicole.fenton@uqat.ca (email)
  • Bergeron, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail:
article id 79, category Research article
Jean-Philippe Légaré, Christian Hébert, Jean-Claude Ruel. (2011). Alternative silvicultural practices in irregular boreal forests: response of beetle assemblages. Silva Fennica vol. 45 no. 5 article id 79. https://doi.org/10.14214/sf.79
In the process of implementing sustainable management in the eastern Canadian boreal forest, we tested two selection cutting methods and compared them with two widely used practices in the boreal forest: clearcutting with protection of the advanced growth and soils and irregular shelterwood cutting leaving small merchantable stems. We used old-growth irregular stands as references in comparing the impact of these silvicultural treatments on the diversity and abundance of beetles. Three groups were targeted: saproxylic flying beetles, epigaeic saproxylic beetles and epigaeic non-saproxylic beetles. A sampling design including 320 pitfall traps and 80 multidirectional flight-interception traps was deployed in 2007. A total of 26 906 beetles was captured including 407 taxa distributed among 52 families. We found that clearcutting with protection of the advanced growth and soils and irregular shelterwood cutting leaving small merchantable stems had a greater impact on beetle communities than both selection cuttings. Canopy opening as well as the presence of snags and downed woody debris appear as important attributes for several saproxylic and non-saproxylic species. Beetle communities in selection cuttings remained more similar to those found in controls; these silvicultural treatments are new tools to implement ecosystemic and sustainable management in irregular boreal forests.
  • Légaré, Université Laval, Faculté de foresterie, de géographie et de géomatique, Pavillon Abitibi-Price, Québec, Canada ORCID ID:E-mail:
  • Hébert, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec (Québec), G1V 4C7, Canada ORCID ID:E-mail: christian.hebert@rncan.gc.ca (email)
  • Ruel, Université Laval, Faculté de foresterie, de géographie et de géomatique, Pavillon Abitibi-Price, Québec, Canada ORCID ID:E-mail:
article id 76, category Research article
Alessandra Bottero, Matteo Garbarino, Vojislav Dukic, Zoran Govedar, Emanuele Lingua, Thomas A. Nagel, Renzo Motta. (2011). Gap-phase dynamics in the old-growth forest of Lom, Bosnia and Herzegovina. Silva Fennica vol. 45 no. 5 article id 76. https://doi.org/10.14214/sf.76
We investigated forest canopy gaps in the mixed beech (Fagus sylvatica L.), silver fir (Abies alba Miller), and Norway spruce (Picea abies (L.) Karst.) old-growth forest of Lom in the Dinaric Mountains of Bosnia and Herzegovina. Gap size, age, gap fraction, gapmaker characteristics and the structure and composition of gapfillers were documented to investigate gap dynamics. The percentages of forest area in canopy and expanded gaps were 19% and 41%, respectively. The median canopy gap size was 77 m2, and ranged from 11 to 708 m2. Although there were many single tree-fall gaps, the majority had multiple gapmakers that were often in different stages of decay, suggesting gap expansion is important at the study site. Of the gapmakers recorded, 14% were uprooted stems, 60% snapped stems, and 26% were standing dead trees. Dendroecological analysis suggests that gap formation varied in time. The density of gapfillers was not correlated to gap size, and the species composition of gapfillers varied between seedling, sapling, and tree life stages. The results suggest that gaps are mainly formed by endogenous senescence of single canopy trees. Exogenous disturbance agents, most likely related to wind and snow, act mainly as secondary agents in breaking weakened trees and in expanding previously established gaps. Although the findings are partially consistent with other studies of gap disturbance processes in similar old-growth forests in central Europe, the observed gap dynamic places the Lom core area at the end of a gradient that ranges from forests controlled by very small-scale processes to those where large, stand replacing disturbances predominate.
  • Bottero, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail: alessandra.bottero@unito.it (email)
  • Garbarino, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail:
  • Dukic, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina ORCID ID:E-mail:
  • Govedar, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina ORCID ID:E-mail:
  • Lingua, University of Padua, Department of TeSAF, Legnaro (PD), Italy ORCID ID:E-mail:
  • Nagel, University of Ljubljana, Department of Forestry and Renewable Forest Resources, Ljubljana, Slovenia ORCID ID:E-mail:
  • Motta, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail:
article id 75, category Research article
Silvia Lamedica, Emanuele Lingua, Ionel Popa, Renzo Motta, Marco Carrer. (2011). Spatial structure in four Norway spruce stands with different management history in the Alps and Carpathians. Silva Fennica vol. 45 no. 5 article id 75. https://doi.org/10.14214/sf.75
In Europe most Norway spruce (Picea abies (L.) Karst.) mountain forests have been altered by human activities, leading to a lack of reference condition concerning their original structure. Nonetheless, remnants of Norway spruce primeval forests still exist in the Carpathians. Our objective was to assess the differences in structure between managed and unmanaged stands, concerning diameter distributions, amount of standing deadwood, spatial distributions and spatial structure of trees. We established four permanent plots: one in a virgin forest in the Eastern Carpathians and three in a previously managed forest in the Alps. In each plot, species, DBH, and position of the live and dead standing trees were collected. Spatial distribution and structure of all the trees was analysed through several indices. In the Carpathians forest there are clear signs of natural density-dependent mortality processes whereas in the Alpine plots such dynamics are less evident. In these latter plots, the lower snags volume and the random trees spatial distribution can be considered the legacies of past management. Nonetheless, despite the different history of the four stands, they all seem to converge towards a similar spatial structure with the presence of groups (30–40 m) of trees of similar size.
  • Lamedica, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail:
  • Lingua, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail:
  • Popa, Forest Research and Management Institute, Research Station for Norway Spruce Silviculture, Câmpulung Moldovenesc, Romania ORCID ID:E-mail:
  • Motta, Department AGROSELVITER, University of Torino, Grugliasco (TO), Italy ORCID ID:E-mail:
  • Carrer, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail: marco.carrer@unipd.it (email)
article id 107, category Research article
Jaana Luoranen, Risto Rikala, Heikki Smolander. (2011). Machine planting of Norway spruce by Bracke and Ecoplanter: an evaluation of soil preparation, planting method and seedling performance. Silva Fennica vol. 45 no. 3 article id 107. https://doi.org/10.14214/sf.107
We evaluated the effects of planting date and planting machine (Bracke: three machines, 69 regeneration areas in three years; Ecoplanter: six areas, two years) on the quality and field performance one and three years after planting of Norway spruce (Picea abies (L.) Karst.) seedlings in central Finland. Both machine types planted on average 1800 seedlings per hectare, and after three years approximately 1600 (Bracke) and 1200 (Ecoplanter) were still alive. This study suggests that planting with a Bracke machine can achieve better regeneration rates than those observed in privately-owned Finnish forests. We characterized the quality of mounding and planting with the Bracke machine as excellent and that of the Ecoplanter as good. The soil preparation method of the Ecoplanter produced humus-rich mounds where seedlings were susceptible to pine weevils and consequently suffered higher mortality. Different machines were used in different regional areas and each machine was operated by different driver/s which may have influenced the results. No negative effects of planting date were observed. Seedling growth decreased if they were tall in relation to their root plug volume, grown too densely in the nursery, and if stored in the field for several months prior to planting. We conclude that mechanized planting is successful when the soil preparation method produces mounds covered by purely mineral soil. Planting from May to the end of September is suitable for seedlings intended for use during this period.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 106, category Research article
Hannu Hökkä, Heli Hyttinen, Hannu Marttila, Juha Jämsen, Bjørn Kløve. (2011). Effect of peak runoff control method on growth of Scots pine stands on drained peatlands in central Finland. Silva Fennica vol. 45 no. 3 article id 106. https://doi.org/10.14214/sf.106
In drained peatland forests ditch networks need regular maintenance operations in order to sustain their drainage capacity. These operations however have a significant impact on the quality of the runoff water from the ditched areas. Peak runoff control (PRC) method has been proposed as a possible method to diminish the load to water courses through retention of the runoff temporarily in the ditch network during maximum runoff events using dams with a plastic control pipe. However, blocking water into the ditched area for periods of varying length during the growing season may have a negative impact on the growth of the tree stands. In this study past stand growth was investigated in Central Finland in altogether 10 sample Scots pine thinning stands in which the PRC method has been applied 5 growing seasons earlier. In each stand, a pair of sample plots was established: one plot next to the dam within the influence of periodic flooding and the other one outside the effect of periodic flooding. For determining stand growth, field measurements were made in August 2009. Stand growth near the dam was on average 0.54 m3 ha-1 a-1 lower than farther away from the dam but the analysis of covariance showed that the dam effect was not significant. The results of this study suggest that the PCR method does not decrease Scots pine stand growth during the first five year growth period after ditch cleaning.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Hyttinen, Metsänhoitoyhdistys Keski-Suomi, Viitasaari, Finland ORCID ID:E-mail:
  • Marttila, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
  • Jämsen, Forestry Centre Keski-Suomi, Pihtipudas, Finland ORCID ID:E-mail:
  • Kløve, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
article id 105, category Research article
Jaana Luoranen, Risto Rikala. (2011). Nutrient loading of Norway spruce seedlings hastens bud burst and enhances root growth after outplanting. Silva Fennica vol. 45 no. 3 article id 105. https://doi.org/10.14214/sf.105
We studied the effects of late season nutrient loading (NLOAD) on the timing of bud burst, growth and changes in nitrogen (N) concentrations in the first growing season after seedlings were outplanted. Two-year-old Norway spruce (Picea abies (L.) Karst.) seedlings with three foliar nitrogen concentration levels (NLOAD levels 11.3, 22.5 and 27.5 g N kg-1 for L, M- and H-seedlings, respectively) were examined in the following three experiments: root growth capacity test (RGC), rooting experiment in the field and soil fertility experiment (‘rich’ or ‘poor’ soil) in the field. Bud burst in RGC was monitored daily and foliar N concentration (field experiments), height and root growth (rooting experiment) at monthly intervals. With respect to the RGC test, no differences in root growth were observed among the three NLOAD levels, but buds of H-seedlings burst 2–6 days earlier than others. In the rooting experiment, nutrient loading increased height and root growth but did not affect the timing of height growth. In the soil fertility experiment, foliar N of H- and M-seedlings decreased rapidly, but the decline was slower in rich soil. Current-year needles had more N in seedlings growing in rich soil and the N concentration declined until height growth ceased whereafter it increased until autumn. Improved growth from nutrient loading seems to last only for the first season after planting and the greatest benefits are enjoyed by seedlings planted in poor soils.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail:
article id 31, category Research article
Jeovanna Lowe, David Pothier, Jean-Pierre L. Savard, Ghislain Rompré, Mathieu Bouchard. (2011). Snag characteristics and cavity-nesting birds in the unmanaged post-fire northeastern Canadian boreal forest. Silva Fennica vol. 45 no. 1 article id 31. https://doi.org/10.14214/sf.31
We studied the availability and characteristics of snags and their use by cavity-nesting birds in the northeastern part of the Canadian boreal forest. We built up two long-term (> 200 years) chronosequences following time since the last fire in the unmanaged boreal forest of northeastern Québec, one in the balsam fir-white birch domain (southern region) and one in the spruce-mosses domain (northern region). We then sampled and characterized snags and live trees in 30 stands from each of these two chronosequences. We also looked for nest cavities on all sampled snags, performed bird inventories by point counts, and calculated tree mortality rate from permanent sample plots. Results show that mortality rates follow a U-shaped pattern, with more snags of large diameter (> 20 cm DBH) in young (< 50 years) and in old (> 200 years) forests. In the latter, we also found more nest cavities than in any other age classes. Although abundance of primary cavity nesters (excavating species) did not vary among age classes, secondary cavity nesters (using cavities already available) tend to be more numerous in older forests. Our results highlight the capacity for young and old-growth forests to provide quality habitat for species that are dependent on large snags. Proper forest management should maintain a mosaic of different age forest stands, including snags, to promote biodiversity and provide important resources for resident bird species.
  • Lowe, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada ORCID ID:E-mail: jeovannalowe@gmail.com (email)
  • Pothier, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada ORCID ID:E-mail:
  • Savard, Wildlife Research, Science and Technology, Québec Region, 1141 Route de l’Église, P.O. Box 10100, Québec, Québec, G1V 4H5, Canada ORCID ID:E-mail:
  • Rompré, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada & Department of Biology and Health Sciences, 84 West South Street, Wilkes University, PA 18766, USA ORCID ID:E-mail:
  • Bouchard, Ministère des Ressources naturelles et de la Faune, Direction de l’Environnement et de la Protection des Forets, 880 Chemin Ste-Foy, Quebec, Québec, G1S 4X4, Canada ORCID ID:E-mail:
article id 120, category Research article
Antti J. Lukkarinen, Seppo Ruotsalainen, Teijo Nikkanen, Heli Peltola. (2010). Survival, height growth and damages of Siberian (Larix sibirica Ledeb.) and Dahurian (Larix gmelinii Rupr.) larch provenances in field trials located in southern and northern Finland. Silva Fennica vol. 44 no. 5 article id 120. https://doi.org/10.14214/sf.120
The aim of this study was to analyse differences in the survival and height growth of, as well as damages to Siberian (Larix sibirica Ledeb.) and Dahurian (Larix gmelinii Rupr.) larch provenances over four growing seasons in field trials established in 2006 in southern (Punkaharju) and northern Finland (Kivalo). In this context, the study also investigated if the geographical and climatic conditions of the origin of the provenance could explain the differences between the provenances. The study material consisted of 20 Russian Siberian and Dahurian larch provenances and five seed sources from Finland (4) and Russia (1) as comparison lots. It was found that the Finnish seed sources of Siberian larch survived well in both the Kivalo and Punkaharju trials. Five northern latitude Russian provenances, of which one was Dahurian and the remainder were Siberian larches, had the highest survival in Kivalo. However, the differences observed in survival between provenances were only significant (p < 0.05) in Kivalo. Regardless of the trial, the differences, however, in height growth were significant and large between provenances. The southern Dahurian larches had a superior height growth in Punkaharju. The northern Dahurian larch provenance from Magadan (59°50′N, 150°40′E) had the largest height growth in Kivalo, among some northern Siberian larches. Damages were diverse, though Dahurian larches had less mammal damage than the Siberian larches. In general, the differences between provenances were not significant. Latitude and altitude best explained the differences between provenances, but also mean temperature, temperature sum and continentality index affected them (p < 0.05).
  • Lukkarinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.lukkarinen@pp.inet.fi (email)
  • Ruotsalainen, Finnish Forest Research Institute, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Nikkanen, Finnish Forest Research Institute, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Peltola, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 111, category Research article
Ilona Pietilä, Annika Kangas, Antti Mäkinen, Lauri Mehtätalo. (2010). Influence of growth prediction errors on the expected losses from forest decisions. Silva Fennica vol. 44 no. 5 article id 111. https://doi.org/10.14214/sf.111
In forest planning, forest inventory information is used for predicting future development of forests under different treatments. Model predictions always include some errors, which can lead to sub-optimal decisions and economic loss. The influence of growth prediction errors on the reliability of projected forest variables and on the treatment propositions have previously been examined in a few studies, but economic losses due to growth prediction errors is an almost unexplored subject. The aim of this study was to examine how the growth prediction errors affected the expected losses caused by incorrect harvest decisions, when the inventory interval increased. The growth models applied in the analysis were stand-level growth models for basal area and dominant height. The focus was entirely on the effects of growth prediction errors, other sources of uncertainty being ignored. The results show that inoptimality losses increased with the inventory interval. Average relative inoptimality loss was 3.3% when the inventory interval was 5 years and 11.6% when it was 60 years. Average absolute inoptimality loss was 230 euro ha–1 when the inventory interval was 5 years and 860 euro ha–1 when it was 60 years. The average inoptimality losses varied between development classes, site classes and main tree species.
  • Pietilä, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Kangas, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: annika.kangas@helsinki.fi (email)
  • Mäkinen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Mehtätalo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 453, category Research article
Eduard Schiessl, Michael Grabner, Gerald Golesch, Thomas Geburek, Silvio Schueler. (2010). Sub-montane Norway spruce as alternative seed source for a changing climate? A genetic and growth analysis at the fringe of its natural range in Austria. Silva Fennica vol. 44 no. 4 article id 453. https://doi.org/10.14214/sf.453
Insights into the intraspecific variation in climate response of forest trees and the utilization of suitable seed sources are required to maintain forest ecoystems under expected climate change. Individuals of Norway spruce with an anomalous spherical-shaped crown were characterized by genetic (using a mtDNA marker) and dendroclimatic analysis. Such trees occur frequently at the fringe of the spruce distribution in east/south-east Austria. We employed pair-wise comparisons between trees with spherical and “regular” conical crowns on 47 sites. No evidence was found for a different phylogeographic history of spherical and conical spruces, but the high allelic diversity at the nad1 locus highlighted the importance of east/south-east Austria as refugium and migration corridor for Norway spruce. Analysis of mean annual increment revealed a larger amount of earlywood within the sapwood area and fewer negative pointer years for spherical spruces than for conical ones, pointing at a higher vitality and smaller interactions between climate and growth for spherical spruces. Although the results cannot explain the anomalous crown form, they suggest spherical trees to have a higher ability to cope the warm and dry climate of the region than “regular” conical spruces. We discuss the origin of spherical crowns in terms of population history and phenotypic plasticity and speculate on possible effects of crown architecture on canopy-atmosphere exchange.
  • Schiessl, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Grabner, Department of Material Sciences and Process Engineering, Institute of Wood Science and Technology, University of Natural Resources and Applied Life Sciences, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Golesch, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Geburek, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Schueler, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail: silvio.schueler@bfw.gv.at (email)
article id 149, category Research article
Juha Kaitera, Heikki Nuorteva. (2010). Effects of Melampyrum extracts on the growth of axenic cultures of Cronartium flaccidum and Peridermium pini. Silva Fennica vol. 44 no. 2 article id 149. https://doi.org/10.14214/sf.149
For 3–6 months, mycelial colonies cultured from 5 isolates of each of two pine stem rusts (Cronartium flaccidum and Peridermium pini) were grown on nutrient-rich agar supplemented with Melampyrum extracts. Non-autoclaved extracts of M. pratense significantly reduced the growth of P. pini. The growth of C. flaccidum isolates was slightly stimulated after the second month of incubation but after that was inhibited during incubation months 4–6. We observed considerable variation in colony growth, a significant component of which was explained by incubation time, isolate, growth medium and their interaction. Rust species (C. flaccidum or P. pini) was not an important factor in growth variation. While sterilized extracts of M. pratense, M. sylvaticum and M. nemorosum did not significantly affect growth, colonies of C. flaccidum were slightly stimulated, whereas colonies of P. pini were slightly inhibited. Generally, isolates of P. pini grew better and showed a slower rate of degeneration than C. flaccidum on all media.
  • Kaitera, Finnish Forest Research Institute, Northern Finland Regional Unit, FI-91500 Muhos, Finland ORCID ID:E-mail: juha.kaitera@metla.fi (email)
  • Nuorteva, Finnish Forest Research Institute, Southern Finland Regional Unit, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 187, category Research article
Tobias Biechele, Leif Nutto, Gero Becker. (2009). Growth strain in Eucalyptus nitens at different stages of development. Silva Fennica vol. 43 no. 4 article id 187. https://doi.org/10.14214/sf.187
Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree’s development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.
  • Biechele, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail: tobias.biechele@fobawi.uni-freiburg.de (email)
  • Nutto, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
article id 187, category Research article
Tobias Biechele, Leif Nutto, Gero Becker. (2009). Growth strain in Eucalyptus nitens at different stages of development. Silva Fennica vol. 43 no. 4 article id 187. https://doi.org/10.14214/sf.187
Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree’s development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.
  • Biechele, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail: tobias.biechele@fobawi.uni-freiburg.de (email)
  • Nutto, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
article id 196, category Research article
Aaron R. Weiskittel, Laura S. Kenefic, Robert S. Seymour, Leah M. Phillips. (2009). Long-term effects of precommercial thinning on the stem dimensions, form and branch characteristics of red spruce and balsam fir crop trees in Maine, USA. Silva Fennica vol. 43 no. 3 article id 196. https://doi.org/10.14214/sf.196
The effects of precommercial thinning (PCT) on stem dimensions, form, volume, and branch attributes of red spruce [Picea rubens Sarg.] and balsam fir [Abies balsamea (L.) Mill.] crop trees were assessed 25 years after treatment in an even-aged northern conifer stand. Treatments were a uniform 2.4 x 2.4-m spacing and a control (no PCT). The PCT treatment significantly increased individual tree diameter at breast height (DBH), height growth, crown ratio, and crown width, while it reduced the tree height to DBH ratio. PCT also significantly increased stem taper and consequently, regional volume equations overpredicted observed stem volume by 2 to 15%, particularly for the spaced trees. PCT also increased the number and maximum size of branches on the lower bole. The sizes of knots on half of the sampled spruce crop trees in the spaced plots precluded them from being used as select structural lumber; there were no other effects on log grade. Our findings indicate that PCT can have a long-term influence on the structural attributes of individual trees, and that improved stem-volume prediction equations are needed in the Acadian region of North America.
  • Weiskittel, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail: aaron.weiskittel@umit.maine.edu (email)
  • Kenefic, U.S. Forest Service, Northern Research Station, Bradley, ME 04411, USA ORCID ID:E-mail:
  • Seymour, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail:
  • Phillips, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail:
article id 193, category Research article
Jaume Gort, Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Johanna Routa, Raimo Jaatinen. (2009). Differences in fibre properties in Scots pine (Pinus sylvestris L.) genetic entries grown at different spacing and sites. Silva Fennica vol. 43 no. 3 article id 193. https://doi.org/10.14214/sf.193
In forest breeding, stem volume growth and sawn timber quality indicators have been used as the most important selection traits for Scots pine, whereas less attention has been given to characteristics such as fibre properties. In the above context, we investigated the differences in fibre properties (i.e. fibre length, fibre width and coarseness) in 20 year old Scots pine (Pinus sylvestris L.) genetic entries as affected by spacing and site, but also the phenotypic correlations between fibre properties, yield and wood density. The study was based on materials harvested from 10 genetic entries grown in a spacing trial (site 1) in central Finland, with a current stand density of 2000 (spacing 1), 2000–2500 (spacing 2) and 4000 trees/ha (spacing 3). In order to study the effects of site, we harvested additional material (4 of 7 genetic entries same as on site 1) from a trial located in southern Finland with a corresponding stand density of 2000 trees/ha (site 2). On site 1, spacing 1 and 3, all average values for analysed fibre properties were similar. In spacing 2 average values were slightly higher. On site 2, the average values for different fibre properties were similar compared to the corresponding spacing 1 on site 1. Spacing affected (p < 0.05) all average fibre properties on site 1; as did also site, when comparing same genetic entries grown on both sites. Regardless of spacing and site, the phenotypic correlations between average fibre length, fibre width and coarseness showed, on average, moderate to strong correlation (p < 0.05). Fibre width showed, in general, low and positive phenotypic correlation with diameter at breast height, stem volume and wood density on site 1. However, as a whole, the ranking of genetic entries changed depending on the trait and spacing considered. Thus, no overall ranking between genetic entries was possible.
  • Gort, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: jaume.gort@joensuu.fi (email)
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie ORCID ID:E-mail:
  • Routa, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie ORCID ID:E-mail:
article id 209, category Research article
Jaana Luoranen, Kyösti Konttinen, Risto Rikala. (2009). Frost hardening and risk of a second flush in Norway spruce seedlings after an early-season short-day treatment. Silva Fennica vol. 43 no. 2 article id 209. https://doi.org/10.14214/sf.209
There have been years in Finland when container seedlings of Norway spruce (Picea abies (L.) Karsten) planted in the summer have been damaged by early-autumn frosts. For August and September plantings, the seedlings can be hardened by means of short-day (SD) treatment, but little information is available about its usability for earlier plantings. We studied the effects of early-season SD treatment on the frost hardiness and risk of a second flush of Norway spruce seedlings. In three successive years, second-year seedlings were grown in a greenhouse or outdoors in the spring and early summer and then subjected to two or three-week SD treatment beginning on the second, third, or fourth week of June. We monitored the height growth cessation, bud formation, and frost hardiness of the seedlings in the nursery. All SD treatments made the height growth cease, but the risk of a second flush increased if the temperature sum was less than 300 d.d. before the beginning of the SD treatment or more than 450 d.d. between the end of the treatment and mid-August. Clearly, then, SD treatment reduced the risk of a second flush in seedlings that had been grown in a greenhouse in the spring. Early-season SD treatment increased the frost hardiness of both needles and stems for late July to early September in comparison with untreated seedlings. Later in the autumn, however, the differences disappeared. Before recommending the use of early-season SD-treated seedlings for summer planting, the method has to be tested in practical field conditions.
  • Luoranen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Konttinen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Rikala, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland 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 215, category Research article
Antti J. Lukkarinen, Seppo Ruotsalainen, Teijo Nikkanen, Heli Peltola. (2009). The growth rhythm and height growth of seedlings of Siberian (Larix sibirica Ledeb.) and Dahurian (Larix gmelinii Rupr.) larch provenances in greenhouse conditions. Silva Fennica vol. 43 no. 1 article id 215. https://doi.org/10.14214/sf.215
The aim of this study was to determine whether the growth rhythm and height growth differ between various larch provenances grown in greenhouse conditions. We also investigated whether the geographic and climatic conditions at the origin of the provenance could explain the possible differences between the provenances. The study material consisted of 16 Russian Siberian (Larix sibirica Ledeb.) and Dahurian larch (Larix gmelinii Rupr.) provenances and four seed sources from Finland as comparison lots. The growth rhythm differences were clearest between the southern and northern provenances; the southern provenances grew for a longer period and the proportion of late summer height growth was larger. Autumn colouration also developed later in these provenances. In the Russian larch material the provenances with a longer growing period had greater height growth. In the whole material the relationship was not so linear due to the deviating behaviour of the comparison material. Several of the Russian larch provenances were taller than the Finnish comparison seed lots, although the difference was not statistically significant. However, the growth of these provenances must be followed for a much longer period in field trials before any conclusions can be drawn about their usability in practical forestry.
  • Lukkarinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.lukkarinen@pp.inet.fi (email)
  • Ruotsalainen, Finnish Forest Research Institute, Punkaharju Research Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Nikkanen, Finnish Forest Research Institute, Punkaharju Research Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 215, category Research article
Antti J. Lukkarinen, Seppo Ruotsalainen, Teijo Nikkanen, Heli Peltola. (2009). The growth rhythm and height growth of seedlings of Siberian (Larix sibirica Ledeb.) and Dahurian (Larix gmelinii Rupr.) larch provenances in greenhouse conditions. Silva Fennica vol. 43 no. 1 article id 215. https://doi.org/10.14214/sf.215
The aim of this study was to determine whether the growth rhythm and height growth differ between various larch provenances grown in greenhouse conditions. We also investigated whether the geographic and climatic conditions at the origin of the provenance could explain the possible differences between the provenances. The study material consisted of 16 Russian Siberian (Larix sibirica Ledeb.) and Dahurian larch (Larix gmelinii Rupr.) provenances and four seed sources from Finland as comparison lots. The growth rhythm differences were clearest between the southern and northern provenances; the southern provenances grew for a longer period and the proportion of late summer height growth was larger. Autumn colouration also developed later in these provenances. In the Russian larch material the provenances with a longer growing period had greater height growth. In the whole material the relationship was not so linear due to the deviating behaviour of the comparison material. Several of the Russian larch provenances were taller than the Finnish comparison seed lots, although the difference was not statistically significant. However, the growth of these provenances must be followed for a much longer period in field trials before any conclusions can be drawn about their usability in practical forestry.
  • Lukkarinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.lukkarinen@pp.inet.fi (email)
  • Ruotsalainen, Finnish Forest Research Institute, Punkaharju Research Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Nikkanen, Finnish Forest Research Institute, Punkaharju Research Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 245, category Research article
Saija Huuskonen, Jari Hynynen, Risto Ojansuu. (2008). Stand characteristics and external quality of young Scots pine stands in Finland. Silva Fennica vol. 42 no. 3 article id 245. https://doi.org/10.14214/sf.245
The effects of silvicultural practices (regeneration method and young stand management) on the stand characteristics of young Scots pine (Pinus sylvestris (L.)) stands were studied. Stand density, mean diameter, crown ratio and external quality of young Scots pine stands were analysed on the basis of extensive inventory data. The study material consisted of 181 stands containing inventory growth plots, representing the most common site types for Scots pine and covering all the important wood production areas in Finland. Intensive management practices, i.e. artificial regeneration and precommercial thinning, clearly enhanced mean diameter development of the stand. The overall stand density of the crop trees was relatively low in the material (1925 trees ha–1). In more than one third of the stands, the stem number of crop trees was below 1500 trees ha–1. Stand density was not affected by forest management, but it was slightly higher in Southern than in Northern Finland. The geographical location, in terms of annual effective temperature sum, affected the average slenderness and crown ratio. At a given mean stand diameter, the dominant height of the stand was lower, and the mean crown ratio was higher, in Northern than in Southern Finland. The average external quality of the Scots pine trees was relatively low. The proportion of trees without any observed defects was 54%. The most common external defects were curved stems (23%) and branchiness (9%). Branchiness was more frequent among the largest trees, while curved stems were more common in smaller trees. Defects were the most frequent in planted stands, and in stands growing on fresh sites. The defects were more frequent in Northern Finland than in Southern Finland. The relatively low stand density and poor external quality of the young stands emphasize the importance of stem quality as a tree selection criterion in commercial thinnings of Scots pine stands, if the goal is to produce high quality timber.
  • Huuskonen, University of Helsinki, Department of Forest Ecology, Helsinki, Finland ORCID ID:E-mail: saija.huuskonen@helsinki.fi (email)
  • Hynynen, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland ORCID ID:E-mail:
  • Ojansuu, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland ORCID ID:E-mail:
article id 262, category Research article
Julian C. Fox, Huiquan Bi, Peter K. Ades. (2008). Modelling spatial dependence in an irregular natural forest. Silva Fennica vol. 42 no. 1 article id 262. https://doi.org/10.14214/sf.262
The spatial dependence present in a natural stand of Eucalyptus pilularis (Smith) dominated mixed species forest was characterised and modelled. Two wildfires imposed a significant spatial dependence on the post disturbance stand. It was hypothesised that spatial variation in the intensity of the wildfires generated the observed structures. The influence of patch formation, micro-site variability and competitive influences were also noted in the residuals of a distance-dependent individual-tree growth model. A methodology capable of modelling these complicated patterns of observed dependence was sought, and candidates included the spatial interaction, direct specification and Papadakis methods. The spatial interaction method with a moving average autoregression was identified as the most appropriate method for explicitly modelling spatial dependence. Both the direct specification and Papadakis methods failed to capture the influence of competition. This study highlights the possibility that stand disturbances such as natural and artificial fires, insect and fungal attacks, and wind and snow damage are capable of imposing powerful spatial dependencies on the post disturbance stand. These dependencies need to be considered if individual tree growth models are to provide valid predictions in disturbed stands.
  • Fox, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia ORCID ID:E-mail: jcfox@unimelb.edu.au (email)
  • Bi, Forest Resources Research, New South Wales Department of Primary Industries, PO Box 100, Beecroft, NSW 2119 Australia ORCID ID:E-mail:
  • Ades, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia 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 320, category Research article
Saija Huuskonen, Jari Hynynen. (2006). Timing and intensity of precommercial thinning and their effects on the first commercial thinning in Scots pine stands. Silva Fennica vol. 40 no. 4 article id 320. https://doi.org/10.14214/sf.320
The effects of the timing and intensity of precommercial thinning on the stand diameter development and wood production in Scots pine stands was addressed. A model was developed in order to assess the thinning response of the stand diameter development. The effect of precommercial and first commercial thinning on the stand volume and the thinning removal at first commercial thinning were also modelled. The models were developed to be applicable for forest management planning purposes. The results are based on Scots pine (Pinus sylvestris L.) trials (13 experiments and 169 plots) located in Southern and Central Finland. Precommercial thinning considerably enhanced the diameter development. Precommercial thinning (at Hdom 3 m to 2000 trees per hectare) increased the mean diameter by 15% at the first commercial thinning stage (Hdom 14 m) compared to the unthinned stand (3000 trees ha–1). Early and intensive precommercial thinning resulted in the strongest response in diameter development. Wide spacing also enhanced the diameter increment. In naturally regenerated stands the diameter development was ca 13% slower than that in seeded stands. The total volume at the time of first commercial thinning was affected by the timing of thinning and the stand structure. The volume of merchantable thinning removal depended on the timing and intensity of precommercial and first commercial thinnings. Delaying the first commercial thinning from 12 meters (Hdom) to 16 meters increased the volume of thinning removal by ca.70%. The early and light precommercial thinning (Hdom 3 m, to density of 3000 trees per hectare) increased the thinning removal by 40% compared to the late and intensive precommercial thinning (at 7 meters to the density of 2000 trees per hectare).
  • Huuskonen, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Hynynen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 320, category Research article
Saija Huuskonen, Jari Hynynen. (2006). Timing and intensity of precommercial thinning and their effects on the first commercial thinning in Scots pine stands. Silva Fennica vol. 40 no. 4 article id 320. https://doi.org/10.14214/sf.320
The effects of the timing and intensity of precommercial thinning on the stand diameter development and wood production in Scots pine stands was addressed. A model was developed in order to assess the thinning response of the stand diameter development. The effect of precommercial and first commercial thinning on the stand volume and the thinning removal at first commercial thinning were also modelled. The models were developed to be applicable for forest management planning purposes. The results are based on Scots pine (Pinus sylvestris L.) trials (13 experiments and 169 plots) located in Southern and Central Finland. Precommercial thinning considerably enhanced the diameter development. Precommercial thinning (at Hdom 3 m to 2000 trees per hectare) increased the mean diameter by 15% at the first commercial thinning stage (Hdom 14 m) compared to the unthinned stand (3000 trees ha–1). Early and intensive precommercial thinning resulted in the strongest response in diameter development. Wide spacing also enhanced the diameter increment. In naturally regenerated stands the diameter development was ca 13% slower than that in seeded stands. The total volume at the time of first commercial thinning was affected by the timing of thinning and the stand structure. The volume of merchantable thinning removal depended on the timing and intensity of precommercial and first commercial thinnings. Delaying the first commercial thinning from 12 meters (Hdom) to 16 meters increased the volume of thinning removal by ca.70%. The early and light precommercial thinning (Hdom 3 m, to density of 3000 trees per hectare) increased the thinning removal by 40% compared to the late and intensive precommercial thinning (at 7 meters to the density of 2000 trees per hectare).
  • Huuskonen, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Hynynen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 344, category Research article
Juha Lappi. (2006). Smooth height/age curves from stem analysis with linear programming. Silva Fennica vol. 40 no. 2 article id 344. https://doi.org/10.14214/sf.344
Stem analysis data defines a range of possible heights for each age. A smooth stem/age curve is obtained with linear programming (LP) when the sum of the absolute second differences of heights is minimized subject to constraints obtained from the stem analysis. The method is analogous to cubic splines. A LP problem can include additional constraints that are based on the assumption that the crosscut is randomly located within the annual height increment. The method produces smoother height curves than Issa method which is utilizing second order differences of ring counts. It was found using simulated data that the method provides better results than earlier methods for short bolts if height growth is sufficiently regular.
  • Lappi, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juha.lappi@metla.fi (email)
article id 342, category Research article
Jaana Luoranen, Juha Lappi, Gang Zhang, Heikki Smolander. (2006). Field performance of hybrid aspen clones planted in summer. Silva Fennica vol. 40 no. 2 article id 342. https://doi.org/10.14214/sf.342
We investigated the possibility to plant clonal hybrid aspen (Populus tremula x tremuloides) during the summer of propagation when the plants are 20–25 cm tall and only a few months old. In four experiments carried out in years 1998–2001, survival of summer-planted hybrid aspens was at least as high as that of hybrid aspen planted in autumn and spring. In all experiments, compared to planting in September or the following May, height growth was greater with planting in July and early August. Root egress of hybrid aspens planted in July and August was also greater than that of aspens planted in autumn or the following spring. Summer planting was thus possible both with plants produced by micropropagation and with those produced from root cuttings.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Lappi, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Zhang, College of Horticulture, Agricultural University of Hebei, Baoding, Hebei, China ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 342, category Research article
Jaana Luoranen, Juha Lappi, Gang Zhang, Heikki Smolander. (2006). Field performance of hybrid aspen clones planted in summer. Silva Fennica vol. 40 no. 2 article id 342. https://doi.org/10.14214/sf.342
We investigated the possibility to plant clonal hybrid aspen (Populus tremula x tremuloides) during the summer of propagation when the plants are 20–25 cm tall and only a few months old. In four experiments carried out in years 1998–2001, survival of summer-planted hybrid aspens was at least as high as that of hybrid aspen planted in autumn and spring. In all experiments, compared to planting in September or the following May, height growth was greater with planting in July and early August. Root egress of hybrid aspens planted in July and August was also greater than that of aspens planted in autumn or the following spring. Summer planting was thus possible both with plants produced by micropropagation and with those produced from root cuttings.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Lappi, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Zhang, College of Horticulture, Agricultural University of Hebei, Baoding, Hebei, China ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 341, category Research article
Sanni Raiskila, Pekka Saranpää, Kurt Fagerstedt, Tapio Laakso, Mia Löija, Riitta Mahlberg, Leena Paajanen, Anne-Christine Ritschkoff. (2006). Growth rate and wood properties of Norway spruce cutting clones on different sites. Silva Fennica vol. 40 no. 2 article id 341. https://doi.org/10.14214/sf.341
The effect of growth rate on weight density and strength properties of three Norway spruce cutting clones growing on three different sites in different geographic locations was studied. The purpose was to follow variation in wood physical and mechanical properties and in quality between fast-growing clones grown in environments differing in nutritional and soil properties and climate within the boreal zone. The cloned trees had been selected on grounds of good growth, health and quality. The cuttings were collected from three-year-old seedlings and rooted. The rooted cuttings were planted in the 1970’s and they were on average 26 years old at a time of felling. The variation of weight density was studied within the annual ring and within the stem between the juvenile and mature wood from the pith to the bark with an X-ray densitometric method. The average annual ring width (and latewood proportion, %) varied between the clones from 2.92±1.36 mm (15.34%) to 3.30±1.25 mm (11.80%) and between the sites from 2.76±1.07 mm (14.71%) to 3.70±1.22 mm (13.29%). The mean weight density was 0.461±0.077 g cm–3 and latewood density 0.750±0.125 g cm–3 in this material. The mean modulus of elasticity was 9.88±1.43 GPa, modulus of rupture 67.51±11.50 MPa and weight density of the test samples (ρ12) 414±44 kg m–3 in mature wood. The parameters studied showed clearly that the environment had a large effect while the three clones differed from each other similarly in the different sites, e.g. the fastest growing clone was fastest on all sites.
  • Raiskila, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Saranpää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.saranpaa@metla.fi (email)
  • Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
article id 339, category Research article
John W. McCarthy, Gordon Weetman. (2006). Age and size structure of gap-dynamic, old-growth boreal forest stands in Newfoundland. Silva Fennica vol. 40 no. 2 article id 339. https://doi.org/10.14214/sf.339
The age and size structure of trees in old Abies-Picea-Betula forests on Newfoundland’s Great Northern Peninsula were examined. It was hypothesized that the size and age structure of both the tree and regeneration “strata” of these stands display the complex structural heterogeneity characteristic of classic, self-regenerating, uneven-aged old-growth stands, and that the development and dynamics of such structures occur over long periods of time. With all tree species combined, dbh (diameter at breast height) and height distributions exhibited a strong reverse-J character, with well-defined, semi-logarithmic rotated sigmoid height and size frequencies. Seedling height and basal diameter frequency distributions were reverse-J in character. Live tree ages for all species, except white birch (Betula papyrifera Marsh), ranged from 25 to 269 years, and were characterized by all-age frequency distributions. Tree age and size were poorly correlated. On average, balsam fir (Abies balsamea (L.) Mill.) required 62 years to reach breast height (1.3 m), with black spruce (Picea mariana (Mill.) B.S.P.) and white spruce (Picea glauca (Moench) Voss) requiring 40 and 48 years, respectively. Total age of dead standing trees ranged from 45 to 232 years. Reverse-J age frequencies characterized the seedling bank, with balsam fir seedlings present in nearly all age classes up to 110, 120 and 85 years in three sample stands. Seedling size (height and basal diameter)-age relationships were characteristic of decades-long suppression. The combination of tree and seedling bank size and age structure provide strong evidence of quasi-equilibrium, small-scale, gap dynamic old-growth boreal forest stands.
  • McCarthy, University of British Columbia, Forest Sciences Department, 2424 Main Mall, Vancouver, B.C., Canada V6T 1Z4 ORCID ID:E-mail: jmccarthy@jesuits.ca (email)
  • Weetman, University of British Columbia, Forest Sciences Department, 2424 Main Mall, Vancouver, B.C., Canada V6T 1Z4 ORCID ID:E-mail: gw@n.ca
article id 353, category Research article
Jaakko Repola, Hannu Hökkä, Timo Penttilä. (2006). Thinning intensity and growth of mixed spruce-birch stands on drained peatlands in Finland. Silva Fennica vol. 40 no. 1 article id 353. https://doi.org/10.14214/sf.353
The impacts of thinning at various intensities on the growth and mortality of mixed spruce-birch stands were investigated in thinning experiments on spruce swamps in northern and south-eastern Finland. At the time of establishment, three of the stands had recently reached the first commercial thinning stage and four were more advanced. The monitoring period was mainly 15 years, and the thinning intensity varied from heavy thinning (ca. 46 per cent of the basal area removed) to no thinning. Basal area removals of light and moderate thinning were ca. 22% and 39%, respectively. Unthinned plots had the highest volume increment. Light and moderate thinning slightly decreased the 15-year volume increment by, on an average, 1% and 8%, respectively. Heavy thinning led to a greater reduction (22%) in volume increment. The growth response to thinning intensity was evident as a higher relative volume and mean diameter increment of the living trees with decreasing stand density. Part of the volume increment on the unthinned plots was lost through natural mortality. Even light thinning significantly decreased natural mortality.
  • 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)
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Penttilä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 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 362, category Research article
Hannu Salminen, Risto Jalkanen. (2005). Modelling the effect of temperature on height increment of Scots pine at high latitudes. Silva Fennica vol. 39 no. 4 article id 362. https://doi.org/10.14214/sf.362
The effect of temperature and precipitation on the height increment of Pinus sylvestris (L.) was modelled using data gathered from a total of 49 felled sample trees from five stands of Scots pine located along a latitudinal transect from the Arctic Circle up to the northern timberline in Finland. A multilevel mixed effects model and cross-correlation analysis of prewhitened time series was used to analyse the dependence between height increment and monthly meteorological observations. The effect of the mean July temperature of the previous year on height increment proved to be very strong at high latitudes (r > 0.7). The mean November temperature of the year before the previous affected statistically significantly on height increment in the three northernmost stands. There was no correlation between height increment and precipitation in any of the sites. The final height increment model based on all stands included tree age, long-term mean temperature sum of site, and the mean July temperature of the previous year as independent variables. According to the model, one degree’s change in July temperature results on average in 1.8 cm change in the next year’s height increment. There was a modest but significant polynomial age-effect. The proportion of explained variance (at the year level) was 74%. The July temperature dependence on height increment was shown to be very strong, suggesting a high value of height increment in climate modelling at the tree line.
  • Salminen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.salminen@metla.fi (email)
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 361, category Research article
Jaana Luoranen, Risto Rikala, Kyösti Konttinen, Heikki Smolander. (2005). Extending the planting period of dormant and growing Norway spruce container seedlings to early summer. Silva Fennica vol. 39 no. 4 article id 361. https://doi.org/10.14214/sf.361
In order to make mechanized planting economically viable, the present spring planting period for Norway spruce (Picea abies (L.) Karst.) seedlings in Scandinavia needs to be extended. To evaluate the possibilities to extend the planting period, six field experiments were established in four years during which frozen-stored, dormant seedlings and actively growing seedlings targeted for spring planting were planted regularly from mid-May to mid-July or the end of August. The survival of actively growing seedlings did not differ between planting dates from mid-May to mid-July. For dormant seedlings, however, the later in summer they were planted the lower was the survival. Oversized seedlings grown in the nursery in containers of too small volume, which were usually planted after mid-June, resulted in reduced growth of seedlings after planting. Root egress (growth of roots from root plugs into the surrounding soil) was most rapid in July and early August and slowest in May and September. Results showed that with dormant seedlings the planting period can be extended from May to mid-June without increasing mortality or reducing growth. The planting period for seedlings stored outdoors and those seedlings that were already growing in June for the purpose of spring plantings can be extended even longer, but it must be kept in mind that the risk of mechanical damage and reduced growth increase due to brittleness of the shoot and increased height. Further research is needed to evaluate the risks in practical scale plantings and with seedlings that are specially targeted for planting after mid-June.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Konttinen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 361, category Research article
Jaana Luoranen, Risto Rikala, Kyösti Konttinen, Heikki Smolander. (2005). Extending the planting period of dormant and growing Norway spruce container seedlings to early summer. Silva Fennica vol. 39 no. 4 article id 361. https://doi.org/10.14214/sf.361
In order to make mechanized planting economically viable, the present spring planting period for Norway spruce (Picea abies (L.) Karst.) seedlings in Scandinavia needs to be extended. To evaluate the possibilities to extend the planting period, six field experiments were established in four years during which frozen-stored, dormant seedlings and actively growing seedlings targeted for spring planting were planted regularly from mid-May to mid-July or the end of August. The survival of actively growing seedlings did not differ between planting dates from mid-May to mid-July. For dormant seedlings, however, the later in summer they were planted the lower was the survival. Oversized seedlings grown in the nursery in containers of too small volume, which were usually planted after mid-June, resulted in reduced growth of seedlings after planting. Root egress (growth of roots from root plugs into the surrounding soil) was most rapid in July and early August and slowest in May and September. Results showed that with dormant seedlings the planting period can be extended from May to mid-June without increasing mortality or reducing growth. The planting period for seedlings stored outdoors and those seedlings that were already growing in June for the purpose of spring plantings can be extended even longer, but it must be kept in mind that the risk of mechanical damage and reduced growth increase due to brittleness of the shoot and increased height. Further research is needed to evaluate the risks in practical scale plantings and with seedlings that are specially targeted for planting after mid-June.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Konttinen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 360, category Research article
Timo Kurkela, Tarmo Aalto, Martti Varama, Risto Jalkanen. (2005). Defoliation by the common pine sawfly (Diprion pini) and subsequent growth reduction in Scots pine: a retrospective approach. Silva Fennica vol. 39 no. 4 article id 360. https://doi.org/10.14214/sf.360
The foliage status in the main stem of Scots pines (Pinus sylvestris) was studied retrospectively using the needle trace method (NTM) on a stand, seriously defoliated by the pine sawfly (Diprion pini) in the 1980s. Needle density increased abruptly in the seasons following the defoliation. The strongest reduction in annual needle production occurred one year later. As a consequence of lower needle production, the annual number of attached needles decreased three to five years after the defoliation. Needle retention and the average age of attached needles tended to increase after defoliation. In analyses of covariance with the NTM variables, needle density (logarithmic transformed values) and average age of attached needles, had the highest, significant, negative relationship with radial and height increments both in the period prior to the defoliation and in the time when the trees were suffering from defoliation. The relationships between height increment and the number of needles and needle loss were positive and significant. Also radial increment had a positive relationship with the number of needles but not with needle loss. Interestingly, an abrupt increase in the needle density gave a good indication of the effects of a sudden defoliation in pines.
  • Kurkela, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: timo.kurkela@metla.fi (email)
  • Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Varama, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 360, category Research article
Timo Kurkela, Tarmo Aalto, Martti Varama, Risto Jalkanen. (2005). Defoliation by the common pine sawfly (Diprion pini) and subsequent growth reduction in Scots pine: a retrospective approach. Silva Fennica vol. 39 no. 4 article id 360. https://doi.org/10.14214/sf.360
The foliage status in the main stem of Scots pines (Pinus sylvestris) was studied retrospectively using the needle trace method (NTM) on a stand, seriously defoliated by the pine sawfly (Diprion pini) in the 1980s. Needle density increased abruptly in the seasons following the defoliation. The strongest reduction in annual needle production occurred one year later. As a consequence of lower needle production, the annual number of attached needles decreased three to five years after the defoliation. Needle retention and the average age of attached needles tended to increase after defoliation. In analyses of covariance with the NTM variables, needle density (logarithmic transformed values) and average age of attached needles, had the highest, significant, negative relationship with radial and height increments both in the period prior to the defoliation and in the time when the trees were suffering from defoliation. The relationships between height increment and the number of needles and needle loss were positive and significant. Also radial increment had a positive relationship with the number of needles but not with needle loss. Interestingly, an abrupt increase in the needle density gave a good indication of the effects of a sudden defoliation in pines.
  • Kurkela, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: timo.kurkela@metla.fi (email)
  • Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Varama, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 377, category Research article
Saara Lilja, Timo Kuuluvainen. (2005). Structure of old Pinus sylvestris dominated forest stands along a geographic and human impact gradient in mid-boreal Fennoscandia. Silva Fennica vol. 39 no. 3 article id 377. https://doi.org/10.14214/sf.377
Stand structural characteristics were examined in old Pinus sylvestris dominated sites in three regions along a broad geographic and human impact gradient in mid-boreal Fennoscandia. The study regions were: 1) Häme in south-western Finland, with a long history of forest utilization, 2) Kuhmo in north-eastern Finland, with a more recent history of intensive forest utilization, and 3) Vienansalo in Russian Karelia, still characterized by a large near-natural forest landscape. Within each region the sampled sites were divided into three human impact classes: 1) near-natural stands, 2) stands selectively logged in the past, and 3) managed stands treated with thinnings. The near-natural and selectively logged stands in Häme and Kuhmo had a significantly higher Picea proportion compared to stands in Vienansalo. In comparison, the proportions of deciduous tree volumes were higher in near-natural stands in Vienansalo compared to near-natural stands in Häme. The pooled tree diameter distributions, both in near-natural and selectively logged stands, were descending whereas managed stands had a bimodal diameter distribution. Structural diversity characteristics such as broken trunks were most common in near-natural stands and in stands selectively logged in the past. The results demonstrate the higher structural complexity of near-natural stands and stands selectively logged in the past compared to managed stands, and highlight that old near-natural stands and stands selectively logged in the past vary widely in their structures. This obviously reflects both their natural variability but also various combinations of pre-industrial land use and human impact on fire disturbance. These factors need to be acknowledged when using “natural” forest structures as a reference in developing strategies for forest management, restoration and nature conservation.
  • Lilja, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: saara.lilja@helsinki.fi (email)
  • Kuuluvainen, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 376, category Research article
Nils Lexerød, Trond Eid. (2005). Recruitment models for Norway spruce, Scots pine, birch and other broadleaves in young growth forests in Norway. Silva Fennica vol. 39 no. 3 article id 376. https://doi.org/10.14214/sf.376
The objective of the present study was to develop recruitment models for Norway spruce, Scots pine, birch and other broadleaves in young growth forests in Norway. The models were developed from permanent sample plots established by the National Forest Inventory, and they will be included in a growth simulator that is part of a large-scale forestry scenario model. The modelling was therefore restricted to independent variables directly or indirectly available from inventories for practical forest management planning. A two-stage modelling approach that suited the stochastic nature of recruitment in boreal forests was used. Models predicting the probability of recruitment were estimated in a first stage, and conditional models for the number of recruits were developed in a second. The probability models as well as the conditional models were biologically realistic and logical. The goodness of fit tests revealed that the probability models fitted the data well, while the coefficients of determination for the conditional models were relatively low. No independent test data were available, but comparisons of predicted and observed number of recruits in different sub-groups of the data revealed few large deviations. The high level of large random errors was probably due to the great variability observed in number of recruits rather than inappropriate specifications of the models. Provided the generally high level of uncertainty connected to analysis performed with large-scale forestry scenario models and the stochastic nature of recruitment, the presented models seem to give satisfactory levels of accuracy.
  • Lexerød, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: nils.lexerod@umb.no (email)
  • Eid, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway. E-mail nils.lexerod@umb.no ORCID ID:E-mail:
article id 373, category Research article
Anna Saarsalmi, Pekka Tamminen. (2005). Boron, phosphorus and nitrogen fertilization in Norway spruce stands suffering from growth disturbances. Silva Fennica vol. 39 no. 3 article id 373. https://doi.org/10.14214/sf.373
Growth disturbance symptoms typical of B deficiency have been reported on Norway spruce (Picea abies (L.) Karst.) trees in many parts of eastern Finland. In order to test the B deficiency hypothesis and explore the possibilities of curing the disturbed trees with B fertilization, three experiments were established in October 1999 in young Norway spruce stands growing on fertile sites in eastern Finland. All the stands contained healthy, slightly and severely damaged trees with growth disturbances typical of B deficiency (B < 5 mg kg–1). 40 healthy, 40 slightly damaged, and 40 severely damaged trees were selected as sample trees in each stand. In May 2000, the trees were fertilized with 2.0 kg B ha–1 as borax (B), 2.0 kg B ha–1 and 40 kg P ha–1 as superphosphate (B+P) or 200 kg N ha–1 as urea (N). The control trees were not fertilized (0). The needle response to B fertilization was rapid, relatively high B concentrations being achieved already after one growing season. Boron fertilization cured the growth disorders and increased height growth within four years, but had no effect on diameter growth. The trees also recovered without B fertilization, but to a lesser extent compared to the B fertilized trees. Compared to the control, boron fertilization increased the height growth in all the disorder classes, i.e. 5, 17 and 19 cm yr–1 for healthy, slightly and severely damaged trees, respectively. As the healthy trees also seemed to benefit from B fertilization, this indicates that B deficiency in fact retards height growth before any disorder symptoms become apparent in individual trees. Compared with B alone, the application of P together with B gave no additional benefit. Nitrogen fertilization alone appeared to have a detrimental effect on height growth in the severely disturbed trees.
  • Saarsalmi, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 373, category Research article
Anna Saarsalmi, Pekka Tamminen. (2005). Boron, phosphorus and nitrogen fertilization in Norway spruce stands suffering from growth disturbances. Silva Fennica vol. 39 no. 3 article id 373. https://doi.org/10.14214/sf.373
Growth disturbance symptoms typical of B deficiency have been reported on Norway spruce (Picea abies (L.) Karst.) trees in many parts of eastern Finland. In order to test the B deficiency hypothesis and explore the possibilities of curing the disturbed trees with B fertilization, three experiments were established in October 1999 in young Norway spruce stands growing on fertile sites in eastern Finland. All the stands contained healthy, slightly and severely damaged trees with growth disturbances typical of B deficiency (B < 5 mg kg–1). 40 healthy, 40 slightly damaged, and 40 severely damaged trees were selected as sample trees in each stand. In May 2000, the trees were fertilized with 2.0 kg B ha–1 as borax (B), 2.0 kg B ha–1 and 40 kg P ha–1 as superphosphate (B+P) or 200 kg N ha–1 as urea (N). The control trees were not fertilized (0). The needle response to B fertilization was rapid, relatively high B concentrations being achieved already after one growing season. Boron fertilization cured the growth disorders and increased height growth within four years, but had no effect on diameter growth. The trees also recovered without B fertilization, but to a lesser extent compared to the B fertilized trees. Compared to the control, boron fertilization increased the height growth in all the disorder classes, i.e. 5, 17 and 19 cm yr–1 for healthy, slightly and severely damaged trees, respectively. As the healthy trees also seemed to benefit from B fertilization, this indicates that B deficiency in fact retards height growth before any disorder symptoms become apparent in individual trees. Compared with B alone, the application of P together with B gave no additional benefit. Nitrogen fertilization alone appeared to have a detrimental effect on height growth in the severely disturbed trees.
  • Saarsalmi, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 409, category Research article
Hubert Sterba. (2004). Equilibrium curves and growth models to deal with forests in transition to uneven-aged structure – application in two sample stands. Silva Fennica vol. 38 no. 4 article id 409. https://doi.org/10.14214/sf.409
Stem number distributions in uneven-aged forests are assumed to be stable, if they follow special functions, e.g. de Liocourt’s reverse J-shaped breast height diameter distribution. These distributions therefore are frequently regarded as a target in all-aged forests. Intending to convert an even-aged forest or any other forest, not yet exhibiting this sort of equilibrium, towards a steady state forest, the question rises, how to choose an appropriate equilibrium curve and how to achieve this stem number distribution by an appropriate thinning and harvesting schedule. Two stands are investigated: One dominated by Norway spruce (Picea abies), having developed from a 120 year old even-aged stand 25 years ago, after several “target diameter thinnings”. The other one is a mixed species stand of Norway spruce, white fir (Abies alba), larch (Larix europea), common beech (Fagus silvatica), and Scots pine (Pinus sylvestris), having lost its typical uneven-aged structure 20 years ago. These stands were used, together with the distance independent individual tree growth model PrognAus, to reveal that 1) there are more than only one equilibrium curve per stand, 2) not every hypothesised equilibrium can be reached with any stand, 3) an equilibrium in stem number does not necessarily mean a stable species distribution, and 4) growth models provide an excellent help to decide between several equilibrium curves and harvesting schedules to reach them.
  • Sterba, BOKU – University of Natural Resources an Applied Life Sciences, Vienna, Peter Jordanstrasse 82, A-1190 Vienna, Austria ORCID ID:E-mail: hubert.sterba@boku.ac.at (email)
article id 407, category Research article
Soili Kojola, Timo Penttilä, Raija Laiho. (2004). Impacts of different thinning regimes on the yield of uneven-structured Scots pine stands on drained peatland. Silva Fennica vol. 38 no. 4 article id 407. https://doi.org/10.14214/sf.407
Drained peatlands in northern Europe comprise more than 10 million ha of forestland and thus constitute a considerable production potential in forestry. Much of this area consists of stands dominated by Scots pine and close to maturity regarding commercial thinning. The trees within these stands typically vary in terms of age, size, and growth rate. The impacts of silvicultural cuttings on these uneven-structured stands are inadequately known. We simulated the impacts of a control regime with no thinnings, and three different thinning regimes, involving different thinning intensities, on the development of fifteen pine-dominated stands in Finland. The simulations started from the first thinnings and were continued until regeneration maturity. The predicted total yields ranged from 244 to 595 m3 ha–1, depending on site and thinning regime. The highest total yields were observed for the control regime in which 18–38% of the yield was, however, predicted to self-thin by the end of the simulation. Thus, the differences in the yields of merchantable wood were fairly small among the compared regimes. However, the regimes involving thinnings generally needed less time than the control regime to reach regeneration maturity. The mean annual increment of total stem volume was at its highest in the control regime. The highest mean annual increment of merchantable wood was obtained in the regime involving two moderate thinnings, but excluding the most low-productive sites where thinnings did not increase the yield of merchantable wood.
  • Kojola, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: soili.kojola@metla.fi (email)
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Laiho, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 404, category Research article
William L. Mason, Colin Edwards, Sophie E. Hale. (2004). Survival and early seedling growth of conifers with different shade tolerance in a Sitka spruce spacing trial and relationship to understorey light climate. Silva Fennica vol. 38 no. 4 article id 404. https://doi.org/10.14214/sf.404
Alternative silvicultural systems to clearfelling are being adopted in Great Britain as a means of increasing the species and structural diversity of conifer plantation forests. One area where knowledge is lacking is the critical level of below-canopy light for survival and growth of young seedlings. This was investigated by planting seedlings of European larch Larix decidua (Mill.), Scots pine Pinus sylvestris L., Sitka spruce Picea sitchensis (Bong.(Carr.)), Douglas fir Pseudotsuga menziesii (Mirb.(Franco.)), and western hemlock Tsuga heterophylla (Raf. (Sarg.)) in a Sitka spruce plantation thinned to 3 different spacings. The incident light intensity beneath the canopy ranged from about 2 to over 60 per cent of full light. Planting in an adjoining open area provided an indication of growth under full light. Growth and survival of these seedlings were followed for 4 growing seasons. The highest seedling survival was found under the widest spacing and declined with closer spacing and lower light intensity. Only Douglas fir and western hemlock seedlings survived at the closest spacing, and in low percentages. The tallest seedlings of each species were found in the open grown conditions but survival was variable due to increased weed competition. Species-specific growth responses showed little difference under high light conditions but performance at low light was generally consistent with shade tolerance rankings in the literature except that Sitka spruce shade tolerance was slightly lower than expected. Minimum light requirements for these species increased from 10 to 30 per cent of full light with decreasing shade tolerance. Other studies of incident light in Sitka spruce plantations indicated that target basal areas in the range 25–30 m2 ha–1 are required if these light conditions are to be met, which suggests an irregular shelterwood system with frequent interventions should be favoured.
  • Mason, Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, UK, EH25 9SY ORCID ID:E-mail: bill.mason@forestry.gsi.gov.uk (email)
  • Edwards, Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, UK, EH25 9SY ORCID ID:E-mail:
  • Hale, Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, UK, EH25 9SY ORCID ID:E-mail:
article id 418, category Research article
Tron Eid. (2004). Testing a large-scale forestry scenario model by means of successive inventories on a forest property. Silva Fennica vol. 38 no. 3 article id 418. https://doi.org/10.14214/sf.418
Modellers of large-scale forestry scenario models face numerous challenges. Information and sub-models from different disciplines within forestry, along with statistical and mathematical methodology, have to be considered. The individual biological sub-models (i.e. models for recruitment, growth and mortality) applied in large-scale forestry scenario models are in general well documented and extensively evaluated. However, evaluations by means of full-scale comparisons of observed and predicted values for continuous forest areas, where the totality of the large-scale forestry scenario model including interactions between sub-models and other parts of the model, are considered, have rarely been seen. The aim of the present work was to test the totality of the Norwegian large-scale forestry scenario model AVVIRK-2000, and thereby evaluate the applicability of the model for use in management planning. The test was done by means of successive inventories and accurate recordings of treatments over a period of 30 years for a property comprising 78.5 ha forest-land. Seen in the perspective of management planning, the differences between observed and predicted values for potential harvest level, growing stock and growth were small, e.g. a difference between observed growing stock in year 2000 and growing stock in the same year predicted from 1970 of 2.6%. The model may therefore be applied for practical purposes without any fundamental changes or calibrations of the biological model basis. However, the present test should be seen as an example that failed to falsify the model, rather than a final validation. As long as the model is in practical use, further evaluations should continue and subsequent possible calibrations should be performed.
  • Eid, Agricultural University of Norway, Dept of Ecology and Natural Resource Management, P.O. Box 5003 NO-1432 Ås, Norway ORCID ID:E-mail: tron.eid@ina.nlh.no (email)
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 425, category Research article
Petteri Vanninen. (2004). Allocation of above-ground growth in Pinus sylvestris – impacts of tree size and competition. Silva Fennica vol. 38 no. 2 article id 425. https://doi.org/10.14214/sf.425
The effect of tree age, size and competition on above ground growth allocation was studied with 69 Pinus sylvestris trees. Competition was described by tree-level indicators (needle density, crown ratio and height-diameter ratio). The stem, branch and needle growth were determined by stem and branch radial increments and tree level biomass analysis. Combined growth of compartments was strongly correlated with needle mass. Furthermore, tree age, size and competition indicators affected the allocation of growth among the compartments. The allocation of growth to stem and needle increased with tree age and size while the allocation of growth to branch decreased. The increasing crown ratio increased allocation of growth to branches. The combined growth of the components and separate growth of needles, branches and stem were related to needle mass. However, competition and tree size were significant additional explanatory variables when the stem, branch and needle growth were estimated according to needle mass. The growth efficiency increased with relative tree height and decreased with increasing needle density.
  • Vanninen, University of Helsinki, Department of Forest Ecology; mailing address: SAIMA – Centre for Environmental Sciences, Linnankatu 11, FIN-57130 Savonlinna, Finland ORCID ID:E-mail: petteri.vanninen@helsinki.fi (email)
article id 439, category Research article
Christina Lundgren. (2004). Microfibril angle and density patterns of fertilized and irrigated Norway spruce. Silva Fennica vol. 38 no. 1 article id 439. https://doi.org/10.14214/sf.439
Two Norway spruce nutrient optimisation trials, one in the north of Sweden and one in the south, were used to study the effects of intensive growth and fertilization on wood density and microfibril angle. Three different treatments and a control were available; daily irrigation, daily liquid fertilization and solid fertilization. The nutrient optimisation was based on foliage analysis and the solid fertilization essentially comprised the same amount of nutrients but was applied annually in solid form. Measurements of density and microfibril angle (MFA) were performed using X-ray diffraction. Growth rate, expressed as a transformation of annual ring width, was very important at the southern site when the effect of cambial maturation had been taken into account. Effects of both fertilization and irrigation remained strong and significant for density, and irrigation was a significant factor explaining MFA. At the northern site distance from pith was the dominant factor but the effect of growth rate was also strong and the treatment effect was significant for both density and MFA. The combination of higher MFA and decrease in density for fertilized trees resulted in a lower calculated strength of the wood. An over 100% increase in ring width only corresponded to approximately a 20% decrease in wood density and the production of wood dry matter was hence increased by treatments.
  • Lundgren, SLU, Dept. of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: christina.lundgren@spm.slu.se (email)
article id 436, category Research article
Martti Varmola, Hannu Salminen, Mauri Timonen. (2004). Thinning response and growth trends of seeded Scots pine stands at the arctic timberline. Silva Fennica vol. 38 no. 1 article id 436. https://doi.org/10.14214/sf.436
Growth patterns and reactions of Scots pine (Pinus sylvestris L.) to thinning in extremely harsh climatic conditions were studied in two seeded Scots pine stands located on the arctic timberline. Coniferous trees usually do not form closed stands at the timberline, but occur only in scattered tree groups. The trial was established in two stands in 1985–1986 when the trees were at an age of 47 and 56 years and an average dominant height of 6.0–6.9 m. The trial was remeasured in 1998. The thinning treatments reduced the stem number for five different levels; final density of 300, 550, 800, 1050, and 1300 stems ha–1 and unthinned. The experiment had a randomised block design with four replications in each stand. The increased growing space provided by thinning accelerated diameter growth after a delay of 2–3 years. The differences between the radial growth of the thinning treatments were very clear during the whole 13- to 14-year observation period. Annual increment of the mean diameter was regularly the higher, the larger the spacing. Dominant diameter was less influenced by treatments. There were no significant differences in dominant height between any of the treatments. Both basal area and volume were regularly the greater the higher the stem number was. Even a relatively light thinning had a distinct positive effect on tree growth, i.e. not carrying out thinning resulted in a production loss of merchantable wood. According to the results, seeded stands on the arctic timberline can grow surprisingly well in favourable conditions and reach a dominant height of 12–14 m in 100 years and a mean annual increment of 1.0–1.5 m3 ha–1 y–1 over a rotation period of 130–160 years. Based on increment figures and thinning reactions, a spacing of ca. 1000 stems ha–1 can be recommended.
  • Varmola, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail: martti.varmola@metla.fi (email)
  • Salminen, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Timonen, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 491, category Research article
Lars Rytter, Lars-Göran Stener. (2003). Clonal variation in nutrient content in woody biomass of hybrid aspen (Populus tremula L. x P. tremuloides Michx.). Silva Fennica vol. 37 no. 3 article id 491. https://doi.org/10.14214/sf.491
Differences in the nutrient concentrations and nutrient amounts of stems and branches amongst clones of hybrid aspen (Populus tremula L. x P. tremuloides Michx.) were investigated. Seven clones with superior and seven with medium growth rates were selected from a test of 119 clones in southern Sweden. Four trees per clone were randomly identified and harvested in dormant conditions. Sample discs from the stems and branches were collected and analysed for N, K, P, Ca, Mg, and S concentrations, as well as wood density. The analyses revealed significant genetic differences in wood density, K, P, and Mg concentrations in the stems. There were weak (non-significant) and negative genetic correlations between stem volume and concentrations of all the nutrients, except potassium, suggesting that nutrient-efficient clones could be selected without significantly sacrificing genetic gain for growth. In the branches K, Ca, and Mg concentrations differed significantly among clones. After selecting more nutrient efficient clones, the potential savings of nutrients compared with current hybrid aspen material was estimated to be around 5%, which seems fairly low, at least in a short-term perspective. However, the use of clones with different nutrient storage strategies may be regarded as a possible way in the long run to save nutrients in hybrid aspen ecosystems, or of removing them when sludge is applied.
  • Rytter, Forestry Research Institute of Sweden, Skogforsk, Ekebo 2250, SE-26890, Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se (email)
  • Stener, Forestry Research Institute of Sweden, Skogforsk, Ekebo 2250, SE-26890, Svalöv, Sweden 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 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 524, category Research article
Timo Pukkala, Jari Miina, Marc Palahí. (2002). Thinning response and thinning bias in a young Scots pine stand. Silva Fennica vol. 36 no. 4 article id 524. https://doi.org/10.14214/sf.524
The study analyses the annual post-thinning response and thinning bias of a young Scots pine stand as a function of tree size, competition faced by the tree, and competition that is removed around the tree in the thinning treatment. The thinning response of a tree was defined as the change of tree growth due to a thinning treatment. The thinning bias was defined as the difference between the true growth and model prediction. A distance-dependent (spatial) and a distance-independent (non-spatial) growth model were used in the calculations. The empirical data were measured from a thinning experiment consisting of ten plots, each 40 x 30 m in size, which were thinned to different stand densities. The ten-year post-thinning growth of every remaining tree was measured. The results indicated that the highest thinning response is among medium-sized and co-dominant trees. The thinning response is quite small, and even negative for some trees, for two years after thinning but it becomes clearly positive from the third year onwards. The spatial model underestimated the growth of small trees (which usually face high competition) while the non-spatial model overestimated the growth of trees that are small or face much competition. The spatial model used in this study overemphasized the effect of competition while the non-spatial model underestimated this effect. Both growth models overestimated the growth of trees in heavily thinned places, but this bias disappeared in two years. The negative bias was more pronounced with a spatial growth model because the tendency of the non-spatial model to underestimate the growth of trees facing little competition partly compensated for the negative bias.
  • Pukkala, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)
  • Miina, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Palahí, European Forest Institute, Torikatu 34, FIN-80100 Joensuu, Finland ORCID ID:E-mail:
article id 523, category Research article
Heli Peltola, Jari Miina, Ismo Rouvinen, Seppo Kellomäki. (2002). Effect of early thinning on the diameter growth distribution along the stem of Scots pine. Silva Fennica vol. 36 no. 4 article id 523. https://doi.org/10.14214/sf.523
The absolute and relative effects of the first thinning on the diameter growth distribution along the stems were studied in 98 Scots pines (Pinus sylvestris L.) at heights of 1.3, 4, 6 and 8 m. The data cover one 3-year pre-thinning period and four 3-year post-thinning periods in plots with densities varying from 575 to 3400 stems ha–1. A shift in the point of maximum diameter growth down the bole was found during the first 3 years after thinning, with a shift back up the stem later. The thinning response over the whole 12-year post-thinning period was strongest the nearer the stem base and the heavier the thinning. The largest trees had the highest diameter growth after thinning in absolute terms, and the growth was greater the heavier the thinning. The absolute thinning response over the 12-year post-thinning period was highest in the medium tree size and in the largest trees, especially on the heavily thinned and lightly thinned plots. Whereas in the moderately thinned stand the smaller and larger trees responded more than did those of medium size on average. In relative sense, however, the small trees on heavily or moderately thinned plots responded more rapidly and more strongly than the medium-sized or large trees over the whole stem. The small trees on the lightly thinned plots responded only slightly to thinning. The results suggest that it is possible to affect the uniformity of wood properties (such as ring width) both within and between trees by thinning.
  • Peltola, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@forest.joensuu.fi (email)
  • Miina, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Rouvinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kellomäki, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 523, category Research article
Heli Peltola, Jari Miina, Ismo Rouvinen, Seppo Kellomäki. (2002). Effect of early thinning on the diameter growth distribution along the stem of Scots pine. Silva Fennica vol. 36 no. 4 article id 523. https://doi.org/10.14214/sf.523
The absolute and relative effects of the first thinning on the diameter growth distribution along the stems were studied in 98 Scots pines (Pinus sylvestris L.) at heights of 1.3, 4, 6 and 8 m. The data cover one 3-year pre-thinning period and four 3-year post-thinning periods in plots with densities varying from 575 to 3400 stems ha–1. A shift in the point of maximum diameter growth down the bole was found during the first 3 years after thinning, with a shift back up the stem later. The thinning response over the whole 12-year post-thinning period was strongest the nearer the stem base and the heavier the thinning. The largest trees had the highest diameter growth after thinning in absolute terms, and the growth was greater the heavier the thinning. The absolute thinning response over the 12-year post-thinning period was highest in the medium tree size and in the largest trees, especially on the heavily thinned and lightly thinned plots. Whereas in the moderately thinned stand the smaller and larger trees responded more than did those of medium size on average. In relative sense, however, the small trees on heavily or moderately thinned plots responded more rapidly and more strongly than the medium-sized or large trees over the whole stem. The small trees on the lightly thinned plots responded only slightly to thinning. The results suggest that it is possible to affect the uniformity of wood properties (such as ring width) both within and between trees by thinning.
  • Peltola, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@forest.joensuu.fi (email)
  • Miina, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Rouvinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kellomäki, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 542, category Research article
Håkan Lindström. (2002). Intra-tree models of juvenile wood in Norway spruce as an input to simulation software. Silva Fennica vol. 36 no. 2 article id 542. https://doi.org/10.14214/sf.542
Juvenile wood found in the first 5–25 growth rings of a conifer has a structure and properties that differ from mature wood. Juvenile wood is therefore said to influence processing and the end-use of sawn products. Consequently, models describing the juvenile wood content, within and between trees, could be useful in improving the utilisation and value of wood as an industrial raw material. The objective of the present study was to develop juvenile wood models, based on Norway spruce trees, which could be used within a model system for conversion simulation studies. Nineteen stands of Norway spruce (Picea abies [L.] Karst.) were selected throughout Sweden. Based on DBH, two small, two medium, and two large diameter timber trees were taken from each stand. DBH varied between 180–470 mm, tree height between 17–34 m, and total age between 51–152 years. Each selected tree was cross-cut into logs; discs were prepared from the large end of each log and from the top end of the top log. Image analysis was used to determine growth ring development on sampled discs. Using tree and growth variables, the juvenile core radius and the logarithmic value of juvenile wood percentage were modelled. The two models had an R2Adj of 0.71 and 0.88 respectively.
  • Lindström, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch, New Zealand ORCID ID:E-mail: lindstromhakan@netscape.net (email)
article id 540, category Research article
Finn H. Brække, Nagwa Salih. (2002). Reliability of foliar analyses of Norway spruce stands in a Nordic gradient. Silva Fennica vol. 36 no. 2 article id 540. https://doi.org/10.14214/sf.540
Norway spruce stands at eleven sites in Finland, Norway and Sweden have been studied under various climates, atmospheric deposition of N and S and fertilisation regimes. Nitrogen was growth restricting at eight inland sites, while P was growth restricting at three coastal sites. Liming and N fertilisation caused serious B deficiency on some of the inland sites. It is likely that liming affects uptake of B, whereas N fertilisation causes a dilution due to increased growth. Application of S combined with N probably caused K deficiency at one of the sites. The reliability of foliar analyses as a method to diagnose nutrient status and the likely changes after nutrient input to spruce forests in the Nordic countries, are discussed. The CR- and the DOP-method are evaluated for diagnostic purposes. Both methods seem to give reliable conclusions even if the CR-method often produces more specific results. Interpretation based on both current and one year old foliage improved the diagnostic prognoses. The accuracy of diagnosis also relies on knowledge and ability of the interpreter. Based on the results it is reason to be cautious about recommendations of single element fertilisations, e.g. with N alone, because the demand of other elements beyond available pools frequently occurs. Forest trees in the boreal region are probably well adapted to N deficiency, which means that they can handle the physiological consequences rather well, while deficiencies of other elements usually are more detrimental to growth vigour and stress related diseases.
  • Brække, Department of Forest Sciences, Agricultural University of Norway (AUN), P.O. Box 5044, N-1432 Ås, Norway ORCID ID:E-mail: finn.braekke@isf.nlh.no (email)
  • Salih, Department of Ecology and Environmental Research, Swedish University of Agricultural Sciences (SLU), P.O. Box 7072, S-750 07 Uppsala, Sweden 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 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 595, category Research article
Kenneth Nyström, Göran Ståhl. (2001). Forecasting probability distributions of forest yield allowing for a Bayesian approach to management planning. Silva Fennica vol. 35 no. 2 article id 595. https://doi.org/10.14214/sf.595
Probability distributions of stand basal area were predicted and evaluated in young mixed stands of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in Sweden. Based on an extensive survey of young stands, individual tree basal area growth models were estimated using a mixed model approach to account for dependencies in data and derive the variance/covariance components needed. While most of the stands were reinventoried only once, a subset of the stands was revisited a second time. This subset was used to evaluate the accuracy of the predicted stand basal area distributions. Predicting distributions of forest yield, rather than point estimates, allows for a Bayesian approach to planning and decisions can be made with due regard to the quality of the information.
  • Nyström, SLU, Department of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kenneth.nystrom@resgeom.slu.se (email)
  • Ståhl, SLU, Department of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 591, category Research article
Qibin Yu. (2001). Can physiological and anatomical characters be used for selecting high yielding hybrid aspen clones? Silva Fennica vol. 35 no. 2 article id 591. https://doi.org/10.14214/sf.591
Stomatal, CO2 exchange parameters and several leaf and growth traits were recorded in a five-year-old hybrid aspen clone trial. The field trial consisted of four aspen hybrid clones (Populus tremula L. x P. tremuloides Michx.) and one local Populus tremula seedling source. The mean estimated height of hybrid aspen clones was 1.6 times higher than for P. tremula. Similarly, basal diameter was 1.5 times and breast diameter 1.8 times higher in the hybrids. Differences were observed for physiological and growth traits among hybrid clones and P. tremula, but, only stomatal characters of hybrid clones differed significantly from those in P. tremula. Hybrid clones had larger guard cells (22.9 mm) than P. tremula (19.2 mm), whereas P. tremula had a higher stomatal density (211.3/mm2) than the hybrid clones (164.4/mm2). Among four hybrid clones, net photosynthesis was strongly correlated with foliar nitrogen. Height correlated significantly with foliar nitrogen, but negatively with leaf fresh weight, leaf dry weight and stomatal density. The results suggested that yield components could be controlled by many genes, specific to each clone. No single gas exchange or morphological variable can provide a reliable indicator of yield potential.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: qibin.yu@helsinki.fi (email)
article id 603, category Research article
Kari Minkkinen, Jukka Laine, Hannu Hökkä. (2001). Tree stand development and carbon sequestration in drained peatland stands in Finland – a simulation study. Silva Fennica vol. 35 no. 1 article id 603. https://doi.org/10.14214/sf.603
Drained peatland forests form an important timber resource in Finland. They also form a sink for atmospheric carbon (C) because of the increased growth and C sequestration rates following drainage. These rates have, however, been poorly quantified. We simulated the tree stand dynamics for drained peatland stands with and without cuttings over two stand rotations. Simulations were done on four peatland site types and two regions in Finland with different climatic conditions, using recently published peatland tree growth models applied in a stand simulator. We then calculated the amount of C stored in the stands on the basis of previously published tree-level biomass and C content models. Finally, we developed regression models to estimate C stores in the tree stands using stand stem volume as the predictor variable. In the managed stands, the mean growth (annual volume increment) ranged from 2 to 9 m3 ha–1 a–1, depending on the rotation (first/second), site type and region. Total yield during one rotation varied from 250 to 920 m3 ha–1. The maximum stand volumes varied from 220 to 520 m3 ha–1 in the managed stands and from 360 to 770 m3 ha–1 in the unmanaged. By the end of the first post-drainage rotation the total C store in the managed stands had increased by 6–12 kg C m–2 (i.e. 45–140 g C m–2 a–1) compared to that in the undrained situation. Averaged over two rotations, the increase in the total C store was 3–6 kg C m–2. In the corresponding unmanaged stands the C stores increased by 8–15 kg m–2 over the same periods. At stand level, the C stores were almost linearly related to the stem volume and the developed regression equations could explain the variation in the simulated C stores almost entirely.
  • Minkkinen, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.minkkinen@helsinki.fi (email)
  • Laine, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 600, category Research article
Qibin Yu, P. M. A. Tigerstedt, Matti Haapanen. (2001). Growth and phenology of hybrid aspen clones (Populus tremula L. x Populus tremuloides Michx.). Silva Fennica vol. 35 no. 1 article id 600. https://doi.org/10.14214/sf.600
Height, basal diameter, diameter at breast height, bud burst, and leaf development were recorded in a 5-year-old hybrid aspen clonal trial. The field trial consisted of four aspen hybrid clones (Populus tremula x Populus tremuloides) and one local P. tremula seedling source. Phenological traits were observed in the 3rd year. Growth patterns were recorded during the 3rd and 4th years. Phenological traits were explored in relation to hybrid vigor expressed as growth traits. Differences were observed for phenological and growth traits among hybrid clones and P. tremula. The growth period varied from 143–158 days for the four hybrid clones, and was 112 days for P. tremula. The correlation between growth period and yield was highly significant. The annual growth rate of height for the hybrids was 4.2 cm per 7 days (2.4 for P. tremula) in the 3rd year and 6.4 cm per 7 days (2.9 for P. tremula) in the 4th year. After 5 years, mean estimated stem volume of the hybrids was 3.9 times that of P. tremula. Significant clone by year interaction was observed for height, diameter, and volume growth. The hybrid vigor seems to be mainly attributable to a longer growth period.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: qibin.yu@helsinki.fi (email)
  • Tigerstedt, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Haapanen, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 600, category Research article
Qibin Yu, P. M. A. Tigerstedt, Matti Haapanen. (2001). Growth and phenology of hybrid aspen clones (Populus tremula L. x Populus tremuloides Michx.). Silva Fennica vol. 35 no. 1 article id 600. https://doi.org/10.14214/sf.600
Height, basal diameter, diameter at breast height, bud burst, and leaf development were recorded in a 5-year-old hybrid aspen clonal trial. The field trial consisted of four aspen hybrid clones (Populus tremula x Populus tremuloides) and one local P. tremula seedling source. Phenological traits were observed in the 3rd year. Growth patterns were recorded during the 3rd and 4th years. Phenological traits were explored in relation to hybrid vigor expressed as growth traits. Differences were observed for phenological and growth traits among hybrid clones and P. tremula. The growth period varied from 143–158 days for the four hybrid clones, and was 112 days for P. tremula. The correlation between growth period and yield was highly significant. The annual growth rate of height for the hybrids was 4.2 cm per 7 days (2.4 for P. tremula) in the 3rd year and 6.4 cm per 7 days (2.9 for P. tremula) in the 4th year. After 5 years, mean estimated stem volume of the hybrids was 3.9 times that of P. tremula. Significant clone by year interaction was observed for height, diameter, and volume growth. The hybrid vigor seems to be mainly attributable to a longer growth period.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: qibin.yu@helsinki.fi (email)
  • Tigerstedt, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Haapanen, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 622, category Research article
Håkan Lindström. (2000). Intra-tree models of basic density in Norway spruce as an input to simulation software. Silva Fennica vol. 34 no. 4 article id 622. https://doi.org/10.14214/sf.622
Basic density is said to influence aspects of conversion, properties, and end-use of forest products. Consequently, it is argued that accurate models of basic density variation, within and between trees, could be used to improve the utilisation of wood as an industrial raw material. The objective of the present study was to develop basic density models based on Norway spruce trees, that could be used within a model system for conversion simulation studies. Nineteen stands of Norway spruce (Picea abies (L.) Karst.) were selected throughout Sweden. Based on dbh, two small, two moderate, and two large timber trees were taken from each stand. Dbh varied between 180–470 mm, tree height between 17–34 m, and total age between 51–152 years. Each selected tree was cross-cut into logs; discs were prepared from the butt end of each log and from the top end of the top log. Computed tomography scanning and image analysis were used to determine basic density and growth ring development on sampled discs. Basic density development in 20-mm segments from pith outwards was modelled in models based on ring width, tree and growth condition data. The resulting models had an adjusted R2 of 0.37–0.51 and a RMSE of 37–41 kg/m3.
  • Lindström, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch, New Zealand ORCID ID:E-mail: lindstromhakan@netscape.net (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 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 656, category Research article
Klaus Silfverberg, Markus Hartman. (1999). Effects of different phosphorus fertilisers on the nutrient status and growth of Scots pine stands on drained peatlands. Silva Fennica vol. 33 no. 3 article id 656. https://doi.org/10.14214/sf.656
The aim of the study was to compare the effects of phosphorus fertilisers of different solubility and different phosphorus doses. The material was collected from 8 field experiments situated on drained peatlands in southern and central Finland (60°–65°N). The sites were drained, oligotrophic pine fens and pine bogs, which had been fertilised between 1961 and 1977 with different combinations of N, K and P. In 1991–94 stand measurements and foliar and peat sampling were carried out on 162 sample plots. Apatite, rock phosphate and superphosphate affected basal area growth to a rather similar extent. However, apatite slightly surpassed superphosphate and rock phosphate at the end of the study period in two hollow-rich S. fuscum bogs. Higher doses of phosphorus did not significantly increase the basal area growth. The foliar phosphorus concentrations clearly reflected the effect of the P fertilisation. Especially on the pine bogs basic fertilisation with 66 kg P/ha maintained the needle phosphorus concentrations at a satisfactory level for more than 25 years after fertilisation. The amount of phosphorus in the 0–20 cm peat layer was not significantly increased either by basic fertilisation or refertilisation. The phosphorus reserves in the peat in the individual experiments were between 88 and 327 kg/ha. There was a strong correlation between the amounts of phosphorus and iron in the peat. Large amounts of iron in peat may reduce the solubility and availability of phosphorus. According to the foliar phosphorus concentrations in the basic-fertilised plots, the need for refertilisation seems to be unnecessary during the 25-year postfertilisation period at least. None of the basic fertilisation treatments seriously retarded the basal area growth compared to the refertilised treatments. There seems to be a greater shortage of potassium than of phosphorus, because the foliar potassium concentrations and the amounts of potassium in the 0–20 cm peat layer were very low in several of the experiments.
  • Silfverberg, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: klaus.silfverberg@metla.fi (email)
  • Hartman, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 670, category Research article
Jouni Vettenranta. (1999). Distance-dependent models for predicting the development of mixed coniferous forests in Finland. Silva Fennica vol. 33 no. 1 article id 670. https://doi.org/10.14214/sf.670
Distance-dependent growth models and crown models, based on extensive material, were built for Scots pine and Norway spruce growing in a mixed forest. The crown ratio was also used as a predictor in a diameter growth model to better describe the thinning reaction. The effect of crown ratio on the growth dynamics was studied in simulation examples. Monte Carlo simulation was used to correct the bias caused by nonlinear transformations of predictors and response. After thinnings the crown ratio as a predictor was found to be a clear growth-retarding factor. The growth retarding effect was stronger among pines with thinnings from below, whereas the estimated yield of spruces over rotation was slightly greater when the crown ratio was included than without it. With each type of thinning the effect of crown ratio on pine growth was almost the same, but the growth of spruces was clearly delayed when the stand was thinned from above. Simulation examples also showed that it is profitable to raise the proportion of spruces during rotation, since spruces maintain the growth more vigorous at older ages. The total yield during 90 years rotation was about 20% higher if the stand was transformed into a pure spruce stand instead of pine.
  • Vettenranta, Kivirinnanpolku 4, FIN-40950 Muurame, Finland ORCID ID:E-mail: vettenr@cc.joensuu.fi (email)
article id 666, category Research article
Rolf Pape. (1999). Influence of thinning on spiral grain in Norway spruce grown on highly productive sites in southern Sweden. Silva Fennica vol. 33 no. 1 article id 666. https://doi.org/10.14214/sf.666
Grain spirality was investigated in eight stands of Norway spruce (Picea abies (L.) Karst.) subjected to different thinning regimes. The dominating general pattern of spiral grain found in this study was typical for conifers, with a maximum of left-handed spirality close to the pith, which decreased towards the bark and sometimes changed to right-handed spiral grain in the outer growth rings. However, there was a large amount of between-tree variation in spiral grain. The effect of thinning on grain spirality was investigated by relating annual ring width to spiral grain, since thinning affects growth rate. A positive correlation between ring width and grain angle was found, but a considerable number of trees showed no or a negative correlation. A statistically significant effect of ring width was only found in five of the eight stands. Heavy thinnings, removing 60% of the basal area of a stand, considerably increased spiral grain, whereas the effects of light thinnings were inconsistent. These results support the findings of earlier studies indicating that spiral grain formation is under considerable genetic control, while its expression can be changed by silvicultural methods which affect growth rate.
  • Pape, Swedish University of Agricultural Sciences, Department of Forest Yield Research, P.O. Box 7061, S-750 07 Uppsala, Sweden ORCID ID:E-mail: rolf.pape@sprod.slu.se (email)
article id 686, category Research article
Jean Yves Fraysse, Loïc Crémière. (1998). Nursery factors influencing containerized Pinus pinaster seedlings’ initial growth. Silva Fennica vol. 32 no. 3 article id 686. https://doi.org/10.14214/sf.686
Maritime pine (Pinus pinaster) containerized seedlings were raised outdoors at different fertilizer regimes, sowing date or culture duration to assess nursery factors influencing first year growth in the field. Seedling biomass, and N, P and K content before outplanting were affected by these different factors but the one year field growth was more related to N concentration than with morphological traits. The results are discussed in view to improve the plant stock quality in nursery.
  • Fraysse, AFOCEL, Domaine de Sivaillan, 33480 Moulis-en-Médoc, France ORCID ID:E-mail: sudouest@afocel.fr (email)
  • Crémière, AFOCEL, Domaine de Sivaillan, 33480 Moulis-en-Médoc, France ORCID ID:E-mail:
article id 684, category Research article
H. M. McKay. (1998). Root electrolyte leakage and root growth potential as indicators of spruce and larch establishment. Silva Fennica vol. 32 no. 3 article id 684. https://doi.org/10.14214/sf.684
The relationship between the condition of bare-rooted 2-year-old seedlings of Sitka spruce and larch at the time of planting and their survival and growth after 2 years was examined. Data were analysed for 2 experiments using seedlings lifted and stored at +1 °C throughout the winter for planting in April and also for 2 experiments using seedlings planted directly on different dates without cold storage. Electrolyte leakage from the fine roots of spruce was closely correlated to survival following direct planting at different times from September to April and fine root leakage was a more accurate indicator of spruce performance than root growth potential. However the pattern of larch survival of directly planted stock was more closely related to root growth potential than to root leakage. When seedlings were cold-stored, root electrolyte leakage and root growth potential were modified during storage and following cold storage, the performance of both species was more closely related to root electrolyte leakage than root growth potential. These results are interpreted as meaning that successful establishment of bare-rooted seedlings requires a functional nursery root system that is capable of both supplying adequate water for a limited period immediately after transplanting and of producing roots to meet the seedling’s increased water demand later in the growing season.
  • McKay, Forest Commission Research Agency, Northern Research Station, Roslin, Midlothian, EH25 9SY, Scotland ORCID ID:E-mail: h.mckay@forestry.gov.uk (email)
article id 691, category Research article
Jacek Oleksyn, Mark G. Tjoelker, Peter B. Reich. (1998). Adaptation to changing environment in Scots pine populations across a latitudinal gradient. Silva Fennica vol. 32 no. 2 article id 691. https://doi.org/10.14214/sf.691
In several growth chamber and field experiments we examined the growth response of Scots pine (Pinus sylvestris L.) populations from a wide latitudinal range to temperature and photoperiod. The duration of the shoot elongation period of one-year-old seedlings was affected by temperature and photoperiod. In contrasting temperatures, 23/20 °C, 20/17 °C, and 17/14 °C (day/night), shoot elongation period for all populations was shortest in the high and longest in the low temperature treatments. The northern populations from 61–57°N ceased height growth earlier than the other populations in the southern 50°N photoperiod. The order of growth cessation among populations at 50°N in the chamber experiment and at 52°N in the field experiment was similar and related to observed population differences in terminal leader growth and total tree height. Since the length of growing season is under strong environmentally-mediated genetic control in Scots pine, potential climatic changes such as increasing temperature will probably alter the length and timing of growth in aboveground tree parts, but likely in the opposite direction (a shorter growing season) than has been often hypothesized (a longer growing season). Tree-ring analyses of a provenance experiment established in 1912 indicate that the main climatic factors that limited ring-width growth in Scots pine were air temperatures in the winter months of December through March. Low winter temperatures were followed by the formation of narrow rings over the next summer. Based on responses to temperature, Scots pine populations from the continuous European range can be divided in several geographic groups along a latitudinal gradient. Our results suggest that in developing new models to predict the response of Scots pine to changing environmental conditions, it is necessary to include intraspecific differentiation in acclimation and adaptation to environmental factors.
  • Oleksyn, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62-035 Kórnik, Poland; University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail: oleks001@gold.tc.umn.edu (email)
  • Tjoelker, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:
  • Reich, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:
article id 697, category Research article
Kari Pasanen. (1998). Integrating variation in tree growth into forest planning. Silva Fennica vol. 32 no. 1 article id 697. https://doi.org/10.14214/sf.697
Forest planning is always influenced by uncertain factors. Variations in growth, outcome of regeneration, timber prices, costs and mortality cannot be avoided, whereas the quality of inventory data and the models used for estimation of the state and development of forests can be improved. Methods have been developed for incorporating risk and attitude toward risk in decision analysis, but there has been a lack of good models for dealing with the various sources of risk. The aim of this study was to estimate stochastic models for the variation in growth of Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and birch (Betula pendula and Betula pubescens). The said models had to be capable of generating growth scenarios, and thus correlations between series had to be taken into account. ARMA models were estimated for mean growth index series from Pohjois-Karjala, eastern Finland. Several ARMA models, some of which had seasonal parameters, were found to be adequate for each series. Non-seasonal AR(1) and seasonal AR(1,1) models were used to produce growth scenarios in the case study, in which variation in growth was integrated into forest planning.
  • Pasanen, University of Joensuu, Faculty of Forestry, P.O. BOX 111, 80101 Joensuu, Finland ORCID ID:E-mail: pasanen@gis.joensuu.fi (email)
article id 696, category Research article
Jukka Lippu. (1998). Redistribution of 14C-labelled reserve carbon in Pinus sylvestris seedlings during shoot elongation. Silva Fennica vol. 32 no. 1 article id 696. https://doi.org/10.14214/sf.696
This study examined the later use of 14C reserves formed in previous autumn in Scots pine (Pinus sylvestris L.) seedlings. The seedlings were allowed to photosynthesise 14CO2 in early September when shoot and needle growth was over. The following spring the seedlings were harvested in five samplings during the shoot growth period. The distribution and concentration of 14C were determined and the results were compared with the growth data. It was observed that reserves were not used markedly for the new growth. Most of the 14C was found in one-year-old needles (30–40%) and in the root system (40–50%) which was due to both their high activity as a storage sink and their large sink size. The high initial 14C-activity in the finest roots decreased indicating respiration of reserves. Only a small percent of the reserve carbon was found in the new shoots which indicated that reserves are of minor importance in building a new shoot. An allocation of about 15% of the autumn storage to the stem suggested that in seedlings the stem is of minor importance as a storage organ.
  • Lippu, Department of Forest Ecology, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: jukka.lippu@helsinki.fi (email)
article id 696, category Research article
Jukka Lippu. (1998). Redistribution of 14C-labelled reserve carbon in Pinus sylvestris seedlings during shoot elongation. Silva Fennica vol. 32 no. 1 article id 696. https://doi.org/10.14214/sf.696
This study examined the later use of 14C reserves formed in previous autumn in Scots pine (Pinus sylvestris L.) seedlings. The seedlings were allowed to photosynthesise 14CO2 in early September when shoot and needle growth was over. The following spring the seedlings were harvested in five samplings during the shoot growth period. The distribution and concentration of 14C were determined and the results were compared with the growth data. It was observed that reserves were not used markedly for the new growth. Most of the 14C was found in one-year-old needles (30–40%) and in the root system (40–50%) which was due to both their high activity as a storage sink and their large sink size. The high initial 14C-activity in the finest roots decreased indicating respiration of reserves. Only a small percent of the reserve carbon was found in the new shoots which indicated that reserves are of minor importance in building a new shoot. An allocation of about 15% of the autumn storage to the stem suggested that in seedlings the stem is of minor importance as a storage organ.
  • Lippu, Department of Forest Ecology, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: jukka.lippu@helsinki.fi (email)

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 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 249, category Review article
Rimvydas Vasaitis, Jan Stenlid, Iben M. Thomsen, Pia Barklund, Anders Dahlberg. (2008). Stump removal to control root rot in forest stands. A literature study. Silva Fennica vol. 42 no. 3 article id 249. https://doi.org/10.14214/sf.249
Tree stumps are expected to be increasingly used for energy production in Fennoscandia, thus environmental consequences of stump removal from forest land must be assessed. Aim of this work was to compile available data on the efficacy of stump removal in eradication of root rot fungi (Heterobasidion, Armillaria, and Phellinus), and to review its potential impacts on establishment and productivity of next forest generation. Site disturbance and some technical and economical aspects are discussed, and needs for future research outlined in northern European context. The review demonstrates that stump removal from clear-felled forest areas in most cases results in, a) reduction of root rot in the next forest generation, b) improved seedling establishment, and c) increased tree growth and stand productivity. Observed disturbances caused to a site by stumping operations are normally acceptable. The available data strongly suggests that possibly many (if achievable, all) rot-containing stumps must be removed during harvesting of stumps. Provided equal availability, the priority should be given for stump removal from root rot-infested forest areas, instead of healthy ones. As most studies were done in North America and Britain, several questions must be yet answered under Fennoscandian conditions: a) if and to which extent the conventional stump removal for biofuel on clear-felled sites could reduce the occurrence of Heterobasidion and Armillaria in the next forest generation, b) what impact is it likely to have on survival of replanted tree seedlings, and c) what consequences will there be for growth and productivity of next forest generation.
  • Vasaitis, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail: rimvys.vasaitis@mykopat.slu.se (email)
  • Stenlid, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Thomsen, Forest & Landscape, University of Copenhagen, Hoersholm Kongevej 11, DK-2970 Hoersholm, Denmark ORCID ID:E-mail:
  • Barklund, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Dahlberg, Swedish Species Information Centre, Swedish University of Agricultural Sciences, P.O. Box 7007, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
article id 693, category Review article
Erik G. Ståhl. (1998). Changes in wood and stem properties of Pinus sylvestris caused by provenance transfer. Silva Fennica vol. 32 no. 2 article id 693. https://doi.org/10.14214/sf.693
Wood properties focused in forest tree breeding should be of economic importance, have a large total variation and a high heritability. The properties of interest are those that influence the strength and durability of sawn products or the amount and properties of pulp produced. The following wood properties are treated: width of the annual ring, juvenile wood, late wood content, heart wood, tracheid dimensions, basic density, stem straightness and branch diameter. The provenance variation in wood properties can be related to differences in growth phenology. In the northern part of distribution P. sylvestris (L.) provenances transferred a few degrees southwards have a high survival and yield but stem wood production is low. Trees from these provenances will be straight and with few spike knots or other injuries. The shoot elongation period will be short and the temperature sum required for wood formation sufficient. Provenances transferred southwards will form thin annual rings, few and thin branches, little early wood, high basic density and slender tracheids with thick cell walls in comparison to local provenances. An example of the effect of alternative transfers on the yield and wood properties is evaluated. In regions with deviating climatic patterns alternative provenance transfer patterns may be better. The objectives of the land owner should influence the provenance choice. The importance of integrating tree improvement with silvicultural management is discussed with reference to spacing.
  • Ståhl, College of Dalarna, CITU Centre for Industrial Technology and Development, S-781 88 Borlänge, Sweden ORCID ID:E-mail: esl@du.se (email)

Category: Research note

article id 10014, category Research note
Āris Jansons, Roberts Matisons, Virgilijus Baliuckas, Līga Purina, Oskars Krišāns, Jānis Jansons, Imants Baumanis. (2018). Performance variation of lodgepole pine provenances in Latvia. Silva Fennica vol. 52 no. 5 article id 10014. https://doi.org/10.14214/sf.10014
Highlights: Performance of 36 provenances of lodgepole pine in 14 trials was studied; The 29 year survival was ca. 40%; Provenance and provenance × trial interaction affected dimensions of lodgepole pine; Provenances from lower latitudes were the most productive.

Lodgepole pine (Pinus contorta var. latifolia Engelm.) has been extensively introduced in Scandinavia on less productive sites. Under a changing climate, it also has a high potential in the eastern Baltic region; still, its performance there has scarcely been reported. This study investigated the performance of 36 Canadian provenances in 14 trials in western Latvia. Tree dimensions showed notable provenance and provenance-by-environment variation, implying that local selection by provenance can be applied for improved yield. Southern provenances showed the best height growth, while southwestern (more oceanic) provenances excelled in diameter growth. Most of the quality traits were affected by provenance or provenance-by-environment interaction, yet the variation was lower than for the growth traits.

  • Jansons, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: aris.jansons@silava.lv (email)
  • Matisons, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: robism@inbox.lv
  • Baliuckas, Forest Institute, Lithuanian Centre for Agriculture and Forestry, Department of Forest Tree Genetics and Breeding, Liepu St. 1, Girionys, LT-53101 Kaunas distr., Lithuania ORCID ID:E-mail: virgilijus.baliuckas@mi.lt
  • Purina, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: liga.purina@silava.lv
  • Krišāns, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: oskars.krisans@silava.lv
  • Jansons, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: janis.jansons.silava@gmail.com
  • Baumanis, Latvian State Forest Research Institute ”Silava”, Department of Forest Tree Breeding, Rigas St.t. 111, Salaspils LV-2169, Latvia ORCID ID:E-mail: imants.baumanis@silava.lv
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 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 403, category Research note
Timo Saksa, Juha Heiskanen, Jari Miina, Jaakko Tuomola, Taneli Kolström. (2005). Multilevel modelling of height growth in young Norway spruce plantations in southern Finland. Silva Fennica vol. 39 no. 1 article id 403. https://doi.org/10.14214/sf.403
Height development of Norway spruce (Picea abies (L.) Karst.) transplants was studied on 22 sites prepared by disc trenching or mounding. At the age of 4–9 years the plantations were surveyed using a multistage sampling design. For every planted spruce on a plot, the past annual height increments were measured as far into the past as possible. Multilevel mixed linear modelling was used to analyse the variation in growth at different levels (year, stand, cluster, plot, tree) and the effects of climatic and site characteristics on height growth. The within-plantation variation in height growth was higher on mounded sites than on disc-trenched sites. The mean temperature and the precipitation sum of the summer months affected height growth positively. Soil characteristics measured from undisturbed soil did not explain the height growth of seedlings on mounded sites, whereas on disc-trenched sites, the depth of the organic layer and the soil temperature had a positive effect and the depth of the eluvial horizon a negative effect. The modelling approach used proved to be a useful method for examining the sources of variation in development of young plantations.
  • Saksa, The Finnish Forest Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Heiskanen, The Finnish Forest Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Miina, The Finnish Forest Institute, Joensuu Research Centre, P. O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Tuomola, The University of Joensuu, Mekrijärvi Research Station, FI-82900 Ilomantsi, Finland ORCID ID:E-mail:
  • Kolström, The University of Joensuu, Mekrijärvi Research Station, FI-82900 Ilomantsi, Finland ORCID ID:E-mail:
article id 421, category Research note
Pekka Helenius, Jaana Luoranen, Risto Rikala. (2004). Effect of thawing duration and temperature on field performance of frozen-stored Norway spruce container seedlings. Silva Fennica vol. 38 no. 3 article id 421. https://doi.org/10.14214/sf.421
Increasing use of frozen storage in nurseries at northern latitudes calls for thawing methods that are safe, economical and easy to apply on a large scale. The easiest and most economical method would be to thaw seedlings in the same boxes they were stored in. However, doing this safely requires more knowledge about how long and at what temperatures seedlings should or can be kept in the boxes without reducing field performance. In this study, 1-yr-old frozen-stored Norway spruce (Picea abies (L.) Karst.) container seedlings were thawed for 4, 8 or 16 days at 4 or 12 °C in cardboard boxes before planting on a reforestation site and on experimental field in mid-June. Some seedlings were also planted on these locations after thawing for only 7 hours at 12 °C in order to separate frozen root plugs. We found some evidence that planting seedlings after short thawing periods (7 hours at 12 °C and 4 days at 4 °C), under which conditions the root plugs remain completely or partly frozen, has a negative effect on field performance of Norway spruce seedlings. Thawing over a 4-8 day period in cardboard boxes at ca. 12 °C appears to ensure complete thawing of the root plugs and unaffected field performance, but is short enough to prevent the growth of mould.
  • Helenius, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: pekka.helenius@metla.fi (email)
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 608, category Research note
Jouni Partanen, Ilkka Leinonen, Tapani Repo. (2001). Effect of accumulated duration of the light period on bud burst in Norway spruce (Picea abies) of varying ages. Silva Fennica vol. 35 no. 1 article id 608. https://doi.org/10.14214/sf.608
One-year-old seedlings (two sowing times), two-year-old seedlings and 14- and 18-year-old cuttings of Norway spruce (Picea abies (L.) Karst.) were exposed to shortening photoperiod (initially 16 h), lengthening photoperiod (initially 6 h) and constant short photoperiod (6 h) treatments with uniform temperature conditions in growth chambers. The timing of bud burst was examined. In all plants, shortening photoperiod treatment seemed to promote bud burst compared with other treatments. This effect was clearest in the oldest material. The results suggest that, in addition to temperature sum, the accumulated duration of the light period may promote bud burst of Norway spruce.
  • Partanen, Finnish Forest Research Institute, Punkaharju Research Station, Finlandiantie 18, FIN-58450 Punkaharju, Finland ORCID ID:E-mail: jouni.partanen@metla.fi (email)
  • Leinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Repo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 659, category Research note
Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659
The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.
  • Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Discussion article

article id 536, category Discussion article
Ian Cowan. (2002). Fit, fitter, fittest; where does optimisation fit in? Silva Fennica vol. 36 no. 3 article id 536. https://doi.org/10.14214/sf.536
  • Cowan, Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia ORCID ID:E-mail: iancowan@bigpond.com.au (email)

Category: Article

article id 7170, category Article
Yrjö Ilvessalo. (1967). Luonnonnormaalien metsiköiden kehityksestä Kainuussa ja sen lähiympäristössä. Acta Forestalia Fennica vol. 81 no. 5 article id 7170. https://doi.org/10.14214/aff.7170
English title: The development of natural normal forest stands in southeastern Northern Finland.

Examination of stands developed under natural conditions can be used to provide basis for comparison for study of the development and yield of stands treated with intermediate fellings. In Finland, the first investigation and the yield and the structure of natural normal stands were published in 1920. This investigation on development and yield of the natural forests of Kainuu in southeastern Northern Finland is based on 92 sample plots on three forest types; Empetrum-Vaccinium type (EVT), Empetrum-Calluna type (ECT) and Vaccinium-Myrtillus type (VMT).

The Scots pine (Pinus sylvestris L.) sample plots represented variation of age classes for construction of mean development series. The Norway spruce (Picea abies (L.) H. Karst.) of the region are so old that development series could be obtained only for dominant trees based on stem analysis.

The average development of Scots pine stand on EMT type within the region is on average more rapid and the yield in cubic volume quantitatively larger and structurally better than that on ECT type. Self-thinning during the early decades of EVT is slower. The pine stands are denser in the age of 70 in Kainuu compared to Central Northern Finland, but the development and yield are similar.

The development, yield and structure of natural Norway spruce stand on VMT proved considerably inferior to the average level of pine stands on EVT, and to a major part on ECT. The mixed pines on spruce sample plots have developed better than spruces of equal age. Spruce stands on VMT in the area developed markedly better than Geranium-Dryopteris-Myrtillus (GDMT) in Central Northern Finland.

It seems that a spruce stand seems to require more fertile site type in north than in the southern part of Finland. These fertile types are relative rare in the north. In the region, the best results are received with pine. As a rule, also the yield of birch (Betula sp.) is poor in the region.

The PDF includes a summary in English.

  • Ilvessalo, 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 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 7157, category Article
Leo Heikurainen, Kustaa Seppälä. (1965). Regionality in stand increment and its dependence on the temperature factor on drained swamps. Acta Forestalia Fennica vol. 78 no. 4 article id 7157. https://doi.org/10.14214/aff.7157

The aim of this work was to study, on the basis of material published earlier (Heikurainen 1959), the effect of temperature on stand increment, to find out if there is any differences between Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.), and to study the effect of site quality on the relationship between stand increment and temperature. The calculations were based on data collected from 396 sample plots on drained peatlands in different parts of Finland.

There seemed to be no differences due to tree species or site quality in the relative amounts of growth under different climatic conditions. Thus, differences in the absolute growth between poor and fertile sites are noticeably smaller in Northern Finland than in Southern Finland. The author suggests that this implies that the lasting maximal increase of growth which can be produced, for instance, by using soil-improving agents must be less in unfavourable conditions than in favourable.

  • Heikurainen, ORCID ID:E-mail:
  • Seppälä, ORCID ID:E-mail:
article id 7155, category Article
Bo Högnäs. (1966). Investigations on forest types and stand development in Åland in Finland. Acta Forestalia Fennica vol. 78 no. 2 article id 7155. https://doi.org/10.14214/aff.7155

The purpose of this study is to clarify the forest types in pure coniferous stands in Åland in Finland, to study them in a biological light and account for the production of the stands on respective sites. The flora of the forest types in Åland has been described in an earlier study, but as the plant associations have not been described it has often been difficult to determine the correct types in field work. Sample plots were chosen in coniferous forests with maximum 20% of other species. The vegetation analysis was limited to determine composition of species, projected coverage and the frequency of species. In addition, cubic volume and growth of the growing stock was calculated for the stands.

The results of the study showed that site type and fertility correspond to each other nearly without exception only on normal moraines, if only the ground vegetation is used as a criterion for the type. The general occurense of soils of different qualities makes it necessary to determine, besides forest type, other characteristics in the stands, preferably the dominant height. The total production of coniferous forests with great probability is smaller in Åland than in mainland Finland. The results can be applied also to Åboland’s archipelago, where the milieu of the coniferous forests is similar.

The PDF includes a summary in English.

  • Högnäs, ORCID ID:E-mail:
article id 7147, category Article
S. A. Wilde, J. G. Iyer. (1963). Effect of natural subirrigation on the uptake of nutrients by forest plantations. Acta Forestalia Fennica vol. 76 no. 7 article id 7147. https://doi.org/10.14214/aff.7147

Result of a survey of soils supporting forest plantations in Wisconsin in the United States indicated a close correlation between the levels of fertility of non-phreatic, coarse-textured soils and the growth of red pine (Pinus resinosa Roezl) stands aged from 15 to 32. This relationship, however was not observed in plantations established on deep-gley soils, underlain at a depth of 3–9 fl by ground water.

The survey encountered 20 red pine plantations on soils underlain by a deep ground water table accessible to tree roots thorough their contact with gley horizon or with extended capillary fringe. The average growth of the stands was 80 cubic feet/acre (5.6 m3/ha) at the age of 22 years. Thus, mensuration analysis suggested that the soils are the choice grounds for forestry enterprise. However, the analysis of soil samples showed that in many instances the soils are extremely low in mineral colloids, organic matter and nutrients. Many of the sites would be regarded as critically deficient in nitrogen, phosphorus and potassium.

The following hypothesis are suggested to explain this discrepancy:

a) The moisture content of coarse-textured non-phreatic soils remain near the wilting point during a large apart of the growing season with subsequent reduction of transpiration and uptake of nutrients. If a capillary fringe provides a supply of water for the root system, trees may derive an adequate supply of salts and exchangeable ions from comparatively infertile substrata.

b) The suitably located ground water provides adequate aeration of the surface soil layers which is not impeded by capillary fringe, increasing activity of mycorrhiza, and a mycotrophic uptake of nutrients from unweathered minerals.

c) The above effects of natural subirrigation should change the concept of soil fertility based on mere chemical analysis. The time during which the roots are engaged in active absorption appears to be of equal importance as the concentration of nutrients in available form.

The PDF includes a summary in Finnish.

  • Wilde, ORCID ID:E-mail:
  • Iyer, ORCID ID:E-mail:
article id 7138, category Article
Kullervo Kuusela, Pekka Kilkki. (1963). Multiple regression of increment percentage on other characteristics in Scots pine stands. Acta Forestalia Fennica vol. 75 no. 4 article id 7138. https://doi.org/10.14214/aff.7138

The objective of this study has been to discover some of the basic principles on which an increment for a large forest area might be forecast. Because the stands in a large forest area vary considerably in density and are subject to different kinds of treatment, the main interest falls on the stand characteristics which determine the increment percentage in such forest conditions as these. The material used in the study has been published earlier, it consisted of sample plots of Scots pine (Pinus sylvestris L.) stands (Nyyssönen 1954).

Increment functions are of great importance in the increment forecast for cutting budget. Because 60-80% of the variation in the increment percentage can be explained by stand characteristics in circumstances where the age of the stand is 40-130 years and the volume vary with a coefficient of variation 0.6-0.7, regression equations for increment percentage may be based on a number of sample plots smaller than in a growing stock inventory in the same conditions. It is possible to get accurate results with relatively small number of sample plots. Furthermore, the smaller amount of increment sample plots makes it possible to develop measurement techniques.

The increment functions enable study of increment as a biological process. However, conclusions about biological process on the basis of regression equations should be made with caution. Still, regression analysis is a powerful tool in yield studies.

The PDF includes a summary in Finnish.

  • Kuusela, ORCID ID:E-mail:
  • Kilkki, 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 7112, category Article
Kustaa Kallio. (1960). Etelä-Suomen kylvömänniköiden rakenteesta ja kehityksestä. Acta Forestalia Fennica vol. 71 no. 3 article id 7112. https://doi.org/10.14214/aff.7112
English title: Structure and development of Scots pine stands established by sowing in Southern Finland.

In Southern Finland Scots pine (Pinus sylvestris L.) is mainly sown on Vaccinium and Myrtillus-type sites. The material for the study was collected by measuring sample plots in pure, even-aged pine stand that had been sown. The sample stands had been thinned from below.

The volume of the stands was roughly the same as that of repeatedly thinned pine stands. The cubic volume of sown pine stands is 65–90%, varying according to age, of that of natural-normal pine stands. The current annual volume increment of stands on Myrtillus-type was 8–9 m3/ha at age of 20–30 years. The peak was reached at age of 35 years with 9 m3/ha, in the following years the increment is about 8 m3/ha until the age of 60 years. On Vaccinium type sites increment reaches 6–7 m3 level at age of 30 years, and attains the peak of 7 m3/ha at the age of 45 years. Annual increment was in young and middle-aged Myrtillus-type stands about 10% greater, and on Vaccinium-type stands 15–20% greater than in natural-normal pine stands.

The total volume increment in 70 years old Myrtillus-type stands was 580 m3/ha over bark, and in 80 years old Vaccinium-type stands 520 m3/ha. The total removal on Myrtillus-type sites totalled nearly 350 m3/ha in sown pine stands up to 70 years of age, and 280 m3/ha on Vaccinium-type stands. The total yield in sawn timber per hectare rises up to 6,300 cubic ft in a 70 years old stand on Myrtillus-type stands, and 5,300 cubic ft in Vaccinium-type stands. In conclusion, the volume and increment development of managed pine stands established by sowing up to 70–80 years of age is largely the same as in repeatedly thinned pine stands, but the structure and yield offer greater advantages. The investigation demonstrates that, in the case of Scots pine, sowing is an advantageous method of regeneration. Sowing is an advantage especially in the cases where natural regeneration is uncertain and slow.

The PDF includes a summary in English.

  • Kallio, ORCID ID:E-mail:
article id 7475, category Article
Peitsa Mikola. (1958). Liberation of nitrogen from alder leaf litter. Acta Forestalia Fennica vol. 67 no. 1 article id 7475. https://doi.org/10.14214/aff.7475

Litters of different plant species vary greatly in regard to their nutrient content and other properties. The aim of the study was to compare different litters from the standpoint of their value as soil fertilizer. In an experiment Scots pine (Pinus sylvestris L.) seedlings were grown in pot cultures in which known amounts of different litters had been mixed with the soil. The tested litters were Pinus sylvestris (L.), Larix sibirica (Ledeb.), Betula sp., Populus tremula (L.), Alnus incana (L.) Moench, A. glutinosa (L.) (Gaertn.), Sorbus aucuparia (L.), Tilia cordata (Mill.), Acer platanoides (L.), Corylus avellana (L.), Eupteris aquilina (L.), and Deschampsia flexuosa (L.) Trin.

A striking difference was found between alder (Alnus sp.) leaf litter and all the other litters tested. The difference can be seen from the second growth season on, becaus the young seedling uses mainly the nutrients included in the seed. The leaf litter has mainly unfavourable effect on the growth of the pine seedlings. Only both alder species improve the growth. This is mainly due to the nitrogen content of alder leaves. Tree leaves and other forest litter are often composted in the forest nurseries. It seems that adding nitrogen to the compost is necessary, otherwise compost added to the soil may have a harmful effect on the seedlings. Alder, on the other hand, has nitrogen binding Actinomyces growing in symbiosis in its root nodules, and is able to utilize atmospheric nitrogen.

The PDF includes a summary in Finnish.

  • Mikola, ORCID ID:E-mail:
article id 7473, category Article
Kustaa Kallio. (1957). Käenkaali-mustikkatyypin kuusikoiden kehityksestä Suomen lounaisosassa. Acta Forestalia Fennica vol. 66 no. 3 article id 7473. https://doi.org/10.14214/aff.7473
English title: On the development of spruce forests of the Oxalis-Myrtillus site type in the south-west of Finland.

In this investigation was studied 1) Volume growth and yield of timber in managed Norway spruce (Picea abies (L.) Karst.) forests under different rotations. 2) Value growth, net forest income and soil expectation value of managed forests under different rotations, and 3) The rotations of spruce forests managed on different rotation principles. The data was collected from Oxalis-Myrtillus type forests in South-West Finland.

Two developmental series of stands were constructed for the research, one of which were of better sites than the other. Sample plots were pure, even-aged spruce stands in well-managed forests. The stands had been thinned from below. The age varied from 25-30 years to the age of final cutting.

According to the study, in the artificially regenerated spruce stands the highest mean annual volume growth, 9.7 m3/ha, and also the highest net annual income of 14,50 Finnish marks/ha (calculated from average stumpages) was reached in rotation of 70 years. In the other managed spruce forests a mean annual volume growth of 6.6-8.8 m3/ha and the net annual income of 10,500-14,500 Finnish marks/ha were reached in the rotation of 70-100 years. The rotation for the maximum mean annual volume growth varied in the different series between 67-92 years. The maximum mean annual forest rent was only achieved in series B in a rotation of about 100 years, and in a naturally normal stand in a rotation of about 120 years. The intensity of thinnings and silviculture had a greater effect on value growth and on net income than on volume growth.

The PDF includes a summary in English.

  • Kallio, ORCID ID:E-mail:
article id 7473, category Article
Kustaa Kallio. (1957). Käenkaali-mustikkatyypin kuusikoiden kehityksestä Suomen lounaisosassa. Acta Forestalia Fennica vol. 66 no. 3 article id 7473. https://doi.org/10.14214/aff.7473
English title: On the development of spruce forests of the Oxalis-Myrtillus site type in the south-west of Finland.

In this investigation was studied 1) Volume growth and yield of timber in managed Norway spruce (Picea abies (L.) Karst.) forests under different rotations. 2) Value growth, net forest income and soil expectation value of managed forests under different rotations, and 3) The rotations of spruce forests managed on different rotation principles. The data was collected from Oxalis-Myrtillus type forests in South-West Finland.

Two developmental series of stands were constructed for the research, one of which were of better sites than the other. Sample plots were pure, even-aged spruce stands in well-managed forests. The stands had been thinned from below. The age varied from 25-30 years to the age of final cutting.

According to the study, in the artificially regenerated spruce stands the highest mean annual volume growth, 9.7 m3/ha, and also the highest net annual income of 14,50 Finnish marks/ha (calculated from average stumpages) was reached in rotation of 70 years. In the other managed spruce forests a mean annual volume growth of 6.6-8.8 m3/ha and the net annual income of 10,500-14,500 Finnish marks/ha were reached in the rotation of 70-100 years. The rotation for the maximum mean annual volume growth varied in the different series between 67-92 years. The maximum mean annual forest rent was only achieved in series B in a rotation of about 100 years, and in a naturally normal stand in a rotation of about 120 years. The intensity of thinnings and silviculture had a greater effect on value growth and on net income than on volume growth.

The PDF includes a summary in English.

  • Kallio, ORCID ID:E-mail:
article id 7473, category Article
Kustaa Kallio. (1957). Käenkaali-mustikkatyypin kuusikoiden kehityksestä Suomen lounaisosassa. Acta Forestalia Fennica vol. 66 no. 3 article id 7473. https://doi.org/10.14214/aff.7473
English title: On the development of spruce forests of the Oxalis-Myrtillus site type in the south-west of Finland.

In this investigation was studied 1) Volume growth and yield of timber in managed Norway spruce (Picea abies (L.) Karst.) forests under different rotations. 2) Value growth, net forest income and soil expectation value of managed forests under different rotations, and 3) The rotations of spruce forests managed on different rotation principles. The data was collected from Oxalis-Myrtillus type forests in South-West Finland.

Two developmental series of stands were constructed for the research, one of which were of better sites than the other. Sample plots were pure, even-aged spruce stands in well-managed forests. The stands had been thinned from below. The age varied from 25-30 years to the age of final cutting.

According to the study, in the artificially regenerated spruce stands the highest mean annual volume growth, 9.7 m3/ha, and also the highest net annual income of 14,50 Finnish marks/ha (calculated from average stumpages) was reached in rotation of 70 years. In the other managed spruce forests a mean annual volume growth of 6.6-8.8 m3/ha and the net annual income of 10,500-14,500 Finnish marks/ha were reached in the rotation of 70-100 years. The rotation for the maximum mean annual volume growth varied in the different series between 67-92 years. The maximum mean annual forest rent was only achieved in series B in a rotation of about 100 years, and in a naturally normal stand in a rotation of about 120 years. The intensity of thinnings and silviculture had a greater effect on value growth and on net income than on volume growth.

The PDF includes a summary in English.

  • Kallio, ORCID ID:E-mail:
article id 7439, category Article
Leo Heikurainen. (1954). Rämemänniköiden uudistamisesta paljaaksihakkausta käyttäen. Acta Forestalia Fennica vol. 61 no. 27 article id 7439. https://doi.org/10.14214/aff.7439
English title: Regeneration of Scots pine stands of pine swamps through clear cutting.

Pine swamps are easily regenerated by natural regeneration of Scots pine (Pinus sylvestris L.). Usually seeding felling is used, but also strip system or clear cutting and regeneration along stand edge has been suggested. This article discusses the regeneration by clear cutting and sparing the existing undergrowth. The article focuses on pine swamps to be drained and the ones in natural state.

Pine swamps in natural state usually have plenty of trees of smaller diameter classes, that can be trusted to form the future tree generation after the felling. This shortens the rotation by 20-30 years. The undergrowth has been shown to recover quickly. The method suits for regeneration of drained peatlands but could fit also for regeneration of pine swamps in natural state.

The seedlings in the pine swamps are mainly 1-5 years old, and the stock is changing. It seems that larger trees produce a wider selection of age groups, but the seedlings survive longer under smaller mother trees. Part of the younger generations of seedlings seem to be destroyed when the peatland is drained. Further studies are needed to investigate how the draining and felling are to be performed to spare the young 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.

  • Heikurainen, ORCID ID:E-mail:
article id 7433, category Article
Yrjö Ilvessalo. (1954). Nationwide surveys of forest resources and wood utilization in Finland. Acta Forestalia Fennica vol. 61 no. 21 article id 7433. https://doi.org/10.14214/aff.7433

The first estimates on the forest resources of Finland were presented in the middle of the 1900th century. The first line survey was conducted in 1912 in Central Finland. In 1921-1923 a survey of the forests of the whole country was commenced. The method consisted in measurement of sample plots in conjunction with ocular estimation of all the stands within the range of the lines. The methods were further developed in the second National Forest Survey in 1936-1938, which payed special attention to the silvicultural condition of the forests, and the growth in the light of climatic variation. When 3.3 million ha of forests were ceded to the Soviet Union in the peace treaty of 1944, the results of the survey had to be recalculated. The next survey was conducted 1951-1953. In this survey, the recovery of stands on drained peatlands was studied. The results of the inventories show that forest resources of Finland had icreased since the 1936-1938 survey.

The first investigation of wood utilization in Finland was carried out in 1927, after the first National Forest Survey had provided information on the forest resources, and knowledge of the other side of the forest balance was desired. The most difficult part was to determine the domestic wood consumption of the rural population. This was accomplished by studying 1,337 sample farms. The second investigation was commenced in 1938, and third in 1954.

These two investigations have made it possible to determine the annual removal and annual growth, and by comparing these results, growth balance. A forest balance is an essential condition for judicious forestry.

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

  • Ilvessalo, ORCID ID:E-mail:
article id 7407, category Article
Olli Vaartaja. (1951). Alikasvosasemasta vapautettujen männyn taimistojen toipumisesta ja merkityksestä metsänhoidossa. Acta Forestalia Fennica vol. 59 no. 3 article id 7407. https://doi.org/10.14214/aff.7407
English title: On the recovery of released Scots pine undergrowth and its silvicultural importance.

There are contrary opinions on the ability of Scots pine (Pinus sylvestris L.) seedlings to withstand oppression by hold-overs and recover after their felling. The recovery potential of oppressed pine stands in Southern and Northern Finland was studied using two kinds of material, fully recovered Scots pine stands and stands recently released. The volume and volume increment of the stand were measured, and the health of the sample trees was determined.

The study showed that those released pine stands that had been in oppressed state very long (25-60 years) had recovered after clear-cutting. After the release the stands grew at first slowly, but after recovery at about the same rate as natural normal stands of a similar height. The smaller, younger, and less stunted the seedlings were when they were released, and the better the site, the faster was the recovery. At the base of released pine stands various defects was detected. When the trees were released, the defects decrease their technical value. A heavy partial cutting had generally a disadvantageous effect on the stand. Recovering seedlings were found clearly to hinder the development of younger seedlings nearby. This inhibition seemed to be a result of the rapid spread of the root system of released pine trees.

The PDF includes a summary in English.

  • Vaartaja, ORCID ID:E-mail:
article id 7402, category Article
Gustaf Sirén. (1950). Alikasvoskuusten biologiaa. Acta Forestalia Fennica vol. 58 no. 2 article id 7402. https://doi.org/10.14214/aff.7402
English title: On the biology of undergrown Norway spruce.

Norway spruce (Picea abies (L.) Karst.) invading sites is common in Finland. The species tends to establish itself as undergrowth, and takes over when it gets space to grow. To determine whether the undergrowth is suitable as the new generation requires knowledge on the biology of spruce undergrowth. One of the issues is determining the age of the stunted trees. In this investigation, 100 undergrown spruce trees, their crown and their root systems were studied. A method was developed to determine the age of the trees.

The root system of all trees in Vaccinium sites and of stunted trees in Myrtillius sites were superficial. The root systems of older spruces were purely of adventitious origin. The longer the period of stunting growth, the younger is the root system. In addition to acropetal and general adventitious ramification there is often adventitious branching of the roots of pathological causes. Mortality among the long roots is frequent.

A stunted tree has not the same ability as a viable tree to make use of already existing branches for building assimilating surface. When comparing trees with equally large assimilating surface, a stunted tree had greater sum of roots compared to a viable tree. The root system of a stunted undergrown spruce was very superficial compared with the other trees.

The PDF includes a summary in English.

  • Sirén, ORCID ID:E-mail:
article id 7398, category Article
Erkki K. Kalela. (1949). Männiköiden ja kuusikoiden juurisuhteista I. Acta Forestalia Fennica vol. 57 no. 2 article id 7398. https://doi.org/10.14214/aff.7398
English title: On the horizontal roots in Scots pine and Norway spruce stands.

The purpose of the investigation was to study the amount, quality and distribution by layers of depth of horizontal roots in Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands in Southern Finland. The sample plots included stands on soil varying from sandy to stony, and stands of  varying ages from seedling stands to an old stand, in Myrtillus and Vaccinium type forests.

In a Norway spruce stand, the amount of roots increases rapidly and reaches its maximum, about 450 meters/m3, at an age of 100-110 years. In a Scots pine stand the maximum, about 370 m/m3, is reached earlier, at an age of 60-70 years. The root system of pine expands more rapidly than that of spruce. The total length of the horizontal root system of pine amounts to 1,000 m soon after 40 years of growth, of spruce at the age of 60. Later the situation changes, and at the age of 110 the root systems of both species are about the same size, but older trees of spruce have more extensive root system.

Majority of horizontal roots are under 1 mm in diameter. Of the horizontal roots of spruce stands the majority lie in the humus layer and in the topmost mineral soil stratum. Over half of horizontal spruce roots are, thus, at a maximum depth of 5 cm, while majority of the roots of Scots pine lie at maximum in depth of 10 cm. At the same layer grow also the roots of the ground vegetation, which may affect the competition between the species.

The PDF includes a summary in English.

  • Kalela, ORCID ID:E-mail:
article id 7361, category Article
M. Lappi-Seppälä. (1942). Siperian lehtikuusen kasvusta sekametsiköissä Evon valtionpuistossa. Acta Forestalia Fennica vol. 50 no. 8 article id 7361. https://doi.org/10.14214/aff.7361
English title: Growth of Siberian larch in mixed stands in state forests of Evo in Finland.

Of the foreign tree species Siberian larch (Larix sibirica Ledeb.) has the biggest economical potential in Finland. In its natural distribution the species grows mostly in mixed stands in other areas than the core of its range in Siberia, where it grows also in pure stands. However, growth studies have given contradictory results about how Siberian larch can manage competition of different tree species in mixed stands. In this study two-year old Siberian larch seedlings were planted in areas previously sown with Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). The growth of the trees was measured when the stands were 50 years old.

It appears that the stands, about 3700 larch seedlings per hectare, have originally been too been too dense. In the two thinnings done in the area, larch has probably been favoured, which has resulted in varying mix of pine and spruce. In the 50-year old stands, Siberian larch has developed faster than Scots pine and Norway spruce. Contrary to some previous studies, the results show that Siberian larch can be grown also in mixed stands, but the growth will probably be slower than in pure stands. Best growth is achieved in pure stands that have been planted thinly enough.

The PDF includes a summary in German.

  • Lappi-Seppälä, ORCID ID:E-mail:
article id 7359, category Article
V. T. Aaltonen. (1942). Muutamia kasvukokeita puuntaimilla. Acta Forestalia Fennica vol. 50 no. 6 article id 7359. https://doi.org/10.14214/aff.7359
English title: Growth studies on tree seedlings.

The aim of the study was to investigate effect of growth conditions on germination and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings in greenhouse conditions. Germination of seeds becomes markedly slower as the soil temperature decreases. It seems that low temperatures affect more Norway spruce than Scots pine. When temperature rises, the fresh weight of the seedlings increases more in pine seedlings than in spruce seedlings. Accordingly, lower temperatures affect less the weight growth of spruce seedling than that of pine seedlings.

An experiment testing how root competition affect germination showed that adjacent seedlings decrease germination of seeds more than shading with branches. The effect was strongest on pine and spruce seedlings when the shading tree species was fast growing birch (Betula sp.). On the other hand, shading affected most height growth of birch seedlings. Growing space can vary in relatively large range without it affecting greatly tree growth.

The PDF includes a summary in German.

  • Aaltonen, 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 7298, category Article
V. T. Aaltonen. (1934). Die Entwicklung des Waldbestandes und die Wachstumsfaktoren. Acta Forestalia Fennica vol. 40 no. 21 article id 7298. https://doi.org/10.14214/aff.7298
English title: The development of a forest stand and the growth factors.

Water and amount of light are the most important growth factors and the article discusses their relationship. It is knows that the more space is needed by a tree the worse the site is. The number of stems varies between tree species. Common understanding is that amount of light is decisive to self-thinning and regeneration of a stand. On a good site the adequacy of water may substitute the lack of light. However, the fertility of soil and moisture content is more important than light.

The question of the importance of light, soil fertility and water content, as well as their relationship is important when optimizing the forest management.       

The PDF contains a summary in Finnish.  

  • Aaltonen, ORCID ID:E-mail:
article id 7245, category Article
Erik Lönnroth. (1929). Theoretisches über den Volumzuwachs und -abgang des Waldbestandes. Acta Forestalia Fennica vol. 34 no. 32 article id 7245. https://doi.org/10.14214/aff.7245
English title: Theoretical observations on volume growth and drain of a forest stand.
Original keywords: Waldzuwachs; Volumabgang; Volumzuwachs

In a natural state growing closed forest the amount of timber grows yearly. However, in the same time the timber volume also decreases when part of the trees die in the competition for light and other growth factors.

There are many interactive functions and characteristic that influence the growth and drain in a stand. These can be illustrated as mathematical models. The article discusses a set of models.

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

  • Lönnroth, ORCID ID:E-mail:
article id 7231, category Article
Martti Hertz. (1929). Huomioita männyn ja kuusen pituuskehityksen "vuotuisesta" ja vuorokautisesta jaksosta. Acta Forestalia Fennica vol. 34 no. 18 article id 7231. https://doi.org/10.14214/aff.7231
English title: Observations on annual and daily cycles in the height growth of Scots pine and Norway spruce.

The height growth of Scots pine (Pinus sylvestris L.) seedlings were observed in Korkeakoski and Evo in Southern Finland in 1925-1928. The growth was slow in the beginning of the growing season, increased after that to decrease again towards the end of the growing season. The height growth begun in May, reached the fastest growth rates in June, and ended in June-July. According to the earlier studies, the length of the height growth of Scots pine is dependent on the temperature of the previous summer. This study showed that warm temperatures of the same summer promote height growth, and low temperatures slow it down. Also the daily growth fluctuates, being highest during the afternoon and slowest during the early morning. The daily growth is dependent on temperature.

Norway spruce (Picea abies (L.) H. Karst.) begin the height growth in average 9 days later than Scots pine. Compared to pine, the speed of growth in spruce decreases slower towards the late summer.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander. The PDF includes a summary in German.

  • Hertz, 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 7209, category Article
Aarne Boman. (1927). Tutkimuksia männyn paksuuskasvun monivuotisista vaihteluista Suomen eri osista kerätyn aineiston perusteella. Acta Forestalia Fennica vol. 32 no. 4 article id 7209. https://doi.org/10.14214/aff.7209
English title: Studies on annual variations of diameter growth of Scots pine in different parts of Finland.

Discs were collected from sample trees of Scots pine (Pinus sylvestris L.) in different types of peatlands and mineral soil sites in Kajaani, Rovaniemi, Kuusamo; Suojärvi, Pielisjärvi, Evo and Lokalahti in Finland. The growth ring series of the different areas reach as far as in the 1600th century in some sample plots. The diameter growth shows patterns that repeat in cycles of 7, 11, 21, 35 and 70 years. However, the cycles are not exactly equally long. The average lengths of the cycles are relatively similar both in peatlands and in mineral soil sites.

The PDF includes a summary in German.

  • Boman, ORCID ID:E-mail:
article id 5632, category Article
Annikki Mäkelä, Veli-Pekka Ikonen, Petteri Vanninen. (1997). An application of process-based modelling to the development of branchiness in Scots pine. Silva Fennica vol. 31 no. 3 article id 5632. https://doi.org/10.14214/sf.a8534

A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine (Pinus sylvestris L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.

  • Mäkelä, ORCID ID:E-mail:
  • Ikonen, ORCID ID:E-mail:
  • Vanninen, ORCID ID:E-mail:
article id 5630, category Article
John H. M. Thornley. (1997). Modelling allocation with transport/conversion processes. Silva Fennica vol. 31 no. 3 article id 5630. https://doi.org/10.14214/sf.a8532

A shoot-root carbon:nitrogen allocation model, based on the two processes of transport and chemical conversion, is described and explored. The view is proposed that all allocation models, whether built for the purposes of theoretical investigation or practical application, should start with this irreducible framework. In the present implementation, the processes operate according to: for substrate sources, dependence on shoot and root sizes, with possible product inhibition; for transport, movement down a substrate concentration gradient; for substrate sinks or utilization, linear bisubstrate kinetics. The dynamic and equilibrium properties of the model are explored. Failure of this approach to allocation will indicate to the modeller that additional mechanisms to control the processes are needed, and the mode of failure will indicate the type of mechanisms required. Additional mechanisms are discussed which may involve hormones or teleonomic (goal-seeking) controls, and may be added to the irreducible framework. However, these additions should not replace the irreducible framework of transport and chemical conversion, because they do not in reality. Modifications to the basic model to reflect some possibilities such as ontogenesis with the transition from exponential growth towards a steady state or with the scaling of within-plant transport resistances, the influence of hormones, and active transport, are described.

  • Thornley, 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 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 5628, category Article
Séverine Le Dizès, Philippe Balandier, Pierre Cruiziat, Patrick Jacquet, André Lacointe, Xavier Le Roux, Hervé Sinoquet. (1997). A model for simulating structure-function relationships in walnut tree growth processes. Silva Fennica vol. 31 no. 3 article id 5628. https://doi.org/10.14214/sf.a8530

An ecophysiological growth process model, called INCA, for simulating the growth and development of a young walnut tree (Juglans regia L.) during three or four years, is presented. This tool, currently under development, aims at integrating architectural and physiological knowledge of the processes involved, in order to give a more rational understanding of the pruning operation. The model describes a simple three-dimensional representation of tree crown, solar radiation interception, photosynthesis, respiration, growth and partitioning of assimilates to leaves, stems, branches and roots. It supports the hypothesis that the tree grows as a collection of semiautonomous, interacting organs that compete for resources, based on daily sink strengths and proximity to sources. The actual growth rate of organs is not predetermined by empirical data, but reflects the pattern of available resources. The major driving variables are solar radiation, temperature, topological, geometrical and physiological factors. Outputs are hourly and daily photosynthate production and respiration, daily dimensional growth, starch storage, biomass production and total number of different types of organ. The user can interact or override any or all of the input variables to examine the effects of such changes on photosynthate production and growth. Within INCA, the tree entities and the surrounding environment are structured in a frame-based representation whereas the processes are coded in a rule-based language. The simulation mechanism is primarily based on the rule chaining capabilities of an inference engine.

  • Le Dizès, ORCID ID:E-mail:
  • Balandier, ORCID ID:E-mail:
  • Cruiziat, ORCID ID:E-mail:
  • Jacquet, ORCID ID:E-mail:
  • Lacointe, ORCID ID:E-mail:
  • Le Roux, ORCID ID:E-mail:
  • Sinoquet, ORCID ID:E-mail:
article id 5627, category Article
Philippe de Reffye, Daniel Barthélémy, Frédéric Blaise, Thierry Fourcaud, François Houllier. (1997). A functional model of tree growth and tree architecture. Silva Fennica vol. 31 no. 3 article id 5627. https://doi.org/10.14214/sf.a8529

A new approach for modelling plant growth using the software AMAPpara is presented. This software takes into consideration knowledge about plant architecture which has been accumulated at the Plant Modelling Unit of CIRAD for several years, and introduces physiological concepts in order to simulate the dynamic functioning of trees. The plant is considered as a serial connection of vegetative organs which conduct water from the roots to the leaves. Another simple description of the plant as a network of parallel pipes is also presented which allows an analytical formulation of growth to be written. This recurring formula is used for very simple architectures and is useful to understand the role of each organ in water transport and assimilate production. Growth simulations are presented which show the influence of modifications in architecture on plant development.

  • de Reffye, ORCID ID:E-mail:
  • Barthélémy, ORCID ID:E-mail:
  • Blaise, ORCID ID:E-mail:
  • Fourcaud, ORCID ID:E-mail:
  • Houllier, ORCID ID:E-mail:
article id 5627, category Article
Philippe de Reffye, Daniel Barthélémy, Frédéric Blaise, Thierry Fourcaud, François Houllier. (1997). A functional model of tree growth and tree architecture. Silva Fennica vol. 31 no. 3 article id 5627. https://doi.org/10.14214/sf.a8529

A new approach for modelling plant growth using the software AMAPpara is presented. This software takes into consideration knowledge about plant architecture which has been accumulated at the Plant Modelling Unit of CIRAD for several years, and introduces physiological concepts in order to simulate the dynamic functioning of trees. The plant is considered as a serial connection of vegetative organs which conduct water from the roots to the leaves. Another simple description of the plant as a network of parallel pipes is also presented which allows an analytical formulation of growth to be written. This recurring formula is used for very simple architectures and is useful to understand the role of each organ in water transport and assimilate production. Growth simulations are presented which show the influence of modifications in architecture on plant development.

  • de Reffye, ORCID ID:E-mail:
  • Barthélémy, ORCID ID:E-mail:
  • Blaise, ORCID ID:E-mail:
  • Fourcaud, ORCID ID:E-mail:
  • Houllier, 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 5623, category Article
Harry T. Valentine. (1997). Height growth, site index, and carbon metabolism. Silva Fennica vol. 31 no. 3 article id 5623. https://doi.org/10.14214/sf.a8524

A metabolic model of height growth and site index is derived from a parametrization of the annual carbon balance of a tree. The parametrization is based on pipe-model theory. Four principal variants of the height-growth model correspond to four combinations of assumptions regarding carbon allocation: (a) the apical shoot is autonomous or (b) it is not; and (A) the specific rate of elongation of a shoot equals that of a woody root or (B) it does not. The bB model is the most general as it includes the aA, bA, and aB models as special cases. If the physiological parameters are constant, then the aA model reduces to the form of the Mitscherlich model and the bA model to the form of a Bertalanffy model. Responses of height growth to year-to-year variation in atmospheric conditions are rendered through adjustments of a subset of the model's parameters, namely, the specific rate of production of carbon substrate and three specific rates of maintenance respiration. As an example, the effect of the increasing atmospheric concentration of CO2 on the time-course of tree height of loblolly pine (Pinus taeda) is projected over 50-year span from 1986. Site index is predicted to increase and, more importantly, the shape of the site-index curve is predicted to change.

  • Valentine, 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 5616, category Article
Hannu Hökkä, Virpi Alenius, Timo Penttilä. (1997). Individual-tree basal area growth models for Scots pine, pubescent birch and Norway spruce on drained peatlands in Finland. Silva Fennica vol. 31 no. 2 article id 5616. https://doi.org/10.14214/sf.a8517

Models for individual-tree basal area growth were constructed for Scots pine (Pinus sylvestris L.), pubescent birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies (L.) Karst.) growing in drained peatland stands. The data consisted of two separate sets of permanent sample plots forming a large sample of drained peatland stands in Finland. The dependent variable in all models was the 5-year basal area growth of a tree. The independent tree-level variables were tree dbh, tree basal area, and the sum of the basal area of trees larger than the target tree. Independent stand-level variables were stand basal area, the diameter of the tree of median basal area, and temperature sum. Categorical variables describing the site quality, as well as the condition and age of drainage, were used. Differences in tree growth were used as criteria in reclassifying the a priori site types into new yield classes by tree species. All models were constructed as mixed linear models with a random stand effect. The models were tested against the modelling data and against independent data sets.

  • Hökkä, ORCID ID:E-mail:
  • Alenius, ORCID ID:E-mail:
  • Penttilä, ORCID ID:E-mail:
article id 5607, category Article
Paola Virgilietti, Joseph Buongiorno. (1997). Modeling forest growth with management data: A matrix approach for the Italian Alps. Silva Fennica vol. 31 no. 1 article id 5607. https://doi.org/10.14214/sf.a8508

This paper reports on the possibility and difficulties in building growth models from past Forest Administration records on cut and growth in the Italian Alps. As a case study, a matrix model was calibrated for uneven-aged forests in the Valsugana valley of the Trentino province. The model gave reliable predictions over 30 years, and plausible long-term forest dynamics, including steady-states that are similar to virgin forests. The results support the view that the current forests are deeply altered as to composition, relative to what would obtain from natural growth. They also support the concept of long cyclic changes in natural stands, gradually approaching a climax state. Shortcomings of the data are that they do not come from an experimental design, they are not always accurate, and they must be supplemented with other information, especially concerning mortality. Still, these cheap and available data can lead to workable models adapted to local conditions, with many management applications.

  • Virgilietti, ORCID ID:E-mail:
  • Buongiorno, ORCID ID:E-mail:
article id 5582, category Article
Jonathan J. Ruel, Matthew P. Ayres. (1996). Variation in temperature responses among populations of Betula papyrifera. Silva Fennica vol. 30 no. 2–3 article id 5582. https://doi.org/10.14214/sf.a9227

How will global warming affect southern populations of boreal trees? In paper birch, Betula papyrifera (Betulaceae), alpine trees with an evolutionary history of relatively cool summers may be more sensitive to climate warming than valley populations. We evaluated this scenario by growing seedlings from different populations in four temperature treatments (mountain field site, valley field site, and two greenhouse rooms).

Populations from low elevations germinated earlier and had higher germination success than population from high elevations (16.8 vs. 22.0 d; 72% vs. 11%). At the valley site, seedlings from native populations grew faster than seedlings from higher elevations (mean ± SE = 0.25 ± 0.02 vs. 0.09 ± 0.04 mm · cm-1 · d-1) while at the mountain site, all seedlings grew at similar rates. Seedling grown in cooler environments had higher root : shoot ratios, perhaps to compensate for temperature limitations in nutrient uptake by roots. Leaf area varied among populations but was not affected by environmental differences across the field sites. Net photosynthetic rates at valley temperatures were higher for seedlings grown in the valley than for seedling grown in the mountains or the warm greenhouse (12.0 vs. 10.3 and 5.8 μmoles · m-2 · s-1), perhaps due to adaptive phenotypic adjustments. Climatic warming could rapidly produce important phenotypic changes in birch trees (e.g. decreased root : shoot ratio, reduced growth in alpine populations). On a longer time-scale, warming could also result in genetic changes as natural selection favours valley genotypes in alpine sites where they are presently rare.

  • Ruel, ORCID ID:E-mail:
  • Ayres, ORCID ID:E-mail:
article id 5581, category Article
Oddvar Skre, Knut Nes. (1996). Combined effects of elevated winter temperatures and CO2 on Norway spruce seedlings. Silva Fennica vol. 30 no. 2–3 article id 5581. https://doi.org/10.14214/sf.a9226

A total of 1,800 3-year old seedlings of Norway spruce (Picea abies (L.) H. Karst.) from two Norwegian and one German provenance were treated with two different nitrogen levels during the 1992 growth season. The plants were kept during the following winter at two different temperature levels. In the spring of 1993, the nutrient application was resumed, and the plants were divided between three different treatments, 350 and 650 p.p.m. in open top chamber and a control plot outside the chambers. This treatment was repeated also during the following 1994 growth season.

The growth and primary production were studied by photosynthesis experiments and by non-destructive growth measurements. The result indicate that raised winter temperature may lead to increased needle loss and reduced growth the following season, particularly in northern provenances. Carbon dioxide significantly influenced growth in addition to nutrient level and winter temperature. High CO2 also seemed to cause increased photosynthesis at early season, and earlier budbreak and growth cessation than in control plants.

  • Skre, ORCID ID:E-mail:
  • Nes, 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 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 5541, category Article
Anneli Viherä-Aarnio. (1994). Performance of micropropagated plants of silver birch (Betula pendula) in a field trial. Silva Fennica vol. 28 no. 4 article id 5541. https://doi.org/10.14214/sf.a9181

Micropropagated and seed-borne plants of sliver birch (Betula pendula Roth) were compared for survival and growth in a field trial at the age of six years. Three clones for micropropagation were selected from open-pollinated progenies of selected southern Finnish plus trees at the age of 17 and 20. The three seed-borne lots were of southern Finnish stand origin. The best two lots of the experiment as regards the height and diameter growth at the age of six were the clones. The best of these differed significantly from the best-growing seed-grown lot. The weakest lot of the experiment was also a clone which was clearly slow-growing with a dense and bushy crown. Survival of the material was high (mean = 94%), and there was no damage caused by voles and elks, for example. The results clearly show that the selection of material for clonal propagation should be done carefully. The clones should also be tested for performance in the field before propagation on a large scale.

  • Viherä-Aarnio, ORCID ID:E-mail:
article id 5534, category Article
Hyun Kang, Inger Ekberg, Gösta Eriksson, Johan Ununger. (1994). Second and third growth period responses of Picea abies families to first growth period photoperiodic, light intensity and temperature treatments. Silva Fennica vol. 28 no. 4 article id 5534. https://doi.org/10.14214/sf.a9174

Seedlings of Picea abies (L.) H. Karst. full-sib families of contrasting origins were cultivated in a phytotron under different photoperiodic, light-intensity and temperature treatments during their first growth period. The effects of the treatments on juvenile growth traits – whether enhanced or delayed maturation was induces – were observed during the two subsequent growth periods. The following hypotheses were tested: (A) Enhanced maturation can be induced in the first growth period from sowing with (i) a long period of continuous light during active growth (24 weeks vs. 8 weeks); (ii) a shorter night during bud maturation (12 h vs. 16 h); high temperature (25°C vs. 20°C) during (iii) active growth, growth cessation and bud maturation; and during (iv) the latter part of growth cessation and bud maturation only. (B) Delayed maturation can be induced after (i) low light intensity during growth cessation and bud maturation (114 μmol m-2 s-1 vs. 340 μmol m-2 s-1); low temperature (15°C vs. 20°C) during (ii) active growth, growth cessation and bud maturation; and during (iii) the latter part of growth cessation and bud maturation only.

The most dramatic effect was observed after 24 weeks of continuous light during active growth. All traits showed a significantly more mature performance in the second growth period compared with the control. The effect for all but one trait was carried over to the third growth period. This is in accordance with the hypothesis that the activity of apical shoot meristems controls the maturation process. For the other treatments there was only weak or no support for the hypothesis of induction of enhanced or delayed maturation. Strong family effects were observed for all traits. Differential responses of the various latitudinal families were observed, suggesting that family effects must be considered to predict and interpret correctly how plants will respond to environmental effects.

  • Kang, ORCID ID:E-mail:
  • Ekberg, ORCID ID:E-mail:
  • Eriksson, ORCID ID:E-mail:
  • Ununger, ORCID ID:E-mail:
article id 5529, category Article
Jukka Lippu. (1994). Patterns of dry matter partitioning and 14C-photosynthate allocation in 1.5-year-old Scots pine seedlings. Silva Fennica vol. 28 no. 3 article id 5529. https://doi.org/10.14214/sf.a9169

Change in dry matter partitioning, 14C-incorporation, and sink 14C-activity of 1.5-year-old Scots pine (Pinus sylvestris L.) seedlings grown in growth chamber conditions were studied during a 91-day experiment. On five sampling dates, seedlings were labelled with 14CO2 and whole-plant allocation patterns were determined. Intensively growing shoots modified the dry matter partitioning: during shoot growth the proportion of roots decreased but after that it increased. Based on their large proportion of dry matter, the needles (excluding current needles) were the strongest sink of carbon containing 40% of the incorporated 14C. Despite their small initial sink size, the elongating shoots (current main shoot + current branch) and their needles were the second strongest sink (30–40% of the total 14C) which reflects their high physiological activity. The proportion of 14C in the current year’s main shoot increased during shoot growth but decreased as the growth began to decline after 70 days. 10–20% of the total assimilated 14C was translocated to the roots. Laterals above 2nd order were the strongest sink in the root system, containing twice as much 14C as the other roots together. Alternation between shoot and root growth can be seen clearly: carbon allocation to roots was relatively high before and after the period of intensive shoot growth. Changes in root sink strength resulted primarily from changes in root sink activity rather than sink size.

  • Lippu, ORCID ID:E-mail:
article id 5529, category Article
Jukka Lippu. (1994). Patterns of dry matter partitioning and 14C-photosynthate allocation in 1.5-year-old Scots pine seedlings. Silva Fennica vol. 28 no. 3 article id 5529. https://doi.org/10.14214/sf.a9169

Change in dry matter partitioning, 14C-incorporation, and sink 14C-activity of 1.5-year-old Scots pine (Pinus sylvestris L.) seedlings grown in growth chamber conditions were studied during a 91-day experiment. On five sampling dates, seedlings were labelled with 14CO2 and whole-plant allocation patterns were determined. Intensively growing shoots modified the dry matter partitioning: during shoot growth the proportion of roots decreased but after that it increased. Based on their large proportion of dry matter, the needles (excluding current needles) were the strongest sink of carbon containing 40% of the incorporated 14C. Despite their small initial sink size, the elongating shoots (current main shoot + current branch) and their needles were the second strongest sink (30–40% of the total 14C) which reflects their high physiological activity. The proportion of 14C in the current year’s main shoot increased during shoot growth but decreased as the growth began to decline after 70 days. 10–20% of the total assimilated 14C was translocated to the roots. Laterals above 2nd order were the strongest sink in the root system, containing twice as much 14C as the other roots together. Alternation between shoot and root growth can be seen clearly: carbon allocation to roots was relatively high before and after the period of intensive shoot growth. Changes in root sink strength resulted primarily from changes in root sink activity rather than sink size.

  • Lippu, ORCID ID:E-mail:
article id 5400, category Article
Kari J. Jokinen, Don J. Durzan. (1994). Properties of rescued embryonal suspensor masses of Norway spruce determined by the genotype and the environment in vitro. Silva Fennica vol. 28 no. 2 article id 5400. https://doi.org/10.14214/sf.a9165

53 genotypes of embryonal suspensor masses (ESMs) rescued from mature seeds of Norway spruce (Picea abies (L.) H. Karst.) were examined for their pattern of growth and development under standardized culture conditions in vitro. Patterns were classified according to the colour of the colonies grown in darkness, clarity of cell masses and proembryos in the mucilaginous ESM, surface boundary topology of colonies, structure of suspensors, growth rate of the ESM, and recovery of mature embryos.

Five distinctive major growth patterns were observed among ESM colonies under standardized culture conditions. The multiplication of proembryos and early embryos by cleavage and budding polyembryony was the main factor contributing to proliferation and colony growth and further determined the morphology of the colonies. Callus and teratological structures were induced from early embryos by changing the standardized culture conditions i.e. inadequate subculture, excessive dose of 2,4-D in the medium and premature exposure of the colonies to light. Results enable the selection of ESM genotypes for the predictable recovery of mature somatic embryos.

  • Jokinen, ORCID ID:E-mail:
  • Durzan, ORCID ID:E-mail:
article id 5525, category Article
Jari Miina. (1994). Spatial growth model for Scots pine on drained peatland. Silva Fennica vol. 28 no. 1 article id 5525. https://doi.org/10.14214/sf.a9159

A spatial growth model is presented for Scots pine (Pinus sylvestris L.) on a dwarf-shrub pine mire drained 14 years earlier. The growth model accounts for the variation in tree diameter growth owing to the competition between trees, the distance between tree and ditch, and the time passed since drainage. The model was used to study the effect of tree arrangement on the post-drainage growth of a pine stand. Clustering of trees decreased the volume growth by 9–20% as compared to a regular spatial distribution. Stand volume growth, for a given number of stems, was at its maximum and variation in diameter growth at its minimum when the stand density on the ditch border was 1.5–5 higher than midway between two adjacent ditches.

  • Miina, ORCID ID:E-mail:
article id 5518, category Article
Heikki Hänninen, Seppo Kellomäki, Kaisa Laitinen, Brita Pajari, Tapani Repo. (1993). Effect of increased winter temperature on the onset of height growth of Scots pine: a field test of a phenological model. Silva Fennica vol. 27 no. 4 article id 5518. https://doi.org/10.14214/sf.a15679

According to a recently presented hypothesis, the predicted climatic warming will cause height growth onset of trees during mild spells in winter and heavy frost damage during subsequent periods of frost in northern conditions. The hypothesis was based on computer simulations involving a model employing air temperature as the only environmental factor influencing height growth onset. In the present study, the model was tested in the case of eastern Finnish Scots pine (Pinus sylvestris L.) saplings. Four experimental saplings growing on their natural site were surrounded by transparent chambers in autumn 1990. The air temperature in the chambers was raised during the winter to present an extremely warm winter under the predicted conditions of a double level of atmospheric carbon dioxide. The temperature treatment hastened height growth onset by two months as compared to the control saplings, but not as much as expected on the basis of the previous simulation study. This finding suggests that 1) the model used in the simulation study needs to be developed further, either by modifying the modelled effect of air temperature or by introducing other environmental factors, and 2) the predicted climatic warming will not increase the risk of frost damage in trees as much as suggested by the previous simulation study.

The PDF includes an abstract in Finnish.

  • Hänninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Laitinen, ORCID ID:E-mail:
  • Pajari, ORCID ID:E-mail:
  • Repo, ORCID ID:E-mail:
article id 5512, category Article
Christian Messier, Pasi Puttonen. (1993). Coniferous and non-coniferous fine-root and rhizome production in Scots pine stands using the ingrowth bag method. Silva Fennica vol. 27 no. 3 article id 5512. https://doi.org/10.14214/sf.a15673

Coniferous and non-coniferous fine root and rhizome production was measured after one growing season using the ingrowth bag method in Scots pine (Pinus sylvestris L.) stands differing in ages from 7 to 105 years in Southern Finland. Total fine-root production decreased from the 7-year to 20-year-old stands, and then increased slightly in the 85- to 105-year-old stands. Most of the total fine-root biomass in the youngest age groups came from non-conifer species, whereas most of the total fine-root biomass in the three older age groups came from conifer species. The maximum coniferous fine-root production was found to occur at crown closure in the 11- to 13-year-old stands. Rhizome production was the lowest and highest in the 20- and 85- to 105-year-old stands, respectively. The increase in rhizome production in the 85- to 105-year-old stands was associated with an abundant understory cover of Vaccinium myrtillus and V. vitis-idaea and an increase in light penetration. The ingrowth bag method was found to be useful in assessing the relative fine-root production among species-group and successional stages of Scots pine stands.

The PDF includes an abstract in Finnish.

  • Messier, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5512, category Article
Christian Messier, Pasi Puttonen. (1993). Coniferous and non-coniferous fine-root and rhizome production in Scots pine stands using the ingrowth bag method. Silva Fennica vol. 27 no. 3 article id 5512. https://doi.org/10.14214/sf.a15673

Coniferous and non-coniferous fine root and rhizome production was measured after one growing season using the ingrowth bag method in Scots pine (Pinus sylvestris L.) stands differing in ages from 7 to 105 years in Southern Finland. Total fine-root production decreased from the 7-year to 20-year-old stands, and then increased slightly in the 85- to 105-year-old stands. Most of the total fine-root biomass in the youngest age groups came from non-conifer species, whereas most of the total fine-root biomass in the three older age groups came from conifer species. The maximum coniferous fine-root production was found to occur at crown closure in the 11- to 13-year-old stands. Rhizome production was the lowest and highest in the 20- and 85- to 105-year-old stands, respectively. The increase in rhizome production in the 85- to 105-year-old stands was associated with an abundant understory cover of Vaccinium myrtillus and V. vitis-idaea and an increase in light penetration. The ingrowth bag method was found to be useful in assessing the relative fine-root production among species-group and successional stages of Scots pine stands.

The PDF includes an abstract in Finnish.

  • Messier, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5510, category Article
Esa Koistinen, Sauli Valkonen. (1993). Models for height development of Norway spruce and Scots pine advance growth after release in southern Finland. Silva Fennica vol. 27 no. 3 article id 5510. https://doi.org/10.14214/sf.a15671

Mixed linear models were constructed to describe the height development of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) advance growth after release cutting. The models related density of the overstory, time elapsed since release cutting and tree size with annual height increment. Parameters of preliminary models were estimated from a limited data set to judge the feasibility of the approach for further studies.

The PDF includes an abstract in Finnish.

  • Koistinen, ORCID ID:E-mail:
  • Valkonen, ORCID ID:E-mail:
article id 5510, category Article
Esa Koistinen, Sauli Valkonen. (1993). Models for height development of Norway spruce and Scots pine advance growth after release in southern Finland. Silva Fennica vol. 27 no. 3 article id 5510. https://doi.org/10.14214/sf.a15671

Mixed linear models were constructed to describe the height development of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) advance growth after release cutting. The models related density of the overstory, time elapsed since release cutting and tree size with annual height increment. Parameters of preliminary models were estimated from a limited data set to judge the feasibility of the approach for further studies.

The PDF includes an abstract in Finnish.

  • Koistinen, ORCID ID:E-mail:
  • Valkonen, ORCID ID:E-mail:
article id 5503, category Article
Juha Heiskanen. (1993). Variation in water retention characteristics of peat growth media used in tree nurseries. Silva Fennica vol. 27 no. 2 article id 5503. https://doi.org/10.14214/sf.a15664

The water retention characteristics and their variation in tree nurseries and related physical properties were determined for commercially produced growth media made of light slightly humified Sphagnum peat. A total of 100 samples of peat media were collected from filled seedling trays in the greenhouses of four Finnish nurseries in 1990. In addition, the physical properties were determined for two growth media made of compressed peat sheets and chips. The variation in water retention characteristics in nurseries was described using linear models with fixed and random effects. The sources of variation in the mixed linear models were producer, grade, batch (greenhouse) and sample (tray).

The water retention of the peat media at different matric potentials was comparable to that given in the literature. The media shrank an average of 0–16% during desorption. The peat grades were finer than the Nordic quality standards for peat growth media. Particles < 1 mm increased and particles 1–5 mm decreased the water retention characteristics measured. The greatest total variation in water retention was at -1 kPa. The water retention of the peat media differed least at -5 and -10 kPa. The water retention characteristics of media from different producers usually differed significantly. The grades, on the other hand, did not differ from each other in their water retention characteristics nor were there significant interactions between producer and grade. The batch effect was marked but was lower than the effect within batches, where the sample (tray) effect was greater than the effect due to random measurement error. At -10 kPa, the measurement error was, however, clearly greater than the sample effect. The random measurement error was comparable to the batch effect. Aeration of the growth media is dependent on the water content retained between saturation and -1 kPa. The water availability to seedlings at the nursery phase is affected mainly by water retention between -1 and -10 kPa.
The PDF includes an abstract in Finnish.

  • Heiskanen, ORCID ID:E-mail:
article id 7094, category Article
S. E. Multamäki. (1923). Tutkimuksia ojitettujen turvemaiden metsänkasvusta. Acta Forestalia Fennica vol. 27 no. 1 article id 7094. https://doi.org/10.14214/aff.7094
English title: Studies on the growth of drained peatlands in Finland.

Only about 24,000 hectares of peatlands have been drained in the state lands by the 1921. The aim of this study was to define how much the growth of the trees in the drained peatland revives. Sample plots were measured in previously drained peatlands that had sufficient Scots pine (Pinus sylvestris L.) tree stand. A stem analysis was performed to one of the sample trees. The evenness of the stands was dependent on how evenly the peatlands had dried when the stand was regenerated. Thus, the sample stands were not always fully stocked. However, they had capacity to develop towards evenly structured forests as the peatlands continued to dry further. The diameter and height growth of the dried peatlands have corresponded the similar stands in mineral soil sites. In trees that have grown stunted in the peatlands, the diameter growth seems to increase faster than the height growth. The volume growth is slightly smaller than in the similar mineral soil sites due to less favorable stem form. After the draining, the roots of the trees continued to grow from the old branches of root, but start then to form new roots. When the ground water level drops, the root layer grows deeper.

The PDF includes a summary in German.

  • Multamäki, ORCID ID:E-mail:
article id 7094, category Article
S. E. Multamäki. (1923). Tutkimuksia ojitettujen turvemaiden metsänkasvusta. Acta Forestalia Fennica vol. 27 no. 1 article id 7094. https://doi.org/10.14214/aff.7094
English title: Studies on the growth of drained peatlands in Finland.

Only about 24,000 hectares of peatlands have been drained in the state lands by the 1921. The aim of this study was to define how much the growth of the trees in the drained peatland revives. Sample plots were measured in previously drained peatlands that had sufficient Scots pine (Pinus sylvestris L.) tree stand. A stem analysis was performed to one of the sample trees. The evenness of the stands was dependent on how evenly the peatlands had dried when the stand was regenerated. Thus, the sample stands were not always fully stocked. However, they had capacity to develop towards evenly structured forests as the peatlands continued to dry further. The diameter and height growth of the dried peatlands have corresponded the similar stands in mineral soil sites. In trees that have grown stunted in the peatlands, the diameter growth seems to increase faster than the height growth. The volume growth is slightly smaller than in the similar mineral soil sites due to less favorable stem form. After the draining, the roots of the trees continued to grow from the old branches of root, but start then to form new roots. When the ground water level drops, the root layer grows deeper.

The PDF includes a summary in German.

  • Multamäki, ORCID ID:E-mail:
article id 5487, category Article
Maarit Kytö. (1992). Lygus bugs as agents of growth disorders in permethrin-treated pine seedlings in regeneration areas. Silva Fennica vol. 26 no. 4 article id 5487. https://doi.org/10.14214/sf.a15648

The ability of Lygus bugs to cause growth disorders in permethrin-treated Scots pine (Pinus sylvestris L.) seedlings after planting was studied in two regeneration areas. There were three treatments: exposure of the seedlings to Lygus, mechanical protection of the seedlings from insects, and control seedlings. There were no significant differences in the rate of growth disorders between the treatments. The permethrin application protected the seedlings against Lygus bugs in the early summer, as well as when the bug abundance was low. The development of these seedlings, as well as the multiple-leadered and bushy seedlings on a third regeneration area, was followed for two years. Multiple leaders reduced height growth and bud number of a seedling, but caused marked losses in growth only when the seedlings still had multiple leaders the following year, or when they formed several, equally developed stems.
The PDF includes an abstract in Finnish.

  • Kytö, ORCID ID:E-mail:
article id 5475, category Article
Jyrki Hytönen. (1992). Allelopathic potential of peatland plant species on germination and early seedling growth of Scots pine, silver birch and downy birch. Silva Fennica vol. 26 no. 2 article id 5475. https://doi.org/10.14214/sf.a15636

The potential alleopathic inhibitive effects of aqueous extracts of 13 peatland plant species on germination, radicle and seedling growth of Scots pine (Pinus sylvestris L.), silver and downy birch (Betula pendula Roth., B. pubescens Ehrh.) were studied. Freshly cut plant parts were finely ground, mixed with distilled water and agitated. The proportions of fresh plant mass in the mass-based extracts varied within the range of 1, 5, 10 and 20% (w/w). The seeds were germinated in petri dishes moistened with the plant extracts. In a separate experiment growth of birch seedlings irrigated with the extracts was studied.

Ledum palustre, Vaccinium uliginosum and Empetrum nigrum extracts, and in certain experiments extracts of other species, inhibited the germination of Scots pine and birch seeds. Results from the different experiments were not, however, fully consistent. None of the low (1% w/w) extract concentrations had any effect on germination. Strong extract concentrations (20% w/w) inhibited germination of pine seedlings significantly. The extracts affected only slightly the growth of potted birch seedlings.

The PDF includes an abstract in Finnish.

  • Hytönen, ORCID ID:E-mail:
article id 5470, category Article
Juha Heiskanen, Jukka Laitinen. (1992). A measurement system for determining temperature, water potential and aeration of growth medium. Silva Fennica vol. 26 no. 1 article id 5470. https://doi.org/10.14214/sf.a15629

A measurement system developed for the parallel and real-time measurement of temperature, matric potential and oxygen diffusion rate (ODR) of a growth medium was assessed. The system consisted of a portable computer, a datalogger, temperature sensors, tensiometers and an ODR-meter with Pt-sensors.

For the measurements, proper sensor contact with the growth medium was needed. For matric potential measurement, appropriate shape and material of the tensiometer tips should be selected for different measurement purposes. The determination of oxygen diffusion rate is based on single, non-continuous measurements. The ODR-measurement required special care with the insertion and handling of the electrodes and selection of applied voltage. The ODR-measurement of a coarse peat medium was applicable only at matric potentials > -5 kPa. This measurement system was shown to be useful and suitable for accurate determination of thermal-, water- and aeration conditions of a growth medium under greenhouse conditions.

The PDF includes an abstract in Finnish.

  • Heiskanen, ORCID ID:E-mail:
  • Laitinen, ORCID ID:E-mail:
article id 5469, category Article
Risto Heikkilä, Kari Löyttyniemi. (1992). Growth response of young Scots pines to artificial shoot breaking simulating moose damage. Silva Fennica vol. 26 no. 1 article id 5469. https://doi.org/10.14214/sf.a15627

The main stem of young Scots pine (Pinus sylvestris L.) trees was cut off halfway along the current leading shoot and the two previous years’ leading shoots to simulate moose (Alces alces) damage. Trees of the same size were chosen as controls before treatments. The experiment was inspected ten years after artificial stem breakage. Removing the current leading shoot and the second shoot did not essentially affect the height and diameter growth of the trees. Removal down to the third shoot reduced the height as well as diameter growth. The average loss in growth was equivalent to less than one year’s growth. When the stem was cut off at the second or third shoot, stem crookedness and the presence of knots resulted in stem defects that will subsequently reduce the sawtimber quality. A high proportion of the stem defects will obviously still be visible at the first thinning cutting. Removing injured trees as pulpwood and pruning the remaining parts of cut stems evidently improves the quality of pine stand with moose damage.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Löyttyniemi, ORCID ID:E-mail:
article id 5469, category Article
Risto Heikkilä, Kari Löyttyniemi. (1992). Growth response of young Scots pines to artificial shoot breaking simulating moose damage. Silva Fennica vol. 26 no. 1 article id 5469. https://doi.org/10.14214/sf.a15627

The main stem of young Scots pine (Pinus sylvestris L.) trees was cut off halfway along the current leading shoot and the two previous years’ leading shoots to simulate moose (Alces alces) damage. Trees of the same size were chosen as controls before treatments. The experiment was inspected ten years after artificial stem breakage. Removing the current leading shoot and the second shoot did not essentially affect the height and diameter growth of the trees. Removal down to the third shoot reduced the height as well as diameter growth. The average loss in growth was equivalent to less than one year’s growth. When the stem was cut off at the second or third shoot, stem crookedness and the presence of knots resulted in stem defects that will subsequently reduce the sawtimber quality. A high proportion of the stem defects will obviously still be visible at the first thinning cutting. Removing injured trees as pulpwood and pruning the remaining parts of cut stems evidently improves the quality of pine stand with moose damage.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Löyttyniemi, ORCID ID:E-mail:
article id 7086, category Article
P. Kokkonen. (1923). Beobachtungen über das Wurzelsystem der Kiefer im Moorböden. Acta Forestalia Fennica vol. 25 no. 11 article id 7086. https://doi.org/10.14214/aff.7086
English title: Observations on the root system of pine on marshy soils.
English keywords: peatlands; root system; root growth; pine

The data has been collected during 1919 and 1920 in different region of Finland. The studied peatlands varied from fuscum pine swamps to pine swamps and partly to better sedge pine swamps.

The study presents five different forms of root systems. The root growth of pine on peatlands seems to vary strongly from the root form on mineral soils. On the peatlands, where the ground water near to soil cover is, can the roots grow only near the soil surface where the conditions are suitable. For the pine typical tap root is in most cases absent or grows along the soil surface. Also the frost heaving, snow and characteristics of peat affect the root system.   

  • Kokkonen, ORCID ID:E-mail:
article id 5462, category Article
Wladyslaw Chalupka. (1991). Usefulness of hormonal stimulation in the production of genetically improved seeds. Silva Fennica vol. 25 no. 4 article id 5462. https://doi.org/10.14214/sf.a15620

Application of growth regulators, primarily gibberellins, has become an efficient method of flowering regulation in many coniferous forest trees. In this paper some results are discussed with respect to various genetic processes in seed orchards. It is concluded that there are still several unsolved problems in the regulation of flowering in forest seed orchards. These problems are related to different genetic processes occurring in the seed orchards and they should be taken into account in endeavouring to produce genetically improved seeds. 

  • Chalupka, ORCID ID:E-mail:
article id 5450, category Article
Bo Långström, Claes Hellqvist. (1991). Shoot damage and growth losses following three years of Tomicus-attacks in Scots pine stands close to a timber storage site. Silva Fennica vol. 25 no. 3 article id 5450. https://doi.org/10.14214/sf.a15604

Shoot losses due to maturation feeding by pine shoot beetles (Tomicus piniperda (L.) and T. minor (Hart.), Col., Scolytidae) and subsequent growth losses were studied in Scots pine (Pinus sylvestris L.) stands growing at different distances from a timber yard, where pine timber was stored during the years 1982–84. In autumn 1985, pine trees were felled at 20, 40, 80, 500 and 1,500 m distance from the timber yard, five trees in each distance class. Trees were analysed for beetle attack, needle biomass and growth. In autumn 1988, increment cores were taken from 20 trees in each distance class.

In 1985, different damage estimates showed that beetle damage was more than 10-fold in the crowns of pine trees growing close to the timber yard as compared to less damaged trees in greater distance. Crude needle biomass estimates indicated that the trees attacked most had lost more than half of the total foliage. Following three years of attack, basal area growth decreased for 2–3 years and recovered during the subsequent 3 years, the total period of loss thus being 5–6 years. The loss in volume growth during 1983–85 was ca. 70, 40, 20 and 10% at 20, 40, 80 and 500 m distance from the beetle source, respectively, compared to the stand at 1,500. Growth losses did not occur until the number of beetle-attacks, ”pegs”, exceeded ca. 200 per tree. The highest observed growth losses occurred in trees with more than 1,000 pegs per tree.

The PDF includes an abstract in Finnish

  • Långström, ORCID ID:E-mail:
  • Hellqvist, ORCID ID:E-mail:
article id 5449, category Article
Timo Pukkala, Taneli Kolström. (1991). Effect of spatial pattern of trees on the growth of Norway spruce stand. Silva Fennica vol. 25 no. 3 article id 5449. https://doi.org/10.14214/sf.a15603

The simulation model consists of a method to generate theoretical Norway spruce (Picea abies (L.) H. Karst.) stands, and a spatial growth model to predict the growth of these stands. The stand generation procedure first predicts the tree diameters from a few stand characteristics and from tree locations. Tree age and height are predicted using spatial models. Spatial growth models were made for both diameter growth and basal area growth. Past growth was used as a predictor in one pair of models and omitted in another pair. The stand generation method and the growth models were utilized in studying the effect of tree arrangement and thinning method on the growth of a Norway spruce stand.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
article id 7077, category Article
Aimo Kaarlo Cajander. (1923). Über das Verhältnis zwischen Waldzuwachs und Holzverbrauch in Finnland. Acta Forestalia Fennica vol. 25 no. 2 article id 7077. https://doi.org/10.14214/aff.7077
English title: On the relation between forest growth and timber consumption in Finland.

The article is a presentation given by the author on occasion of visit from Austrian timber industry and foresters (August 17th 1923), and again for the German visitors (August 20th 1923) in Punkaharju, Finland. The speech deals with the question of the overuse of Finnish forest compared to their growth. The developments of slash-and-burn-culture and forest inventories are described. The results of the inventories show, though still in preliminary state, that there is no nationwide overuse in total, though there are some locations where the felling are bigger than growth. 

  • Cajander, ORCID ID:E-mail:
article id 5445, category Article
Taneli Kolström. (1991). Kuusen kylvö- ja istutuskoe viljavilla kivennäismailla Pohjois-Karjalassa. Silva Fennica vol. 25 no. 2 article id 5445. https://doi.org/10.14214/sf.a15599
English title: Results from the sowing and planting experiment of Norway spruce (Picea abies) on fertile sites in North Karelia, Finland.

Different methods of sowing and planting of Norway spruce (Picea abies (L.) H. Karst.) were compared on fertile sites in North Karelia (62°20’N, 29°35’E, 85–120 m a.s.l.). The planting material were 4-year-old bare-rooted transplants, 2-year-old bare-rooted seedlings, and 2-year-old containerized seedlings raised in plastic greenhouse. The sowing methods were band sowing and shelter sowing. Ground vegetation was controlled during the first growing season mechanically or chemically, or the control was omitted totally.

Planting of spruce gave better results than sowing. After eight growing seasons there were sowed seedlings left in 30% of the sowing pots. The average height of them was 35 cm. Seedling survival was best with large bare-rooted transplants (91%). Survival of containerized seedlings was 79% and of small bare-rooted transplants 71%. The average height of large bare-rooted transplants was 131 cm, of containerized seedlings 86 cm and small bare-rooted seedlings 68 cm.

Sowing is not an advisable method for regeneration of spruce due to the small survival rate and slow initial development when ground vegetation is controlled only once. Also 2-year-old seedlings gave a satisfactory result in regeneration. Seedlings raised in greenhouse were more sensitive to frost damage than seedlings grown on open ground.

The PDF includes an abstract in English.

  • Kolström, ORCID ID:E-mail:
article id 5430, category Article
Winai Sirikul, Markku Kanninen. (1990). Shoot growth and its clonal variation in Pinus kesiya. Silva Fennica vol. 24 no. 3 article id 5430. https://doi.org/10.14214/sf.a15584

Shoot elongation of Pinus kesiya Royle ex Gordon was studied using 2-year old grafts in a clonal seed orchard of the Pine Improvement Centre, located at the Huey Bong Experimental Station near Chiangmai, Thailand (19° 17’ N, 99° 15’ E, 900 m a.s.l.).

The seed orchard had a completely randomized block design with 30 blocks and 80 single-tree plots (clones) in each block. Eleven clones in four blocks were selected out of the total of 80 grafts (clones). From each graft, three lateral branches at the height of 1.6 m from the ground level were selected. Thus, total of 109 branches were measured. Shoot length of branches was measured between July 3, 1983 and March 11, 1984 at approximately bi-weekly intervals. Method of classical growth analysis were used in describing the shoot growth.

The annual shoot growth pattern of P. kesiya exhibited two consecutive sigmoid growth curves, i.e. it consisted of two flushes of shoot elongation, both formed by free growth. Thus, the pattern of shoot growth resembled the caribaea pattern. However, the annual shoot was composed of summer and winter shoots. These could be distinguished from each other by the reproductive organs, which always occur on winter shoot. The shoot contributed 61% of the total annual shoot length.

There were significant differences in the pattern of shoot elongation between the studied clones, which may reflect differences in the adaptation to different environmental conditions.

The PDF includes an abstract in Finnish.

  • Sirikul, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 5409, category Article
Jukka Lippu, Pasi Puttonen. (1990). Istutustaimen juuriston alkukehitys kasvupaikalla. Silva Fennica vol. 24 no. 1 article id 5409. https://doi.org/10.14214/sf.a15561
English title: The early development of seedling roots at the planting site: A literature review.

The structure and functional responses of roots in planted seedlings when acclimatizing at the planting site are reviewed. A wide range of methods for classifying roots has been employed, and the terminology used is not uniform. Roots can be classified by their morphology, origin, and function. The temporal and spatial variation of soil temperature, moisture, structure, and concentration of nutrients are among the most important properties to which root systems acclimatize. In order to reliably describe the function of the root system, several parameters usually have to be measured. Studies on the root-soil interface have indicated that roots are not necessarily in continuous contact with soil. The control mechanism of root growth is inadequately known and theoretically formulated. Generally, only the mass needed for water and nutrient uptake has been allocated to the roots. However, the amount of photosynthates allocated to the roots is high. Acclimatization of seedlings out at the planting site is a complicated process which is influenced by the growing conditions at both the nursery and at the site. The function, distribution and structure of roots are controlled by the environment in a way similar to the shoot, but the control mechanism is imperfectly known.

The PDF includes an abstract in English.

  • Lippu, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5388, category Article
Martti Varmola. (1989). Männyn istutustaimikoiden lustonleveysmalli. Silva Fennica vol. 23 no. 4 article id 5388. https://doi.org/10.14214/sf.a15546
English title: A model for ring width of planted Scots pine.

Ring width at breast height is presented as a function of stem radius at breast height, the ratio between the diameter of a tree and the basal area median diameter, site index, and density of stand. By means of a conversion model ring width at stump height can be estimated as a function of ring width at breast height.

According to previous studies substantially better wood quality can be expected if mean width near the pith at stump height decreases from 3 to 2 mm. According to the present study only on the poorest sites suitable for Scots pine (Pinus sylvestris L.) planting (poor Vaccinium type) the ring width is less than 3 mm at stump height even in the thickest trees. On more fertile sites a substantial increase in the recommended planting density is required, if the mean ring width is aimed to be less than 3 mm. On the best sites it is impossible to reach mean ring width of less than 2 mm, when the density is less than 4,000 stems/ha. Only the thinnest trees on the poorest sites can have a mean ring width less than 2mm.

The PDF includes an abstract in English.

  • Varmola, ORCID ID:E-mail:
article id 5384, category Article
Raija-Liisa Petäistö. (1989). Syyskoulinnan ajankohdan vaikutus männyn taimien kuiva-ainepitoisuuteen, neulasten pitolujuuteen ja juurten uudistumiskykyyn. Silva Fennica vol. 23 no. 3 article id 5384. https://doi.org/10.14214/sf.a15541
English title: The influence of autumn transplanting date on the dry matter content, needle retention values and root regeneration of Scots pine (Pinus sylvestris) seedlings.

The experiment was performed in 1982–85 at the forest tree nursery in Suonenjoki, Central Finland. There were four to five transplanting dates ranging from the beginning of August to the end of September. The dry matter content, root regeneration and needle retention value of Scots pine (Pinus sylvestris L.) seedlings were examined. Development of the needle retention value in autumn was followed in nurseries at Suonenjoki, Rantasalmi, Mäntyharju and Taavetti in 1982.

Root regeneration was usually the worse, the later the seedlings were transplanted in the autumn. The dry matter content was generally lowest in the seedlings transplanted later in the autumn, and also to some extent in the seedlings transplanted at the beginning of August. The needle retention value increased as autumn advanced. Early transplanting in autumn had an adverse effect on the development of needle retention, and the values were highest in the seedlings transplanted later in the autumn.

The PDF includes an abstract English.

  • Petäistö, ORCID ID:E-mail:
article id 5383, category Article
Pasi Miettinen, Aino Smolander. (1989). Growth requirements of Frankia strains isolated from Casuarina equisetifolia, and the influence of the isolates on the growth of the host plant. Silva Fennica vol. 23 no. 3 article id 5383. https://doi.org/10.14214/sf.a15540

Frankia was isolated from the root nodules of Casuarina equisetifolia L. seedlings, grown in a growth chamber, after inoculation with soil originating from an old east Kenyan casuarina forest. Optimum pH for the growth of the two isolates ranged from 6.4 to 6.9. The optimum temperature for their growth was 32°C. The growth of these cultures ceased at NaCl concentration above 2%. The influence of the isolates on the growth of the host plant was determined in a growth chamber experiment in which an American Frankia strain (HFPCc13) was used as a reference. The biomass of the inoculated seedlings was 2.4–4.1 fold those of the non-inoculated control seedlings at the end of the 7-month experiment.

The PDF includes an abstract in Finnish.

  • Miettinen, ORCID ID:E-mail:
  • Smolander, 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 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 5363, category Article
Veli Pohjonen, Timo Pukkala. (1988). Profitability of establishing Eucalyptus globulus plantations in the Central Highlands of Ethiopia. Silva Fennica vol. 22 no. 4 article id 5363. https://doi.org/10.14214/sf.a15520

The economic analysis is based on computer simulations which covered a seedling rotation and three successive coppice rotations. Calculations were carried out for the four site productivity classes in Eucalyptus globulus plantations. The rotation length that maximized the land expectation value is 12–20 years for seedling rotation and 8–16 years for coppice rotations with discounting rates 2–8%. The mean wood production is over 40 m3/ha/a in the best site class and about 10 m3/ha/a in the poorest class with rotation lengths ranging from 10 to over 20 years. Thinnings increase the wood production and land expectation value by a few percentage points. In areas suitable to Eucalyptus globulus growth, the land expectation value is considerably higher in forestry than in agriculture, except in very poor areas or with very high rate of interest.

The PDF includes an abstract in Finnish.

  • Pohjonen, ORCID ID:E-mail:
  • Pukkala, ORCID ID:E-mail:
article id 5360, category Article
Risto Rikala, Pasi Puttonen. (1988). Maan lämpötilan vaikutus kuivuusrasitukseen perustuvassa taimien laatutestissä. Silva Fennica vol. 22 no. 4 article id 5360. https://doi.org/10.14214/sf.a15517
English title: Effect of soil temperature in drought exposure-based test of seedling quality.

The effect of root exposure on the shoot and root development of Pinus sylvestris (L.) seedlings was studied at two soil temperatures. Roots of bare-rooted three-year-old seedlings were exposed to the temperature of 32°C at relative humidity of 50–40% for 85, 155 and 270 minutes which corresponds to accumulated water pressure deficit of 24, 47 and 91 mbar·h, respectively. Thereafter, seedlings were grown for 65 days at the soil temperatures of 12 and 23°C. Drought exposures inhibited new root initiation, delayed shoot elongation, and reduced shoot and needle growth. The stronger the exposure the larger the proportion of needles from the lower part of current shoot that remained undeveloped. Low soil temperature increased the effect of exposures so that needle elongation and initiation of new root tips of seedlings in cold soil with the longest exposure were inhibited totally. Root growth assessments made in warm soil may overestimate the acclimation potential of planted seedlings.

The PDF includes an abstract in English.

  • Rikala, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5360, category Article
Risto Rikala, Pasi Puttonen. (1988). Maan lämpötilan vaikutus kuivuusrasitukseen perustuvassa taimien laatutestissä. Silva Fennica vol. 22 no. 4 article id 5360. https://doi.org/10.14214/sf.a15517
English title: Effect of soil temperature in drought exposure-based test of seedling quality.

The effect of root exposure on the shoot and root development of Pinus sylvestris (L.) seedlings was studied at two soil temperatures. Roots of bare-rooted three-year-old seedlings were exposed to the temperature of 32°C at relative humidity of 50–40% for 85, 155 and 270 minutes which corresponds to accumulated water pressure deficit of 24, 47 and 91 mbar·h, respectively. Thereafter, seedlings were grown for 65 days at the soil temperatures of 12 and 23°C. Drought exposures inhibited new root initiation, delayed shoot elongation, and reduced shoot and needle growth. The stronger the exposure the larger the proportion of needles from the lower part of current shoot that remained undeveloped. Low soil temperature increased the effect of exposures so that needle elongation and initiation of new root tips of seedlings in cold soil with the longest exposure were inhibited totally. Root growth assessments made in warm soil may overestimate the acclimation potential of planted seedlings.

The PDF includes an abstract in English.

  • Rikala, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5360, category Article
Risto Rikala, Pasi Puttonen. (1988). Maan lämpötilan vaikutus kuivuusrasitukseen perustuvassa taimien laatutestissä. Silva Fennica vol. 22 no. 4 article id 5360. https://doi.org/10.14214/sf.a15517
English title: Effect of soil temperature in drought exposure-based test of seedling quality.

The effect of root exposure on the shoot and root development of Pinus sylvestris (L.) seedlings was studied at two soil temperatures. Roots of bare-rooted three-year-old seedlings were exposed to the temperature of 32°C at relative humidity of 50–40% for 85, 155 and 270 minutes which corresponds to accumulated water pressure deficit of 24, 47 and 91 mbar·h, respectively. Thereafter, seedlings were grown for 65 days at the soil temperatures of 12 and 23°C. Drought exposures inhibited new root initiation, delayed shoot elongation, and reduced shoot and needle growth. The stronger the exposure the larger the proportion of needles from the lower part of current shoot that remained undeveloped. Low soil temperature increased the effect of exposures so that needle elongation and initiation of new root tips of seedlings in cold soil with the longest exposure were inhibited totally. Root growth assessments made in warm soil may overestimate the acclimation potential of planted seedlings.

The PDF includes an abstract in English.

  • Rikala, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5359, category Article
Olli Haltia, Markku Simula. (1988). Linkages of forestry and forest industry in the Finnish economy. Silva Fennica vol. 22 no. 4 article id 5359. https://doi.org/10.14214/sf.a15516

The purpose was to analyse the importance of forestry and forest industry in the Finnish economic development since the 1950’s, and to find out how the sector has contributed to the growth of the national economy through other sectors. Data were derived from the input-output tables of 1959, 1970 and 1980. Information provided by Hirschmanian linkages was expanded by taking into account e.g. induced, consumption, final demand and absorption linkages. The linkages of forestry and forest industry had multiplied during the study period. Both final demand linkages and intermediate product linkages were significant. The sector’s contribution to the development of metal and machinery and equipment industries as well as that of energy/water supply was significant. Integration with most other sectors has increased. Indirect production coefficients of forestry and forest industry were larger than on average in manufacturing. Because of labour productivity growth, production and employment coefficients were different.

The PDF includes an abstract in Finnish.

  • Haltia, ORCID ID:E-mail:
  • Simula, ORCID ID:E-mail:
article id 5353, category Article
Øystein Johnsen, Inger Apeland. (1988). Screening early autumn frost hardiness among progenies from Norway spruce seed orchards. Silva Fennica vol. 22 no. 3 article id 5353. https://doi.org/10.14214/sf.a15510

Nursery grown Norway spruce (Picea abies (L.) H. Karst.) seedlings from 12 different seed orchards were tested for early autumn frost hardiness using artificial freezing tests. Seed orchards containing grafted parent clones originating from high altitudes produced seedlings showing higher damage than commercial control seed lots of the commercial controls. A seed orchard containing both German and Norwegian clones produced seedlings showing high damage. The correlation between bud-set and frost damage was high at the provenance level, but lower at the half- and full-sib-levels. Families with good growth capacity in progeny field tests showed large between-family variation in frost damage in the artificial freezing tests. This indicates the possibility to combine high growth rate with acceptable autumn frost hardiness in the selection of parent trees.

The PDF includes an abstract in Finnish.

  • Johnsen, ORCID ID:E-mail:
  • Apeland, ORCID ID:E-mail:
article id 5338, category Article
Timo Pukkala. (1988). Effect of spatial distribution of trees on the volume increment of a young Scots pine stand. Silva Fennica vol. 22 no. 1 article id 5338. https://doi.org/10.14214/sf.a15495

The effect of grouping on 5-year old volume increment was studied by a simulation technique using spatial growth models estimated in Scots pine (Pinus sylvestris L.) stands in the phase of the first commercial thinning. A total of 24 model stands were regenerated by applying 12 spatial processes for two different diameter distributions. In addition to model stands, 6 different thinnings were simulated in two real stands. The clustering of trees was described with Fisher’s grouping index and by estimating the relative interception of diffuse radiation. In model stands with constant diameter distribution the correlation between the grouping index and volume increment ranged from -0.81 to -0.91. The correlation between volume increment and interception was 0.81–0.83 with one diameter distribution and 0.70 if both distributions were combined. In one thinned stand the correlation between the growth estimate and grouping index varied between -0.33 and 0.76. The correlation between interception and growth was about 0.30 in one stand and 0.72 if both stands were combined. Small irregularities do not decrease the volume production of a young Scots pine stand, but if the clustering is considerable or there are reasonably wide harvest strips, growth will be reduced by 10–20%.

The PDF includes a summary in Finnish.

  • Pukkala, ORCID ID:E-mail:
article id 5312, category Article
Timo Pukkala. (1987). Siementuotannon vaikutus kuusen ja männyn vuotuiseen kasvuun. Silva Fennica vol. 21 no. 2 article id 5312. https://doi.org/10.14214/sf.a15469
English title: Effect of seed production on the annual growth of Picea abies and Pinus sylvestris.

The study material consisted of 13 rather old Norway spruce (Picea abies (L.) H. Karst.) and 17 Scots pine (Pinus sylvestris L.) stands located in different parts of Finland. In each stand the seed crops, radial growth and amount of latewood were measured during a period of about ten years. Seed production reduces the radial growth of spruce and pine in the year of seed maturing. In Southern and Central Finland also the proportion of latewood is reduced. Seed production accounts for about 14% of the variation in radial growth of a spruce stand growing in Lapland, and 27% in other parts of Finland. In pine stands the seed crop explains 19% of the variation in radial growth in Lapland, and only 7% in the rest of Finland. In spruce stands an average seed crop reduces radial growth by 14% in Lapland and 5% in the rest of the country. An abundant seed production causes a reduction of about 20%. In southern parts of Finland, the proportion of latewood is reduced by 5% in an average seed year and by 24% in a good seed year. In pine stands an average seed crop decreases the width of annual ring by 5%, and a good seed crop by 15%. Outside Lapland, also the proportion of latewood is reduced: in an average seed year by 5%, and in a good seed year by 16%. The reduction in volume growth of spruce stands due to an average seed crop was estimated to be about 10% in Lapland, and 6% in other parts of Finland. A prolific seed production causes a reduction of 20%. In old pine stands the reduction is 5% in an average seed year, and 15% in a good seed year.

The PDF includes an abstract in English.

  • Pukkala, 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 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 5254, category Article
Kristina Palmgren, Anna Saarsalmi, Assi Weber. (1985). Nitrogen fixation and biomass production in some alder clones. Silva Fennica vol. 19 no. 4 article id 5254. https://doi.org/10.14214/sf.a15433

In a greenhouse experiment that lasted for two years, nitrogenase activity, height growth and biomass production was compared in six clones of alder of which four were clones of Alnus incana and two A. incana x A. glutinos hybrids. In addition, the effect of a fertilizer nitrogen gradient was tested on one of the clones.

Clonal differences in height growth and nitrogenase activity were recorded at the end of the first growing season. The growth rhythm of some of the clones changed markedly during the second growing season but differences in nitrogenase activity between clones levelled out. Nitrogen fertilization suppressed nodulation during the first growing season, and also the following year the nitrogenase activity was significantly higher in alders grown without nitrogen supplement. Height growth and total biomass production was also depressed at rather low nitrogen levels.

The PDF includes a summary in Finnish.

  • Palmgren, ORCID ID:E-mail:
  • Saarsalmi, ORCID ID:E-mail:
  • Weber, ORCID ID:E-mail:
article id 5253, category Article
Carl Johan Westman, Matti Leikola, Tapio Nummi. (1985). Käytännön typpilannoituksen vaikutus varttuneiden kuusikoiden kasvuun ja tuotokseen. Silva Fennica vol. 19 no. 4 article id 5253. https://doi.org/10.14214/sf.a15432
English title: The effect of large-scale nitrogen fertilization on growth and yield of mature Norway spruce stands in south-western Finland.

A method for calculation of the effect of practical fertilization for economic evaluation is presented and discussed. 55 Norway spruce (Picea abies (L.) H. Karst.) dominated stands on Oxalis-Myrtillus type sites were surveyed five to eight years after fertilization with nitrogen (90-170 kg/ha). The relationships between the fertilization effect and various stand characteristics were discussed. Fertilization increased the growth of the stands on an average by 2.2 m3/ha/year. In total the increase of tree growth during the research period was 17.5 m3/ha. This corresponds to a yield of 525–659 FIM/ha.

The PDF includes a summary in English.

  • Westman, ORCID ID:E-mail:
  • Leikola, ORCID ID:E-mail:
  • Nummi, ORCID ID:E-mail:
article id 5251, category Article
Markku Halinen. (1985). Männyn nuoruusvaiheen kasvunopeuden vaikutus sahatavaran laatuun. Silva Fennica vol. 19 no. 4 article id 5251. https://doi.org/10.14214/sf.a15430
English title: The effect of the growth rate of young Scots pine on the quality of sawn goods.

Totally 653 battens and planks sawn from butt logsof Scots pine (Pinus sylvestris L.) were chosen from 3 saw mills. The sawn goods were sorted according to normal sorting principles. In order to determine growth rate in the youth, the mean value of the average ring width was measured at the butt end at various distances from the pith.

The average ring width increased as the quality of the sawn goods decreased. The difference between the quality classes in ring width was measured between 2 and 4 cm from the pith. As the size of sawn goods, and, simultaneously, the log size increased, the average ring width increased in a given quality class. Research reinforced previous results, in which slow diameter growth of young Scots pines has been shown to reflect the good quality of sawn goods.

The PDF includes a summary in English.

  • Halinen, ORCID ID:E-mail:
article id 5251, category Article
Markku Halinen. (1985). Männyn nuoruusvaiheen kasvunopeuden vaikutus sahatavaran laatuun. Silva Fennica vol. 19 no. 4 article id 5251. https://doi.org/10.14214/sf.a15430
English title: The effect of the growth rate of young Scots pine on the quality of sawn goods.

Totally 653 battens and planks sawn from butt logsof Scots pine (Pinus sylvestris L.) were chosen from 3 saw mills. The sawn goods were sorted according to normal sorting principles. In order to determine growth rate in the youth, the mean value of the average ring width was measured at the butt end at various distances from the pith.

The average ring width increased as the quality of the sawn goods decreased. The difference between the quality classes in ring width was measured between 2 and 4 cm from the pith. As the size of sawn goods, and, simultaneously, the log size increased, the average ring width increased in a given quality class. Research reinforced previous results, in which slow diameter growth of young Scots pines has been shown to reflect the good quality of sawn goods.

The PDF includes a summary in English.

  • Halinen, ORCID ID:E-mail:
article id 5249, category Article
Jari Parviainen. (1985). Istuttamalla perustetun nuoren männikön, kuusikon, siperianlehtikuusikon ja rauduskoivikon kasvu. Silva Fennica vol. 19 no. 4 article id 5249. https://doi.org/10.14214/sf.a15428
English title: Growth of young Scots pine, Norway spruce, siberian larch and silver birch plantations.

Early growth of four different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Larix sibirica Ledeb and Betula pendula Roth) 16–23 years after planting were compared in a field experiment of 16 square plots established on a stony, grove-like upland (Oxalis-Myrtillus forest type) in Southern Finland. This study gives additional results to the publication Folia Forestalia 386/1979.

At this early stage, the growth of the spruce stand was clearly slower than that of the other species for all parameters to be measured (height, diameter, and volume growth). Height growth was most rapid in the silver birch stand and diameter growth in the larch stand. No clear differences were found in the mean volume of the 100 thickest trees in the stand between the larch and silver birch.

The PDF includes a summary in English.

  • Parviainen, ORCID ID:E-mail:
article id 5249, category Article
Jari Parviainen. (1985). Istuttamalla perustetun nuoren männikön, kuusikon, siperianlehtikuusikon ja rauduskoivikon kasvu. Silva Fennica vol. 19 no. 4 article id 5249. https://doi.org/10.14214/sf.a15428
English title: Growth of young Scots pine, Norway spruce, siberian larch and silver birch plantations.

Early growth of four different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Larix sibirica Ledeb and Betula pendula Roth) 16–23 years after planting were compared in a field experiment of 16 square plots established on a stony, grove-like upland (Oxalis-Myrtillus forest type) in Southern Finland. This study gives additional results to the publication Folia Forestalia 386/1979.

At this early stage, the growth of the spruce stand was clearly slower than that of the other species for all parameters to be measured (height, diameter, and volume growth). Height growth was most rapid in the silver birch stand and diameter growth in the larch stand. No clear differences were found in the mean volume of the 100 thickest trees in the stand between the larch and silver birch.

The PDF includes a summary in English.

  • Parviainen, ORCID ID:E-mail:
article id 5249, category Article
Jari Parviainen. (1985). Istuttamalla perustetun nuoren männikön, kuusikon, siperianlehtikuusikon ja rauduskoivikon kasvu. Silva Fennica vol. 19 no. 4 article id 5249. https://doi.org/10.14214/sf.a15428
English title: Growth of young Scots pine, Norway spruce, siberian larch and silver birch plantations.

Early growth of four different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Larix sibirica Ledeb and Betula pendula Roth) 16–23 years after planting were compared in a field experiment of 16 square plots established on a stony, grove-like upland (Oxalis-Myrtillus forest type) in Southern Finland. This study gives additional results to the publication Folia Forestalia 386/1979.

At this early stage, the growth of the spruce stand was clearly slower than that of the other species for all parameters to be measured (height, diameter, and volume growth). Height growth was most rapid in the silver birch stand and diameter growth in the larch stand. No clear differences were found in the mean volume of the 100 thickest trees in the stand between the larch and silver birch.

The PDF includes a summary in English.

  • Parviainen, ORCID ID:E-mail:
article id 5238, category Article
Matti Kärkkäinen. (1985). Suomalaisen kuusen puuaineen vertailua Keski-Euroopassa kasvaneiden kuusi- ja jalokuusilajien puuaineeseen. Silva Fennica vol. 19 no. 2 article id 5238. https://doi.org/10.14214/sf.a15417
English title: Norway spruce wood grown in Finland compared with spruce and fir wood grown in Central Europe.

The aim of this literature review was to compare Finnish Norway spruce (Picea abies (L.) H. Karst.) sawn goods to Central European spruce sawn goods which contain fir in some amount. However, it was found that no statistically valid comparisons have been made. Therefore, conclusions have been based mainly on the relationship between various properties and growth rate. According to this analysis, most properties of Finnish spruce are better, although small in practice.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5237, category Article
Leo Heikurainen, Jukka Laine. (1985). Duration of the height growth response of young pine stands to NPK-fertilization on oligotrophic pine bogs in Finland. Silva Fennica vol. 19 no. 2 article id 5237. https://doi.org/10.14214/sf.a15416

This is the latest report in a series of publications from an on-going investigation which is concerned with the influence of different fertilization treatments and ditch spacings on the growth of Scots pine (Pinus sylvestris L.) seedlings and transplants growing on nutrient drained poor bogs in different parts of Finland. This paper concentrates on duration of the growth response to NPK-fertilization on the experimental plots. The experiment was established and the treatments performed in 1965–66.

The results show that climate, expressed as effective temperature sum (dd°C, threshold +5°C) has a clear influence on the duration of the fertilization effect. In Southern Finland (>1,200 dd°C), the duration was at least 15 years. In Central Finland (1,200–1,000 dd°C), it appears to be almost 10 years, and in Northern Finland (<1,000 dd°C), slightly shorter. The amount of fertilizer applied clearly influenced the duration of the fertilization effect. The dosage of 500 kg/ha (N 14, P 7.8, K 8.3 per cent) had, on average, a shorter duration than the greater dosages of 1,000 and 1,500 kg/ha. However, there was no clear difference between the latter two dosages.

The PDF includes a summary in Finnish.

  • Heikurainen, ORCID ID:E-mail:
  • Laine, 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 5208, category Article
Matti Kärkkäinen. (1984). Effect of tree social status on basic density of Norway spruce. Silva Fennica vol. 18 no. 2 article id 5208. https://doi.org/10.14214/sf.a15387

The effect of growth rate on wood basic density in even-age Norway spruce (Picea abies (L.) H. Karst.) plantations was studied on the basis of samples collected from 53 stands; 30 trees were sampled in each stand. The prediction of basic density with the help of growth rate and some other tree characteristics could be improved if the social status of the tree was taken into account. Within a stand, the smaller trees had a lower density, while taller trees had a higher density than they should have had on the basis of growth rate alone.

The PDF includes a summary in Finnish.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5199, category Article
Pekka Saranpää. (1983). Puuaineen tiheyden ja vuosiluston leveyden vaikutus kuusen iskutaivutuslujuuteen Etelä- ja Pohjois-Suomessa. Silva Fennica vol. 17 no. 4 article id 5199. https://doi.org/10.14214/sf.a15182
English title: The influence of basic density and growth ring width on the impact strength of Norway spruce wood from Southern and Northern Finland.

Basic density and absorbed energy in impact bending were measured for 500 Norway spruce (Picea abies (L.) H. Karst.) samples from Northern and Southern Finland. Statistical analysis showed that the relationship between impact strength and basic density was significant and regression analysis showed that it was linear.

Furthermore, with constant density, the impact strength was higher in Northern than in Southern Finland. This was due to growth ring width: i.e. when density was kept constant the impact strength increased with decreasing growth ring width. In addition, when the growth ring width was kept constant, the basic density of wood was higher in Southern Finland than in Northern Finland.

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  • Saranpää, ORCID ID:E-mail:
article id 5198, category Article
Leo Heikurainen, Jukka Laine, Jarmo Lepola. (1983). Lannoitus- ja sarkaleveyskokeita karujen rämeiden uudistamisessa ja taimikoiden kasvatuksessa. Silva Fennica vol. 17 no. 4 article id 5198. https://doi.org/10.14214/sf.a15181
English title: Fertilization and ditch spacing experiments concerned with regeneration and growth of young Scots pine stands on nutrient poor pine bogs.

The effects of variations in the intensity of drainage and NPK fertilization on the natural regeneration and planting results and the subsequent development of seedling stands under various climatic conditions on drained nutrient poor pine bogs was investigated in a 16-year-old study.

Comparison of height development of Scots pine (Pinus sylvestris L.) stands on drained peatlands to that of pine stands growing in mineral soil sites show that in Southern Finland the most efficient forest improvement measures (10 m ditch spacing and 1,000 kg/ha NPK-fertilization) resulted in growth that corresponds a to a height index of a stand in a Vaccinium type site. Less efficient treatment (30 m ditch spacing and no fertilizer) resulted in growth corresponding the development of young stand in a Calluna type site. In Northern Finland the effect of fertilization on height growth was almost negligible. This is possibly due to a decrease in the nitrogen mobilization from south to north of Finland. Thus, it seems evident that fertilization of young Scots pine stands on nutrient poor drained peatlands can be recommended only in the southern part of the country.

The effect of ditch spacing is same in the whole country. The narrower the spacing the better the height growth. In the south planted stands thrive better than naturally regenerated stands, but the situation is reversed in the north.

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  • Heikurainen, ORCID ID:E-mail:
  • Laine, ORCID ID:E-mail:
  • Lepola, ORCID ID:E-mail:
article id 5197, category Article
Kari Heliövaara, Erkki Annila, Eero Terho. (1983). Effect of nitrogen fertilization and insecticides on the population density of pine bark bug, Aradus cinnamomeus (Heteroptera, Aradidae). Silva Fennica vol. 17 no. 4 article id 5197. https://doi.org/10.14214/sf.a15180

The effect of nitrogen fertilization and two insecticides on the occurrence of the plant pine bark bug, Aradus cinnamomeus Panzer, was investigated in a young Scots pine (Pinus sylvestris L.) stand in Southern Finland. Three years after the treatment the bug density was lowest in the trees treated with lindane or dimethoate. However, in spite of the increasing height growth of the trees, they did not grow significantly faster than the control trees. Nitrogen fertilization increased both bug density and the height growth of the trees. Thus, the value of nitrogen fertilization against Aradus cinnamomeus remains obscure.

The PDF includes a summary in Finnish.

  • Heliövaara, ORCID ID:E-mail:
  • Annila, ORCID ID:E-mail:
  • Terho, ORCID ID:E-mail:
article id 5181, category Article
Matti Kärkkäinen, Olle Dumell. (1983). Kuusipuun taivutuslujuuden riippuvuus tiheydestä ja vuosiluston leveydestä Etelä- ja Pohjois-Suomessa. Silva Fennica vol. 17 no. 2 article id 5181. https://doi.org/10.14214/sf.a15097
English title: Effect of basic density and growth ring width on the bending strength of Norway spruce wood from southern and northern Finland.

A population consisting of 450 Norway spruce (Picea abies (L.) H. Karst.) samples was gathered from northern and southern Finnish wood. The static bending strength was affected greatly by the density of the wood. However, keeping the density constant, the bending strength was higher in northern than in southern Finnish wood. The reason was the effect of the growth ring width.

The basic density was affected by the growth rate. Keeping the growth ring width constant, the basic density was over 5 kg/m3 lower in northern than in southern Finnish wood. This result supports the earlier findings on the effect of latitude.

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  • Kärkkäinen, ORCID ID:E-mail:
  • Dumell, ORCID ID:E-mail:
article id 7049, category Article
Erkki Laitakari. (1920). Tutkimuksia sääsuhteiden vaikutuksesta männyn pituus- ja paksuuskasvuun. Acta Forestalia Fennica vol. 17 no. 1 article id 7049. https://doi.org/10.14214/aff.7049
English title: Studies on the effect of weather conditions on diameter and height growth of Scots pine.
English keywords: diameter growth; height growth

The height and diameter growth measured from different Scots pine (Pinus sylvestris L.) stands in Southern Finland was compared with meteorological information. The height growth benefits from warm weather in late summer in the previous year, and especially from high temperatures in June. Precipitation or the temperature in the same year did not affect the height growth. Diameter growth benefits from high temperatures in the spring of the same year, especially in April. High precipitation in the spring has in some cases negative impact on the diameter growth. The different combinations of precipitation and temperature can have variable effects on tree growth. In the diameter growth was seen a periodicity that coincides with sunspots.

  • Laitakari, ORCID ID:E-mail:
article id 7049, category Article
Erkki Laitakari. (1920). Tutkimuksia sääsuhteiden vaikutuksesta männyn pituus- ja paksuuskasvuun. Acta Forestalia Fennica vol. 17 no. 1 article id 7049. https://doi.org/10.14214/aff.7049
English title: Studies on the effect of weather conditions on diameter and height growth of Scots pine.
English keywords: diameter growth; height growth

The height and diameter growth measured from different Scots pine (Pinus sylvestris L.) stands in Southern Finland was compared with meteorological information. The height growth benefits from warm weather in late summer in the previous year, and especially from high temperatures in June. Precipitation or the temperature in the same year did not affect the height growth. Diameter growth benefits from high temperatures in the spring of the same year, especially in April. High precipitation in the spring has in some cases negative impact on the diameter growth. The different combinations of precipitation and temperature can have variable effects on tree growth. In the diameter growth was seen a periodicity that coincides with sunspots.

  • Laitakari, ORCID ID:E-mail:
article id 5174, category Article
Tiina Heinonen. (1983). Haavikon lannoituskoe. Silva Fennica vol. 17 no. 1 article id 5174. https://doi.org/10.14214/sf.a15089
English title: A fertilization experiment in a Populus tremula stand.
Original keywords: haapa; lannoitus; typpi; pohjapinta-ala

The growth response of aspen (Populus tremula L.) to fertilization was studied in an experiment laid out in a naturally regenerated 35-year old stand on a previously burned-over land. The site was rather fertile. One-tree plot method was used. Applications of nitrogen (150 kg/ha as ammonium nitrate with lime), phosphorus (35 kg/ha as superphosphate), and potassium (66 kg/ha as potassium chloride) separately and in all possible combinations were used; the test included 11 replications. The growth reaction was measured as basal area growth excluding bark during 5 years. The factorial effects were computed using Yates method.

Potassium did not have any effect on basal growth of the trees. The response to phosphorus was also rather small. On the other hand, nitrogen appeared to have increased the basal area growth. The growth increase obtained with nitrogen alone was greater than when it was applied together with phosphorus and/or potassium.

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  • Heinonen, ORCID ID:E-mail:
article id 5169, category Article
Seppo Kellomäki, Pasi Puttonen, Heikki Tamminen, Carl Johan Westman. (1982). Effect of nitrogen fertilization on photosynthesis and growth in young Scots pines. Preliminary results. Silva Fennica vol. 16 no. 4 article id 5169. https://doi.org/10.14214/sf.a15084

Application of nitrogen at levels of 200, 400 and 600 kg ha-1 resulted in increases of 35, 18 and 12% in the photosynthetic rate in young Scots pine (Pinus sylvestris L.). The number of buds, degree of branching, and needle size were positively related to the amount of nitrogen applied. A 10–40% increase in the average needle area was found. A positive correlation was found between total photosynthesis and stem growth.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
  • Tamminen, ORCID ID:E-mail:
  • Westman, ORCID ID:E-mail:
article id 5168, category Article
Kari Heliövaara. (1982). The pine bark bug, Aradus cinnamomeus (Heteroptera, Aradidae) and the height growth rate of young Scots pines. Silva Fennica vol. 16 no. 4 article id 5168. https://doi.org/10.14214/sf.a15083

Relationships between densities of pine bark bug, Aradus cinnamomeus Panzer and the height growth of young Scots pine (Pinus sylvestris L.) were studied in several habitats, including a highly infested area in Southern Finland. The slower the growth of the pines was, the greater was the height up to which bugs were found. On the average, maximum bug density was noted at a height corresponding to a fifth of the height of the tree. In stands restocked by natural generation, the greatest bug densities were noted in pines about three metres high and over twenty years old. Bug densities in trees whose height growth had been decelerating for five years were twice those in trees whose growth was accelerating. A significant negative correlation was found between the bug density and the last-year height increment.

The PDF includes a summary in Finnish.

  • Heliövaara, ORCID ID:E-mail:
article id 5163, category Article
Leo Heikurainen. (1982). Ojitusalueiden taimistojen kehityksestä vuosina 1964-68 toimeenpannun suometsäkilpailun koealojen valossa. Silva Fennica vol. 16 no. 3 article id 5163. https://doi.org/10.14214/sf.a15078
English title: Development of seedling stands on drained peatlands in Southern Finland.

The aim of the paper was to describe the development of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedling stands on drained peatlands and to find out the principal factors influencing their growth. The material under survey consists of 180 sample plots distributed from southern coast of Finland to the Polar Circle.

The most important growth factors have been the accumulated temperature sum, site quality, drainage intensity and silvicultural condition, such as the density of the stand, the proportion of birch in the stand, and the amount of possible shelterwoods. The influence of these factors, and to some extent the influence of fertilizing, and the disturbing effects of some forest damages, such as frost, growth disturbances and elk damages were investigated. Comparisons of the development in the seedling stands on drained peatlands with the known development of seedling stands in mineral soils were made.

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  • Heikurainen, ORCID ID:E-mail:
article id 5155, category Article
K. M. Bhat, Matti Kärkkäinen. (1982). Wood anatomy and physical properties of the wood and bark in Betula nana growing in Finland. Silva Fennica vol. 16 no. 1 article id 5155. https://doi.org/10.14214/sf.a15070

Eighty Betula nana samples were collected from three swamp sites. In the butt portion of the dwarf shrub the average number of growth rings was 12 and the average diameter of the sprouts 6 mm. The basic density of wood was 457 kg/m3 and that of bark 544 kg/m3. The proportion of bark was 32–38% of weight or volume. The vessel elements and fibres were short and their diameter small. The proportion of vessels was 15%, that of fibres 70% and that of rays 15%.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5151, category Article
A. Mäkelä, P. Hari, Seppo Kellomäki. (1981). A model for the effect of air pollutants on forest growth. Silva Fennica vol. 15 no. 4 article id 5151. https://doi.org/10.14214/sf.a15378

A model was constructed, the aim of which was to predict growth under conditions where air pollutants are present. The model is based on photosynthesis and on the allocation of photosynthetic products for growth. It is assumed that air pollutants released during energy production mainly affect photosynthesis in two ways: 1) directly by injuring the photosynthetic mechanism, and 2) indirectly by leaching nutrients. The two ways were studied empirically in order to identify a sub-model for the photosynthesis of a plant exposed to air pollutants. 

The stand model will be applied to two purposes. The present stage of forests in Finland is compared with the simulated state based on the assumption that no pollutants are present. In addition, the decrease in forest yield under different conditions derived from predictions about long-range pollutant transport in Europe is analysed.

  • Mäkelä, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, 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 5137, category Article
V. C. Runeckles, K. T. Palmer, H. Trabelsi. (1981). Effects of field exposures to SO2 on Douglas fir, Agropyron spicatum and Lolium perenne. Silva Fennica vol. 15 no. 4 article id 5137. https://doi.org/10.14214/sf.a15364

Grasses Agropyron spicatum Pursh, Lolium perenne L. (S23) and 2-year old Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were exposed to low SO2 concentrations under field conditions for approximately eleven weeks. SO2 was released continuously via manifold delivery systems, and provided treatment mean concentrations of 0.007 (ambient air), 0.042, 0.106 and 0.198 ppm. The concentrations in each treatment were approximately log-normally distributed, with standard geometric deviations ranging from 2.58 to 3.24. In both grass species, 0.198 ppm SO2 caused substantial reduction of total growth. In L. perenne, this was largely the result of impaired root growth, whereas both shoot and root growth of A. spicatum were reduced. 0.106 ppm SO2 had no significant effect on A. spicatum growth, but reduced root growth of L. perenne. Growth of Douglas fir was reduced in each of the tree highest concentrations, with root growth being markedly diminished, particularly on trees which showed chlorotic and necrotic injury. However, in these trees the shoot and total leaf weights tended to increase at the highest SO2 concentrations, suggesting that in these plants injury to leaves stimulated further shoot growth at the expense of root development.

  • Runeckles, ORCID ID:E-mail:
  • Palmer, ORCID ID:E-mail:
  • Trabelsi, ORCID ID:E-mail:
article id 5137, category Article
V. C. Runeckles, K. T. Palmer, H. Trabelsi. (1981). Effects of field exposures to SO2 on Douglas fir, Agropyron spicatum and Lolium perenne. Silva Fennica vol. 15 no. 4 article id 5137. https://doi.org/10.14214/sf.a15364

Grasses Agropyron spicatum Pursh, Lolium perenne L. (S23) and 2-year old Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were exposed to low SO2 concentrations under field conditions for approximately eleven weeks. SO2 was released continuously via manifold delivery systems, and provided treatment mean concentrations of 0.007 (ambient air), 0.042, 0.106 and 0.198 ppm. The concentrations in each treatment were approximately log-normally distributed, with standard geometric deviations ranging from 2.58 to 3.24. In both grass species, 0.198 ppm SO2 caused substantial reduction of total growth. In L. perenne, this was largely the result of impaired root growth, whereas both shoot and root growth of A. spicatum were reduced. 0.106 ppm SO2 had no significant effect on A. spicatum growth, but reduced root growth of L. perenne. Growth of Douglas fir was reduced in each of the tree highest concentrations, with root growth being markedly diminished, particularly on trees which showed chlorotic and necrotic injury. However, in these trees the shoot and total leaf weights tended to increase at the highest SO2 concentrations, suggesting that in these plants injury to leaves stimulated further shoot growth at the expense of root development.

  • Runeckles, ORCID ID:E-mail:
  • Palmer, ORCID ID:E-mail:
  • Trabelsi, ORCID ID:E-mail:
article id 5129, category Article
Olavi Luukkanen. (1981). Effects of gibberellins GA4 and GA7 on flowering in Scots pine grafts. Silva Fennica vol. 15 no. 4 article id 5129. https://doi.org/10.14214/sf.a15186

Ethanolic sprays of GA4 or GA7 on 9-year old Scots pine (Pinus sylvestris L.) grafts, repeated four times during the shoot elongation period, resulted in a statistically significant increase in female flowering one year after the treatment. Of the two compounds, GA4 seemed to be somewhat more efficient, yielding 47 female strobili/100 shoots vs. 36 and 6 strobili/100 shoots in GA7 and control treatments respectively. The mixture of GA4 and GA7 compounds was also applied and seemed to have an effect intermediary to those of the pure compounds. However, due to the limited amounts of material, none of the differences between the gibberellins could be statistically confirmed. Male flowering frequencies were also too low to allow any firm conclusions, but the numerical results suggested that the purified gibberellins may promote male and female flowering in different ways.

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  • Luukkanen, 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 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 5128, category Article
Paavo J. Ollinmaa. (1981). Eräistä ojitetuilla soilla kasvaneen puun fysikaalisista ominaisuuksista. Silva Fennica vol. 15 no. 3 article id 5128. https://doi.org/10.14214/sf.a15069
English title: Physical properties of wood growing on drained swamps.

The objective of the investigation was to determine the differences between timber grown on a peatland before and after draining, in respect of compressive strength parallel to the grain, static bending strength and density. In addition, the characteristics of boundary zone between the wood formed before, and after the draining with wider growth rings was studied. 41 Scots pine (Pinus sylvestris L.) and 22 Norway spruce (Picea abies (L.) H. Karst.) trees were studied.

The compressive strength of pine usually decreased from the butt end upwards, but no trend was observed in spruce wood. In coniferous trees, wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior the draining. The density of pine as well as spruce increases as the width of the growth rings decrease up to a certain limit. The strength of the different kinds of wood seems to decrease from the butt end upwards.

In both species, the compressive strength parallel to the grain and the bending strength are lowest in such wood that contains exclusively wide-ringed wood formed subsequent to draining. Also, compressive and bending strength increase with decreasing width of the growth rings. The longitudinal shrinkage of compression wood in spruce was several times that of normal wood, and the bending strength was lower than that of normal wood particularly in spruce. The compressive strength parallel to the grain in dry condition was, however, higher than in normal wood both in pine and spruce.

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  • Ollinmaa, ORCID ID:E-mail:
article id 5125, category Article
Ilppo Greis, Seppo Kellomäki. (1981). Crown structure and stem growth of Norway spruce undergrowth under varying shading. Silva Fennica vol. 15 no. 3 article id 5125. https://doi.org/10.14214/sf.a15066

The crown structure and stem growth of Norway spruce (Picea abies (L.) H. Karst.) undergrowth was studied in relation to the prevailing light conditions and potential photosynthesis. Shading decreased the stem height growth more than the length increment of laterals, producing a plate-shaped crown in deep shade. Needles responded to shading by adopting a horizontal inclination in deep shade. The needles were wide and thin respectively in shade. In the open the needle cross-section was almost square. Stem radial growth and height growth were both affected by shading exhibiting a linear response to the prevailing light conditions and the potential photosynthesis. Light conditions under dominating trees were closely correlated with the basal area of the dominating trees.

The PDF includes a summary in Finnish.

  • Greis, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5125, category Article
Ilppo Greis, Seppo Kellomäki. (1981). Crown structure and stem growth of Norway spruce undergrowth under varying shading. Silva Fennica vol. 15 no. 3 article id 5125. https://doi.org/10.14214/sf.a15066

The crown structure and stem growth of Norway spruce (Picea abies (L.) H. Karst.) undergrowth was studied in relation to the prevailing light conditions and potential photosynthesis. Shading decreased the stem height growth more than the length increment of laterals, producing a plate-shaped crown in deep shade. Needles responded to shading by adopting a horizontal inclination in deep shade. The needles were wide and thin respectively in shade. In the open the needle cross-section was almost square. Stem radial growth and height growth were both affected by shading exhibiting a linear response to the prevailing light conditions and the potential photosynthesis. Light conditions under dominating trees were closely correlated with the basal area of the dominating trees.

The PDF includes a summary in Finnish.

  • Greis, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5123, category Article
Heljä-Sisko Katainen, Seppo Kellomäki. (1981). Happaman veden vaikutus männyn taimiin. Silva Fennica vol. 15 no. 3 article id 5123. https://doi.org/10.14214/sf.a15064
English title: Effect of foliar application of dilute sulphuric acid on Scots pine seedlings.

Needle damages, transpiration, photosynthesis and needle and stem height growth of Scots pine (Pinus sylvestris L.) seedlings treated with dilute sulphuric acid were studied. The acidity of the solution was pH 3. Application of a dilute solution of sulphuric acid equivalent to the normal amount of precipitation occurring during the growing season damaged the surface of two-year-old needles but not that of the current-year needles. A reduction in the photosynthetic rate of 10–30% was observed compared with the untreated seedlings. Transpiration of the seedlings was not affected by the treatment. Needle growth and stem height growth of the seedlings growing on a substrate representing poor sandy soil were reduced. Increased needle growth and stem height growth were characteristic for the seedlings growing on substrate representing fertile moraine.

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  • Katainen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5117, category Article
Päiviö Riihinen. (1981). Forestry and the timber economy in economic development. Silva Fennica vol. 15 no. 2 article id 5117. https://doi.org/10.14214/sf.a15058

The article deals with differences in economic growth in different countries and regions and with reasons for these differences. The central role in investments in economic growth and the mechanism of its differentiation are elucidated. The properties of forestry and the forest industries in equation or differentiating economic growth are considered. In the light of the theories of regional differentiation, the mere production of raw material in some region tends to increase differences in economic development if that raw material is processed in some other region – despite the fact that the level of income rises in both regions. It is therefore desirable that afforestation projects in the development countries are accompanied by the development of the forest industries.

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  • Riihinen, ORCID ID:E-mail:
article id 5111, category Article
Seppo Kellomäki. (1981). Effect of the within-stand light conditions on the share of stem, branch and needle growth in a twenty-year-old Scots pine stand. Silva Fennica vol. 15 no. 2 article id 5111. https://doi.org/10.14214/sf.a15052

The share of stem, branch and needle growth was dependent on the within-stand light regime in a young Scots pine (Pinus sylvestris L.) stand. The share of needle growth increased at the expense of stem and branch growth in poor light conditions. In good light condition the share of branch wood increased substantially. The share of stem wood growth was greatest in moderate shading, emphasizing the role of an adequate stand density for growing high-quality timber. The basic density of the stem wood was considerably greater in suppressed trees than in dominating trees. The differences were related to the illumination of the crown system.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
article id 5092, category Article
Seppo Kellomäki, Markku Kanninen. (1980). Eco-physiological studies on young Scots pine stands. IV. Silva Fennica vol. 14 no. 4 article id 5092. https://doi.org/10.14214/sf.a15033

Crown and stem growth of young Scots pines (Pinus sylvestris L.) were studied in relation to photosynthate supply and light condition in a stand. The magnitude of needle and bud formation, and radial and height growth were to a great extent dependent on the photosynthate supply. However, in shaded conditions the growth of each characteristics was greater than expected on the basis of photosynthate supply. In the stem system this was especially apparent for height growth. Consequently, height growth was favoured at the expense of radial growth in shaded conditions. It also appeared that the basic density of wood was negatively related to both tree position and photosynthate supply.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 5092, category Article
Seppo Kellomäki, Markku Kanninen. (1980). Eco-physiological studies on young Scots pine stands. IV. Silva Fennica vol. 14 no. 4 article id 5092. https://doi.org/10.14214/sf.a15033

Crown and stem growth of young Scots pines (Pinus sylvestris L.) were studied in relation to photosynthate supply and light condition in a stand. The magnitude of needle and bud formation, and radial and height growth were to a great extent dependent on the photosynthate supply. However, in shaded conditions the growth of each characteristics was greater than expected on the basis of photosynthate supply. In the stem system this was especially apparent for height growth. Consequently, height growth was favoured at the expense of radial growth in shaded conditions. It also appeared that the basic density of wood was negatively related to both tree position and photosynthate supply.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 5081, category Article
Reijo Jokinen. (1980). Metsälannoituksella saatavan kasvunlisäyksen arviointi. Silva Fennica vol. 14 no. 3 article id 5081. https://doi.org/10.14214/sf.a15022
English title: Estimation of growth response achieved through forest fertilization.

Dependence of the growth increase given by fertilization on different stand characteristics is examined in this article. The aim was to determine whether the volume growth increase can be accurately determined beforehand when fertilization is carried out on mineral soil sites at a dosage of 120 kg N/ha. The material consisted mostly on of mature stands ready for cutting, a total of 22 Scots pine (Pinus sylvestris L.) and 20 Norway spruce (Picea abies (L.) H. Karst.) stands. Increase in basal area, height quality class and basal area of the stand were found to best explain the increment and its increase in the regression equations calculated for different types of fertilizer and the control level.

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  • Jokinen, ORCID ID:E-mail:
article id 5070, category Article
Olavi Luukkanen, Stig Johansson. (1980). Flower induction by exogenous plant hormones in Scots pine and Norway spruce grafts. Silva Fennica vol. 14 no. 1 article id 5070. https://doi.org/10.14214/sf.a15011

The aim of the present study was to establish whether hormone treatments would promote flowering in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) grafts under Finnish conditions. Also, an attempt was made to test the efficiency of hormones as well as the variation in response among different clones. Six Scots pine and six Norway spruce clones were selected in each seed orchard based on their flowering intensity, and treated with growth hormones (GA, NAA) of different dosages by spraying. Flowering was observed one year after the treatments.

None of the treated or untreated spruce grafts flowered. However, poor flowering in the natural stands indicated that the environmental conditions during the previous years did not favour flowering. On the other hand, a distinct increase in flowering in Scots pine was observed as a result of spraying with hormone solutions. Treatments with gibberellin had a distinct promoting effect both on male and female flowering in the Scots pine grafts, although the responses varied between the different hormones or clones. The relative effect was generally stronger in male flowering.

The PDF includes a summary in Finnish.

  • Luukkanen, ORCID ID:E-mail:
  • Johansson, ORCID ID:E-mail:
article id 5069, category Article
Jouni Mikola. (1980). The effect of seed size and duration of growth on the height of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) provenances and progenies at the nursery stage. Silva Fennica vol. 14 no. 1 article id 5069. https://doi.org/10.14214/sf.a15010

In this paper the connection between seed weight and amount and duration of growth are studied at the progeny level within stands or climatically uniform areas, and at the provenance level within larger geographic areas. The material consists of materials of several experiments in the nursery of Maisala in Southern Finland in 1971–76. The origins of the plant material used in the different experiments ranged from progenies of individual Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies (L.) H. Karst.) trees to provenance selections covering almost the whole natural range of these species.

The effect of seed weight on plant height is strongest immediately after germination and subsequently decreases steadily, when the genetic growth properties of the plants themselves become effective. The effect is usually visible at least until the end of the 1st growing season. This relationship varies considerably depending on the material studied. The connections between the duration and the amount of height growth also proved to differ according to the nature of genetic variation. In wide selection of provenances, which show clear genetic differentiation in annual growth rhythm. The variation in the duration of growth accounts for most of the differences in total height growth. At the individual and family level or between provenances of a limited area, there seems to be no clear connection between the duration and the amount of growth. It seems that the duration of the annual growing period is a genetic property, which is not affected by seed weight.

The total height alone in 1-year old test material grown in a greenhouse had hardly any value in the forecasting of growth capacity. The growth differences were caused mainly by the variation in seed size and growth rate differences during the growing period.

The PDF includes a summary in Finnish.

  • Mikola, ORCID ID:E-mail:
article id 5069, category Article
Jouni Mikola. (1980). The effect of seed size and duration of growth on the height of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) provenances and progenies at the nursery stage. Silva Fennica vol. 14 no. 1 article id 5069. https://doi.org/10.14214/sf.a15010

In this paper the connection between seed weight and amount and duration of growth are studied at the progeny level within stands or climatically uniform areas, and at the provenance level within larger geographic areas. The material consists of materials of several experiments in the nursery of Maisala in Southern Finland in 1971–76. The origins of the plant material used in the different experiments ranged from progenies of individual Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies (L.) H. Karst.) trees to provenance selections covering almost the whole natural range of these species.

The effect of seed weight on plant height is strongest immediately after germination and subsequently decreases steadily, when the genetic growth properties of the plants themselves become effective. The effect is usually visible at least until the end of the 1st growing season. This relationship varies considerably depending on the material studied. The connections between the duration and the amount of height growth also proved to differ according to the nature of genetic variation. In wide selection of provenances, which show clear genetic differentiation in annual growth rhythm. The variation in the duration of growth accounts for most of the differences in total height growth. At the individual and family level or between provenances of a limited area, there seems to be no clear connection between the duration and the amount of growth. It seems that the duration of the annual growing period is a genetic property, which is not affected by seed weight.

The total height alone in 1-year old test material grown in a greenhouse had hardly any value in the forecasting of growth capacity. The growth differences were caused mainly by the variation in seed size and growth rate differences during the growing period.

The PDF includes a summary in Finnish.

  • Mikola, ORCID ID:E-mail:
article id 5056, category Article
Liisa Nylund, Antti Haapanen, Seppo Kellomäki, Markku Nylund. (1980). Radial growth of Scots pine and soil conditions at some camping sites in southern Finland. Silva Fennica vol. 14 no. 1 article id 5056. https://doi.org/10.14214/sf.a14997

Radial growth of Scots pine (Pinus sylvestris L.) was investigated in seven camping areas located in Southern Finland. Radial growth reduction of 20–40% were found. The magnitude of this reduction was related to the amount of damage in the trees, and the age of the trees. A loss of humus, exposure of the roots and soil compaction were associated with the use of area but not related to the reduction in growth.

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 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 5049, category Article
Pirkko Ilonen, Pertti Hari, Markku Kanninen, Seppo Kellomäki. (1979). On distribution of growth in crown system of young Scots pine stands. Silva Fennica vol. 13 no. 4 article id 5049. https://doi.org/10.14214/sf.a14906

Branching and terminal growth of lateral shoots and needle growth of Scots pine (Pinus sylvestris L.) is investigated as a function of the whorl’s position and age and prevailing light climate. Number of buds per whorl was linearly and positively related to the whorl’s position and prevailing light climate. The growing whorl’s number counting from the apex was associated with declining bud number. The terminal growth of lateral shoots increased exponentially within the values 0.6–1.0 of the whorls position. Under these values the terminal growth was negligible. The growing whorl’s number indicated curvlinear decrease in shoot growth respectively, and only negligible growth occurred when the whorl’s age exceeded 10 years. The shoot growth was linearly related to the prevailing light climate but differences between dominating and dominated trees were apparent. The distribution of needle growth in the crown system was similar to that of shoot growth.

The PDF includes a summary in Finnish.

  • Ilonen, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5033, category Article
Tapani Haapanen, Pertti Hari, Seppo Kellomäki. (1979). Effect of fertilization and thinning on radial growth of Scots pine. Silva Fennica vol. 13 no. 2 article id 5033. https://doi.org/10.14214/sf.a14890

The radial growth of Scots pine (Pinus sylvestris L.) stands at the age 30–40 years was measured retrospectively five years after the fertilizing and thinning of the stands. The abrupt effect of fertilizing was culminated 3–4 years after the treatment. The effect of thinning increased throughout the monitoring period. In stands that had been both thinned and fertilized, the effect of thinning was covered almost entirely by the effect of fertilizing, but fertilizing and thinning gave greater response than applying fertilizer or thinning only. 

The PDF includes a summary in Finnish.

  • Haapanen, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5021, category Article
Antti Koskimäki, Pertti Hari, Markku Kanninen, Seppo Kellomäki. (1979). Inherent growth rythm of some Larix-species grown in a plastic greenhouse. Silva Fennica vol. 13 no. 1 article id 5021. https://doi.org/10.14214/sf.a14875

The daily height growth rate of several larch species and progenies (Larix decidua, Larix sibirica, Larix laricina, Larix leptolepis) grown in a plastic greenhouse and in the open was measured. The growth pattern indoors was completely different compared with the normal outdoor growth pattern. The onset of growth took place in the greenhouse much earlier than outdoors and the phase of increasing growth was much shorter, as was expected. However, the phase of maximum growth was unexpectedly long. This fact suggests that there is great potential for using greenhouse cultivation to change the growth pattern of cultivated plants in order to obtain more complete utilization of the potential growing season.

The PDF includes a summary in Finnish.

  • Koskimäki, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5021, category Article
Antti Koskimäki, Pertti Hari, Markku Kanninen, Seppo Kellomäki. (1979). Inherent growth rythm of some Larix-species grown in a plastic greenhouse. Silva Fennica vol. 13 no. 1 article id 5021. https://doi.org/10.14214/sf.a14875

The daily height growth rate of several larch species and progenies (Larix decidua, Larix sibirica, Larix laricina, Larix leptolepis) grown in a plastic greenhouse and in the open was measured. The growth pattern indoors was completely different compared with the normal outdoor growth pattern. The onset of growth took place in the greenhouse much earlier than outdoors and the phase of increasing growth was much shorter, as was expected. However, the phase of maximum growth was unexpectedly long. This fact suggests that there is great potential for using greenhouse cultivation to change the growth pattern of cultivated plants in order to obtain more complete utilization of the potential growing season.

The PDF includes a summary in Finnish.

  • Koskimäki, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5012, category Article
Jyrki Hari, Pertti Hari, Markku Kanninen. (1978). An electronic auxanometer for field use. Silva Fennica vol. 12 no. 4 article id 5012. https://doi.org/10.14214/sf.a14866

This paper describes the design and functioning of an electronic auxanometer designed for field use, and some results obtained with it. The changes in stem radius are monitored with a micrometer screw turned by an electirc motor. A potentiometer transforms the position of the screw into an electronic signal, which is recorded. The accuracy of the device is approximately 1–2 μm. Field experiments with the auxanometer are described and discussed. The accuracy of the device was found to be sufficient for measuring hourly changes in stem radius.

The PDF includes a summary in Finnish.

  • Hari, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 4980, category Article
Eero Väisänen, Pertti Hari, Seppo Kellomäki. (1977). Annual growth level of some plant species as a function of light available for photosynthesis. Silva Fennica vol. 11 no. 4 article id 4980. https://doi.org/10.14214/sf.a14834

A quantitative method for determining the annual growth level of plant species has been presented. In particular, attention was paid to the dependence of the growth level on the amount of light available for photosynthesis. A mathematical model for the dependence of structural matter production on photosynthetic production has been presented for some plant species.

The study is based on the assumption that the total amount of annual net photosynthesis plays a role of primary importance in determining the relationship between photosynthetic production and structural matter production. The basic environmental factors determining the photosynthetic rate are light and temperature, if the water and nutrient supply is adequate. The dependence of photosynthetic rate on light and temperature was determined by monitoring the CO2 uptake rate of natural plant populations between the photosynthetic levels of different plant populations with an infrared gas analyser.

The PDF includes a summary in Finnish.

  • Väisänen, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 4959, category Article
Irja Lehtonen, Pertti Hari, Seppo Kellomäki, Eero Väisänen. (1977). On control of daily structural matter production in population of Avenella flexuosa (L.) Parl. Silva Fennica vol. 11 no. 1 article id 4959. https://doi.org/10.1421