Silva Fennica

article id 290, category Special section

Mikko Peltoniemi, Esther Thürig, Stephen Ogle, Taru Palosuo, Marion Schrumpf, Thomas Wutzler, Klaus Butterbach-Bahl, Oleg Chertov, Alexander Komarov, Aleksey Mikhailov, Annemieke Gärdenäs, Charles Perry, Jari Liski, Pete Smith, Raisa Mäkipää. (2007). Models in country scale carbon accounting of forest soils. Silva Fennica vol. 41 no. 3 article id 290. https://doi.org/10.14214/sf.290

Keywords: National Forest Inventory; soil carbon; greenhouse gas inventory; decomposition; IPCC; regional and national modeling; soil model

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Countries need to assess changes in the carbon stocks of forest soils as a part of national greenhouse gas (GHG) inventories under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol (KP). Since measuring these changes is expensive, it is likely that many countries will use alternative methods to prepare these estimates. We reviewed seven well-known soil carbon models from the point of view of preparing country-scale soil C change estimates. We first introduced the models and explained how they incorporated the most important input variables. Second, we evaluated their applicability at regional scale considering commonly available data sources. Third, we compiled references to data that exist for evaluation of model performance in forest soils. A range of process-based soil carbon models differing in input data requirements exist, allowing some flexibility to forest soil C accounting. Simple models may be the only reasonable option to estimate soil C changes if available resources are limited. More complex models may be used as integral parts of sophisticated inventories assimilating several data sources. Currently, measurement data for model evaluation are common for agricultural soils, but less data have been collected in forest soils. Definitions of model and measured soil pools often differ, ancillary model inputs require scaling of data, and soil C measurements are uncertain. These issues complicate the preparation of model estimates and their evaluation with empirical data, at large scale. Assessment of uncertainties that accounts for the effect of model choice is important part of inventories estimating large-scale soil C changes. Joint development of models and large-scale soil measurement campaigns could reduce the inconsistencies between models and empirical data, and eventually also the uncertainties of model predictions.

Peltoniemi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: mikko.peltoniemi@metla.fi
Thürig, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland; European Forest Institute, Joensuu, Finland E-mail: et@nn.ch
Ogle, Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, USA E-mail: so@nn.us
Palosuo, European Forest Institute, Joensuu, Finland E-mail: tp@nn.fi
Schrumpf, Max-Planck-Institute for Biogeochemistry, Jena, Germany E-mail: ms@nn.de
Wutzler, Max-Planck-Institute for Biogeochemistry, Jena, Germany E-mail: tw@nn.de
Butterbach-Bahl, Institute for Meteorology and Climate Research, Forschungszentrum Karlsruhe GmbH, Garmisch-Partenkirchen, Germany E-mail: kbb@nn.de
Chertov, St. Petersburg State University, St. Petersburg-Peterhof, Russia E-mail: oc@nn.ru
Komarov, Institute of Physicochemical and Biological Problems in Soil Science of Russian Academy of Sciences, Pushchino, Russia E-mail: ak@nn.ru
Mikhailov, Institute of Physicochemical and Biological Problems in Soil Science of Russian Academy of Sciences, Pushchino, Russia E-mail: am@nn.ru
Gärdenäs, Dept. of Soil Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden E-mail: ag@nn.se
Perry, USDA Forest Service, Northern Research Station, St. Paul, MN USA E-mail: cp@nn.us
Liski, Finnish Environment Institute, Helsinki, Finland E-mail: jl@nn.fi
Smith, School of Biological Sciences, University of Aberdeen, Aberdeen, UK E-mail: ps@nn.uk
Mäkipää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: raisa.makipaa@metla.fi

article id 24045, category Research article

Kari T. Korhonen, Minna Räty, Helena Haakana, Juha Heikkinen, Juha-Pekka Hotanen, Mikko Kuronen, Juho Pitkänen. (2024). Forests of Finland 2019–2023 and their development 1921–2023. Silva Fennica vol. 58 no. 5 article id 24045. https://doi.org/10.14214/sf.24045

Keywords: forest management; National Forest Inventory; growing stock; forest resources; forest damage; increment; monitoring indicators of biodiversity

Highlights: The latest Finnish National Forest Inventory is presented; Volume of growing stock has almost doubled since the 1920s and has continued to increase since the previous inventory; Volume increment is more than double the increment 100 years ago but has declined recently; Mortality is increasing at alarming rate; Amount of dead wood has now increased also in North Finland.

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In 2019–2023 the 13th Finnish National Forest Inventory (NFI) was implemented by measuring a total of 62 266 sample plots across the country. The methodology of the sampling and measurements was similar as in the previous inventory, but the proportion and number of remeasured permanent plots was increased to improve the monitoring of annual increment and other changes in the forests. Only 6.2 M ha (14%) of Finland’s total land area (30.4 M ha) is other land than forestry land. Productive and poorly productive forests cover 22.9 M ha (75%) of the total land area. The forest area has remained stable in recent decades but the forest area available for wood supply (FAWS) has decreased due to increased forest protection – 23% of the forestry land and 10% of the productive forest are not available for wood supply. Compared to the previous inventory, forest resources have continued to increase but the average annual increment has declined from 107.8 M m³ to 103.0 M m³. The quality of forests from the timber production point of view has remained relatively good or improved slightly. The area of observed forest damage on FAWS is 8.4 M ha (46% of FAWS area), half of these minor damages with no impact on stand quality. Although the area of forest damage has not increased, the amount of mortality has continued to increase, and is now 8.8 M m³ year^–1. The amount of dead wood has continued to increase in South Finland, while in North Finland the declining trend has turned into a slight increase. Since the 1920s, the area of forestry land has remained stable, but the area of productive forest has increased due to the drainage of poorly productive or treeless peatlands. The total volume of growing stock has increased by 84% and annual increment has more than doubled.

Korhonen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-6198-853X E-mail: kari.t.korhonen@luke.fi
Räty, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0001-9898-8712 E-mail: minna.raty@luke.fi
Haakana, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland E-mail: helena.haakana@luke.fi
Heikkinen, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0003-3527-774X E-mail: juha.heikkinen@luke.fi
Hotanen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland E-mail: juha-pekka.hotanen@luke.fi
Kuronen, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0002-8089-7895 E-mail: mikko.kuronen@luke.fi
Pitkänen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-7583-6297 E-mail: juho.pitkanen@luke.fi

article id 23080, category Research article

Irene Kuhmonen, Annukka Näyhä, Miisa Solaranta, Janne Keränen. (2024). Can small and medium-sized companies increase the value added from wood-based side streams? Silva Fennica vol. 58 no. 5 article id 23080. https://doi.org/10.14214/sf.23080

Keywords: circular bioeconomy; dynamic capabilities; forest-based sector; strategic niche management; sustainability transition; wood-based SMEs

Highlights: Upgrading the use of wood-based side streams is necessary for circular bioeconomy; Small and medium-sized companies offer innovative solutions for using wood-based side streams; Companies utilizing the side streams host a variety of dynamic capabilities; Strong technological orientation reduces horizontal networking among innovative small and medium-sized companies; The forest-based regime resists the spread of innovations aiming for higher value added.

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One of the central goals of circular bioeconomy in the Finnish forest-based sector is upgrading the use of wood-based materials, especially wood-based side streams, to higher value-added products. However, despite these ambitions, most wood-based side streams are used in energy production. Within the forest-based sector, innovative solutions for higher value-added production of wood-based side streams are being developed within small and medium-sized companies (SMEs). Therefore, to promote the process of upscaling these solutions, understanding the success of these companies is pivotal. For this end, we conducted a qualitative study with 10 forest-based SMEs utilizing wood-based side streams to understand both the internal and external factors affecting their ability to scale up their business models. By applying the dynamic capabilities approach from management research and the strategic niche management approach from sociotechnical transition studies, we found that even though the companies are internally well positioned to succeed in their growth aspirations, they face barriers from the dominant forest-based regime. The studied SMEs are facing a mismatch between their own business models and the rules and operating principles of the forest-based sector based on linear economy. Overcoming these barriers and challenging the dominant structures within the Finnish forest-based regime would require joint efforts from the companies. However, the companies have a strong technological orientation, which makes them hesitant with regard to horizontal networking. They also operate in diverse markets, making it difficult for them to find common ground. As a result, the pressure for systemic transformation within the forest-based sector remains nominal.

Kuhmonen, University of Jyväskylä, School of Business and Economics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland https://orcid.org/0000-0002-1407-8349 E-mail: irene.a.kuhmonen@jyu.fi
Näyhä, University of Jyväskylä, School of Business and Economics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: annukka.nayha@jyu.fi
Solaranta, University of Jyväskylä, School of Business and Economics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: miisa.solaranta@gmail.com
Keränen, VTT Technical Research Centre of Finland Ltd, P.O. Box 1603, FI-40101 Jyväskylä, Finland https://orcid.org/0000-0002-5626-2929 E-mail: janne.keranen@vtt.fi

article id 23030, category Research article

Harri Silvennoinen, Laura Pikkarainen, Heini Nakola, Matti Koivula, Liisa Tyrväinen, Jukka Tikkanen, Philip Chambers, Heli Peltola. (2024). Consistency of video and photo surveys in measuring attractiveness of forest stands managed with varying intensities. Silva Fennica vol. 58 no. 3 article id 23030. https://doi.org/10.14214/sf.23030

Keywords: environment; assessment; forest treatment; preference; visualization

Highlights: The more intensely a forest is treated silviculturally, the less it corresponds to people’s wishes and expectations for nature; It is possible to assess the attractiveness of nature from both photographs and videos; Evaluations from videos and images differed slightly, but these differences do not affect how treatments are ranked; Photo and video assessments are not easy for everyone.

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We evaluated the consistency of video, ordinary photo, and panoramic photo surveys in measuring the attractiveness (recreational use, scenic values etc.) of forest stands managed with varying intensities. We also evaluated possible effects on the results caused by the personal background of citizen respondents and how the respondents experienced the evaluation events. Our experimental sites were in mature Scots pine (Pinus sylvestris L.) forests in eastern Finland and included two replicate sites which were unharvested (control, basal area 26 m² ha^–1), a selective cutting site (basal area 18 m² ha^–1), small openings sites (gap cut) with 5 and 20% retained trees, respectively, and one site which was clear cut with 3% retained trees. In our study, 71 volunteer forestry students evaluated the attractiveness of these sites from an ordinary photo, a panoramic photo, and a video, with a 0–10 scale. Based on this study, the unharvested forest was the most attractive and clear cutting was the least attractive, regardless of the evaluation method. This result was in line with a previous study using on-site evaluations of the same sites. The differences of respondents considering in how easy they felt to assess the attractiveness of the environment as a whole and in using different visualisation methods affected the result, unlike background variables of the respondents. The results of forest attractiveness were consistent between panoramic and ordinary photos, and the attractiveness scoring was slightly higher for them than for the video. We conclude that all the compared visualisation methods seem to be suitable for assessment of the attractiveness of forest views.

Silvennoinen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-9095-7986 E-mail: harri.silvennoinen@uef.fi
Pikkarainen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0001-5301-3639 E-mail: laura.pikkarainen@uef.fi
Nakola, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heini.nakola@gmail.com
Koivula, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0001-6415-4904 E-mail: matti.koivula@luke.fi
Tyrväinen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0001-5144-7150 E-mail: liisa.tyrvainen@luke.fi
Tikkanen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-9693-8209 E-mail: jukka.tikkanen@uef.fi
Chambers, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-0586-3142 E-mail: philip.chambers@uef.fi
Peltola, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0003-1384-9153 E-mail: heli.peltola@uef.fi

article id 23065, category Research article

Pentti Niemistö, Heikki Korpunen, Yrjö Nuutinen. (2024). Harvesting efficiency and understory damage with different cutting methods on two storied stands of silver birch and Norway spruce. Silva Fennica vol. 58 no. 2 article id 23065. https://doi.org/10.14214/sf.23065

Keywords: productivity; thinning; costs; harvesting damage; mixed stand; continuous cover; multistorey forest

Highlights: With careful, well-timed harvesting of overstory birch, it is possible to successfully use initial understory spruce in producing the next tree generation; Preserving understory spruce when cutting overstory birch reduced harvesting productivity by 30% in comparison to unpreserved harvesting; Removal of overstory birch had a positive correlation in cutting productivity but negative correlation in the quality of remaining understory spruce.

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Uneven-aged forests set certain challenges for cut-to-length harvesting work. It is a challenge to cost-effectively remove larger trees while leaving a healthy understory for regrowth. The study’s aim was to evaluate productivity and costs of harvesting two-storied Silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.) stands by creating time consumption models for cutting, and using existing models for forwarding. Damage to the remaining understory spruce was also examined. Four different harvesting methods were used: 1) all dominant birches were cut; 2) half of them thinned and understory was preserved; compared to 3) normal thinning of birch stand without understory; and 4) clear cutting of two-storied stand. Results showed the time needed for birch cutting was 26–30% lower when the understory was not preserved. Pulpwood harvesting of small sized spruces that prevent birch cutting was expensive, especially because of forwarding of small amounts with low timber density on the strip roads. Generally, when taking the cutting and forwarding into account, the unit cost at clear cuttings was lowest, due to lesser limitations on work. It was noted that with increasing removal from 100 to 300 m³ ha^–1, the relative share of initial undamaged spruces after the harvest decreased from 65 to 50% when the aim was to preserve them. During summertime harvesting, the amount of stem damage was bigger than during winter. In conclusion, two-storied stands are possible to transit to spruce stands by accepting some losses in harvesting productivity and damages on remaining trees.

Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland https://orcid.org/0000-0002-9152-2108 E-mail: ext.pentti.niemisto@luke.fi
Korpunen, Norsk institutt for bioøkonomi (NIBIO), Division of Forest and Forest Resources, Department of Forest operations and digitalization, Divisjon for skog og utmark, Avdeling for Driftsteknikk og digitalisering, Høgskoleveien 8, 1433 Ås, Norway https://orcid.org/0000-0001-9749-5684 E-mail: heikki.korpunen@nibio.no
Nuutinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland https://orcid.org/0000-0003-3360-4444 E-mail: yrjo.nuutinen@luke.fi

article id 23072, category Research article

Matti Haapanen. (2024). Realised genetic gains from past Finnish silver birch seed orchards. Silva Fennica vol. 58 no. 1 article id 23072. https://doi.org/10.14214/sf.23072

Keywords: Betula pendula; seed orchards; genetic gain; forest reproductive materials

Highlights: Seed orchard materials generally outperformed unimproved trees in all growth and quality traits, but individual seed orchards showed substantial performance variability; Realised gains in stem volume and forking showed an increasing temporal trend, whereas gains in branch quality were positive and steady; Gains in stem volume and branch quality trade off slightly; The bi-clonal seed orchard variety “JR-2” emerged as the best overall performer across all the seed orchards, whereas the older variety “JR-1” was mediocre; An alternative statistical concept, D-value, was introduced to compare levels of genetic gains for different scaled, normally distributed traits.

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Genetic gains realised through silver birch (Betula pendula Roth) seed orchards were studied using data from common-garden trials established at 34 sites in southern and central Finland. The test materials include seedlots representing 19 commercial seed orchards that operated between 1972 and 2009, and 21 natural stands. All the trials were assessed for several growth and quality traits between the ages of 9 and 24. Realised gains were estimated based on univariate linear mixed models with corrections for latitudinal seed transfer effects. Overall, seed orchard materials outperformed unimproved reference materials in all the traits but results for individual seed orchards varied substantially. Stem volume gains ranged from 1.0% to 31.1%. Improved trees had, on average, 6.8% (up to 26.7%) fewer ramicorn branches and 16.2% (up to 57.6%) fewer forks than unimproved trees. Branch and overall quality showed consistently positive gains. More recently established seed orchards performed better than older ones, and seed orchards with fewer clones outperformed those with dozens of clones. "JR-1" and "JR-2" bi-clonal seed orchards fared differently, with "JR-1" showing modest genetic gains and "JR-2" emerging as the top overall performer across all seed orchards. An alternative statistical concept, the D-value, was utilised to assess the magnitude of genetic gain for different scaled, normally distributed traits. Average D-values implied a similar level of improvement for stem volume, branch quality, and forking, and a smaller gain for stem slenderness and the number of ramicorn branches. The results for individual seed orchards suggest a slight trade-off between stem volume growth and branch quality.

Haapanen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland https://orcid.org/0000-0003-3294-501X E-mail: matti.haapanen@luke.fi

article id 23021, category Research article

Virpi Stenman, Annika Kangas, Markus Holopainen. (2023). Upper stem diameter and volume prediction strategies in the National Forest Inventory of Finland. Silva Fennica vol. 57 no. 3 article id 23021. https://doi.org/10.14214/sf.23021

Keywords: forest inventory; measurement errors; accuracy; Bland-Altman plot

Highlights: National Forest Inventory specific methods were applied with a number of measurement instruments, including a laser-based dendrometer, to collect tree stem diameter measurements; Bland-Altman plots and measurement error variances were used to determine measurement precision and accuracy; The laser-based dendrometer did not perform better than the other instruments in the study.

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In forest inventories, field data are needed for the prediction of tree volumes. However, gathering field data requires resources, such as labour, equipment, and data management operations. This means that time and budget, as well as quality, must be carefully considered when National Forest Inventory (NFI) field measurement activities are planned. Therefore, the development of cost efficient, simple, safe and reliable measurement methods and tools are of great interest. To date, upper stem diameter (d6), which provides a more reliable estimation of tree stem volume, has typically been measured with a parabolic calliper. In this study, the performance of the Criterion laser-based dendrometer was examined for d6 measurements. A total of 326 sample trees were measured multiple times with three different measurement instruments. These instruments were used to measure diameter at breast height (dbh) as well as d6 measurements. Bland-Altman plots and measurement error variances were used to determine measurement instrument reliability. For all trees, the standard deviation for the laser based dendrometer was 18.73 mm at dbh and 15.36 mm for the d6 measurements. When the performance of Criterion was analysed with reference to the mean value of repeated measurements, the standard deviation in the dbh measurements was 12.21 mm, and 8.88 mm in the d6 measurements.

Stenman, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland https://orcid.org/0000-0003-1176-7840 E-mail: virpi.stenman@helsinki.fi
Kangas, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, P.O. Box 68, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-8637-5668 E-mail: annika.kangas@luke.fi
Holopainen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: markus.holopainen@helsinki.fi

article id 10663, category Research article

Back Tomas Ersson, Lars-Göran Sundblad, Jussi Manner. (2022). Cost analysis of seedling supply systems adapted for mechanized tree planting: a case study from southern Sweden. Silva Fennica vol. 56 no. 2 article id 10663. https://doi.org/10.14214/sf.10663

Keywords: logistics; silviculture; reforestation; tree planting machine; containerized seedling; seedling handling; system analysis

Highlights: The total cost of cardboard box concepts that increase the productivity of tree planting machines is higher than of the cultivation tray system (5–49% in the basic scenario); Increasing the boxes’ packing densities and/or the planting machines’ hourly cost increases the boxes’ cost-competitiveness; Packing density is a key factor in achieving highly cost-efficient seedling supply systems for mechanized tree planting.

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Because today’s tree planting machines do a good job silviculturally, the Nordic forest sector is interested in finding ways to increase the planting machines’ productivity. Faster seedling reloading increases machine productivity, but that solution might require investments in specially designed seedling packaging. The objective of our study was to compare the cost-efficiency of cardboard box concepts that increase the productivity of tree planting machines with that of today’s two most common seedling packaging systems in southern Sweden. We modelled the total cost of these five different seedling packaging systems using data from numerous sources including manufacturers, nurseries, contractors, and forest companies. Under these southern Swedish conditions, the total cost of cardboard box concepts that increase the productivity of intermittently advancing tree planting machines was higher than the cost of the cultivation tray system (5–49% in the basic scenario). However, the conceptual packaging system named ManBox_fast did show promise, especially with increasing primary transport distances and increased planting machine productivities and hourly costs. Thus, our results show that high seedling packing density is of fundamental importance for cost-efficiency of cardboard box systems designed for mechanized tree planting. Our results also illustrate how different factors in the seedling supply chain affect the cost-efficiency of tree planting machines. Consequently, our results underscore that the key development factor for mechanized tree planting in the Nordic countries is the development of cost-efficient seedling handling systems between nurseries and planting machines.

Ersson, SLU, School of Forest Management, SE-739 21 Skinnskatteberg, Sweden https://orcid.org/0000-0003-2442-7482 E-mail: back.tomas.ersson@slu.se
Sundblad, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars-goran.sundblad@skogforsk.se
Manner, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se

article id 10550, category Research article

Miro Demol, Phil Wilkes, Pasi Raumonen, Sruthi M. Krishna Moorthy, Kim Calders, Bert Gielen, Hans Verbeeck. (2022). Volumetric overestimation of small branches in 3D reconstructions of Fraxinus excelsior. Silva Fennica vol. 56 no. 1 article id 10550. https://doi.org/10.14214/sf.10550

Keywords: aboveground biomass; crown architecture; LIDAR; quantitative structure models; common ash; woody tree volume

Highlights: We compare branch diameter and tree woody volume estimates from terrestrial laser scanning data with manual measurements of two Fraxinus excelsior trees; Smaller branch diameters are generally overestimated due to scattering and misalignment errors in the point cloud; Consequently, tree woody volume is overestimated by 38% to 52%; Filtering by reflectance and improved alignment partly mitigate this effect.

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Terrestrial laser scanning (TLS) has been applied to estimate forest wood volume based on detailed 3D tree reconstructions from point cloud data. However, sources of uncertainties in the point cloud data (alignment and scattering errors, occlusion, foliage...) and the reconstruction algorithm type and parameterisation are known to affect the reconstruction, especially around finer branches. To better understand the impacts of these uncertainties on the accuracy of TLS-derived woody volume, high-quality TLS scans were collected in leaf-off conditions prior to destructive harvesting of two forest-grown common ash trees (Fraxinus excelsior L.; diameter at breast height ~28 cm, woody volume of 732 and 868 L). We manually measured branch diameters at 265 locations in these trees. Estimates of branch diameters and tree volume from Quantitative Structure Models (QSM) were compared with these manual measurements. The accuracy of QSM branch diameter estimates decreased with smaller branch diameters. Tree woody volume was overestimated (+336 L and +392 L) in both trees. Branches measuring < 5 cm in diameter accounted for 80% and 83% of this overestimation respectively. Filtering for scattering errors or improved coregistration approximately halved the overestimation. Range filtering and modified scanning layouts had mixed effects. The small branch overestimations originated primarily in limitations in scanner characteristics and coregistration errors rather than suboptimal QSM parameterisation. For TLS-derived estimates of tree volume, a higher quality point cloud allows smaller branches to be accurately reconstructed. Additional experiments need to elucidate if these results can be generalised beyond the setup of this study.

Demol, CAVElab – Computational and Applied Vegetation Ecology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; PLECO – Plants and Ecosystems, Faculty of Science, Antwerp University, Universiteitsplein 1, B-2610 Wilrijk, Belgium https://orcid.org/0000-0002-5492-2874 E-mail: miro.demol@ugent.be
Wilkes, UCL Department of Geography, Gower Street, London WC1E 6BT, UK; NERC National Centre for Earth Observation (NCEO), UK https://orcid.org/0000-0001-6048-536X E-mail: p.wilkes@ucl.ac.uk
Raumonen, Mathematics, Tampere University, FI-33101 Tampere, Finland https://orcid.org/0000-0001-5471-0970 E-mail: pasi.raumonen@tuni.fi
Krishna Moorthy, CAVElab – Computational and Applied Vegetation Ecology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium https://orcid.org/0000-0002-6838-2880 E-mail: Sruthi.KrishnaMoorthyParvathi@ugent.be
Calders, CAVElab – Computational and Applied Vegetation Ecology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium https://orcid.org/0000-0002-4562-2538 E-mail: kim.calders@ugent.be
Gielen, PLECO – Plants and Ecosystems, Faculty of Science, Antwerp University, Universiteitsplein 1, B-2610 Wilrijk, Belgium https://orcid.org/0000-0002-4890-3060 E-mail: bert.gielen@uantwerpen.be
Verbeeck, CAVElab – Computational and Applied Vegetation Ecology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium https://orcid.org/0000-0003-1490-0168 E-mail: hans.verbeeck@ugent.be

article id 10662, category Research article

Kari T. Korhonen, Arto Ahola, Juha Heikkinen, Helena M. Henttonen, Juha-Pekka Hotanen, Antti Ihalainen, Markus Melin, Juho Pitkänen, Minna Räty, Maria Sirviö, Mikael Strandström. (2021). Forests of Finland 2014–2018 and their development 1921–2018. Silva Fennica vol. 55 no. 5 article id 10662. https://doi.org/10.14214/sf.10662

Keywords: biodiversity; National Forest Inventory; growing stock; forest resources; forest damage

Highlights: Current volume of growing stock, 2500 M m³, is 1.7 times the volume in the 1920s; Annual volume increment is 107.8 M m³, which is double the increment estimated in the 1930s; Serious damage is observed on 2% of the forests available for wood supply; The amount of dead wood is on average 5.8 m³ per ha on productive forest.

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We describe the methodology applied in the 12th national forest inventory of Finland (NFI12) and describe the state of Finland’s forests as well as the development of some key parameters since 1920s. According to the NFI12, the area of forestry land (consisting of productive and poorly productive forest, unproductive land, and other forestry land) is 26.2 M ha. The area of forestry land has decreased from 1920s to 1960s due to expansion of agriculture and built-up land. 20% of the forestry land is not available for wood supply and 13% is only partly available for wood supply. The area of peatlands is 8.8 M ha, which is one third of the forestry land. 53% of the current area of peatlands is drained. The volume of growing stock, 2500 M m³, is 1.7 times the volume estimated in NFI1 in the 1920s for the current territory of Finland. The estimated annual volume increment is 107.8 M m³. The increment estimate has doubled since the estimate of NFI2 implemented in late 1930s. The annual mortality is estimated to 7 M m³, which is 0.5 M m³ more than according to the previous inventory. Serious or complete damage was observed on 2% of the productive forest available for wood supply. The amount of dead wood is on average 5.8 m³ ha^–1 in productive forests. Since the NFI9 (1996–2003) the amount of dead wood has increased in South Finland and decreased in North Finland both in protected forests and forests available for wood supply (FAWS). The area of natural or almost natural forests on productive forest is 380 000 ha, out of this, 42 000 ha are in FAWS and 340 000 ha in protected forests.

Korhonen, Natural Resources Institute Finland (Luke), P.O. Box 68, FI-80100 Joensuu, Finland E-mail: kari.t.korhonen@luke.fi
Ahola, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: arto.ahola@luke.fi
Heikkinen, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: juha.heikkinen@luke.fi
Henttonen, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: helena.henttonen@luke.fi
Hotanen, Natural Resources Institute Finland (Luke), P.O. Box 68, FI-80100 Joensuu, Finland E-mail: juha-pekka.hotanen@luke.fi
Ihalainen, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: anttivj.ihalainen@elisanet.fi
Melin, Natural Resources Institute Finland (Luke), P.O. Box 68, FI-80100 Joensuu, Finland E-mail: markus.melin@luke.fi
Pitkänen, Natural Resources Institute Finland (Luke), P.O. Box 68, FI-80100 Joensuu, Finland E-mail: juho.pitkanen@luke.fi
Räty, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: minna.raty@luke.fi
Sirviö, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: maria.sirvio@uudenmaanliitto.fi
Strandström, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00790, Helsinki, Finland E-mail: mikael.strandstrom@luke.fi

article id 10483, category Research article

Māra Kitenberga, Guntars Šņepsts, Jānis Vuguls, Didzis Elferts, Ieva Jaunslaviete, Āris Jansons. (2021). Tree- and stand-scale factors shape the probability of wind damage to birch in hemiboreal forests. Silva Fennica vol. 55 no. 2 article id 10483. https://doi.org/10.14214/sf.10483

Keywords: stem breakage; Betula pendula; snapping height; stem damage; stem fracture; tree stability

Highlights: Prior stem and root damage significantly increased the probability of birch being wind-damaged; Trees with a high slenderness ratio had a lower relative snapping height; The snapping height was significantly negatively affected by the prior stem and root damage.

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Strong wind is the major natural disturbance in European forests, that periodically causes tremendous damages to forestry. Yet, factors that affect the probability of wind damage for birch (Betula pendula Roth and B. pubescens Ehrh.), the most common deciduous tree species in hemiboreal forests, are studied scarcely. This study aimed to assess the effects of several tree- and stand-scale variables on the probability of wind damage to birch using data from the Latvian National Forest Inventory (2004–2018), and determine individual tree characteristics that affect the height of the stem breakage. The data analysis was done using the Bayesian binary logistic generalized linear mixed-effects model and a linear mixed-effects model. The probability of wind damage significantly increased by stand age, basal area, and slenderness ratio. Trees with prior damage had a significantly higher probability (odds ratio 4.32) for wind damage. For wind-damaged trees, the snapping height was significantly decreased by an increase in the slenderness ratio (p = 0.03) and prior damage (p = 0.003). Previously damaged trees were more frequently (73%) snapped in the lowest 40% of tree height than trees without prior damage (54%). The probability of wind damage is largely set by factors related to the selection of site, species composition, and rotation. The damage probability could be decreased by management measures that lower competition within the stand with particular regard to preserving intact remaining trees during these manipulations. Factors that reduce the probability of the damage simultaneously increase the snapping height, emphasizing their relevance for mitigation of the wind damages.

Kitenberga, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia https://orcid.org/0000-0002-6192-988X E-mail: mara.kitenberga@silava.lv
Šņepsts, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia E-mail: guntars.snepsts@silava.lv
Vuguls, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia E-mail: janis.vuguls@silava.lv
Elferts, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia; Faculty of Biology, University of Latvia, Jelgavas Street 1, LV–1004, Rīga, Latvia https://orcid.org/0000-0002-9401-1231 E-mail: didzis.elferts@lu.lv
Jaunslaviete, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia E-mail: ieva.jaunslaviete@silava.lv
Jansons, Latvian State Forest Research Institute ‘Silava’, Rigas Street 111, LV–2169, Salaspils, Latvia https://orcid.org/0000-0001-7981-4346 E-mail: aris.jansons@silava.lv

article id 10409, category Research article

Noé Dumas, Mathieu Dassot, Jonathan Pitaud, Jérôme Piat, Lucie Arnaudet, Claudine Richter, Catherine Collet. (2021). Four-year-performance of oak and pine seedlings following mechanical site preparation with lightweight excavators. Silva Fennica vol. 55 no. 2 article id 10409. https://doi.org/10.14214/sf.10409

Keywords: vegetation control; reforestation; seedling growth; seedling survival

Highlights: Mechanical site preparation (MSP) with lightweight excavators controls highly competitive plant species (Molinia caerulea, Pteridium aquilinum) much more efficiently than MSP with conventional methods; This MSP approach improves four-year survival and growth of pine seedlings, but it is less evident for oak seedlings.

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Mechanical site preparation methods that used tools mounted on lightweight excavators and that provided localised intensive preparation were tested in eight experimental sites across France where the vegetation was dominated either by Molinia caerulea (L.) Moench or Pteridium aquilinum (L.) Kuhn. Two lightweight tools (Deep Scarifier: DS; Deep Scarifier followed by Multifunction Subsoiler: DS+MS) were tested in pine (Pinus sylvestris L., Pinus nigra var. corsicana (Loudon) Hyl. or Pinus pinaster Aiton) and oak (Quercus petraea (Matt.) Liebl. or Quercus robur L.) plantations. Regional methods commonly used locally (herbicide, disk harrow, mouldboard plow) and experimental methods (repeated herbicide application; untreated control) were used as references in the experiments. Neighbouring vegetation cover, seedling survival, height and basal diameter were assessed over three to five years after plantation. For pines growing in M. caerulea, seedling diameter after four years was 37% and 98% greater in DS and DS+MS, respectively, than in the untreated control. For pines growing in P. aquilinum, it was 62% and 107% greater in the same treatments. For oak, diameter was only 4% and 15% greater in M. caerulea, and 13% and 25% greater in P. aquilinum, in the same treatments. For pines, the survival rate after four years was 26% and 32% higher in M. caerulea and 64% and 70% higher in P. aquilinum, in the same treatments. For oak, it was 3% and 29% higher in M. caerulea and 37% and 31% higher in P. aquilinum. Herbicide, when applied for three or four years after planting, provided the best growth performances for pines growing in M. caerulea and P. aquilinum and for oaks growing in P. aquilinum. For these species and site combinations, DS+MS and DS treatments reduced the neighbouring vegetation cover for one to four years following site preparation.

Dumas, Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000 Nancy, France E-mail: noe.dumas@inrae.fr
Dassot, EcoSustain, Environmental Engineering Office, Research and Development, 31, rue de Volmerange, 57330 Kanfen, France; Institut National de l’Information Géographique et Forestière, 1 rue des Blanches Terres, 54250 Champigneulles, France E-mail: mathieu.dassot@ign.fr
Pitaud, Office National des Forêts, Département Recherche Développement et Innovation, route d’Amance, 54280 Champenoux, France E-mail: jonathan.pitaud@onf.fr
Piat, Office National des Forêts, Département Recherche Développement et Innovation, 3 rue du petit château, 60200 Compiègne, France E-mail: jerome.piat@onf.fr
Arnaudet, Office National des Forêts, Département Recherche Développement et Innovation, 100 boulevard de la Salle, 45760 Boigny-sur-Bionne, France E-mail: lucie.arnaudet@onf.fr
Richter, Office National des Forêts, Département Recherche Développement et Innovation, Boulevard de Constance, 77300 Fontainebleau, France E-mail: claudine.richter@onf.fr
Collet, Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000 Nancy, France https://orcid.org/0000-0003-0861-7796 E-mail: catherine.collet@inrae.fr

article id 10272, category Research article

Ana de Lera Garrido, Terje Gobakken, Hans Ole Ørka, Erik Næsset, Ole M. Bollandsås. (2020). Reuse of field data in ALS-assisted forest inventory. Silva Fennica vol. 54 no. 5 article id 10272. https://doi.org/10.14214/sf.10272

Keywords: airborne laser scanning; data reuse; temporal model transferability

Highlights: Six biophysical forest attributes were estimated for small stands without using up-to-date field data; The approaches included reused model relationships and forecasted field data; The accuracy of height estimates was comparable with the accuracy of an ordinary forest inventory with up-to-date field- and ALS data; Both approaches tended to produce estimates systematically different from the ground reference.

Abstract | Full text in HTML | Full text in PDF | Author Info

Forest inventories assisted by wall-to-wall airborne laser scanning (ALS), have become common practice in many countries. One major cost component in these inventories is the measurement of field sample plots used for constructing models relating biophysical forest attributes to metrics derived from ALS data. In areas where ALS-assisted forest inventories are planned, and in which the previous inventories were performed with the same method, reusing previously acquired field data can potentially reduce costs, either by (1) temporally transferring previously constructed models or (2) projecting field reference data using growth models that can serve as field reference data for model construction with up-to-date ALS data. In this study, we analyzed these two approaches of reusing field data acquired 15 years prior to the current ALS acquisition to estimate six up-to-date forest attributes (dominant tree height, mean tree height, stem number, stand basal area, volume, and aboveground biomass). Both approaches were evaluated within small stands with sizes of approximately 0.37 ha, assessing differences between estimates and ground reference values. The estimates were also compared to results from an up-to-date forest inventory relying on concurrent field- and ALS data. The results showed that even though the reuse of historical information has some potential and could be beneficial for forest inventories, systematic errors may appear prominent and need to be overcome to use it operationally. Our study showed systematic trends towards the overestimation of lower-range ground references and underestimation of the upper-range ground references.

de Lera Garrido, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway E-mail: ana.maria.lera.garrido@nmbu.no
Gobakken, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway E-mail: terje.gobakken@nmbu.no
Ørka, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway E-mail: hans-ole.orka@nmbu.no
Næsset, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway E-mail: erik.naesset@nmbu.no
Bollandsås, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway E-mail: ole.martin.bollandsas@nmbu.no

article id 10273, category Research article

Lasse Aro, Anssi Ahtikoski, Jyrki Hytönen. (2020). Profitability of growing Scots pine on cutaway peatlands. Silva Fennica vol. 54 no. 3 article id 10273. https://doi.org/10.14214/sf.10273

Keywords: Pinus sylvestris; afforestation; bare land value; financial performance; peat cutaway area; stand-level optimization

Highlights: The potential wood production on cutaway peatlands can be high; Afforestation with seeding or planting was profitable at 3% rate of interest; In northern Finland, the afforestation method, ditch spacing and fertilization affected the bare land value.

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A major after-use option for former peat harvesting areas has been afforestation. The profitability of afforestation with Scots pine trees (Pinus sylvestris L.) was studied in two 31–32-year old experiments in southern and northern Finland. The stands were established by seeding and planting, and various fertilization treatments and drainage intensities were tested. The financial performance for each plot was assessed in three steps. First, the costs occurred during the measurement time were summed up according to their present value. Then, for the rest of the rotation (i.e., from the age of 31/32 onwards) the stand management was optimized in order to maximize the net present value (MaxNPV). Finally, bare land values (BLVs) were calculated by summing up the present value of costs and the MaxNPV and converting the sum of the series into infinity. The afforestation method did not affect the mean annual increment (MAI; 9.2–9.5 m³ ha^–1 a^–1) in the southern experiment. In the northern experiment the afforestation method, ditch spacing and fertilization had significant effects on the MAI of the stands. The average MAI of the planted pines was 8.9 m³ ha^–1 a^–1, and for seeded pines it was 7.5 m³ ha^–1 a^–1. The BLV at an interest rate of 3% was positive for all stands in both regions. In the northern region afforestation method, ditch spacing and fertilization also had a significant effect on the BLV. When the interest rate was 5%, almost two thirds of the stands had a negative BLV in both regions.

Aro, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Itäinen Pitkäkatu 4A, FI-20520 Turku, Finland E-mail: lasse.aro@luke.fi
Ahtikoski, Natural Resources Institute Finland (Luke), Natural resources, Paavo Havaksentie 3, FI-90570 Oulu, Finland https://orcid.org/0000-0003-1658-3813 E-mail: anssi.ahtikoski@luke.fi
Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland http://orcid.org/0000-0001-8475-3568 E-mail: jyrki.hytonen@luke.fi

article id 10143, category Research article

Olga Grigorieva, Olga Brovkina, Alisher Saidov. (2020). An original method for tree species classification using multitemporal multispectral and hyperspectral satellite data. Silva Fennica vol. 54 no. 2 article id 10143. https://doi.org/10.14214/sf.10143

Keywords: boreal forest; phenological period; space spectroscopy; spectral signature

Highlights: Differences between spectral reflectance of tree species are statistically significant in the sub-seasons of spring, first half of summer, and main autumn; Classification using multitemporal multispectral data is more productive than is classification using a single hyperspectral image; the method improves recent forest mapping in the study regions.

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This study proposes an original method for tree species classification by satellite remote sensing. The method uses multitemporal multispectral (Landsat OLI) and hyperspectral (Resurs-P) data acquired from determined vegetation periods. The method is based on an original database of spectral features taking into account seasonal variations of tree species spectra. Changes in the spectral signatures of forest classes are analyzed and new spectral–temporal features are created for the classification. Study sites are located in the Czech Republic and northwest (NW) Russia. The differences in spectral reflectance between tree species are shown as statistically significant in the sub-seasons of spring, first half of summer, and main autumn for both study sites. Most of the errors are related to the classification of deciduous species and misclassification of birch as pine (NW Russia site), pine as mixture of pine and spruce, and pine as mixture of spruce and beech (Czech site). Forest species are mapped with accuracy as high as 80% (NW Russia site) and 81% (Czech site). The classification using multitemporal multispectral data has a kappa coefficient 1.7 times higher than does that of classification using a single multispectral image and 1.3 times greater than that of the classification using single hyperspectral images. Potentially, classification accuracy can be improved by the method when applying multitemporal satellite hyperspectral data, such as in using new, near-future products EnMap and/or HyspIRI with high revisit time.

Grigorieva, A.F. Mozhaysky’s Military-Space Academy, Krasnogo Kursanta Street 19a, 197198, Saint Petersburg, Russia E-mail: alenka12003@gmail.com
Brovkina, Global Change Research Institute CAS, Bělidla 986/4a, 603 00, Brno, Czech Republic E-mail: brovkina.o@czechglobe.cz
Saidov, A.F. Mozhaysky’s Military-Space Academy, Krasnogo Kursanta Street 19a, 197198, Saint Petersburg, Russia E-mail: celestial.azura@gmail.com

article id 10242, category Research article

Shisheng Long, Siqi Zeng, Falin Liu, Guangxing Wang. (2020). Influence of slope, aspect and competition index on the height-diameter relationship of Cyclobalanopsis glauca trees for improving prediction of height in mixed forests. Silva Fennica vol. 54 no. 1 article id 10242. https://doi.org/10.14214/sf.10242

Keywords: secondary forest; effect; improved Hegyi_I; topographic feature; tree height estimation

Highlights: In this study, the effects of slope, aspect and competition index (CI) on the H-DBH relationship were explored and an improved CI was developed and included to improve predictions of Cyclobalanopsis glauca tree height; It was found that the effects were statistically significant and considering slope, aspect and CI for developing the H-DBH models significantly increased the H prediction accuracy.

Abstract | Full text in HTML | Full text in PDF | Author Info

Diameter at breast height (DBH) and height (H) of trees are two important variables used in forest management plans. However, collecting the measurements of H is time-consuming and costly. Instead, the H-DBH relationship is modeled and used to estimate H. But, ignoring the effects of slope, aspect and tree competition on the H-DBH relationship often impedes the improvement of H predictions. In this study, to improve predictions of Cyclobalanopsis glauca (Thunb.) Oerst. tree H in mixed forests, we compared eleven H-DBH models and examined the influence of slope and aspect on the H-DBH relationship using 426 trees. We then improved Hegyi competition index and explored its effect on the H predictions by including it in the selected models. Results showed 1) There were statistically significant effects of slope and aspect on the H-DBH relationship; 2) The log transformation and exponential model performed best for sunny- and shady-steep, respectively, and the Gompertz’s model was optimal for both sunny- and shady-gentle; 3) Compared with the whole dataset, the division of the data into the slope and aspect sub-datasets significantly reduced the RMSE of H predictions; 4) Compared with the selected models without competition index, adding the original Hegyi and improved Hegyi_I into the models improved the H predictions but only the models containing the improved Hegyi_I significantly increased the prediction accuracy at the significant level of 0.1. This study implied that modeling the H-DBH relationship under different slopes and aspects and including the improved Hegyi_I provided the great potential to improve the H predictions.

Long, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China E-mail: shisheng3604@21cn.com
Zeng, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China E-mail: zengsiqi@21cn.com
Liu, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China E-mail: liufl680@126.com
Wang, Research Center of Forestry Remote Sensing & Information Engineering, Central South University of Forestry and Technology, Changsha 410004, China; Department of Geography and Environmental Resources, Southern Illinois University, Carbondale, IL 62901, USA E-mail: gxwang@siu.edu

article id 10178, category Research article

Franz Holzleitner, Magdalena Langmaier, Eduard Hochbichler, Bernhardt Obermayer, Karl Stampfer, Christian Kanzian. (2019). Effect of prior tree marking, thinning method and topping diameter on harvester performance in a first thinning operation – a field experiment. Silva Fennica vol. 53 no. 3 article id 10178. https://doi.org/10.14214/sf.10178

Keywords: productivity; time study; harvester; prior tree marking; thinning method; topping diameter; video analysis

Highlights: No effect on harvester performance due to prior tree marking detected; Operator selection versus prior tree marking was assessed; Operator could apply two different thinning methods; Prior tree marking seems to have a positive effect on residual stand damage.

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The effect of harvester operator tree selection or prior tree marking in thinning operations on satisfactory results and performance has been widely discussed. In harvester operator tree selection, the machine operator decides on the fly which trees are selected to remain or cut. The objective of the study was to analyze the effect of prior tree marking, thinning method and topping diameter on harvester performance in low-diameter thinning operations. The entire thinning operation was captured using video technology. Overall, 2.36 ha divided into 48 plots with 5202 trees were thinned with an average diameter at breast height (dbh) over bark for all plots of between 12.5 and 14.7 cm. In total, 3122 trees were harvested, resulting in 60% removal of stem number over all plots. The harvester achieved a mean productivity of 7.38 m³ PMH₀^–1 with 1.48 m³ PMH₀^–1 SEM, with stem volume having the major influence on harvesting productivity. Prior tree marking, topping and thinning method did not significantly affect productivity. Without prior tree marking by the foresters, harvesting removal was shifted toward lower diameters. Within the unmarked plots, 7.0% of the residual trees were damaged compared with 3.2% in marked plots.

Holzleitner, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria https://orcid.org/0000-0001-8489-3050 E-mail: franz.holzleitner@boku.ac.at
Langmaier, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Silviculture, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria; Austrian Research Centre for Forests, Department of Forest Growth and Silviculture, Seckendorff Gudent Weg 8, A-1130 Vienna, Austria E-mail: magdalena.langmaier@bfw.gv.at
Hochbichler, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Silviculture, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria E-mail: eduard.hochbichler@boku.ac.at
Obermayer, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria; Agricultural Technical School of Pyhra, Kyrnbergstraße 4, A-3143 Pyhra, Austria E-mail: bernhardt.obermayer@lfs-pyhra.ac.at
Stampfer, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria http://orcid.org/0000-0001-9350-2859 E-mail: karl.stampfer@boku.ac.at
Kanzian, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria http://orcid.org/0000-0002-1198-9788 E-mail: christian.kanzian@boku.ac.at

article id 10161, category Research article

Jussi Manner, Anders Mörk, Martin Englund. (2019). Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset. Silva Fennica vol. 53 no. 2 article id 10161. https://doi.org/10.14214/sf.10161

Keywords: automation; cut-to-length logging; haulage; crane work; extraction; boom-tip control

Highlights: Boom-tip control saves time compared to the conventional system; This study introduced a field-study design enabling establishment of causal relationships during ordinary forwarding operations; Although the study design requires some extra arrangements, it efficiently combines the representativeness of conventional follow-up datasets with establishment of causal relationships that traditionally have been possible only through observational time studies or standardized experiments.

Abstract | Full text in HTML | Full text in PDF | Author Info

Crane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deere’s version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (p ≤ 0.05). The corresponding saving when using IBC for unloading work was 7.9% (p ≤ 0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments.

Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
Mörk, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: anders.mork@skogforsk.se
Englund, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: martin.englund@skogforsk.se

article id 10019, category Research article

Junyan Liu, Junfeng Tang, Si-Chong Chen, Wenbao Ma, Zheng Zheng, Tingfa Dong. (2019). Do tree cavity density and characteristics vary across topographical habitats in the tropics? A case study from Xishuangbanna, southwest China. Silva Fennica vol. 53 no. 1 article id 10019. https://doi.org/10.14214/sf.10019

Keywords: heterogeneity; cavity-dependant animals; tropical rainforest; biodiversity conservation

Highlights: Cavities were significantly more abundant in high- and low-slope than high-plateau habitats; There are more “butt hollow” cavities in high-slope habitat and they occurred at a lower height; More “crack” cavities in low-slope habitat and they had a narrower entrance diameter; Certain types of cavities are concentrated in specific habitats, which provide opportunities for forest management and biodiversity conservation.

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Despite the influence of cavities on the survival and distribution of cavity-dependent fauna, the variation in the density and characteristics of tree cavities across different habitat types in tropical forests is unknown. In this study, we surveyed 26 312 living trees from 376 species and compared cavity density and characteristics (height, size, type, and orientation) across five habitat types (valley, low-slope, high-slope, high-gully, and high-plateau) in a 20-hectare tropical rainforest in southwest China. From a total of 2047 cavities, we found that cavity density was mainly driven by habitat rather than tree species richness or diameter at breast height (DBH), and the characteristics of cavities were not uniformly distributed across habitats. Cavities were significantly more abundant in high- and low-slope than high-plateau habitats. Compared with other habitats, more “butt hollow” cavity types were found in high-slope habitat and they occurred at a lower tree height, whereas more “crack” cavities were found in low-slope habitat and they had a narrower entrance diameter. Although the mean orientation of cavities faced towards the northeast, cavity orientation varied significantly across habitat types. Our results indicate that certain types of cavities are concentrated in specific habitat types, which can provide avenues for forest management and biodiversity conservation. We highlight the importance of habitat heterogeneity in providing resources for cavity nesters.

Liu, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China; Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China E-mail: liujunyan2300@163.com
Tang, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China E-mail: jft@nn.ch
Chen, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex RH17 6TN, UK; Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Beer-Sheva 8499000, Israel E-mail: chensichong0528@gmail.com
Ma, Ecological Restoration and Conservation of Forests and Wetlands Key Laboratory of Sichuan Province, Sichuan Academy of Forestry, Chengdu 610081, China E-mail: mawenbao_2000@126.com
Zheng, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China E-mail: dioeco@outlook.com
Dong, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China E-mail: dongtf@aliyun.com

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

Keywords: Pinus sylvestris; climate change; adaptation; shoot phenology; heritability of phenological traits; growth onset; growth cessation

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.

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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 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 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 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 https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se

article id 7763, category Research article

Sergei Senko, Mikko Kurttila, Timo Karjalainen. (2018). Prospects for Nordic intensive forest management solutions in the Republic of Karelia. Silva Fennica vol. 52 no. 4 article id 7763. https://doi.org/10.14214/sf.7763

Keywords: forest management; thinning; forestry; Russia; SWOT

Highlights: SWOT (strengths, weaknesses, opportunities and threats) and multi-criteria decision support analysis were combined to examine the potential for Nordic intensive forest management solutions (NIFMS) in Karelia, Russia; NIFMS looks promising for Karelian forestry; Improving quality-and-value of timber and sustained yield are the highly prioritized strengths; Unprepared forestry regulations are the main threat that needs to be taken into account.

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In this study, the prospects for future forest management in Republic of Karelia, Russia were analyzed. Forestry has an important role in the economy of Karelia. However, productivity and profitability in the forestry sector are extremely low, forest stand structure and quality are weak, the commercial forest land of coniferous species has declined and the wood processing industry struggles with a deficit of raw materials. The situation is typical to many forest regions in Russia with extensive forest management cited as one reason for the current situation. In contrast, the Nordic countries have significant experience in intensive and sustainable forest management and the results have been to a large extent positive. The transfer of Nordic intensive forest management solutions (NIFMS) could improve forestry in Karelia. SWOT analysis, combined with the multi-criteria decision support (MCDS) method was used to identify local operational environments and to assign priorities. Major threats included unprepared regulations, poor road infrastructure, insecure investments, low forestry productivity, forest degradation, high investment costs and a negative attitude to intensive forestry. The main opportunities are high forest resource potential in Karelia, favorable authority development programs, proven Nordic expertise, wood-based energy development and availability of new technology. Results also showed that the main weaknesses that might influence the NIFMS in Karelia are slow return on investments, low market demand for energy wood, high costs associated with young forest thinnings, high demand for skilled specialists and a lack of investment in research and development.

Senko, University of Eastern Finland (UEF), School of Forest Sciences, Yliopistokatu 7, FI-80111 Joensuu, Finland E-mail: sergei.senko@uef.fi
Kurttila, The Natural Resources Institute Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, FI-80100 Joensuu, Finland E-mail: mikko.kurttila@luke.fi
Karjalainen, † Deceased E-mail: tjk@nn.fi

article id 10006, category Research article

Matti Maltamo, Tomi Karjalainen, Jaakko Repola, Jari Vauhkonen. (2018). Incorporating tree- and stand-level information on crown base height into multivariate forest management inventories based on airborne laser scanning. Silva Fennica vol. 52 no. 3 article id 10006. https://doi.org/10.14214/sf.10006

Keywords: forest inventory; LIDAR; alpha shape; crown height; nearest neighbor; mixed-effects model

Highlights: The most accurate tree-level alternative is to include crown base height (CBH) to nearest neighbour imputation; Also mixed-effects models can be applied to predict CBH using tree attributes and airborne laser scanning (ALS) metrics; CBH prediction can be included with an accuracy of 1–1.5 m to forest management inventory applications.

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This study examines the alternatives to include crown base height (CBH) predictions in operational forest inventories based on airborne laser scanning (ALS) data. We studied 265 field sample plots in a strongly pine-dominated area in northeastern Finland. The CBH prediction alternatives used area-based metrics of sparse ALS data to produce this attribute by means of: 1) Tree-level imputation based on the k-nearest neighbor (k-nn) method and full field-measured tree lists including CBH observations as reference data; 2) Tree-level mixed-effects model (LME) prediction based on tree diameter (DBH) and height and ALS metrics as predictors of the models; 3) Plot-level prediction based on analyzing the computational geometry and topology of the ALS point clouds; and 4) Plot-level regression analysis using average CBH observations of the plots for model fitting. The results showed that all of the methods predicted CBH with an accuracy of 1–1.5 m. The plot-level regression model was the most accurate alternative, although alternatives producing tree-level information may be more interesting for inventories aiming at forest management planning. For this purpose, k-nn approach is promising and it only requires that field measurements of CBH is added to the tree lists used as reference data. Alternatively, the LME-approach produced good results especially in the case of dominant trees.

Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: matti.maltamo@uef.fi
Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: tomimkarjalainen@gmail.com
Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: jaakko.repola@luke.fi
Vauhkonen, Natural Resources Institute of Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, 80100 Joensuu, Finland E-mail: jari.vauhkonen@luke.fi

article id 9940, category Research article

Esteban Ceriani-Nakamurakare, Sergio Ramos, Carolina A. Robles, María V. Novas, María F. D´Jonsiles, Paola Gonzalez-Audino, Cecilia Carmarán. (2018). Metagenomic approach of associated fungi with Megaplatypus mutatus (Coleoptera: Platypodinae). Silva Fennica vol. 52 no. 3 article id 9940. https://doi.org/10.14214/sf.9940

Keywords: ambrosia; forest pest; metagenomic; fungi; Platypodinae; insect-fungus interactions

Highlights: There were no significant effects of host plant and location on fungal richness; Two fungal species, belonging to Fusarium and Candida genera, were present in all the studied associations; Results suggest that host plant identity would not be crucial to determine the composition of fungal communities associated to Megaplatypus mutatus.

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Megaplatypus mutatus is a major forest pest in Argentina and an emerging pest in Europe. In this study the multitrophic interactions between M. mutatus and associated fungi were assessed with a metagenomics approach (454-pyrosequencing). A total of 270 collection points from insect galleries from three locations in Argentina were pooled for pyrosequencing analyses. Two hosts, Populus deltoides and Casuarina cunninghamiana, were independently evaluated to characterize the fungal communities associated to M. mutatus; compare the culture-independent approach with previous culturing studies, in terms of data recovery related to the fungal community composition, and test the specificity of the fungal communities amongst locations and hosts. A Generalized Linear Mixed Model was performed to compare the fungal richness in each dataset, which showed no significant differences between taxa richness amongst locations. Principal Coordinates Analyses showed a separation between fungal communities within the same host, suggesting that host identity would not be crucial to determine the specificity in fungal communities. Candida insectalens and one Fusarium species, present in all hosts and locations, achieved 37.6% of the total relative frequency per taxa. These results complement the data from culturing methods previously reported, thus improving the accuracy and understanding of the fungal assemblages associated to M. mutatus.

Ceriani-Nakamurakare, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina E-mail: cerianinaka@gmail.com
Ramos, Instituto Nacional de Tecnología Agropecuaria. Estación Experimental Agropecuaria Concordia. Entre Ríos, (E3200) Argentina E-mail: ramos.sergio@inta.gob.ar
Robles, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina E-mail: carorobles@bg.fcen.uba.ar
Novas, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina E-mail: vicnovas@bg.fcen.uba.ar
D´Jonsiles, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina E-mail: lalijonsi@gmail.com
Gonzalez-Audino, Centro de Investigaciones de Plagas e Insecticidas (CITEFA-CONICET). Buenos Aires, (B1603ALO) Argentina E-mail: pgonzalezaudino@citedef.gob.ar
Carmarán, Centro de Investigaciones de Plagas e Insecticidas (CITEFA-CONICET). Buenos Aires, (B1603ALO) Argentina E-mail: carmaran@bg.fcen.uba.ar

article id 9938, category Research article

Jyrki Hytönen, Egbert Beuker, Anneli Viherä-Aarnio. (2018). Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen. Silva Fennica vol. 52 no. 2 article id 9938. https://doi.org/10.14214/sf.9938

Keywords: moisture content; wood; bark; hybrid aspen; basic density; branches; clonal variation; heating value; ash content

Highlights: Hybrid aspen clones differed in their moisture content, ash content, basic density and heating value; Stem wood had lower ash content, basic density and effective heating value than stem bark; There was significant vertical variation in wood and bark along the stem in moisture content and basic density.

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Hybrid aspen (Populus tremula × P. tremuloides) is one of the fastest growing tree species in Finland. During the mid-1990s, a breeding programme was started with the aim of selecting clones that were superior in producing pulpwood. Hybrid aspen can also be grown as a short-rotation crop for bioenergy. To study clonal variation in wood and bark properties, seven clones were selected from a 12-year-old field trial located in southern Finland. From each clone, five trees were harvested and samples were taken from stem wood, stem bark and branches to determine basic density, effective heating value, moisture and ash content. Vertical within-tree variation in moisture content and basic density was also studied. The differences between clones were significant for almost all studied properties. For all studied properties there was a significant difference between wood and bark. Wood had lower ash content (0.5% vs. 3.9%), basic density (378 kg m^–3 vs. 450 kg m^–3) and effective heating value (18.26 MJ kg^–1 vs. 19.24 MJ kg^–1), but higher moisture content (55% vs. 49%) than bark. The values for branches were intermediate. These results suggest that the properties of hybrid aspen important for energy use could be improved by clonal selection. However, selecting clones based on fast growth only may be challenging since it may lead to a decrease in hybrid aspen wood density.

Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland E-mail: jyrki.hytonen@luke.fi
Beuker, Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 6, FI-57200 Savonlinna, Finland E-mail: egbert.beuker@luke.fi
Viherä-Aarnio, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: anneli.vihera-aarnio@luke.fi

article id 7723, category Research article

Mihails Čugunovs, Eeva-Stiina Tuittila, Ida Sara-Aho, Laura Pekkola, Jari Kouki. (2017). Recovery of boreal forest soil and tree stand characteristics a century after intensive slash-and-burn cultivation. Silva Fennica vol. 51 no. 5 article id 7723. https://doi.org/10.14214/sf.7723

Keywords: restoration; fire disturbance; historical land-use; rewildening

Highlights: Soil organic matter stocks have still not fully recovered after a century of stand succession and passive recovery after slash-and-burn period; Historical slash-and-burn stands feature higher live birch and standing dead wood volume than controls; If passive rewildening is used, Fennoscandian boreal forests need more than a century to regain naturalness.

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Passive rewildening of forest ecosystems is commonly used for rehabilitating degraded habitats closer to their natural origin in addition to costly active restoration measures. However, it is not clear if passive processes are effective and how long the recovery of main ecosystem properties takes. We investigate the recovery of forest soil and tree stand characteristics a century after cessation of slash-and-burn cultivation, a major historical intensive disturbance regime that was applied widely in boreal zone of Finland until late 1800s. We systematically sampled soil and tree stand parameters within former slash-and-burn and nearby control areas. Humus layer thickness and soil organic matter (SOM) stocks were still lower in the historical slash-and-burn than in control areas. Slash-and-burn areas also had a larger volume of live birch trees and a higher standing dead wood volume than control areas. Accordingly, organic matter (humus layer thickness and SOM stocks) correlated negatively with birch standing live tree volume. Combined OM stock in humus and uppermost 10 cm mineral soil layer was positively correlated with lying dead wood volume. Overall, we observed clear recovery of several natural properties but we also found that a century after cessation of frequent anthropogenic burnings, clear legacies of disturbance in the above- and below-ground parts of boreal ecosystem were evident. Our results indicate that if only passive rewildening is applied as a restoration measure, the full recovery of boreal forest is slow and the effects of historical land-use may persist for over hundred years in soil and tree properties.

Čugunovs, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mihails.cugunovs@uef.fi
Tuittila, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland http://orcid.org/0000-0001-8861-3167 E-mail: eeva-stiina.tuittila@uef.fi
Sara-Aho, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: ida.sara-aho@mhy.fi
Pekkola, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: laura.pekkola@gmail.com
Kouki, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland http://orcid.org/0000-0003-2624-8592 E-mail: jari.kouki@uef.fi

article id 7721, category Research article

Sakari Tuominen, Andras Balazs, Eija Honkavaara, Ilkka Pölönen, Heikki Saari, Teemu Hakala, Niko Viljanen. (2017). Hyperspectral UAV-imagery and photogrammetric canopy height model in estimating forest stand variables. Silva Fennica vol. 51 no. 5 article id 7721. https://doi.org/10.14214/sf.7721

Keywords: forest inventory; digital photogrammetry; aerial imagery; hyperspectral imaging; radiometric calibration; UAVs; stereo-photogrammetric canopy modelling

Highlights: Hyperspectral imagery and photogrammetric 3D point cloud based on RGB imagery were acquired under weather conditions changing from cloudy to sunny; Calibration of hyperspectral imagery was required for compensating the effect of varying weather conditions; The combination of hyperspectral imagery and photogrammetric point cloud data resulted in accurate forest estimates, especially for volumes per tree species.

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Remote sensing using unmanned aerial vehicle (UAV) -borne sensors is currently a highly interesting approach for the estimation of forest characteristics. 3D remote sensing data from airborne laser scanning or digital stereo photogrammetry enable highly accurate estimation of forest variables related to the volume of growing stock and dimension of the trees, whereas recognition of tree species dominance and proportion of different tree species has been a major complication in remote sensing-based estimation of stand variables. In this study the use of UAV-borne hyperspectral imagery was examined in combination with a high-resolution photogrammetric canopy height model in estimating forest variables of 298 sample plots. Data were captured from eleven separate test sites under weather conditions varying from sunny to cloudy and partially cloudy. Both calibrated hyperspectral reflectance images and uncalibrated imagery were tested in combination with a canopy height model based on RGB camera imagery using the k-nearest neighbour estimation method. The results indicate that this data combination allows accurate estimation of stand volume, mean height and diameter: the best relative RMSE values for those variables were 22.7%, 7.4% and 14.7%, respectively. In estimating volume and dimension-related variables, the use of a calibrated image mosaic did not bring significant improvement in the results. In estimating the volumes of individual tree species, the use of calibrated hyperspectral imagery generally brought marked improvement in the estimation accuracy; the best relative RMSE values for the volumes for pine, spruce, larch and broadleaved trees were 34.5%, 57.2%, 45.7% and 42.0%, respectively.

Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland http://orcid.org/0000-0001-5429-3433 E-mail: sakari.tuominen@luke.fi
Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: andras.balazs@luke.fi
Honkavaara, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland E-mail: eija.honkavaara@nls.fi
Pölönen, University of Jyväskylä, Faculty of Information Technology, P.O. Box 35, FI-40014 Jyväskylä, Finland E-mail: ilkka.polonen@jyu.fi
Saari, VTT Microelectronics, P.O. Box 1000, FI-02044 VTT, Finland E-mail: heikki.saari@vtt.fi
Hakala, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland E-mail: teemu.hakala@nls.fi
Viljanen, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland E-mail: niko.viljanen@nls.fi

article id 1743, category Research article

Gintare Sabalinkiene, Darius Danusevicius, Michael Manton, Gediminas Brazaitis, Kastytis Simkevicius. (2017). Differentiation of European roe deer populations and ecotypes in Lithuania based on DNA markers, cranium and antler morphometry. Silva Fennica vol. 51 no. 3 article id 1743. https://doi.org/10.14214/sf.1743

Keywords: genetic structure; inbreeding; Capreolus capreolus; polymorphism; wild game management

Highlights: Lithuanian roe deer populations are genetically structured into southern and northern groups, most likely affected by a divergent gene flow and Lithuania’s largest rivers slowing down migration; Microsatellite and skull morphology based genetic differentiation between field and forest ecotypes are weak; Geographical location has a significant effect on antler morphometry traits and skull size of male roe deer, the latter increasing northwards.

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The objective of our study was to assess the genetic and morphological differentiation of European roe deer (Capreolus capreolus L.) in Lithuania based on DNA markers, skull and anther morphology. DNA was extracted from 79 culled individuals at 13 locations and genotyped at five nuclear microsatellite loci. Based on culling location, individuals were assigned to either a field (N = 43) or a forest ecotype (N = 36). Skull and antler morphometry was studied on 603 and 292 individuals, respectively. Results showed no significant genetic and skull morphology differentiation between the ecotypes. The forest ecotype tends to exhibit lower genetic diversity compared to the field ecotype, particularly for male individuals. The genetic differentiation of roe deer in Lithuania was significant based on the R_ST values, but not on the F_ST values. A STRUCTURE analyses revealed southern and northern genetic clusters, most likely affected by divergent gene flow. The country’s major rivers Nemunas and Neris are likely to increase differentiation between the clusters. ANOVA on skull morphology by gender and age indicated a significant effect of geographical location. Skull size (especially length) is greater in the northern part of the country. We also found significant effects of age, ecotype and geographical location on most of the roe deer male antler morphometric traits.

Sabalinkiene, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania E-mail: gintare.sabalinkiene@asu.lt
Danusevicius, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania E-mail: darius.danusevicius@asu.lt
Manton, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania E-mail: michael.manton@asu.lt
Brazaitis, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania E-mail: gediminas.brazaitis@asu.lt
Simkevicius, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania E-mail: kastytis.simkevicius@asu.lt

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

Keywords: Pinus sylvestris; fertilization; vegetation management; shading; agricultural soil; overgrowth; potassium deficiency; production potential

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.

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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 http://orcid.org/0000-0001-8475-3568 E-mail: jyrki.hytonen@luke.fi
Jylhä, Natural Resources Institute Finland (Luke), Green technology, Teknologiakatu 7, FI-67100 Kokkola, Finland E-mail: paula.jylha@luke.fi
Little, Nelson Mandela Metropolitan University, George Campus, Western Cape, South Africa E-mail: keith.little@nmmu.ac.za

article id 1781, category Research article

Petr Čermák, Michal Rybníček, Tomáš Žid, Kjell Andreassen, Isabella Børja, Tomáš Kolář. (2017). Impact of climate change on growth dynamics of Norway spruce in south-eastern Norway. Silva Fennica vol. 51 no. 2 article id 1781. https://doi.org/10.14214/sf.1781

Keywords: Picea abies; precipitation; crown condition; decline; tree-ring width; Oslofjord

Highlights: Correlations between tree-ring width and climate parameters showed temporal instability in their relationship during the period 1915–2012; A statistically significant positive correlation of April–May precipitation on tree-ring growth was identified since the mid-1970s; The concomitant temperature increase may have contributed to the changes of growth dynamics.

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

Čermák, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: cermacek@mendelu.cz
Rybníček, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: michalryb@post.cz
Žid, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: tom.z@centrum.cz
Andreassen, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: Kjell.Andressen@nibio.no
Børja, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: Isabella.Borja@nibio.no
Kolář, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: koldatom@gmail.com

article id 1678, category Research article

Juan F. Jimenez, Pedro Sánchez-Gómez, Jose Luis Cánovas, Isabell Hensen, Miloud Aouissat. (2017). Influence of natural habitat fragmentation on the genetic structure of Canarian populations of Juniperus turbinata. Silva Fennica vol. 51 no. 2 article id 1678. https://doi.org/10.14214/sf.1678

Keywords: genetic diversity; AFLP markers; Canarian juniper; oceanic islands

Highlights: Canarian populations of Juniperus turbinata exhibited levels of genetic diversity similar to those of mainland populations; Despite the historical geologic events occurred in Canary Islands, and the documented decrease of populations since the arrival of settlers, no genetic differentiation between islands has been observed; As it has been observed for other Macaronesian endemics, J. turbinata long dispersal ability seems to be the main force driving the genetic structure of populations.

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Oceanic archipelagos provide an important platform from which to evaluate the effects of isolation and fragmentation on the genetic structure of species. As a result of oceanic isolation, such species usually show lower levels of genetic diversity and higher genetic differentiation than their mainland congeners. However, this is not necessarily the case for long distance dispersal species, whose genetic structure is not strictly defined by population isolation. We assessed the level and distribution of genetic diversity among Canarian populations of Juniperus turbinata in order to evaluate the influence of population isolation on its genetic structure. Using Amplified Fragment Length Polymorphism markers, we analyzed molecular diversity among 175 individuals from five populations occurring across the Canary Island and three Moroccan populations. Principal Coordinate Analysis, neighbor joining clustering, AMOVA and Bayesian-based analysis were applied to examine population structure. Despite the documented habitat loss and decline in Canarian populations, Amplified Fragment Length Polymorphism markers revealed levels of intra-population genetic diversity that were similar to those from mainland populations, and low levels of genetic differentiation. Bayesian analysis of population structure showed three main clusters, one comprising El Hierro population and a few individuals from several islands, a second cluster that grouped the remaining Canarian populations together, and a third cluster grouping Moroccan populations. Our results suggest that the main force driving the genetic structure of Canarian populations of J. turbinata is its capacity for long distance dispersal.

Jimenez, Departamento de Biología Vegetal (Botánica), Universidad de Murcia, Campus de Espinardo s/n, E-30100 Murcia, Spain E-mail: fjimenez@um.es
Sánchez-Gómez, Departamento de Biología Vegetal (Botánica), Universidad de Murcia, Campus de Espinardo s/n, E-30100 Murcia, Spain http://orcid.org/0000-0001-6754-1512 E-mail: psgomez@um.es
Cánovas, Departamento de Biología Vegetal (Botánica), Universidad de Murcia, Campus de Espinardo s/n, E-30100 Murcia, Spain E-mail: joseluis.canovas@um.es
Hensen, Institut für Biologie, Martin-Luther Universitat, 06099 Halle, Germany E-mail: isabell.hensen@botanik.uni-halle.de
Aouissat, Centre Universitaire Salhi Ahmed Naama, BP 66, Naâma, Algérie E-mail: aouissatm@yahoo.fr

article id 1718, category Research article

Mihails Čugunovs, Eeva-Stiina Tuittila, Lauri Mehtätalo, Laura Pekkola, Ida Sara-Aho, Jari Kouki. (2017). Variability and patterns in forest soil and vegetation characteristics after prescribed burning in clear-cuts and restoration burnings. Silva Fennica vol. 51 no. 1 article id 1718. https://doi.org/10.14214/sf.1718

Keywords: disturbance; restoration; sampling; spatial variability; prescribed fire; SOM stocks

Highlights: Soil parameter variability is similar across sites of different disturbance type; Variability of understory vegetation biomass and cover is higher and more different between sites than soil variability; Sites studied here reflect well the assumed disturbance-type gradient based on PCA; Sampling six forest sites per treatment should provide good statistical power to capture the differences in soil organic matter stocks.

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Forest ecological restoration by burning is widely applied to promote natural, early-successional sites and increase landscape biodiversity. Burning is also used as a forest management practice to facilitate forest regeneration after clearcutting. Besides the desired goals, restoration burnings also affect soil biogeochemistry, particularly soil organic matter (SOM) and related soil carbon stocks but the long-term effects are poorly understood. However, in order to study these effects, a reliable estimate of spatial variability is first needed for effective sampling. Here we investigate spatial variability of SOM and vegetation features 13 years after burnings and in combination with variable harvest levels. We sampled four experimental sites representing distinct management and restoration treatments with an undisturbed control. While variability of vegetation cover and biomass was generally higher in disturbed sites, soil parameter variability was not different between the four sites. The joint ecological patterns of soil and vegetation parameters across the whole sample continuum support well the prior assumptions on the characteristic disturbance conditions within each of the study sites. We designed and employed statistical simulations as a means to plan prospective sampling. Sampling six forest sites for each treatment type with 30 independent soil cores per site would provide enough statistical power to adequately capture the impacts of burning on SOM based on the data we obtained here and statistical simulations. In conclusion, we argue that an informed design-based approach to documenting the ecosystem effects of forest burnings is worth applying both through obtaining new data and meta-analysing the existing.

Čugunovs, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mihails.cugunovs@uef.fi
Tuittila, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland http://orcid.org/0000-0001-8861-3167 E-mail: eeva-stiina.tuittila@uef.fi
Mehtätalo, University of Eastern Finland, School of Computing, Science Park, Länsikatu 15, P.O. Box 111, 80101 Joensuu, Finland http://orcid.org/0000-0002-8128-0598 E-mail: lauri.mehtatalo@uef.fi
Pekkola, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: laura.pekkola@gmail.com
Sara-Aho, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: ida.sara-aho@mhy.fi
Kouki, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland http://orcid.org/0000-0003-2624-8592 E-mail: jari.kouki@uef.fi

article id 1588, category Research article

Kouakou Laurent Kouakou, Jonas Patrick Dao, Kouadio Ignace Kouassi, Manehonon Martine Beugré , Mongomaké Koné, Jean-Pierre Baudoin, Irié Arsene Zoro Bi. (2016). Propagation of Garcinia kola (Heckel) by stem and root cuttings. Silva Fennica vol. 50 no. 4 article id 1588. https://doi.org/10.14214/sf.1588

Keywords: coppicing; vegetative propagation; bitter kola; non-mist polypropagators

Highlights: Roots and branches cuttings from mature forest trees are difficult to sprout; The highest mean numbers of roots and buds produced were obtained with softwood cuttings; The aqueous IBA treatment was more effective than the powder in promoting rooting and root development; Non-mist poly-propagator gave the best propagation results; Seedling stockplants cut above node 1 promoted most vigorous shoots production.

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The availability of appropriate propagation techniques is a major constraint to the domestication of the forest trees widely used by rural communities; such as Garcinia kola (Heckel). This study tested the ability of root and stem cuttings to regenerate vegetatively when treated with indole-3-butyric acid (IBA), and set in non-mist poly-propagator within a shaded nursery. It found that G. kola is amenable to propagation by softwood stem cuttings. Attention was given to the effect of cutting age (softwood, semi hardwood) and IBA application with regard to the sprouting and rooting efficiency. Bud and leaf emergence time were also investigated, as was the coppicing ability of the stump. Results revealed that roots and branches from mature forest trees did not sprout under any culture conditions. The highest percentages of rooting (70–85%) were obtained with softwood cuttings set in non-mist poly-propagator, regardless of hormonal treatment. The mean numbers of buds (2.9 ± 0.4) and roots (2.6 ± 0.1) produced by softwood cuttings was significantly greater than those obtained in the Control. The best average emergence time of buds (25.1 days ± 9.3) and leaves (36.8days ± 8.4) was obtained with cuttings treated with IBA and set in non-mist poly-propagator against, 54.4 ± 12.5 and 72.6 ± 3.4 days respectively for the Control. In general, non-mist poly-propagator gave the best propagation results. When coppiced, the shoots emerging from stumps with one node were the most vigorous.

Kouakou, Université Nangui Abrogoua, UFR/SN, Laboratoire de Génomique Fonctionnelle et Amélioration génétique, 02 BP 801 Abidjan, Côte d’Ivoire; Université Nangui Abrogoua, UFR Sciences de la Nature, Laboratoire de Biologie et Amélioration des Productions Végétales, 02 BP 801 Abidjan 02, Côte d’Ivoire E-mail: kk_laurent@yahoo.fr
Dao, Université Nangui Abrogoua, UFR/SN, Laboratoire de Génomique Fonctionnelle et Amélioration génétique, 02 BP 801 Abidjan, Côte d’Ivoire E-mail: daojonas@hotmail.fr
Kouassi, Université Nangui Abrogoua, UFR/SN, Laboratoire de Génomique Fonctionnelle et Amélioration génétique, 02 BP 801 Abidjan, Côte d’Ivoire E-mail: kouadioignace@yahoo.fr
Beugré , Université Nangui Abrogoua, UFR Sciences de la Nature, Laboratoire de Biologie et Amélioration des Productions Végétales, 02 BP 801 Abidjan 02, Côte d’Ivoire E-mail: beugremartine@yahoo.fr
Koné, Université Nangui Abrogoua, UFR Sciences de la Nature, Laboratoire de Biologie et Amélioration des Productions Végétales, 02 BP 801 Abidjan 02, Côte d’Ivoire E-mail: babadaoudi@gmail.com
Baudoin, Université de Liège, Gembloux Agro-Bio Tech, Laboratoire Agroécologie tropicale et Horticulture, Passage des Déportés, 2 B 5030 Gembloux, Belgique E-mail: jean-pierre.baudoin@ulg.ac.be
Zoro Bi, Université Nangui Abrogoua, UFR/SN, Laboratoire de Génomique Fonctionnelle et Amélioration génétique, 02 BP 801 Abidjan, Côte d’Ivoire E-mail: banhiakalou@yahoo.fr

article id 1567, category Research article

Eetu Kotivuori, Lauri Korhonen, Petteri Packalen. (2016). Nationwide airborne laser scanning based models for volume, biomass and dominant height in Finland. Silva Fennica vol. 50 no. 4 article id 1567. https://doi.org/10.14214/sf.1567

Keywords: forest inventory; LIDAR; regression analysis; remote sensing; calibration; area-based approach; mixed-effect models

Highlights: Pooled data from nine inventory projects in Finland were used to create nationwide laser-based regression models for dominant height, volume and biomass; Volume and biomass models provided regionally different means than real means, but for dominant height the mean difference was small; The accuracy of general volume predictions was nevertheless comparable to relascope-based field inventory by compartments.

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The aim of this study was to examine how well stem volume, above-ground biomass and dominant height can be predicted using nationwide airborne laser scanning (ALS) based regression models. The study material consisted of nine practical ALS inventory projects taken from different parts of Finland. We used field sample plots and airborne laser scanning data to create nationwide and regional models for each response variable. The final models had one or two ALS predictors, which were chosen based on the root mean square error (RMSE), and cross-validated. Finally, we tested how much predictions would improve if the nationwide models were calibrated with a small number of regional sample plots. Although forest structures differ among different parts of Finland, the nationwide volume and biomass models performed quite well (leave-inventory-area-out RMSE 22.3% to 33.8%, mean difference [MD] –13.8% to 18.7%) compared with regional models (leave-plot-out RMSE 20.2% to 26.8%). However, the nationwide dominant height model (RMSE 5.4% to 7.7%, MD –2.0% to 2.8%, with the exception of the Tornio region – RMSE 11.4%, MD –9.1%) performed nearly as well as the regional models (RMSE 5.2% to 6.7%). The results show that the nationwide volume and biomass models provided different means than real means at regional level, because forest structure and ALS device have a considerable effect on the predictions. Large MDs appeared especially in northern Finland. Local calibration decreased the MD and RMSE of volume and biomass models. However, the nationwide dominant height model did not benefit much from calibration.

Kotivuori, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: eetu.kotivuori@uef.fi
Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: lauri.korhonen@uef.fi
Packalen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: petteri.packalen@uef.fi

article id 1546, category Research article

Jussi Manner, Lauri Palmroth, Tomas Nordfjell, Ola Lindroos. (2016). Load level forwarding work element analysis based on automatic follow-up data. Silva Fennica vol. 50 no. 3 article id 1546. https://doi.org/10.14214/sf.1546

Keywords: harvesting; cut-to-length logging; haulage; data gathering; automatic recording; classification algorithm; Hidden Markov Models

Highlights: Recent developments in on-board technology enables automatic collection of follow-up data on forwarder work; Time consumption per load was more strongly associated with Loading drive distance than with extraction distance, indicating that the relevance of extraction distance as a main indicator of forwarding productivity should be re-considered; Data, within variables, were positively skewed with a few exceptions with normal distributions.

Abstract | Full text in HTML | Full text in PDF | Author Info

Recent developments in on-board technology have enabled automatic collection of follow-up data on forwarder work. The objective of this study was to exploit this possibility to obtain highly representative information on time consumption of specific work elements (including overlapping crane work and driving), with one load as unit of observation, for large forwarders in final felling operations. The data used were collected by the John Deere TimberLink system as nine operators forwarded 8868 loads, in total, at sites in mid-Sweden. Load-sizes were not available. For the average and median extraction distances (219 and 174 m, respectively), Loading, Unloading, Driving empty, Driving loaded and Other time effective work (PM) accounted for ca. 45, 19, 8.5, 7.5 and 14% of total forwarding time consumption, respectively. The average and median total time consumptions were 45.8 and 42.1 minutes/load, respectively. The developed models explained large proportions of the variation of time consumption for the work elements Driving empty and Driving loaded, but minor proportions for the work elements Loading and Unloading. Based on the means, the crane was used during 74.8% of Loading PM time, the driving speed was nonzero during 31.9% of the Loading PM time, and Simultaneous crane work and driving occurred during 6.7% of the Loading PM time. Time consumption per load was more strongly associated with Loading drive distance than with extraction distance, indicating that the relevance of extraction distance as a main indicator of forwarding productivity should be re-considered.

Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: jussi.manner@skogforsk.se
Palmroth, John Deere Forestry, P.O. Box 472, FI-33101 Tampere, Finland E-mail: PalmrothLauri@JohnDeere.com
Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: tomas.nordfjell@slu.se
Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: ola.lindroos@slu.se

article id 1492, category Research article

Li-Bin Liu, Yang-Yang Wu, Gang Hu, Zhong-Hua Zhang, An-Yun Cheng, Shi-Jie Wang, Jian Ni. (2016). Biomass of karst evergreen and deciduous broad-leaved mixed forest in central Guizhou province, southwestern China: a comprehensive inventory of a 2 ha plot. Silva Fennica vol. 50 no. 3 article id 1492. https://doi.org/10.14214/sf.1492

Keywords: biomass; secondary forest; necromass; karst terrain; carbon inventory

Highlights: Comprehensive inventory of the karst secondary forest based on a 2 ha large plot enhanced the reliability of biomass estimates; The biomass was 158.1 Mg ha⁻¹, and the five dominant tree species accounted for 92.4% of aboveground tree biomass; The estimated necromass of woody debris and litter in the karst secondary forest was 17.6 Mg ha⁻¹.

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The biomass of a secondary evergreen and deciduous broad-leaved mixed forest was comprehensively inventoried in a permanent 2 ha plot in southwestern China. Biomass models, sub-sampling, soil pit method, and published data were utilized to determine the biomass of all components. Results showed that the total biomass of the forest was 158.1 Mg ha⁻¹; the total biomass included the major aboveground (137.7 Mg ha⁻¹) and belowground (20.3 Mg ha⁻¹) biomass components of vascular plants as well as the minor biomass components of bryophytes (0.078 Mg ha⁻¹) and lichens (0.043 Mg ha⁻¹). The necromass was 17.6 Mg ha⁻¹ and included woody debris (9.0 Mg ha⁻¹) and litter (8.6 Mg ha⁻¹). The spatial pattern of the aboveground biomass was determined by the spatial distribution of dominant trees with large diameter, tall height, and dense wood. The belowground biomass differed in terms of root diameter and decreased with increasing soil depth. The belowground biomass in each soil pit in local habitats was not related to the spatial distribution of woody plants and soil pit depth. The karst forest presented lower biomass compared than the nonkarst forests in the subtropical zone. Biomass carbon in the karst terrains would increase substantially if degraded karst vegetation could be successfully restored to the forest. Comprehensive site-based biomass inventory of karst vegetation will contribute not only to provide data for benchmarking global and regional vegetation and carbon models but also for regional carbon inventory and vegetation restoration.

Liu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China; University of Chinese Academy of Sciences, 100049 Beijing, China E-mail: liulibin@mail.gyig.ac.cn
Wu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China; University of Chinese Academy of Sciences, 100049 Beijing, China E-mail: wuyang2468@hotmail.com
Hu, School of Chemistry and Life Science, Guangxi Teachers Education University, 530001 Nanning, China; Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Guangxi Teachers Education University, 530001 Nanning, China E-mail: ahhugang@gmail.com
Zhang, School of Chemistry and Life Science, Guangxi Teachers Education University, 530001 Nanning, China; Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Guangxi Teachers Education University, 530001 Nanning, China E-mail: gxtczzh@gmail.com
Cheng, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China E-mail: chenganyun@vip.skleg.cn
Wang, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China E-mail: wangshijie@vip.skleg.cn
Ni, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China E-mail: nijian@vip.skleg.cn

article id 1441, category Research article

Dorota Zawadzka, Stanisław Drozdowski, Grzegorz Zawadzki, Jerzy Zawadzki. (2016). The availability of cavity trees along an age gradient in fresh pine forests. Silva Fennica vol. 50 no. 3 article id 1441. https://doi.org/10.14214/sf.1441

Keywords: Pinus sylvestris; forest management; Poland; Augustów Forest; cavity-nesting birds; woodpeckers

Highlights: The density of cavity trees in pine-dominated, managed forests varied in relation to stand age and was highest in stands older than 130 years of age; Cavities excavated by woodpeckers dominated among all cavities; The number of trees with cavities appears insufficient to ensure the effective protection of bird diversity in managed stands of Augustów Forest.

Abstract | Full text in HTML | Full text in PDF | Author Info

Given their importance as a resource for many forest organisms, tree cavities were inventoried in the managed pine forests of north-east Poland, in relation to the: 70–100, 101–130 and >130 year age-classes within the clear-cutting system. The densities at which cavities were present was found to depend on forest age, given that stands 70–100 years old were characterised by an average density of 0.62 trees ha^–1, while forests older than 130 years reported 3.28 trees ha^–1. Stands aged 70–100 years differed from those aged 130+ in having just 0.27 trees ha^–1 of cavity trees, as compared with 2.91 trees ha^–1. The total volume of cavity trees in stands up to 100 years old was 0.37 m³ha^–1on average, as compared with 5.42 m³ha^–1 in stands over 130 years old. The cavities created by woodpeckers constituted 76% of all of those found, and included 53% excavated by great spotted woodpeckers (Dendrocopos major L.) and 23% by black woodpeckers (Dryocopus martius L.) The proportion of cavities excavated by D. major was highest in the youngest age class of stands. There, cavities made by D. martius constituted only 8% of the total, as compared with 31% in the oldest stands. The abundance of cavity trees thus differed along an age gradient, though in any event the availability of cavity trees appears to be too limited to provide for the needs of hole-nesting birds. Forest managers must thus take more account than hitherto of the need to protect cavity trees.

Zawadzka, Institute of Forest Science, University of Łódź, Branch in Tomaszów Mazowiecki, Konstytucji 3 Maja 65/67, 97-200 Tomaszów Mazowiecki, Poland E-mail: dorota_zaw@wp.pl
Drozdowski, Department of Silviculture, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland E-mail: stanislaw_drozdowski@sggw.pl
Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland E-mail: grzesiekgfz@op.pl
Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland E-mail: jerzy_zaw@wp.pl

article id 1510, category Research article

Tähti Pohjanmies, Sakina Elshibli, Pertti Pulkkinen, Mari Rusanen, Pekka Vakkari, Helena Korpelainen, Tomas Roslin. (2016). Fragmentation-related patterns of genetic differentiation in pedunculate oak (Quercus robur) at two hierarchical scales. Silva Fennica vol. 50 no. 2 article id 1510. https://doi.org/10.14214/sf.1510

Keywords: marginal populations; Finland; genetic diversity; microsatellites

Highlights: While long-lived, widespread tree species should be resistant to genetic impoverishment, we detected high differentiation among populations and pronounced genetic structure within populations of Quercus robur in Finland; These patterns seem indicative of population processes active at range margins, and of disequilibrium following historic habitat change; Preservation of remaining genetic variation is thus important in the conservation of Q. robur.

Abstract | Full text in HTML | Full text in PDF | Author Info

Populations at species’ range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak (Quercus robur L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing on an island of ca 5 km². As expected, we found the majority of genetic variation in Q. robur to occur within populations. Nonetheless, differentiation among populations was markedly high (F_ST = 0.12) compared with values reported for populations of Q. robur closer to the core of its range. At the landscape level, some spatial and temporal sub-structuring was observed, likely explained by the history of land-use on the island. Overall, Q. robur fulfils the expectation of the central-marginal hypothesis of high differentiation among marginal populations, but the notable population differentiation has most likely been influenced also by the long, ongoing fragmentation of populations. Finnish oak populations may still be adjusting to the drastic habitat changes of the past centuries. Preservation of genetic variation within the remaining stands is thus an important factor in the conservation of Q. robur at its range margin.

Pohjanmies, University of Helsinki, Department of Agricultural Sciences, Spatial Foodweb Ecology Group, P.O. Box 27, FI-00014 University of Helsinki, Finland; University of Jyväskylä, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: tahti.t.pohjanmies@jyu.fi
Elshibli, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 18, FI-01301 Vantaa, Finland; University of Helsinki, Department of Agricultural Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: sakina.elshibli@helsinki.fi
Pulkkinen, Natural Resources Institute Finland (Luke), Green technology, Haapastensyrjäntie 34, FI-12600 Läyliäinen, Finland E-mail: pertti.pulkkinen@luke.fi
Rusanen, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: mari.rusanen@luke.fi
Vakkari, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pekka.vakkari@luke.fi
Korpelainen, University of Helsinki, Department of Agricultural Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: helena.korpelainen@helsinki.fi
Roslin, University of Helsinki, Department of Agricultural Sciences, Spatial Foodweb Ecology Group, P.O. Box 27, FI-00014 University of Helsinki, Finland; Swedish University of Agricultural Sciences, Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: tomas.roslin@helsinki.fi

article id 1410, category Research article

Seppo Nevalainen, Juho Matala, Kari T. Korhonen, Antti Ihalainen, Ari Nikula. (2016). Moose damage in National Forest Inventories (1986–2008) in Finland. Silva Fennica vol. 50 no. 2 article id 1410. https://doi.org/10.14214/sf.1410

Keywords: Populus tremula; Pinus sylvestris; regeneration; soil preparation; thinning; Betula spp.; Keywords Alces alces; seedling stands; tree species mixture

Highlights: Almost 100 000 stands were studied; The proportion of damage doubled during the study period; Tree species mixture had a clear effect on the damage frequency; The damage was more common in mineral soils than in peatlands, in artificially than in naturally regenerated stands and in stands that needed thinning or clearing or in which soil preparation was used.

Abstract | Full text in HTML | Full text in PDF | Author Info

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

Nevalainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: seppo.nevalainen@luke.fi
Matala, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juho.matala@luke.fi
Korhonen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kari.t.korhonen@luke.fi
Ihalainen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: antti.ihalainen@luke.fi
Nikula, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: ari.nikula@luke.fi

article id 1323, category Research article

Tiina Laine, Kalle Kärhä, Antti Hynönen. (2016). A survey of the Finnish mechanized tree-planting industry in 2013 and its success factors. Silva Fennica vol. 50 no. 2 article id 1323. https://doi.org/10.14214/sf.1323

Keywords: regeneration; boreal; forestry; silviculture; mechanization; planting machines; critical success factors (CSFs)

Highlights: In 2013, 31 planting machines were operated by 22 businesses and planted 4.7 million seedlings on 2663 hectares in Finland; Critical success factors included expertise of planting machine operators, high quality planting, adequate amount of work, stoniness, and removal of slash; Growth of the industry will depend on improved cost-efficiency, appropriate worksites, marketing, development of planting machines.

Abstract | Full text in HTML | Full text in PDF | Author Info

The aim of the study was to update the information pertaining to mechanized tree-planting activity in Finland in 2013 and its success factors. All businesses providing a mechanized tree-planting service were interviewed and asked to describe their equipment and activities, identify critical success factors (CSFs), and suggest areas for improvement. In 2013, 31 planting machines (18 Bracke P11.a, 11 M-Planter and 2 Risutec) operated by 22 businesses planted approximately 4.7 million seedlings on 2663 hectares. CSFs included expertise of planting machine operators, high quality planting, adequate amount of work, stoniness, and removal of slash. Based on the survey, some recommendations for improving mechanized planting work can be made. Firstly, improving the cost-efficiency of mechanized planting is necessary to enhance businesses’ profitability. Secondly, worksite selection is crucial as stoniness, stumps and slash debris diminish productivity. Lastly, the popularity of mechanized planting in the future will benefit from more marketing. Many businesses were unwilling to increase the area of service, invest in new equipment, or increase the volume of planting work but they believed that mechanized planting will become more popular in the near future.

Laine, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: tiina.laine@luke.fi
Kärhä, Stora Enso Wood Supply Finland, P.O. Box 309, FI-00101 Helsinki, Finland E-mail: kalle.karha@storaenso.com
Hynönen, University of Eastern Finland, Faculty of Science and Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: hynonena@gmail.com

article id 1428, category Research article

Gernot Erber, Franz Holzleitner, Maximilian Kastner, Karl Stampfer. (2015). Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings. Silva Fennica vol. 50 no. 1 article id 1428. https://doi.org/10.14214/sf.1428

Keywords: productivity; thinning; energy wood; motor-manual; accumulating harvester head; delimbing

Highlights: Harvesting with the accumulating energy wood head EF28 was studied under small tree dimension (8 dm³) in hardwood thinnings; Reasonable productivity was achieved; Maximum achieved cutting diameter in hornbeam stand was 23 cm and 15% lower than in softwood stands; Head has potential under such conditions.

Abstract | Full text in HTML | Full text in PDF | Author Info

Early thinnings are laborious and costly. Thus forest companies are searching for cost and time efficient ways to carry out this task. The study’s purpose was to determine the productivity of the EF28 accumulating energy wood harvesting head in harvesting small-diameter hornbeam (Carpinus betulus L.) undergrowth trees and evaluate the effect of its multi-tree handling (MTH) capacity on time consumption. The harvester was a wheeled, three-axle Komatsu 911. A time study of 7.1 hours on 19 plots, with a total area of 0.76 ha was conducted. On average, the harvested tree volume was 8 dm³ and the stand density was 2666 trees/ha. The productivity was modelled with MTH conduction, mean diameter at breast height and the number of trees handled per cycle as independent variables. On average, MTH took 27% longer per cycle, increased extracted volume per cycle by 33% and consequently increased productivity with 5.0%. In 71.9% of the cycles more than one tree was handled and if so, dimensions were smaller than in single-tree handling (5.8 cm vs. 12.0 cm). Maximum felling diameter of 23 cm was about 15% smaller than in softwood (according to the manufacturer’s specifications) and the driver didn’t exploit the EF28’s theoretical potential in terms of trees handled per cycle. It can be concluded that the head could significantly improve productivity in small-diameter wood procurement.

Erber, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: gernot.erber@boku.ac.at
Holzleitner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: franz.holzleitner@boku.ac.at
Kastner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: maximilian.kastner@boku.ac.at
Stampfer, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: karl.stampfer@boku.ac.at

article id 1395, category Research article

Joseph Buongiorno. (2015). Income and time dependence of forest product demand elasticities and implications for forecasting. Silva Fennica vol. 49 no. 5 article id 1395. https://doi.org/10.14214/sf.1395

Keywords: modeling; structural change; econometrics; markets

Highlights: Elasticities of demand with gross domestic product and prices were stable over time and income level for sawnwood and particleboard only; Other product elasticities differed with income and time, leading in conjunction with a sector model to higher projected world demand and prices than obtained by ignoring differences between countries and over time.

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In view of improving multi-country forest sector models, this study investigated to what extent the price and income elasticity of demand for forest products had changed in the past two decades, and how much they depended on the countries income level. For each of seven major product groups annual observations were divided between high-income (top 20% in gross domestic product per capita) and low-income, and between recent (2004–2013) and older (1992–2003) observations. The results indicated that for sawnwood and particleboard the data could be pooled across all countries and years. For the other commodity groups (veneer & plywood, fiberboard, newsprint, printing & writing paper, other paper & paperboard), there were statistically significant differences in gross domestic product or price elasticity between high and low-income levels or old and recent observations. Efficient elasticities were obtained by pooling the maximum number of observations while respecting the statistically significant differences. The resulting GDP elasticities were the same, or very close, across income levels for all products. The price elasticities differed by income level only for newsprint and for veneer and plywood. International forest sector projections to 2065 obtained with these elasticities compared with those based on pooling all data across time and income levels gave less than 3% difference for world consumption of sawnwood, particleboard, fiberboard, and newsprint, but 19% higher consumption for veneer and plywood, 31% for printing and writing paper, and 18% for other paper and paperboard. The world price was 1% to 11% higher for end products and 3% to 22% higher for raw materials and intermediate products.

Buongiorno, University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, 1630 Linden Drive, Madison, WI 53706, USA E-mail: jbuongio@wisc.edu

article id 1340, category Research article

Mostafa Farhadi, Mulualem Tigabu, Per Christer Odén. (2015). Near Infrared Spectroscopy as non-destructive method for sorting viable, petrified and empty seeds of Larix sibirica. Silva Fennica vol. 49 no. 5 article id 1340. https://doi.org/10.14214/sf.1340

Keywords: larch; NIRS; OPLS; precision sowing; seed sorting; seed quality

Highlights: Near Infrared spectroscopy discriminates filled-viable, empty and petrified seeds of Larix sibirica with 98%, 82% and 87% accuracy, respectively based on spectral differences attributed to moisture and storage reserves; The classification accuracy reached 100% when sorting seeds into viable and non-viable class; The results demonstrate that NIR spectroscopy has great potential as non-destructive sorting technique to upgrade seed lot quality.

Abstract | Full text in HTML | Full text in PDF | Author Info

Larix sibirica Ledeb. is one of the promising timber species for planting in the boreal ecosystem; but poor seed lot quality is the major hurdle for production of sufficient quantity of planting stocks. Here, we evaluated the potential of Near Infrared (NIR) Spectroscopy for sorting viable and non-viable seeds, as the conventional sorting technique is inefficient. NIR reflectance spectra were collected from single seeds, and discriminant models were developed with Orthogonal Projections to Latent Structure – Discriminant Analysis (OPLS-DA). The computed model predicted the class membership of filled-viable, empty and petrified seeds in the test set with 98%, 82% and 87% accuracy, respectively. When two-class OPLS-DA model was fitted to discriminate viable and non-viable (empty and petrified seeds combined), the predicted class membership of test set samples was 100% for both classes. The origins of spectral differences between non-viable (petrified and empty) and viable seeds were attributed to differences in seed moisture content and storage reserves. In conclusion, the result provides evidence that NIR spectroscopy is a powerful non-destructive method for sorting non-viable seeds of Larix sibirica; thus efforts should be made to develop on-line sorting system for large-scale seed handling.

Farhadi, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: mostafa.farhadi@slu.se
Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: mulualem.tigabu@slu.se
Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: per.oden@slu.se

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

Keywords: dendroclimatology; climate-growth relationships; introduced species; earlywood vessel lumen area; wood anatomy; shifting sensitivity

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.

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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 E-mail: robism@inbox.lv
Jansons, Latvian Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV 1006 E-mail: janis.jansons@silava.lv
Katrevičs, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: juris.katrevics@silava.lv
Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: aris.jansons@silava.lv

article id 1243, category Research article

Curt Almqvist, Gunnar Jansson. (2015). Effects of pruning and stand density on cone and pollen production in an experimental Pinus sylvestris seed orchard. Silva Fennica vol. 49 no. 4 article id 1243. https://doi.org/10.14214/sf.1243

Keywords: spacing; seed orchard management; crown management; seed production

Highlights: Pollen production of Pinus sylvestris began at the same age for all studied stand density and pruning height combinations but increased more rapidly at higher densities; Treatments with dense spacing increased seed production earlier; Many combinations of stand density and target height gave comparable levels of seed production, yielding a wide range of viable management options.

Abstract | Full text in HTML | Full text in PDF | Author Info

Seed orchards are the link between tree breeding and reforestation. This paper presents data on cone, seed and pollen production and seed quality gathered over 21 years in a Pinus sylvestris (L.) experimental seed orchard containing plots with 14 different combinations of stand density and targeted pruning height. The treatments’ stand densities ranged from 267 to 4000 stems ha^-1, and the target graft heights ranged from 2 to 6 meters. Pollen production began at the same orchard age for all studied combinations of stand density and target height but the level of pollen production per hectare increased more rapidly in treatments with higher stand densities. In treatments with dense spacing, cone and seed production initially increased more rapidly than in treatments with wider spacing, thereby providing an earlier return on investment and a shorter seed production lag time. However, the levels of cone and seed production in such treatments over the entire study period were not appreciably different to those achieved in treatments with wider spacing and higher target height. The treatments did not differ substantially with respect to seed quality. These results show that comparable levels of seed production can be obtained with different combinations of stand density and target height, giving seed orchard owners and managers a wide range of viable management options.

Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: curt.almqvist@skogforsk.se
Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: gunnar.jansson@skogforsk.se

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

Keywords: Pinus sylvestris; stand growth; peatlands; needle nutrients; P deficiency; K deficiency

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%.

Abstract | Full text in HTML | Full text in PDF | Author Info

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 E-mail: mikko.moilanen@luke.fi
Hytönen, Natural Resources Institute Finland, Natural resources and bioproduction, Silmäjärventie 2, FI-69100 Kannus, Finland E-mail: jyrki.hytonen@luke.fi
Hökkä, Natural Resources Institute Finland, Natural resources and bioproduction, Eteläranta 55, FI-96301 Rovaniemi, Finland E-mail: hannu.hokka@luke.fi
Ahtikoski, Natural Resources Institute Finland, Natural resources and bioproduction, Paavo Havaksen tie 3, FI-90014 Oulu, Finland E-mail: anssi.ahtikoski@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

Keywords: Picea abies; height growth; survival; bud burst; short-day treatment; summer planting

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.

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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 E-mail: jaana.luoranen@luke.fi
Rikala, The Finnish Forest Research Institute, Suonenjoki Unit, Suonenjoki, Finland E-mail: rikala@dnainternet.fi

article id 1190, category Research article

Jaakko Repola, Kristina Ahnlund Ulvcrona. (2014). Modelling biomass of young and dense Scots pine (Pinus sylvestris L.) dominated mixed forests in northern Sweden. Silva Fennica vol. 48 no. 5 article id 1190. https://doi.org/10.14214/sf.1190

Keywords: boreal forests; pine; tree biomass; biomass models; unmanaged stands

Highlights: The biomass allocation to tree components is different in unmanaged and managed young stands; Higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands; Models for trees from young and dense stands provide better estimates of biomass in such stands than those based on data from managed stands.

Abstract | Full text in HTML | Full text in PDF | Author Info

Biomass models for the biomass of above-ground tree components of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in young dense Scots pine dominated forest stands in northern Sweden were constructed. Destructive above-ground biomass sampling was conducted in naturally generated young, dense, Scots pine dominated mixed stands. Three sampling campaigns were undertaken, the first in 1997 and 1998. The second was six years later (2003), and the last 13 years after the first (2010). In total, 280 trees (126 Scots pine, 68 Norway spruce and 86 birches) were sampled from six different stands in northern Sweden. The sampled trees’ diameter at breast height (dbh) was in the range 1–22 cm (Scots pine), 1–21 cm (Norway spruce) and 1–11 cm (birch). Biomass predictions were tested using our models and the widely used biomass models originally constructed for managed stands. The results showed that the biomass allocation to tree components is different in unmanaged and managed young stands; higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands. The overall conclusion is that the biomass models for managed stands did not produce satisfactory biomass estimates in unthinned, dense, young stands.

Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: jaakko.repola@metla.fi
Ahnlund Ulvcrona, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: kristina.ulvcrona@slu.se

article id 1135, category Research article

Matts Lindbladh, Per-Ola Hedwall, Ida Wallin, Annika M. Felton, Henrik Böhlenius, Adam Felton. (2014). Short-rotation bioenergy stands as an alternative to spruce plantations: implications for bird biodiversity. Silva Fennica vol. 48 no. 5 article id 1135. https://doi.org/10.14214/sf.1135

Keywords: Norway spruce; Picea abies; hybrid aspen; Sweden; Populus × wettsteinii; production forests

Highlights: There is a gap in knowledge regarding the biodiversity implications of replacing production forests with bioenergy stands; We compared the avian biodiversity of early rotation hybrid aspen stands and spruce plantations, the latter being the dominant production forest type in southern Sweden; Our results indicate that young hybrid aspen stands can support relatively diverse and distinctive bird communities.

Abstract | Full text in HTML | Full text in PDF | Author Info

Global efforts to decrease dependence on fossil fuels have increased interest in bioenergy production. One source of bioenergy is fast growing deciduous tree species, such as hybrid aspen (Populus × wettsteinii Hämet-Ahti). The majority of research on hybrid aspen which assesses biodiversity implications, has however primarily focused on agricultural lands as the reference condition. This has resulted in a substantial gap in our knowledge regarding the biodiversity implications of replacing production forest types with hybrid aspen, a form of reforestation taking place in northern Europe. In this study we address this knowledge gap by comparing the avian biodiversity of young hybrid aspen and spruce (Picea abies L.) plantations of similar age, the latter being the most prevalent forestry alternative in in southern Sweden. We found that hybrid aspen stands had higher bird species richness and abundance as well as a distinct community composition compared to the spruce stands. We suggest that the most likely driver was the greater structural and tree species complexity in the aspen stands, provided for by the fenced exclusion of ungulates from the regenerating hybrid aspen stands. Our results indicate that at least during early stages of regeneration, and in comparison to the dominating production forest type in the region, hybrid aspen stands can support relatively high levels of bird diversity, and a bird species composition more closely associated with broadleaf habitat types requiring restoration in this region.

Lindbladh, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: matts.lindbladh@slu.se
Hedwall, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: per-ola.hedwall@slu.se
Wallin, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: ida.wallin@slu.se
Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: annika.felton@slu.se
Böhlenius, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: henrik.bohlenius@slu.se
Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: adam.felton@slu.se

article id 1119, category Research article

Beata Woziwoda, Agnieszka Parzych, Dominik Kopeć. (2014). Species diversity, biomass accumulation and carbon sequestration in the understorey of post-agricultural Scots pine forests. Silva Fennica vol. 48 no. 4 article id 1119. https://doi.org/10.14214/sf.1119

Keywords: biodiversity; Pinus sylvestris plantation; overstorey-understorey interaction; biotic homogenization; Leucobryo-Pinetum community

Highlights: Understorey plant species diversity significantly increases with the age of a Scots pine stand; Biomass of mosses decreases by a quarter, while biomass of herbs increases several times; Total understorey’s carbon stock increases over three times. The highest amount of carbon is accumulated in understorey species like Vaccinium myrtillus and Dicranum polysetum; The growing proportion of vascular plants in the understorey biomass results in an increase in the understorey C/N ratio.

Abstract | Full text in HTML | Full text in PDF | Author Info

The purpose of this study was to examine how the age of a stand of post-agricultural Scots pine forests affects the species composition, biomass and the carbon stock of the forest understorey. The community structure and species composition were studied in 75 plots (100 m² in size), the amount of biomass, organic carbon and total nitrogen were analysed in 75 subplots (1/16 m² in size). The plots were located in 21 plantations with the stand age of 41–60, 61–80 and over 80-years. Results show that the understorey species diversity increased with the increasing age of Scots pine stands, and the structure and species composition of secondary forests (although managed for timber production) became similar to the fresh pine forest of the European temperate region (Leucobryo-Pinetum community). Despite the increasing species diversity, however, only six understorey vascular and moss species played an important role in the biomass accumulation and C sequestration. Due to the differences in the dominant species composition, the total amount of understorey biomass significantly differed among the forest stands. The mean moss biomass ranged from 3046 kg ha^–1 in 41–60-year-old stands, trough 2686 kg ha^–1 in 61–80-year-old stands to 2273 kg ha^–1 in over 80-year-old stands, and the mean understorey vascular plant biomass amounted to 2 kg ha^–1, 1924 kg ha^–1 and 3508 kg ha^–1, respectively. The concentration of organic C varied considerably between species; it was the highest in Vaccinium myrtillus (50.6%) and in Dicranum polysetum (49.5%). The total mass of C was nearly 800 kg ha^–1 in the youngest forests, in the subsequent age series it was two times higher and 3.5 times higher in the oldest ones. Differences in the species composition and in the C/N ratio in different species (generally higher for vascular plants and lower for mosses) were expressed in an increase in the understorey C/N ratio, which was 39.5, 46.6 and 48.6, respectively.

Woziwoda, Department of Geobotany and Plant Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland E-mail: woziwoda@biol.uni.lodz.pl
Parzych, Environmental Chemistry Research Unit, Institute of Biology and Environmental Protection, Pomeranian University in Słupsk, Arciszewskiego 22b, 76-200 Słupsk, Poland E-mail: parzycha1@op.pl
Kopeć, Department of Geobotany and Plant Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland E-mail: domin@biol.uni.lodz.pl

article id 1072, category Research article

Polina Volkova, Alexey Shipunov, Polina Borisova, Reed Moseng, Ranelle Ivens. (2014). In search of hybridity: the case of Karelian spruces. Silva Fennica vol. 48 no. 2 article id 1072. https://doi.org/10.14214/sf.1072

Keywords: cpDNA; Picea; plant mtDNA; introgression; northern taiga

Highlights: Karelian spruces have morphology that is typical for P. obovata and characterized with genetic variation, described previously for P. abies; Karelian spruces evolved due to introgression between P. abies and P. obovata. However, it is unclear whether Karelian spruces could be treated as P. fennica, because unequivocal morphological and genetic characters of the latter are still absent.

Abstract | Full text in HTML | Full text in PDF | Author Info

Distribution ranges of spruces, European Picea abies and Siberian P. obovata intersect in the Eastern Europe and Urals, forming wide zone of introgressive hybridization where species discrimination is difficult. We applied both molecular (mtDNA and cpDNA sequences) and morphological approaches with goals of elucidating the origin of spruces in undisturbed forests of Russian Karelia (considered as part of the abovementioned introgression zone). Karelian spruces have morphology that is typical for P. obovata and characterized with genetic variation, described previously for P. abies. This contradiction between morphology and organellar DNA could be itself an evidence of hybrid origin because morphological data should have a genetic basis. If the genes responsible for the observed morphological differences are nuclear, that explains why we did not see any deviation of Karelian spruces towards P. obovata in organellar markers. In this situation nuclear gene flow from P. obovata should be performed via pollen. Thus, we should expect Karelian spruces to have cpDNA haplotypes (inherited paternally in conifers) typical for P. obovata. However, it is not the case for the majority of plants sampled and requires additional explanation like chloroplast capture in the introgresson zone. In all, we think that Karelian spruces evolved due to introgression between P. abies and P. obovata. However, it is unclear whether Karelian spruces could be treated as P. fennica, because unequivocal morphological and genetic characters of this hybridogenous species are still absent.

Volkova, Moscow South-West High School (No. 1543), 26 Bakinskikh komissarov str. 3–5, RU-119571 Moscow, Russia E-mail: avolkov@orc.ru
Shipunov, Department of Biology, Minot State University, Minot, North Dakota, USA 58707 E-mail: dactylorhiza@gmail.com
Borisova, Biological Department, Moscow State University, Vorobjevy Gory, RU-119899, Moscow, Russia E-mail: salixhastata@ya.ru
Moseng, Minot High School, Minot, North Dakota, USA 58701 E-mail: dactylorhiza@gmail.com
Ivens, Department of Biology, Minot State University, Minot, North Dakota, USA 58707 E-mail: dactylorhiza@gmail.com

article id 943, category Research article

Terje Gobakken, Lauri Korhonen, Erik Næsset. (2013). Laser-assisted selection of field plots for an area-based forest inventory. Silva Fennica vol. 47 no. 5 article id 943. https://doi.org/10.14214/sf.943

Keywords: forest inventory; LIDAR; airborne laser scanning; stratified sampling; area-based approach

Highlights: Using laser data as auxiliary information in the selection of field plot locations helps to decrease costs in forest inventories based on airborne laser scanning; Two independent, differently selected sets of field plots were used for model fitting, and third for validation; Using partial instead of ordinary least squares had no major influence on the results; Forty well placed plots produced fairly reliable volume estimates.

Abstract | Full text in HTML | Full text in PDF | Author Info

Field measurements conducted on sample plots are a major cost component in airborne laser scanning (ALS) based forest inventories, as field data is needed to obtain reference variables for the statistical models. The ALS data also provides an excellent source of prior information that may be used in the design phase of the field survey to reduce the size of the field data set. In the current study, we acquired two independent modeling data sets: one with ALS-assisted and another with random plot selection. A third data set was used for validation. One canopy height and one canopy density variable were used as a basis for the ALS-assisted selection. Ordinary and partial least squares regressions for stem volume were fitted for four different strata using the two data sets separately. The results show that the ALS-assisted plot selection helped to decrease the root mean square error (RMSE) of the predicted volume. Although the differences in RMSE were relatively small, models based on random plot selection showed larger mean differences from the reference in the independent validation data. Furthermore, a sub-sampling experiment showed that 40 well placed plots should be enough for fairly reliable predictions.

Gobakken, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, Ås, Norway E-mail: terje.gobakken@umb.no
Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: lauri.korhonen@uef.fi
Næsset, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, Ås, Norway E-mail: erik.naesset@umb.no

article id 970, category Research article

Zhen-Yu Du, Qing-Hua Wang, Shang-Jun Xing, Fang-Chun Liu, Bing-Yao Ma, Hai-Lin Ma, De-Xi Liu. (2013). Fine root distribution, characteristics and rhizosphere soil properties in a mixed stand of Robinia pseudoacacia and Fraxinus velutina in a saline soil. Silva Fennica vol. 47 no. 3 article id 970. https://doi.org/10.14214/sf.970

Keywords: mixed forest; fine root; black locust; velvet ash; rhizhosphere soil

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The spatial distribution and characteristics of fine roots (< 2 mm in diameter), and rhizosphere soil properties were studied in a mixed planted forest of black locust (Robinia pseudoacacia L.) and velvet ash (Fraxinus velutina Torr.) 27 years after planting in a coastal saline soil of the Yellow River delta, China. The results of fine root analysis showed that the fine roots of both black locust and velvet ash were mainly distributed in the soil layer at 0–20 cm depth and 50–150 cm from trees. The fine root distribution of both species suggests a strategy of avoiding salinity rather than salt –tolerance. The horizontal spread distance of fine roots of velvet ash was evidently longer than that of black locust. The fine root biomass, specific root length, specific root area, specific root volume and root activity were significantly higher for velvet ash in comparison with black locust. The results of soil analysis showed that rhizosphere soil pH of black locust and velvet ash were significantly lower compared with non-rhizosphere soil. The available N content in rhizosphere soil of black locust was higher than that of velvet ash. However, the contents of soluble salt, organic matter, available P and available K in rhizosphere soil of velvet ash were higher than those of black locust. The above results indicated that the differences between black locust and velvet ash in fine root distribution, characteristics and rhizosphere soil properties were the major reasons for that velvet ash showed stronger acclimation responses than black locust to the coastal saline soil.

Du, Shandong Academy of Forestry, 42 Wenhua East Road, Jinan 250014, P. R. China E-mail: zydu@qq.com
Wang, Shandong Academy of Forestry, Jinan, P. R. China E-mail: wqh0228@163.com
Xing, Shandong Academy of Forestry, Jinan, P. R. China E-mail: xingsj-126@126.com
Liu, Shandong Academy of Forestry, Jinan, P. R. China E-mail: fchliu@126.com
Ma, Shandong Academy of Forestry, Jinan, P. R. China E-mail: mby777@163.com
Ma, Shandong Academy of Forestry, Jinan, P. R. China E-mail: mahlin@163.com
Liu, Shandong Academy of Forestry, Jinan, P. R. China E-mail: llyldx@163.com

article id 954, category Research article

Anna-Maria Eriksson, Jörgen Olsson, Bengt Gunnar Jonsson, Sara Toivanen, Mattias Edman. (2013). Effects of restoration fire on dead wood heterogeneity and availability in three Pinus sylvestris forests in Sweden. Silva Fennica vol. 47 no. 2 article id 954. https://doi.org/10.14214/sf.954

Keywords: Scots pine; CWD; prescribed burning; decay stage; charred wood

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Restoration fires are increasingly used as a conservation tool in Sweden to recreate forests with characteristics of previous forests that were periodically disturbed by fires and promote fire-dependent species. Restoration fires can result in large inputs of fresh dead wood, but there are risks of losing some of the existing, pre-fire dead wood. To assess these counteracting effects we studied the heterogeneity and availability of dead wood before and after three restoration fires in boreal Scots pine forests. Specifically, we studied volumes of stumps, high stumps, snags and logs. The fires decreased the total volume of pre-fire dead wood (23-41%) and consumed logs in late decay stages (26-54%) to a higher extent than logs in earlier stages. The input of new fresh dead wood after the fires exceeded losses of pre-fire dead wood and resulted in a net increase of dead wood in all three sites. The added dead wood consisted of fresh snags killed by the fires. Fire also affected log characteristics: reducing their vegetation coverage (60-98%), decreasing their ground contact (4-50%) and increasing their surface area of charred wood (>50%). Such changes have important consequences for the micro environmental conditions inside logs, but have been rarely studied in relation to restoration fires. Our results show that restoration fire causes changes in dead wood availability and characteristics of logs. The results imply that ideally stands with low abundance of rare and heavily decayed wood substrates should be burned to optimize dead wood values. Alternatively, management practices should include protection of these substrates during restoration fires.

Eriksson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: anna-maria.eriksson@miun.se
Olsson, Department of Ecology and Environmental Science, Umeå University, SE-901 87, Umeå, Sweden E-mail: jorgen.m.olsson@slu.se
Jonsson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: bengt-gunnar.jonsson@miun.se
Toivanen, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: sara.toivanen@lansstyrelsen.se
Edman, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: mattias.edman@miun.se

article id 925, category Research article

Steen Magnussen. (2013). An assessment of three variance estimators for the k-nearest neighbour technique. Silva Fennica vol. 47 no. 1 article id 925. https://doi.org/10.14214/sf.925

Keywords: forest inventory; simple random sampling; resampling estimators; bootstrap; jackknife; difference estimator; cluster sampling

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A jackknife (JK), a bootstrap (BOOT), and an empirical difference estimator (EDE) of totals and variance were assessed in simulated sampling from three artificial but realistic complex multivariate populations (N = 8000 elements) organized in clusters of four elements. Intra-cluster correlations of the target variables (Y) varied from 0.03 to 0.26. Time-saving implementations of JK and BOOT are detailed. In simple random sampling (SRS), bias in totals was ≤ 0.4% for the two largest sample sizes (n = 200, 300), but slightly larger for n = 50, and 100. In cluster sampling (CLU) bias was typically 0.1% higher and more variable. The lowest overall bias was in EDE. In both SRS and CLU, JK estimates of standard error were slightly (3%) too high, while the bootstrap estimates in both SRS and CLU were too low (8%). Estimates of error suggested a trend in EDE toward an overestimation with increasing sample size. Calculated 95% confidence intervals achieved a coverage that in most cases was fairly close (± 2%) to the nominal level. For estimation of a population total the EDE estimator appears to be slightly better than the JK estimator.

Magnussen, Canadian Forest Service, Natural Resources Canada, 505 West Burnside Road, Victoria BC V8Z 1M5 Canada E-mail: steen.magnussen@nrcan.gc.ca

article id 902, category Research article

Sakari Tuominen, Reija Haapanen. (2013). Estimation of forest biomass by means of genetic algorithm-based optimization of airborne laser scanning and digital aerial photograph features. Silva Fennica vol. 47 no. 1 article id 902. https://doi.org/10.14214/sf.902

Keywords: forest inventory; airborne laser scanning; biomass modelling

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Information on forest biomass is required for several purposes, including estimation of forest bioenergy resources and forest carbon stocks. Airborne laser scanning is today considered the most accurate remote sensing method for forest inventory. The three-dimensional nature of laser scanning data enables estimation of the volumes of the tree canopies. The dimensions of the tree canopies show high correlation with the amount of forest biomass. Optical aerial photographs are often used to complement laser data, for improved distinction between tree species. The paper reports on a study testing the estimation of forest biomass variables in two study areas in Southern Finland. The biomass variables were derived on the basis of tree-level field measurements, with biomass models used for pine, spruce, and birch. The sample-plot-level biomass components were derived on the basis of tree-level data and used as reference data for airborne-laser- and aerial‑photograph-based estimation. Results were slightly better for total biomass (RMSE 22.5% and 23.6% for the two study areas) than total volume (RMSE: 23.4% and 26.1%). Species-specific estimation errors were large in general but varied between the study areas, because of differences in their forest structures.

Tuominen, Finnish Forest Research Institute, P.O.Box 18, FI-01301 Vantaa, Finland E-mail: sakari.tuominen@metla.fi
Haapanen, Finnish Forest Research Institute, P.O.Box 18, FI-01301 Vantaa, Finland E-mail: reija.haapanen@gmail.com

article id 899, category Research article

Franz Holzleitner, Christian Kanzian, Norbert Höller. (2013). Monitoring the chipping and transportation of wood fuels with a fleet management system. Silva Fennica vol. 47 no. 1 article id 899. https://doi.org/10.14214/sf.899

Keywords: forest fuel; supply chain; monitoring; logistic; fleet management; wood chips

Abstract | Full text in HTML | Full text in PDF | Author Info

Controlling and organizing the complex forest-to-consumer supply chain of wood fuels is a challenging task, especially for the chipping and transport processes. Truck mounted chippers and transport trailer-trucks must be scheduled to minimize delay to be profitable. Job management within the supply chain, including machine activity based controlling, offers a new way to increase efficiency and productivity. However, detailed data are required to detect and analyze potential gaps and improve forest fuel supply. Generally, data regarding the wood fuel supply chain process are obtained from extensive time studies that are based on a specific process step. Although time studies can detect details during the production of forest fuels, they only describe certain time frames. Long-term data that are recorded during the entire year could encompass seasonal and short term effects. This study aims to monitor the forest fuel supply processes (semi-automated), specifically regarding time and fuel consumption. Large data sets were automatically and efficiently gathered with little effort by drivers and operators. Data were recorded with fleet management equipment for more than 14 months. Vehicle data, including GPS data, were logged at an interval of one minute. Data management was conducted in a pre-configured database that contained pre-defined reports and were run by the Institute of Forest Engineering, Vienna. Work step assignments were implemented with Structured Query Language (SQL)-routines by using the raw machine activities data and GPS. The chipping and transport activities of more than 240 loads were analyzed by focusing on fuel consumption, time needed and traffic. The average distance between chipping sites and plants was approximately 54 kilometers. Fuel consumption from transport reached 50 l/100 km. The chipping unit reached a productivity of 12.8 odt/PSH15 and had a fuel consumption of 58 liters per operating hour.

Holzleitner, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: franz.holzleitner@boku.ac.at
Kanzian, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: christian.kanzian@boku.ac.at
Höller, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: norbert.hoeller@boku.ac.at

article id 911, category Research article

Marjut Turtiainen, Olli Saastamoinen, Kari Kangas, Matti Vaara. (2012). Picking of wild edible mushrooms in Finland in 1997–1999 and 2011. Silva Fennica vol. 46 no. 4 article id 911. https://doi.org/10.14214/sf.911

Keywords: wild mushrooms; mushroom picking; household use; market use; milk caps; ceps

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This study reports on national survey results concerning mushroom picking in Finland during four separate years: 1997–1999 and 2011. The material was collected by mailed questionnaire surveys amongst Finnish households. The sample size varied from 1858 (in 1998) to 6849 households (in 1997) and the response rates varied from 51% (in 2011) to 70% (in 1999). The results indicate that both the rate of participation in mushroom picking and estimates of the quantities collected varied greatly depending on whether the survey was conducted in a favourable or unfavourable year. In 1998, when the mushroom crop was abundant, a total of 47% of all households were engaged in picking and the total harvest was 16.1 million kg. In 1999, when the crop was poor, the estimates were the lowest (23% and 3.3 million kg, respectively) and in a year with a relatively abundant crop (2011), the estimates were 42% and 15.0 million kg, respectively. Mushrooms were collected mainly for home use, which accounted for 85–90% of the total harvest depending on the year. Only a small proportion of all households (0.3–1.3%) were engaged annually in commercial mushroom picking. In 1997–1999, milk caps formed the major part of the total amount picked (i.e. 37–53% depending on the year), whilst in 2011 their share was approximately one fifth of the total harvest. The results also indicate that the proportion of ceps in commercial picking has increased since the 1990s

Turtiainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: marjut.turtiainen@uef.fi
Saastamoinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: olli.saastamoinen@uef.fi
Kangas, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: kari.kangas@uef.fi
Vaara, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: matti.vaara@uef.fi

article id 907, category Research article

Chunyu Zhang, Yazhou Zhao, Xiuhai Zhao, Klaus von Gadow. (2012). Species-habitat associations in a northern temperate forest in China. Silva Fennica vol. 46 no. 4 article id 907. https://doi.org/10.14214/sf.907

Keywords: species richness; spatial autocorrelation; dispersal limitations; indicator species; topographic differentiation

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This contribution identifies species-habitat associations in a temperate forest in north-eastern China, based on the assumption that habitats are spatially autocorrelated and species are spatially aggregated due to limited seed dispersal. The empirical observations were obtained in a large permanent experimental area covering 660 x 320 m. The experimental area was subdivided into four habitat types using multivariate regression tree (MRT) analysis. According to an indicator species analysis, 38 of the 47 studied species were found to be significant indicators of the MRT habitat types. The relationships between species richness and topographic variables were found to be scale-dependent, while the great majority of the species shows distinct habitat-dependence. There are 188 potential species-habitat associations, and 114 of these were significantly positive or negative based on habitat randomization. We identified 139 significant associations using a species randomization. A habitat is not a closed system it may be both, either a sink or a source. Therefore, additional to the randomization, the Poisson Cluster Model (PCM) was applied. PCM considers the spatial autocorrelation of species and habitats, and thus appears to be more realistic than the traditional randomization processes. It identified only 37 associations that were significant. In conclusion, the deviation from the random process, i.e. the high degree of species spatial mingling may be explained by persistent immigration across habitats.

Zhang, Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, Beijing 100083, China E-mail: zcy_0520@163.com
Zhao, Department of Landscape Architecture, School of Architecture, Tsinghua University, Beijing 100084, China E-mail: yz@nn.cn
Zhao, Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, Beijing 100083, China E-mail: xz@nn.cn
von Gadow, Faculty of Forestry and Forest Ecology, Georg-August-University Göttingen, Büsgenweg 5, D-37077 Göttingen, Germany E-mail: KGadow@gwdg.de

article id 65, category Research article

Kristóf Kelemen, Barbara Mihók, László Gálhidy, Tibor Standovár. (2012). Dynamic response of herbaceous vegetation to gap opening in a Central European beech stand. Silva Fennica vol. 46 no. 1 article id 65. https://doi.org/10.14214/sf.65

Keywords: continuous cover forestry; dispersal; gap colonization; herbs; seed bank type; species richness

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Herbaceous ground vegetation in artificially-created gaps was studied in a managed beech (Fagus sylvatica L.) forest over a period of eight years in Northern Hungary, Central Europe. These gaps were being used as an alternative to the regular shelterwood system to create uneven-aged stands. The effects of gap size (15 and 40 m diameter) and canopy openness on herbaceous species colonization and persistence were assessed in a systematic grid of 5 5 m. Overall, herbaceous cover was low before gap creation, increased soon afterwards, and continued to rise over time. The number of herb species increased in the gaps and, to a lesser extent, in adjacent areas under the remaining tree canopy. Colonization of gaps was rapid and there was substantial turnover of species i.e. various species disappeared from the gaps over time whilst others colonized. Species with both long-term persistent seed banks and long distance dispersal abilities were the most successful types colonizing gaps. Six species occurred preferentially in large gaps, while only one species was found to prefer small gaps. Species present before gap creation survived in both gap sizes. Smaller gaps with a diameter of half the height of canopy trees also tended to remain free of common weed species, whereas large cover of Rubus fruticosus L. and Calamagrostis epigejos (L.) Roth could hamper natural regeneration in larger gaps. For the successful regeneration of beech we recommend the use of small gaps complemented by few large gaps.

Kelemen, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary E-mail: kk@nn.hu
Mihók, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary E-mail: bm@nn.hu
Gálhidy, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary E-mail: lg@nn.hu
Standovár, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary E-mail: standy@ludens.elte.hu

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

Keywords: biodiversity; old-growth forest; irregular stands; selection cutting; coarse woody debris; sustainable management

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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 E-mail: jpl@nn.ca
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 E-mail: christian.hebert@rncan.gc.ca
Ruel, Université Laval, Faculté de foresterie, de géographie et de géomatique, Pavillon Abitibi-Price, Québec, Canada E-mail: jcr@nn.ca

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

Keywords: disturbance regime; Lom; old-growth forest; canopy gaps; beech-spruce-fir; small-scale

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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 E-mail: alessandra.bottero@unito.it
Garbarino, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy E-mail: mg@nn.it
Dukic, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina E-mail: vd@nn.ba
Govedar, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina E-mail: zg@nn.ba
Lingua, University of Padua, Department of TeSAF, Legnaro (PD), Italy E-mail: el@nn.it
Nagel, University of Ljubljana, Department of Forestry and Renewable Forest Resources, Ljubljana, Slovenia E-mail: tan@nn.si
Motta, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy E-mail: rm@nn.it

article id 102, category Research article

Anne Toppinen, Katja Lähtinen, Leena A. Leskinen, Niklas Österman. (2011). Network co-operation as a source of competitiveness in medium-sized Finnish sawmills. Silva Fennica vol. 45 no. 4 article id 102. https://doi.org/10.14214/sf.102

Keywords: collaboration; social capital; strategic resources; competitive advantage; business processes

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In the Finnish sawmill industry, inter-firm collaboration has often been brought up as a means of creating a competitive edge in global markets by achieving economies of scale. According to the resource-based view (RBV), a firm can evaluate its current or potential partners by considering firm-level collaboration as a portfolio of complementary strategic resources. The specific focus of the study is on examining the types and forms of sawmill co-operation, how the co-operation emerged and which firm-specific resources are mainly related to co-operation. Based upon this, we can see how the managers of medium-sized sawmills perceive network co-operation as facilitating the achievement of a sustainable competitive advantage. The empirical data for this study were collected by interviewing 16 managers and employees in medium-sized non-integrated sawmills, a joint-venture marketing company and other co-operative partners. The findings of the study show that meaningful and beneficial co-operation partnerships exist in the Finnish sawmilling industry, but the sawmill managers do not perceive this collaboration as a strategic resource. The marketing company was the only firm in this study that relied on its co-operative networks in seeking a sustainable competitive advantage. To make more of co-operative partnerships, the principles of co-operative networking should be understood better in the sawmilling industry in order to know what to expect from co-operation. Furthermore, the managers should have the courage to engage in more extensive co-operation in order for strategic rents to materialize. Since the selection of the right partners is fundamental, further studies could be conducted on the reasons behind failed or terminated co-operative arrangements to gather further empirical knowledge in this subject area.

Toppinen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: anne.toppinen@helsinki.fi
Lähtinen, Finnish Environment Institute (SYKE), Joensuu, Finland E-mail: kl@nn.fi
Leskinen, Rantalankuja 4, Joensuu, Finland E-mail: lal@nn.fi
Österman, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: no@nn.fi

article id 99, category Research article

Jouni Siipilehto. (2011). Local prediction of stand structure using linear prediction theory in Scots pine-dominated stands in Finland. Silva Fennica vol. 45 no. 4 article id 99. https://doi.org/10.14214/sf.99

Keywords: Pinus sylvestris; linear prediction; diameter distribution; Weibull; Johnson’s SB; height curve; stand characteristics

Abstract | View details | Full text in PDF | Author Info

This study produced a family of models for eight standard stand characteristics, frequency and basal area-based diameter distributions, and a height curve for stands in Finland dominated by Scots pine (Pinus sylvestris L.). The data consisted of 752 National Forest Inventory-based sample plots, measured three times between 1976 and 2001. Of the data, 75% were randomly selected for modelling and 25% left out for model evaluation. Base prediction models were constructed as functions of stand age, location and site providing strongly average expectations. These expectations were then calibrated with the known stand variables using linear prediction theory when estimating the best linear unbiased predictor (BLUP). Three stand variables, typically assessed in Finnish forest management planning fieldwork, were quite effective for calibrating the expectation for the unknown variable. In the case of optional distributions, it was essential to choose the weighting of the diameter distribution model such that the available input variables and the model applied were based on the same scale (e.g. arithmetic stand variables for frequency distribution). Additional input variables generally improved the accuracy of the validated characteristics, but the improvements in the predicted distributions were most noteworthy when the arithmetic mean and basal area-weighted median were simultaneously included in the BLUP estimation. The BLUP method provided a flexible approach for characterising relationships among stand variables, alternative size distributions and the height–diameter curve. Models are intended for practical use in the MOTTI simulator.

Siipilehto, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi

article id 97, category Research article

Hannu Hökkä, Jaakko Repola, Mikko Moilanen, Markku Saarinen. (2011). Seedling survival and establishment in small canopy openings in drained spruce mires in Northern Finland. Silva Fennica vol. 45 no. 4 article id 97. https://doi.org/10.14214/sf.97

Keywords: Picea abies; canopy gaps; natural regeneration; drained peatlands; seedling establishment

Abstract | View details | Full text in PDF | Author Info

A large proportion of drained spruce mire stands is currently approaching regeneration maturity in Finland. Traditional regeneration methods with effective site preparation and planting generally result in satisfactory seedling stands also in spruce mires. However, natural regeneration methods may be more appropriate in protecting watercourses and minimizing regeneration costs. We studied the survival of advance growth and establishment of new seedlings in small canopy openings that were cut at three different diameters in two experimental drained spruce mire stands in Northern Finland (Tervola and Oulu) in 2004. The number of seedlings was repeatedly surveyed from five small circular plots (one 10 m² and four 5 m² plots in size) located within the opening. Advance growth which survived the cutting and new seedlings were separated in the surveys. The density of advance growth was on average 9000 ha^–1 after cutting, and it decreased by 30% during the five-year monitoring period (2006–2010) due to natural mortality. The number of new seedlings increased rapidly within the three years after cutting the openings. In 2010, 11 000–26 000 new seedlings ha^–1 in Tervola and 12 000–16 000 ha^–1 in Oulu on average were observed. The size of the opening had no clear effect on the regeneration result. The proportion of birch of the new seedlings increased with time and opening size in Tervola. The results show that Norway spruce regenerates naturally in small canopy openings cut in mature drained spruce mire stands.

Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, FI-96301 Rovaniemi, Finland E-mail: hannu.hokka@metla.fi
Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, FI-96301 Rovaniemi, Finland E-mail: jr@nn.fi
Moilanen, Finnish Forest Research Institute, Muhos Research Unit, Muhos, Finland E-mail: mm@nn.fi
Saarinen, Finnish Forest Research Institute, Parkano Research Unit, Parkano, Finland E-mail: ms@nn.fi

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

Keywords: Picea abies; late-season fertilization; nitrogen concentration; root growth capacity

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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 E-mail: jaana.luoranen@metla.fi
Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600, Suonenjoki, Finland E-mail: rr@nn.fi

article id 104, category Research article

Eeva Terhonen, Teresa Marco, Hui Sun, Risto Jalkanen, Risto Kasanen, Martti Vuorinen, Fred Asiegbu. (2011). The effect of latitude, season and needle-age on the mycota of Scots pine (Pinus sylvestris) in Finland. Silva Fennica vol. 45 no. 3 article id 104. https://doi.org/10.14214/sf.104

Keywords: Pinus sylvestris; needles; harsh environment; mycota; needle age; cryptic lifecycle; Hormonema dematioides

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The seasonal and latitudinal influences on the diversity and abundance of mycota of Pinus sylvestris needles were investigated. A sample of 1620 needles resulted in a total of 3868 fungal isolates, which were assigned to 68 operational taxonomic units (OTUs). The majority of these OTUs (65%) belong to Ascomycota and only 0.03% was grouped as Basidiomycota. The dominant and most frequently isolated OTU was Hormonema dematioides. Other well-known species with a saprotrophic nutritional mode such as Lophodermium spp. were also observed. The abundance of fungi increased from fall to spring. Frequencies varied significantly in Northern and Southern Finland suggesting that factors associated with latitudinal differences have an impact on the abundance of fungi.

Terhonen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: et@nn.fi
Marco, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: tm@nn.fi
Sun, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: hs@nn.fi
Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, Rovaniemi, Finland E-mail: rj@nn.fi
Kasanen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: rk@nn.fi
Vuorinen, Finnish Forest Research Institute, Suonenjoki Research Unit, Suonenjoki, Finland E-mail: mv@nn.fi
Asiegbu, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: fa@nn.fi

article id 35, category Research article

Tapio Rantala. (2011). Democratic legitimacy of the forest sector and nature conservation decision-making in Finnish print media discussion. Silva Fennica vol. 45 no. 1 article id 35. https://doi.org/10.14214/sf.35

Keywords: legitimacy; democracy; policy evaluation; forest policy; nature conservation policy; national forest program; nature conservation program

Abstract | View details | Full text in PDF | Author Info

The study explores perceived democratic legitimacy of forest-related decision-making processes in the Finnish print media discourse. The data consists of the readers’ letters in four journals (n = 530), and the comments given during the preparation of the Finnish National Forest Program (n = 140). The objective is to identify the patterns of democratic legitimacy and respective performance evaluations of actual decision-making processes. The patterns can be classified as support for: (A) democracy and other forms of government, (B) different forms of participation, and (C) principles of democracy. The principles can be further classified into 1) core regime, 2) input, 3) throughput, and 4) output principles. Democratic legitimacy was found to be an important source of legitimacy in the public discussion since democratic patterns were found in more than half of the texts. The most common core legitimacy principles included freedom of speech, good national and international standing, forerunnership, and legality at national and international level. The central principles related to input legitimacy included popular sovereignty, a voice for the people, popular participation, openness, presenting alternatives, and urgency. The consensus and majority rules were found to be the most prominent throughput principles. Democratic output legitimacy included accountability, responsibility, cooperation, commitment, responsiveness, the possibility to appeal, credibility, comprehensiveness, and understandability. The findings suggest that among the writers of readers’ letters there is less contestation regarding the principles of democratic legitimacy but there are significant disagreements concerning the performance of decision-making processes. The negative performance evaluations were two times more frequent than the positive evaluations.

Rantala, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: tapio.rantala@helsinki.fi

article id 34, category Research article

Natalie Macias, Chris Knowles. (2011). Examining the effect of environmental certification, wood source, and price on architects’ preferences of hardwood flooring. Silva Fennica vol. 45 no. 1 article id 34. https://doi.org/10.14214/sf.34

Keywords: architects; hardwood flooring; conjoint analysis; environmental certification; wood source

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This article examines the importance architects place on three factors, environmental certification, wood source, and price, when specifying hardwood flooring. Architects were presented with nine flooring scenarios, in which the three factors were present in varying levels. They were asked to rank the scenarios from the least preferred to the most preferred. Data were obtained from a mail survey of architects in Oregon and Washington, U.S.A. (n = 402). Conjoint analyses determined that architects consider price and wood source to be the most important factors when specifying hardwood flooring. Interestingly, environmental certification was considered the least important factor. The respondents were then separated into three groups for further analysis based on whether they identified themselves as more influenced by environmental factors (biocentric) or human needs (anthropocentric). This analysis showed that the biocentric group favored wood source over price and environmental certification, while the anthropocentric group favored price.

Macias, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA E-mail: natalie.macias@gmail.com
Knowles, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA E-mail: chris.knowles@oregonstate.edu

article id 29, category Research article

Piotr Androsiuk, Roman Zielinski, Kornelia Polok. (2011). B-SAP markers derived from the bacterial KatG gene differentiate populations of Pinus sylvestris and provide new insights into their postglacial history. Silva Fennica vol. 45 no. 1 article id 29. https://doi.org/10.14214/sf.29

Keywords: Pinus sylvestris; KatG gene; molecular markers; population differentiation; migrations

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The aim of the studies was to evaluate the efficiency of the KatG gene based B-SAP markers as a tool to distinguish morphologically diversified and geographically distant Scots pine populations and to track the routes of migrations. The 19 populations growing in the IUFRO 1982 provenance experiment and representing the natural distribution of the species in Europe were scored using 103 B-SAP loci. Among them 26% loci were polymorphic. The level of polymorphism was associated with the location of primers on the KatG template. The diversity was low, H_e = 0.086, and deposited mostly among populations. Seven unique markers were found that identified populations and likely they were associated with morphology. The overall genetic identity was relatively low, I = 0.933 (D = 0.069). The block of six B-SAP markers discriminated populations into two groups in agreement with their geographic origin and thereby further described as the North and the South. The North group was uniform with genetic diversity, H_e = 0.026 and the overall genetic distance D = 0.022. Presumably, it migrated from refugia in the Alps via France, northern Germany and Denmark, to Scandinavia and Russia. The South group was heterogeneous with H_e = 0.063 and D = 0.047. This group migrated from the Carpathians via Slovakia to Germany and Poland. The Balkans and Asian refugia did not take part in recolonization of Europe. The block of six B-SAP/KatG markers can be recommended for tracking postglacial history of Scots pine.

Androsiuk, University of Warmia and Mazury in Olsztyn, Department of Genetics, Plac Lodzki 3, 10-967 Olsztyn, Poland E-mail: pa@nn.pl
Zielinski, University of Warmia and Mazury in Olsztyn, Department of Genetics, Plac Lodzki 3, 10-967 Olsztyn, Poland E-mail: rz@nn.pl
Polok, University of Warmia and Mazury in Olsztyn, Department of Genetics, Plac Lodzki 3, 10-967 Olsztyn, Poland E-mail: kpolok@moskit.uwm.edu.pl

article id 121, category Research article

Catherine Ky-Dembele, Jules Bayala, Patrice Savadogo, Mulualem Tigabu, Per Christer Odén, Issaka Joseph Boussim. (2010). Comparison of growth responses of Khaya senegalensis seedlings and stecklings to four irrigation regimes. Silva Fennica vol. 44 no. 5 article id 121. https://doi.org/10.14214/sf.121

Keywords: rooted cuttings; water stress; Senegal mahogany

Abstract | View details | Full text in PDF | Author Info

Khaya senegalensis is an important tree species for timber production, native to West Africa, but mahogany shoot borer attacks prevent successful plantations. This research was aimed at comparing the growth of two propagule types, seedlings and stecklings, of Khaya senegalensis subjected to four irrigation regimes, 25, 50, 75 and 100% field capacity in Burkina Faso. The relative growth rate, biomass allocation and intrinsic water use efficiency of the propagules were assessed in a full-factorial pot experiment in block design. Except the relative growth rate of stem basal diameter and specific leaf area, for which mean values were significantly higher for seedlings than stecklings, the two propagule types had similar growth patterns regarding relative growth rates of stem length, leaf, stem, root and the total plant biomass. There was no significant difference between propagule types concerning biomass fraction to total plant biomass of leaf, stem and root, root to stem ratio, leaf area productivity and carbon isotope ratio (δ¹³C). However, the irrigation regimes significantly affected all parameters. In contrast to 75 and 100% field capacity irrigation regimes, the low water supply of 25 and 50% field capacity resulted in plant stress, which was evident from the significant reduction in plant growth and biomass production and an increase in the root biomass to total plant biomass ratio and δ¹³C. It can be concluded that seedlings and stecklings have comparable growth patterns, while water stress is a major growth-limiting factor highlighting the need for selecting drought and borer resistant genotypes for successful plantations.

Ky-Dembele, Département Productions Forestières, Institut de l’Environnement et de Recherches Agricoles, 03 BP 7047 Ouagadougou 03, Burkina Faso & Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53 Alnarp, Sweden (catherine.dembele@slu.se) E-mail: kydembele@hotmail.com
Bayala, World Agroforestry Centre, West Africa and Centre Regional Office, Sahel Node, BP E5118 Bamako, Mali E-mail: jb@nn.ml
Savadogo, Département Productions Forestières, Institut de l’Environnement et de Recherches Agricoles, 03 BP 7047 Ouagadougou 03, Burkina Faso & Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53 Alnarp, Sweden E-mail: ps@nn.bf
Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53, Alnarp, Sweden E-mail: mt@nn.se
Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53, Alnarp, Sweden E-mail: pco@nn.se
Boussim, Université de Ouagadougou, Unité de Formation et Recherche en Sciences de la Vie et de la Terre, 03 BP 7021, Ouagadougou 03, Burkina Faso E-mail: ijb@nn.bf

article id 139, category Research article

Ulf Sikström, Curt Almqvist, Gunnar Jansson. (2010). Growth of Pinus sylvestris after the application of wood ash or P and K fertilizer to a peatland in southern Sweden. Silva Fennica vol. 44 no. 3 article id 139. https://doi.org/10.14214/sf.139

Keywords: fertilization; wood ash; nitrogen; ammonium nitrate; forest yield; needle element concentrations; potassium chloride; raw phosphate

Abstract | View details | Full text in PDF | Author Info

The effects of the application of wood ash and of fertilizer regimes including phosphorus (P) and potassium (K), with and without simultaneous addition of nitrogen (N), were investigated on a stand of Scots pine (Pinus sylvestris L.) saplings growing on a drained oligotrophic peatland site in southern Sweden. A randomized block design was used. Tree growth and concentrations of various elements in the needles were measured. The addition of similar doses of P (approx. 40 kg P ha^–1) from different sources resulted in similar growth responses, amounting to 1.6–1.9 m³ ha^–1 yr^–1 of stem wood over the 26-year study. The P source was either wood ash (2500 kg d.w. ha^–1) or PK-fertilizer (raw phosphate and potassium chloride). In response to several treatments there were both increased numbers of trees and increased growth of individual trees. The high PK-dose (40 kg P ha^–1 and 80 kg K ha^–1) appeared to result in a larger growth increase than the low dose (20 kg P ha^–1 and 40 kg K ha^–1). The N treatment had no additional effect on growth. In the control plots, tree growth was more or less negligible (0.04 m³ ha^–1 yr^–1). After almost 26 years, concentrations of P and K in the needles of treated plants were still higher than in the untreated control plants. Nevertheless, in spite of the elevated P concentration, P appears to limit the growth of Scots pine. In conclusion, after sufficient drainage of this type of peatland site, it is possible for a forest stand to develop to the pole stage if wood ash or PK-fertilizer is applied.

Sikström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: ulf.sikstrom@skogforsk.se
Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: ca@nn.se
Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: gj@nn.se

article id 152, category Research article

Torgny Persson, Bengt Andersson, Tore Ericsson. (2010). Relationship between autumn cold hardiness and field performance in northern Pinus sylvestris. Silva Fennica vol. 44 no. 2 article id 152. https://doi.org/10.14214/sf.152

Keywords: Scots pine; cold hardiness; genetic coefficient of variation; genetic correlation; multivariate analysis; narrow-sense heritability

Abstract | View details | Full text in PDF | Author Info

Results from 3 artificial freezing tests (one-year-old seedlings) and 15 field trials (9- to 21-year old trees) of half-sib offspring from first generation Scots pine (Pinus sylvestris L.) plus-trees were used to estimate the amount of additive genetic variance for autumn cold hardiness and traits assessed in the field, and the genetic correlations between them. Cold hardiness of individual seedlings was scored visually, based on the discoloration of their needles after freezing in a climate chamber. The field traits analyzed were tree vitality, tree height, spike knot frequency, branch diameter, branch angle, stem straightness, and susceptibility to infection by the pathogenic fungi Phacidium infestans L., Gremmeniella abietina (Lagerb.) Morelet, Melampsora pinitorqua (Braun) Rostr. and Lophodermella sulcigena (Rostr.) Höhn. Narrow sense individual heritabilities varied between 0.30 and 0.54 for autumn cold hardiness, 0 and 0.18 for tree vitality, 0.07 and 0.41 for tree height, and 0.01 and 0.26 for the remaining traits. Based on the results of the artificial freeze tests, our estimates of additive genetic correlations indicate that while early selection for cold hardiness can improve seedling survival rates in the field, it may also reduce growth in mild environments. It also has minor effects on quality traits and attack by common fungal diseases. The results indicate that artificial freeze testing is an appropriate method for identifying suitable clones for establishing seed orchards to supply stock for the reforestation of regions with harsh environments.

Persson, Forestry Research Institute of Sweden, Sävar, Sweden E-mail: torgny.persson@skogforsk.se
Andersson, Forestry Research Institute of Sweden, Sävar, Sweden E-mail: ba@nn.se
Ericsson, Forestry Research Institute of Sweden, Sävar, Sweden E-mail: te@nn.se

article id 150, category Research article

Sini Eräjää, Panu Halme, Janne S. Kotiaho, Anni Markkanen, Tero Toivanen. (2010). The volume and composition of dead wood on traditional and forest fuel harvested clear-cuts. Silva Fennica vol. 44 no. 2 article id 150. https://doi.org/10.14214/sf.150

Keywords: dead wood; forest fuel harvesting; fine woody debris (FWD); clear-cut

Abstract | View details | Full text in PDF | Author Info

Logging residue and cut stumps are increasingly used as a renewable energy source known as forest fuel. Forest fuel harvesting obviously reduces the volume of dead wood and is likely to alter the dead wood composition, but the magnitude of the change is not known. Such information is important for the evaluation of the effects of forest fuel harvesting on biodiversity because a large proportion of forest dwelling species are directly dependent on dead wood. We measured the volume and characteristics of all dead wood units with a minimum diameter of 2 cm and a minimum length of 20 cm on 10 forest-fuel harvested and 10 traditional (control) clear-cuts. The total volume of dead wood at forest fuel harvested and control clear-cuts was 26.0 and 42.3 m³/ha, respectively. The volumes were much greater than expected suggesting that the volume of dead wood on clear-cuts has been underestimated in previous studies. Forest fuel harvested clear-cuts had 42% less branches and 81% less cut stumps than control clear-cuts but there were no differences in the volume of logs and pieces of logs, snags or roots. The volume of fine woody debris was negatively affected by forest fuel harvesting. We conclude that fine woody debris and cut stumps form a considerable resource on clear-cuts that is reduced by forest fuel harvesting. These components of dead wood have potential to be of importance in managed forests and thus deserve more attention in future biodiversity studies.

Eräjää, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: se@nn.fi
Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: panu.halme@jyu.fi
Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: jsk@nn.fi
Markkanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: am@nn.fi
Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland E-mail: tt@nn.fi

article id 200, category Research article

Peder Gjerdrum, Mauro Bernabei. (2009). Three-dimensional spiral grain pattern in five large Norway spruce stems. Silva Fennica vol. 43 no. 3 article id 200. https://doi.org/10.14214/sf.200

Keywords: grain angle; 3D-model; tree helix; split disk

Abstract | View details | Full text in PDF | Author Info

There is a great deal of interest involved in investigating and understanding grain angle in trees. The objective of the study presented in this paper has been to identify a joint, three-dimensional model for grain angle in stems of Norway spruce (Picea abies (L.) Karst.) Five large spruce trees were sampled. Transverse disks were extracted at regular intervals along the stem, split through the pith with a blunt knife, and observed for grain angle and cambial age along the north radius, setting pith observation to zero angle. The overall finding confirmed grain pattern congruent to distance from pith along the stem, a pattern that varies from tree to tree. Models expressing distance from the pith in cambial age performed slightly better than models in spatial distance. Grain pattern changed slightly along the stem, and this change was found to be consistent for the five stems: the left-handed grain angle in the juvenile wood was more pronounced upwards in the stem, and the angle changed faster towards right-handed spiralling. The model did not account for grain variation related to knots, undulating pith or other irregularities. Model residuals were normally distributed and seemingly homogeneous for all trees and for all height levels. The model is an extension of existing two-dimensional models for stem cross-cuts. After verification in a wider sample, the results should be applicable in tree and wood modelling.

Gjerdrum, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway E-mail: peder.gjerdrum@skogoglandskap.no
Bernabei, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway E-mail: mb@nn.no

article id 213, category Research article

Bum-Jin Park, Yuko Tsunetsugu, Tamami Kasetani, Takeshi Morikawa, Takahide Kagawa, Yoshifumi Miyazaki. (2009). Physiological effects of forest recreation in a young conifer forest in Hinokage Town, Japan. Silva Fennica vol. 43 no. 2 article id 213. https://doi.org/10.14214/sf.213

Keywords: blood pressure; heart rate variability; pulse rate; relaxation; Shinrin-yoku; therapeutic effects of forest; well-being

Abstract | View details | Full text in PDF | Author Info

It is widely believed that coming into contact with forest environments is somehow beneficial to human well-being and comfort. In Japan, “Shinrin-yoku” (taking in the atmosphere of a forest) has been proposed to be a relaxation activity associated with forest recreation. The purpose of this study was to examine the physiological effects of forest recreation on the autonomic nervous activity. The subjects were twelve male university students (21.8 ± 0.8 years old). On the first day of the experiment, six subjects were sent to a forest area, and the other six to a city area. On the second day, each subject was sent to the area he did not visit on the first day as a cross check. The subjects walked (15 minutes) around their assigned areas before noon, and sat on chairs viewing (15 minutes) the landscapes of their assigned areas in the afternoon. Heart rate variability (HRV), blood pressure, and pulse rate were measured as physiological indices. Measurements were taken at the place of accommodation in the morning, before and after walking, and before and after viewing at their assigned field areas. Pulse rate, diastolic blood pressure and LF/(LF+HF) (LF – low frequency, HF – high frequency) components of HRV were significantly lower in the forest area than in the city area. HF components of HRV tended to be higher in the forest than in the city. In conclusion, the results of the physiological measurements show that forest recreation enabled effective relaxation in people, both of the mind and body.

Park, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: bjpark@faculty.chiba-u.jp
Tsunetsugu, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: yt@nn.jp
Kasetani, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: tk@nn.jp
Morikawa, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: tm@nn.jp
Kagawa, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: tk@nn.jp
Miyazaki, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan E-mail: ym@nn.jp

article id 206, category Research article

Qiaoying Zhang, Yunchun Zhang, Shaolin Peng, Eshetu Yirdaw, Ning Wu. (2009). Spatial structure of alpine trees in Mountain Baima Xueshan on the southeast Tibetan Plateau. Silva Fennica vol. 43 no. 2 article id 206. https://doi.org/10.14214/sf.206

Keywords: treeline; timberline; Abies forestii var. georgei (Orr) Farjon; Juniperus saltuaria Rehder & E.H. Wilson; spatial point pattern

Abstract | View details | Full text in PDF | Author Info

Zhang, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China; Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China E-mail: lsspsl@mail.sysu.edu.cn
Zhang, Shandong Institute of Light Industry, Jinan 250353, Shandong Province, China E-mail: yz@nn.cn
Peng, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China E-mail: sp@nn.cn
Yirdaw, Viikki Tropical Resources Institute (VITRI), P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ey@nn.fi
Wu, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China E-mail: nw@nn.cn

article id 464, category Research article

Christian Kanzian, Franz Holzleitner, Karl Stampfer, Sarah Ashton. (2009). Regional energy wood logistics – optimizing local fuel supply. Silva Fennica vol. 43 no. 1 article id 464. https://doi.org/10.14214/sf.464

Keywords: logistics; energy wood; transport optimization; GIS

Abstract | View details | Full text in PDF | Author Info

The promotion of electric energy production from solid biomass by the Austrian government has lead to a boom in the construction of new combined heat and power plants. The current total demand for wood chips in the research area for energy purposes is 70 400 m³ of loose volume chips per year. The expected increase in demand due to these new plants is more than 4 times greater than current demand: up to 302 700 m³ of loose volume per year. Even if the energy wood feedstock potential is satisfactory, the design of the supply chain is still unresolved. The aim of this study is to give decision-makers a base for further development. To accomplish this, we designed and tested four different supply scenarios: one for 9 plants and one for 16 plants. The scenarios were developed using a combination of geographic information systems (GIS) and linear programming methods. The results indicate that direct transport of solid fuel wood as round wood and chipping at the plant is the cheapest supply system with a resulting cost of 5.6–6.6 EUR/m³ loose. Using harvesting residues can only be recommended for large plants because of poor fuel quality. In this case, residues would be chipped at or near the landing, piled and transported via self-loading trucks at a cost between 8.4 and 9.1 EUR/m³ loose. In order to meet increasing demand and to ensure a continuous supply, especially during the winter and spring seasons it is necessary to optimize the supply chain by including storage terminals. However, using terminals and increased demand both lead to higher logistical costs. For example, if the total volume is handled via terminals, the average supply costs including storage will increase by 26%. Higher demand increases the costs by 24%.

Kanzian, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria E-mail: christian.kanzian@boku.ac.at
Holzleitner, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria E-mail: fh@nn.at
Stampfer, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria E-mail: ks@nn.at
Ashton, Southern Regional Extension Forestry, Forestry Bldg. 4-420, University of Georgia, Athens, GA 30602, USA E-mail: sa@nn.us

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

Keywords: Pinus radiata; harvesting; compaction; wood density; tree growth; stiffness; litter removal; nitrogen deficiency

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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 E-mail: glen.murphy@oregonstate.edu
Brownlie, Scion Research, Rotorua, New Zealand E-mail: rb@nn.nz
Kimberley, Scion Research, Rotorua, New Zealand E-mail: mk@nn.nz
Beets, Scion Research, Rotorua, New Zealand E-mail: pb@nn.nz

article id 217, category Research article

Ville Kankaanhuhta, Timo Saksa, Heikki Smolander. (2009). Variation in the results of Norway spruce planting and Scots pine direct seeding in privately-owned forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 217. https://doi.org/10.14214/sf.217

Keywords: Pinus sylvestris; Picea abies; quality control; forest regeneration survey; forest regeneration inventory; quality management

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This study describes the variation in the planting results for 3-year-old Norway spruce (Picea abies (L.) Karst.) and 4-year-old Scots pine (Pinus sylvestris L.) using direct seeding in privately-owned regeneration areas in southern Finland. The study material consists of operative forest regeneration quality management inventory areas from the years 2000–2006. The effect of both the regional and the administrative levels as well as ecological factors was modelled on the basis of the hierarchy structure forestry centre, Forest Owners’ Association (= FOA), forestry professional, regeneration area and sample plot. The major part of the variation occurred at the sample plot and regeneration area level. Particular attention was paid to observation of the clustered spatial distribution of Scots pine seedlings. The FOA and forestry professional levels explained 5% of the variation in Norway spruce planting and 11% of the variation in Scots pine direct seeding. Applied forest regeneration operations, site and soil characteristics were included in the fixed effects. In the planting of Norway spruce the most important factor explaining the regeneration result was soil preparation. Mounding produced better results than patching and disc trenching. The site and soil characteristics were other important factors in the operations. The selection of direct seeding of Scots pine on too fertile, fine textured or moist sites yielded poor results.

Kankaanhuhta, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: ville.kankaanhuhta@metla.fi
Saksa, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: ts@nn.fi
Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: hs@nn.fi

article id 259, category Research article

Jani Laturi, Jarmo Mikkola, Jussi Uusivuori. (2008). Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050. Silva Fennica vol. 42 no. 2 article id 259. https://doi.org/10.14214/sf.259

Keywords: climate change; wood products; carbon pool; present value; decay function

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This study addresses the question of how much carbon will be sequestered in wood products during the coming decades in Finland. Using sawnwood and other wood material consumption data since the 1950s and inventory data of carbon reservoirs of wood products in the Finnish construction and civil engineering sector, we first derive estimates for the carbon reservoirs in wood products-in-use in that sector. We then extend the estimate to include all wood products-in-use. We find that the carbon pool of wood products in the Finnish construction and civil engineering sector grew by about 12% since an inventory for 2000, and that the overall estimate for carbon reservoirs of Finnish wood products in 2004 was 26.6 million tons of carbon. In building the scenarios until 2050, econometric time series models accounting for the relationship between wood material consumption and the development of GDP were used. The results indicate that the range of carbon reservoirs of wood products in Finland will be 39.6–64.2 million tons of carbon in the year 2050. The impacts of different forms of the decay function on the time-path of a carbon sink and its value in wood products were also studied. When a logistic decay pattern is used, the discounted value of the predicted carbon sink of wood products in Finland is between EUR850 and EUR1380 million – at the price level of EUR15/CO₂ ton – as opposed to 440–900 million euros, if a geometric decay pattern is used.

Laturi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jani.laturi@metla.fi
Mikkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jm@nn.fi
Uusivuori, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ju@nn.fi

article id 265, category Research article

Emil Cienciala, Erkki Tomppo, Arnor Snorrason, Mark Broadmeadow, Antoine Colin, Karsten Dunger, Zuzana Exnerova, Bruno Lasserre, Hans Petersson, Tibor Priwitzer, Gerardo Sanchez, Göran Ståhl. (2008). Preparing emission reporting from forests: use of National Forest Inventories in European countries. Silva Fennica vol. 42 no. 1 article id 265. https://doi.org/10.14214/sf.265

Keywords: forest carbon pools; greenhouse gas inventory; Kyoto Protocol; UNFCCC

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We examine the current status of greenhouse gas inventories of the sector Land Use, Land-Use Change and Forestry (LULUCF), in European countries, with specific focus on the utilization of National Forest Inventory (NFI) programs. LULUCF inventory is an integral part of the reporting obligations under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. The analysis is based on two questionnaires prepared by the COST Action E43 “Harmonisation of National Forest Inventories in Europe”, which were answered by greenhouse gas reporting experts in European countries. The following major conclusions can be drawn from the analysis: 1) definitions used to obtain carbon pool change estimates vary widely among countries and are not directly comparable 2) NFIs play a key role for LULUCF greenhouse gas estimation and reporting under UNFCCC, and provide the fundamental data needed for the estimation of carbon stock changes covering not only living biomass, but increasingly also deadwood, litter and soil compartments. The study highlights the effects of adopting different definitions for two major reporting processes, namely UNFCCC and FAO, and exemplifies the effect of different tree diameter thresholds on carbon stock change estimates for Finland. The results demonstrate that more effort is needed to harmonize forest inventory estimates for the purpose of making the estimates of forest carbon pool changes comparable. This effort should lead to a better utilization of the data from the European NFI programs and improve the European greenhouse gas reporting.

Cienciala, Institute of Forest Ecosystem Research (IFER), Areal 1. Jilovske a.s. 1544, 254 01 Jilove u Prahy, Czech Republic E-mail: emil.cienciala@ifer.cz
Tomppo, Metla, Finnish Forest Research Institute, Finland E-mail: et@nn.fi
Snorrason, Icelandic Forest Research, Iceland E-mail: as@nn.is
Broadmeadow, Forestry Commission, Forest Research Alice Holt Logdge, United Kingdom E-mail: mb@nn.uk
Colin, French National Forest Inventory, France E-mail: ac@nn.fr
Dunger, Federal Research Centre for Forestry and Forest Products, Institute of Forest Ecology and Forest Assessment, Germany E-mail: kd@nn.de
Exnerova, Institute of Forest Ecosystem Research, Czech Republic E-mail: ze@nn.cz
Lasserre, Department of Environment and Territory Sciences and Technologies, University of Molise, Italy E-mail: bl@nn.it
Petersson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: hp@nn.se
Priwitzer, National Forest Centre, Forest Research Institute. Slovak Republic E-mail: tb@nn.sk
Sanchez, Forest Health Unit, General Directorate for Biodiversity, Environmental Ministry, Spain E-mail: gs@nn.es
Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: gs@nn.se

article id 303, category Research article

Lars Lönnstedt. (2007). Industrial timberland ownership in the USA: arguments based on case studies. Silva Fennica vol. 41 no. 2 article id 303. https://doi.org/10.14214/sf.303

Keywords: forest management; backward vertical integration; pricing; secured supply; owner structure

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The forest product companies’ ownership of timberland is decreasing in the United States as in many other countries. In aggregate the forest product industry owned 26.5 million hectares (11.6% of the U.S. timberland) in 2002 compared with 28.5 million hectares in 1987 (FIA 2006). Reasons for this decrease of timberland ownership are several and complex. This article presents four case studies of U.S.-based forest product companies. The vertical integration theory and empirical studies about timberland ownership give a base for the study. Four hypotheses are formulated on the basis of the literature. The results give support to two of them. An important reason for timberland ownership is a wish to secure deliveries. Market conditions are important for the need of owning timberland. Two of the companies did not own timberland, the main reason being more profitable alternative uses of capital. The ownership structure of the company, tradition, and culture are other important explanations for timberland ownership. This study did not show the advantage of timberland ownership for information and coordination.

Lönnstedt, SLU, Department of Forest Products, P.O. Box 7060, SE 750 07 Uppsala, Sweden E-mail: lars.lonnstedt@spm.slu.se

article id 300, category Research article

Jouni Siipilehto, Sakari Sarkkola, Lauri Mehtätalo. (2007). Comparing regression estimation techniques when predicting diameter distributions of Scots pine on drained peatlands. Silva Fennica vol. 41 no. 2 article id 300. https://doi.org/10.14214/sf.300

Keywords: Pinus sylvestris; drained peatland; dbh distribution; Johnson’s SB function; regression estimation methods

Abstract | View details | Full text in PDF | Author Info

We compared different statistical methods for fitting linear regression models to a longitudinal data of breast height diameter (dbh) distributions of Scots pine dominated stands on drained peatlands. The parameter prediction methods for two parameters of Johnson’s S_B distribution, fitted to basal-area dbh distributions, were: 1) a linear model estimated by ordinary least squares (OLS), 2) a multivariate linear model estimated using the seemingly unrelated regression approach (SUR), 3) a linear mixed-effects model with random intercept (MIX), and 4) a multivariate mixed-effects model (MSUR). The aim was to clarify the effect of taking into account the hierarchy of the data, as well as simultaneous estimation of the correlated dependent variables on the model fit and predictions. Instead of the reliability of the predicted parameters, we focused on the reliability of the models in predicting stand conditions. Predicted distributions were validated in terms of bias, RMSE, and error deviation in the generated quantities of the growing stock. The study material consisted of 112 successively measured stands from 12 experimental areas covering the whole of Finland (total of 608 observations). Two independent test data sets were used for model validation. All the advanced regression techniques were superior to OLS, when exactly the same independent stand variables were included. SUR and MSUR were ranked the overall best and second best, respectively. Their ranking was the same in the modeling data, whereas MSUR was superior in the peatland test data and SUR in the mineral soil test data. The ranking of the models was logical, but may not be widely generalized. The SUR and MSUR models were considered to be relevant tools for practical forest management planning purposes over a variety of site types and stand structures.

Siipilehto, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi
Sarkkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ss@nn.fi
Mehtätalo, University of Joensuu, Faculty of Forestry, P.O. Box 111, 80101 Joensuu, Finland E-mail: lm@nn.fi

article id 298, category Research article

Ulfstand Wennström, Urban Bergsten, Jan-Erik Nilsson. (2007). Seedling establishment and growth after direct seeding with Pinus sylvestris: effects of seed type, seed origin, and seeding year. Silva Fennica vol. 41 no. 2 article id 298. https://doi.org/10.14214/sf.298

Keywords: Scots pine; direct seeding; orchard seed; stand seed

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The early effects of seed type, seed origin, and seeding year on seedling emergence, survival, and growth after one to four years was quantified and examined. Two experimental series of Scots pine located at 61°N and 64°N and six orchard seed lots and six stand seed lots of adequate geographical origins in each series were used. Both series were replicated at five sites for up to five years. On average, orchard seed lots had 16% and 12% higher seedling emergence, in relation to sown germinable seeds, than stand seed lots in the northern and southern series. The survival from year 1 to year 4 was also higher for orchard seedlings than for stand seedlings; there was a 77% and 72% survival rate in the northern series and a 58% and 49% survival rate in the southern series for orchard and stand seedlings respectively. On average, after four years orchard seedlings were 26% taller in the northern series and 13% taller in the southern series. The gain in height growth for the orchard seeds was positive at all seeding years, at all sites, and at all seedling ages. If survival was calculated to the height of a four-year-old seedling, the survival of orchard seedlings increased by 3% in the northern and 1% in the southern series as the result of the higher growth of orchard seedlings. Using orchard seeds resulted in 6 percent units higher growth gain when the clear cuts were regenerated with direct seeding than with plants using the same seed material. Changes in the ranking of seed lots and seed types at different sites and seeding years for seedling emergence is an effect of external factors such as grazing and foraging that cannot be related directly to the tested factors.

Wennström, Skogforsk, Box 3, SE-918 21 Sävar, Sweden E-mail: ulfstand.wennstrom@skogforsk.se
Bergsten, SLU, Dept. of Forest Ecology and Management, SE-901 83 Umeå, Sweden & SLU, Vindeln Experimental Forest, SE-922 91 Vindeln, Sweden E-mail: ub@nn.se
Nilsson, SLU, Dept. of Forest Genetics and Plant Physiology E-mail: jen@nn.se

article id 294, category Research article

Ülle Püttsepp, Krista Lõhmus, Andres Koppel. (2007). Decomposition of fine roots and α-cellulose in a short rotation willow (Salix spp.) plantation on abandoned agricultural land. Silva Fennica vol. 41 no. 2 article id 294. https://doi.org/10.14214/sf.294

Keywords: decomposition; α-cellulose; fine roots; acid detergent lignin; short rotation forest; Salix spp.

Abstract | View details | Full text in PDF | Author Info

Decomposition of fine roots (<1 mm in diameter) of the clones of Salix viminalis, S. dasyclados and α-cellulose sheets (50 x 10 x 1 mm) was studied in a 6-years old Salix spp. plantation established on abandoned agricultural land in Estonia. The substrates were incubated in litterbags (mesh size 0.14 mm) in 5–10 cm topsoil, in non-fertilised plots for one year. Changes in the ash-free weight of the fine roots were best described by negative exponential models (S. viminalis R² = 0.98, S. dasyclados R² = 0.96), and by a linear model for α-cellulose (R² = 0.63). The sheets of α-cellulose decomposed roughly twice as rapidly as the fine roots (S. viminalis k = 0.325, S. dasyclados k = 0.165). The remaining (of the initial) ash-free weights of the fine roots were 73.3 ± 0.8% (mean ± SE) and 85.8 ± 2.2% respectively, and of the α-cellulose 35.9 ± 8.5%, in the end of the one year of decomposition. The amount of acid detergent (AD) lignin in the fine-roots of S. viminalis increased significantly and did not change in S. dasyclados, suggesting higher activity of microbial decomposers in the first substrate. Of the studied quality parameters, the AD lignin was the major factor determining the different rate of decomposition of the fine roots of S. viminalis and S. dasyclados. Nitrogen was recycled in the fine root sub-system in both Salix species. This knowledge can be applied in the management of Salix plantations, aimed at bioenergy production.

Püttsepp, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7072, SE-75007 Uppsala, Sweden; Estonian University of Life Sciences, Kreuzwaldi 64, Tartu 51014, Estonia E-mail: ulle.puttsepp@ekol.slu.se
Lõhmus, Institute of Geography, University of Tartu, Vanemuise 46, Tartu 51014, Estonia E-mail: kl@nn.ee
Koppel, Estonian University of Life Sciences, Kreuzwaldi 64, Tartu 51014, Estonia E-mail: ak@nn.ee

article id 306, category Research article

Niina Tanskanen, Hannu Ilvesniemi. (2007). Spatial distribution of fine roots at ploughed Norway spruce forest sites. Silva Fennica vol. 41 no. 1 article id 306. https://doi.org/10.14214/sf.306

Keywords: Picea abies; forest soil; fine roots; ploughing; spatial distribution; specific root length; understorey roots

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We examined the spatial distribution of fine roots at two forest sites that were ploughed 20 (site K1) and 33 years (site K2) before sampling and planted with Norway spruce (Picea abies (L.) Karst.) seedlings. Soil core samples were taken from the tilt and beneath the tilt, the furrow and the intermediate undisturbed soil to a depth of 0.4 m for fine root biomass, length and necromass determinations. Norway spruce fine roots were found throughout the ploughed forest sites. The fine roots were, however, unevenly distributed: the fine root biomass was highest in the tilt (624 and 452 g m^–2 at sites K1 and K2, respectively) and lowest in the undisturbed soil at site K1 (79 g m^–2) and in the furrow at site K2 (145 g m^–2). The estimated average fine root biomass at the ploughed forest sites (268 and 248 g m^–2 at sites K1 and K2, respectively) was, however, similar to those presented in other studies concerning sites that had not been ploughed. In the tilt, a substantial proportion of the fine roots was in the inverted mineral soil horizons and in the new organic horizon above the tilt. Consistent with the fine root biomass findings, the Norway spruce necromass was highest in the tilt but the vertical distribution of the dead roots was different: the necromass was highest in the buried O_BT horizon. The results of this study suggest that at the ploughed forest sites, a substantial part of Norway spruce nutrient and water uptake occured in the tilt during the first 20 or 33 years after plantation.

Tanskanen, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: niina.tanskanen@helsinki.fi
Ilvesniemi, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: hi@nn.fi

article id 304, category Research article

Joanna Kosinska, Andrzej Lewandowski, Wladyslaw Chalupka. (2007). Genetic variability of Scots pine maternal populations and their progenies. Silva Fennica vol. 41 no. 1 article id 304. https://doi.org/10.14214/sf.304

Keywords: Pinus sylvestris L.; genetic variation; allozymes; gene conservation

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The genetic variability of Scots pine was investigated in six populations from Poland representing two maternal populations and their natural and artificial progenies. Thirteen enzyme systems controlled by 25 allozyme loci were analyzed using starch gel electrophoresis. Progeny populations maintained a high and similar level of genetic variation to that observed in the maternal populations. As expected, much closer genetic relationships were observed between maternal populations and their respective progeny than between the two maternal populations themselves. Progeny populations had the same major alleles, but differed in the number of rare alleles. Therefore, probably not all rare alleles were transferred from the maternal stands to the progenies. In addition, new rare alleles appeared in the progeny populations, possibly as a result of external pollen flow into the maternal populations.

Kosinska, Department of Human Medical Genetics, Medical University of Warsaw, Oczki 1, 02-007 Warsaw, Poland E-mail: jk@nn.pl
Lewandowski, Polish Academy of Sciences, Institute of Dendrology, 62-035 Kórnik, Poland E-mail: al@nn.pl
Chalupka, Polish Academy of Sciences, Institute of Dendrology, 62-035 Kórnik, Poland E-mail: wc@nn.pl

article id 336, category Research article

Ann Hedlund. (2006). The attractiveness of the work is affected when production of handcrafted log houses moves indoors. Silva Fennica vol. 40 no. 3 article id 336. https://doi.org/10.14214/sf.336

Keywords: log house building; attractive work; indoor; outdoor; work environment

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Viewed from a historical perspective, a shift has occurred within the forestry and wood sector towards indoor work. In Sweden, the production of handcrafted log houses has now also begun to move indoors. With a point of departure in development processes within the log house sector involving working indoors, education, work attractiveness, between 2001–2005, the aim of this study was to compare indoor work with outdoor work, based on log house builders’ experience of working on handcrafted log houses. Methods used in the interactive development project involving apprentices, experienced log house builders and researchers, were participation with continuous documentation of experiences and opinions; questions; interviews; and measurement of the work environment. The Attractive Work Model has been used in order to analyse perceptions and values. The changes, 15 out of 22 areas, were perceived both negatively and positively. Therefore, it can not be said that working on traditional, handcrafted log houses becomes more attractive if it is moved indoors. The majority wanted to work both outdoors and indoors, while most of the others only wanted to work outdoors. The results indicate that there is scope for developing more attractive work indoors by utilising experiences from log house builders and closely related activities such as the forestry and wood sector. Changes made within one area of work attractiveness affect other areas. Further research is needed both with regard to comparisons between indoor and outdoor work and regarding the interaction between the areas that are identified in the Attractive Work Model.

Hedlund, Dalarna University, SE-781 88 Borlänge, Sweden E-mail: ahd@du.se

article id 343, category Research article

Karin Vestlund, Tomas Nordfjell, Lars Eliasson, Anders Karlsson. (2006). A decision support system for selective cleaning. Silva Fennica vol. 40 no. 2 article id 343. https://doi.org/10.14214/sf.343

Keywords: forestry; pre-commercial thinning; automation; practical cleaning

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Cleaning (pre-commercial thinning) costs have increased relative to logging and regeneration costs, creating a desire for rationalisation. Cleaning with robots may be a solution, but automating stem selections requires a decision support system (DSS) capable of rendering acceptable results. The aims were to develop a DSS for automation of individual stem selections in practical cleaning, and to test, using simulations, if it renders acceptable results. Data on 17 young forest stands were used to develop a DSS that selects stems by species, position (including distance and density parameters), diameter, and damage. Six simulations were run, following the DSS, with different target settings for density, percentage of deciduous stems and minimum distance between stems. The results depend on the initial state of the stands, but generally met the requested targets in an acceptable way. On average, the density results deviated by –20% to +6% from the target values, the amount of deciduous stems shifted towards the target values, and the proportion of stems with defined damaged decreased from initially 14–90% to 4–13%. The mean diameter at breast height increased and the minimum allowed distance between stems was never violated. The simulation results indicate that the DSS is operational. However, for implementation in robotics a crucial problem is to automatically perceive the selected attributes, so additional simulations with erroneous data were run. Correct measurements of diameters are less crucial than to find the majority of the trees and the majority of trees with damages.

Vestlund, Swedish University of Agricultural Sciences, Department of Silviculture, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail: karin.vestlund@ssko.slu.se
Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden E-mail: tn@nn.se
Eliasson, Swedish University of Agricultural Sciences, Department of Silviculture, SE-901 83 Umeå, Sweden E-mail: le@nn.se
Karlsson, Swedish University of Agricultural Sciences, Department of Silviculture, SE-901 83 Umeå, Sweden E-mail: ak@nn.se

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

Keywords: Norway spruce; density; growth rate; mechanical strength; modulus of elasticity; modulus of rupture

Abstract | View details | Full text in PDF | Author Info

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 E-mail: sr@nn.fi
Saranpää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pekka.saranpaa@metla.fi
Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland E-mail: kf@nn.fi
Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tl@nn.fi
Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: lm@nn.fi
Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: rm@nn.fi
Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: lp@nn.fi
Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: acr@nn.fi

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

Keywords: boreal forests; old-growth forests; gap dynamics; age and size structure; rotated sigmoid; Newfoundland

Abstract | View details | Full text in PDF | Author Info

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 E-mail: jmccarthy@jesuits.ca
Weetman, University of British Columbia, Forest Sciences Department, 2424 Main Mall, Vancouver, B.C., Canada V6T 1Z4 E-mail: gw@n.ca

article id 351, category Research article

Jiaojun Zhu, Xiufen Li, Zugen Liu, Wei Cao, Yutaka Gonda, Takeshi Matsuzaki. (2006). Factors affecting the snow and wind induced damage of a montane secondary forest in northeastern China. Silva Fennica vol. 40 no. 1 article id 351. https://doi.org/10.14214/sf.351

Keywords: stem breakage; uprooting; stand structure; snow and wind damages; secondary forests; mixed forests

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In order to understand the processes of snow and wind induced damage in a natural montane, secondary forest in northeastern China, we examined the impacts of site conditions on the snow and wind damage; analyzed if the dominant tree species differed in their susceptibilities to the damage; and established the relationships between the characteristics of tree and stand and the damage. The results indicated that in regard to the topography factors, slope steepness and soil depth played a relatively important role for the damage. Damage ratios of all types combined were positively related with the composition of dominant tree species. The stand density was also important in determining resistance to the damage, i.e., the densely populated stand exhibited less overall damage ratios; however, the dominant tree species were commonly damaged easily by the snow and wind. Four damage modes found (uprooting, stem breakage, canopy damage and bending) were closely related to the stem taper (p < 0.05), and they could be ranked in following order: bending (92.0 ) > uprooting (85.3) > stem breakage (80.1) > canopy damage (65.0). In regard to differences in tree species’ susceptibilities to the damage, Betula costata exhibited the most uprooting, bending and overall damage ratios; while Quercus mongolica showed the highest breakage (both stem breakage and canopy damage) ratio, and Fraxinus mandshurica exhibited the least damage ratio (overall). The major six tree species could also be divided into two groups according to the overall damage ratios, i.e., more susceptible ones (B. costata, Ulmus laciniata and Q. mongolica), and less susceptible ones (F. mandshurica, Acer mono and Juglans mandshurica) to the snow and wind damage.

Zhu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: zrms29@yahoo.com
Li, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: xfl@nn.cn
Liu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: zgl@nn.cn
Cao, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: wc@nn.cn
Gonda, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: yg@nn.jp
Matsuzaki, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: tm@nn.jp

article id 479, category Research article

Ken Olaf Storaunet, Jørund Rolstad, Ivar Gjerde, Vegard S. Gundersen. (2005). Historical logging, productivity, and structural characteristics of boreal coniferous forests in Norway. Silva Fennica vol. 39 no. 3 article id 479. https://doi.org/10.14214/sf.479

Keywords: boreal forest; stand structure; decaying wood; forest history; naturalness; selective logging; dead trees

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Conservation of forest biodiversity has brought about an interest in evaluating the naturalness of forests, and to locate and protect semi-natural and old-growth forests in the Fennoscandian countries. However, it is not always clear how natural these forests really are, and how the past management history has affected their present structural composition. We studied the relationships between cut stumps from historical logging activity (50–100 years ago) and forest structural characteristics of today in a total of 385 0.25 ha plots in three boreal coniferous forests which are parts of National Nature Reserves in Norway. We also studied how forest productivity influenced these relationships. In plots with negligible logging impact we found the amount of living trees, dead wood, and size of the oldest trees mainly to increase with increasing productivity, whereas the age of the oldest trees decreased. The amount of deciduous trees was generally low irrespective of productivity. The intensity of logging did not consistently influence most of these forest structural variables, neither at low- nor at high-productive sites. The only consistent relationship in all study areas was a decreasing amount of dead wood with increasing logging intensity at high-productive sites. Also, the decay class distribution of dead wood was more right-skewed (indicating on-going accumulation of dead wood) the more logging had occurred at high-productive sites. Except from the effects on dead wood, previous logging does not show up as a major determinant of other stand structures of today.

Storaunet, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway E-mail: ken.storaunet@skogforsk.no
Rolstad, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway E-mail: jr@nn.no
Gjerde, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway E-mail: ig@nn.no
Gundersen, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway E-mail: vsg@nn.no

article id 389, category Research article

Ritva Toivonen, Eric Hansen, Erno Järvinen, Raija-Riitta Enroth. (2005). The competitive position of the Nordic wood industry in Germany – intangible quality dimensions. Silva Fennica vol. 39 no. 2 article id 389. https://doi.org/10.14214/sf.389

Keywords: wood products; quality; the intangible product component; performance

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This study examines the importance of various intangible product quality dimensions as perceived by wood-trading retailer and wholesaler companies in Germany. Using perceived importance and perceived performance, the study first examines the dimensionality of intangible product quality and then compares Nordic wood product suppliers with suppliers from other major supply regions. Data was collected from 76 German companies during 2000–2001. Results indicate that intangible product quality can be described in three dimensions, “Behaviour and Image”, “Serviceability and Environment”, and “Reliability”. Results also show that Nordic suppliers do not have a strong competitive position in Germany in terms of intangible product quality dimensions. Thus, Nordic suppliers could improve their competitive position by enhancing their service, logistics and other dimensions of the intangible product offering.

Toivonen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland E-mail: ritva.toivonen@dnainternet.net
Hansen, Oregon State University, Dept. of Wood Science & Engineering, Richardson Hall 108, 97331-5751 Corvallis, OR, USA E-mail: eh@nn.us
Järvinen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland E-mail: ej@nn.fi
Enroth, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland E-mail: rre@nn.fi

article id 387, category Research article

Sanna Laukkanen, Teijo Palander, Jyrki Kangas, Annika Kangas. (2005). Evaluation of the multicriteria approval method for timber-harvesting group decision support. Silva Fennica vol. 39 no. 2 article id 387. https://doi.org/10.14214/sf.387

Keywords: group decision support; multicriteria approval; timber-harvesting planning; voting methods

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The decision support methods most often used in timber-harvesting planning are based on a single criterion. In this study, a voting-theory-based method called multicriteria approval (MA) is introduced to the group decision support of timber-harvesting. The use of voting methods alleviates the problems caused by the multitude of decision objectives involved in forestry decision-making and by the poor quality of information concerning both the preferences of decision-makers and the evaluation of decision alternatives with respect to the objectives often faced in practical timber-harvesting planning. In the case study, the tactical forest management plan of a forest holding jointly owned by three people was specified at the operative timber-harvesting level. The task was to find the best actual operative alternatives for the harvesting that had been proposed in the tactical plan. These timber-harvesting alternatives were combinations of treatment, timber-harvesting system and the timing of logging. Forest owners established multiple criteria under which the alternatives were evaluated. Two versions of MA were tested, one of them based on individual decision analyses and other one based on a composite analysis. The first was markedly modified from the original MA, combining properties of MA and Borda count voting. The other was an original MA with the order of importance for criteria estimated either using Borda count or cumulative voting. The results of the tested MA versions produced were very similar to each other. MA was found to be a useful tool for the group decision support of timber-harvesting.

Laukkanen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: sanna.laukkanen@joensuu.fi
Palander, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: tp@nn.fi
Kangas, UPM-Kymmene Forest, P.O. Box 32, FI-37601 Valkeakoski, Finland E-mail: jk@nn.fi
Kangas, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ak@nn.fi

article id 383, category Research article

Lena Gustafsson, Leif Appelgren, Anders Nordin. (2005). Biodiversity value of potential forest fertilisation stands, as assessed by red-listed and ‘signal’ bryophytes and lichens. Silva Fennica vol. 39 no. 2 article id 383. https://doi.org/10.14214/sf.383

Keywords: biodiversity; conservation; hemi-boreal forest; Sweden; threatened species

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In Sweden ca. 20 000 ha forestland is fertilised each year. By using red-listed and ‘signal’ bryophytes and lichens as indicators, we investigated whether forest stands planned for fertilisation have a biodiversity value, and thus if restrictions due to conservation aspects are motivated. Species occurrences were registered in detailed line-transect analysis, with a record size of 10 x 10 m, in 74 coniferous forest stands with a mean age of 57 years in East-Central Sweden. On the 230 ha totally surveyed, 10 red-listed and 37 signal species were found. The mean number of records ha–1 of red-listed bryophytes and lichens was 0.26 ha–1, which is considerably less than previously found in mature production stands and woodland key habitats. Red-listed species were found in 31% of the stands and signal species in 95%. More than 70% of all records of red-listed species and 30% of the records of the signal species were found in moist micro-sites. If rare bryophytes and lichens are to be preserved in fertilisation stands, improved instructions regarding avoidance of important micro-sites are needed.

Gustafsson, Swedish University of Agricultural Sciences, Department of Conservation Biology, Box 7002, SE-750 07 Uppsala, Sweden E-mail: lena.gustafsson@nvb.slu.se
Appelgren, Belfragegatan 34H, SE-462 37 Vänersborg, Sweden E-mail: la@nn.se
Nordin, Museum of Evolution, Botany, Norbyvägen 16, SE-752 36 Uppsala, Sweden E-mail: an@nn.se

article id 400, category Research article

Antti Mutanen, Anne Toppinen. (2005). Finnish sawlog market under forest taxation reform. Silva Fennica vol. 39 no. 1 article id 400. https://doi.org/10.14214/sf.400

Keywords: forest taxation; reforms; roundwood supply; simultaneous equations

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The stepwise transition in forest taxation from site productivity tax to taxation of profits from timber sales was one of the major institutional changes to impact Finnish non-industrial private forest owners in the 1990s. In this study the effect of the forest taxation reform on the aggregate supply of sawlogs was investigated using time series analysis and quarterly data. In particular, we estimated two simultaneous equations systems for the pine and the spruce sawlog markets. According to the results, the forest taxation reform strengthened the supply of spruce and pine sawlogs in the anticipatory stage of the taxation reform in 1992. Also during the fiscal transition period, which started in 1993, the supply effect of the taxation reform has clearly been positive. The strong own-price elasticity of sawlog supply found in this study indicates high sensitivity to actual and expected wood price changes in the determination of sawlog supply in Finland. Furthermore, the results indicate that the theoretical assumption of a competitive market is suitable for the Finnish sawlog market, but that separate analysis of pine and spruce sawlogs provides additional insights into market behaviour.

Mutanen, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: antti.mutanen@metla.fi
Toppinen, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: at@nn.fi

article id 410, category Research article

Jouni Siipilehto, Juha Siitonen. (2004). Degree of previous cutting in explaining the differences in diameter distributions between mature managed and natural Norway spruce forests. Silva Fennica vol. 38 no. 4 article id 410. https://doi.org/10.14214/sf.410

Keywords: Picea abies; stand structure; naturalness; Johnson’s SB distribution

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The degree of naturalness was assessed in 37 mature (stand age 80 198 yrs) Norway spruce dominated stands located in southern Finland by measuring the number (0 610 ha–1) and basal area (0 33 m2 ha–1) of cut stumps. The Johnson’s SB distribution was fitted for living spruce trees to describe the dbh-frequency and basal area-dbh distributions. Regression models were constructed for predicting the parameters of the SB distribution using traditional stand parameters (median diameter, basal area, stem number) and the cut stump variables (number, basal area). Stump variables improved the models and enabled to explain the differences in diameter distributions between stands with varying intensity of past cutting. Model for basal area-dbh distribution was more accurate than dbh-frequency model in terms of regression statistics, but less accurate in terms of generated stand variables. The number and basal area of cut stumps seem to be useful and simple measures of stand naturalness which have potential uses in stand modelling and biodiversity-oriented forestry planning.

Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi
Siitonen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: juha.siitonen@metla.fi

article id 405, category Research article

Timo Saksa. (2004). Regeneration process from seed crop to saplings – a case study in uneven-aged Norway spruce-dominated stands in southern Finland. Silva Fennica vol. 38 no. 4 article id 405. https://doi.org/10.14214/sf.405

Keywords: boreal forest; Picea abies; regeneration; uneven-aged

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The dynamics of spruce regeneration, from seed crop to saplings, was studied based on five permanent plots in uneven-aged, spruce-dominated, boreal forest stands, cut with single-tree selection in the beginning of the 1990’s. The annual fluctuation of the spruce seed crop was very similar in uneven-aged and even-aged stands. The correlation between seed crop and number of germinants was significant; but stem number, basal area or volume of the stand did not influence on seedling emergence. The effects of good seed crops were seen as peaks or an increase in the number of germinants and smallest seedlings. The mean number of ‘stabilised’ spruce seedlings (height 11 cm to 130 cm) varied from 6000 ha^–1 to over 25 000 spruce seedlings ha^–1 from one monitoring plot to another. On a monitoring plot the number of ‘stabilised’ spruce seedlings was stable over time. Neither stand basal area nor stand volume influenced the number of ‘stabilised’ spruce seedlings, but the height of these seedlings was higher on subplots with lower stand volume and smaller basal area. In this study the monitoring period, 5–10 years, was too short to obtain reliable figures for ingrowth, i.e. the transition of seedlings to the sapling stage (h > 130 cm). The adjusted mean ingrowth was 26 stems ha^–1 year^–1.

Saksa, Finnish Forest Research Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@metla.fi

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

Keywords: seedling growth; light regime; stand density; irregular silviculture

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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 E-mail: bill.mason@forestry.gsi.gov.uk
Edwards, Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, UK, EH25 9SY E-mail: ce@nn.uk
Hale, Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, UK, EH25 9SY E-mail: seh@nn.uk

article id 419, category Research article

Tero Heinonen, Timo Pukkala. (2004). A comparison of one- and two-compartment neighbourhoods in heuristic search with spatial forest management goals. Silva Fennica vol. 38 no. 3 article id 419. https://doi.org/10.14214/sf.419

Keywords: simulated annealing; Hero; tabu search; 2-optimal heuristic; spatial optimisation; random ascent

Abstract | View details | Full text in PDF | Author Info

This study presents a comparison of the performance of four heuristic techniques with one- and two-compartment neighbourhoods in harvest scheduling problems including a spatial objective variable. The tested heuristics were random ascent, Hero, simulated annealing and tabu search. All methods seek better solutions by inspecting the neighbourhood solutions, which are combinations that can be obtained by changing the treatment schedule in one (one-compartment neighbourhood) or two (two-compartment neighbourhood) compartments. The methods and neighbourhoods were examined in one artificial and four real landscapes ranging from 700 to 981 ha in size. The landscapes had 608 to 900 stand compartments, and the examined planning problems had 2986 to 4773 binary decision variables. The objective function was a multi-objective utility function. The spatial objective variable was the percentage of compartment boundary that joins two compartments, both of which are to be cut during the same 20-year period. The non-spatial objectives were net incomes of three consecutive 20-year management periods and the remaining growing stock volume at the end of the third 20-year period. In another problem formulation, the total harvest of the first 20-year period was used as an objective variable together with the spatial objective. The results showed that a two-compartment neighbourhood was systematically and often clearly better than a one-compartment neighbourhood. The improvements were greatest with the simplest heuristics, random ascent and Hero. Of the four heuristics, tabu search and simulated annealing proved to be the best methods, but with a two-compartment neighbourhood the differences between methods were negligible.

Heinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: th@nn.fi
Pukkala, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: timo.pukkala@joensuu.fi

article id 414, category Research article

Markku Larjavaara, Timo Kuuluvainen, Heidi Tanskanen, Ari Venäläinen. (2004). Variation in forest fire ignition probability in Finland. Silva Fennica vol. 38 no. 3 article id 414. https://doi.org/10.14214/sf.414

Keywords: ignition; forest fuel moisture; forest fire; fire regime

Abstract | View details | Full text in PDF | Author Info

We examined climate-caused spatio-temporal variation of forest fire ignition probability in Finland based on empirical ignition experiments and 37 years of meteorological data from 26 meteorological stations scattered across Finland. First, meteorological data was used in order to estimate the variation in forest fuel moisture content with the model of the Finnish forest fire risk index. Second, based on data from empirical ignition experiments, fuel moisture content was linked with forest fire ignition probability. In southern Finland average forest fire ignition probability typically peaks in late May and early June, whereas in the northern part of the country the peak occurs at the end of June. There was a three-fold difference in the average annual ignition probability between the north-eastern part (3%) and south-western part of the country (9%). The observed differences in fire ignition probability suggest that the characteristics of the natural fire regime also vary considerably in the southern versus the northern part of the country.

Larjavaara, University of Helsinki, Dept of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: markku.larjavaara@helsinki.fi
Kuuluvainen, University of Helsinki, Dept of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: tk@nn.fi
Tanskanen, University of Helsinki, Dept of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: ht@nn.fi
Venäläinen, University of Helsinki, Dept of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: av@nn.fi

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

Keywords: tree growth; drained peatland forests; phosphorus availability; sequential fractionation; site type classification

Abstract | View details | Full text in PDF | Author Info

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 E-mail: mika.nieminen@metla.fi
Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tp@nn.fi

article id 424, category Research article

Mats Warensjö, Göran Rune. (2004). Stem straightness and compression wood in a 22-year-old stand of container-grown Scots pine trees. Silva Fennica vol. 38 no. 2 article id 424. https://doi.org/10.14214/sf.424

Keywords: Pinus sylvestris; stem form; eccentricity; reaction wood

Abstract | View details | Full text in PDF | Author Info

The distribution of compression wood in relation to eccentric growth and development of stem straightness was studied in a 22-year-old Scots pine (Pinus sylvestris L.) stand in central Sweden that was established with container-grown seedlings. Stem straightness was measured on the same 440 trees in 1986 and 1997. The number of stems with straight base sections increased from 60% in 1986 to 89% in 1997. Measurements of 72 sample trees in 2001 showed that 96% of the trees had developed straight stem bases. External geometry data of the logs was obtained with a Rema 3D log scanner. A sub-sample of 16 trees was randomly selected for analysis of compression wood distribution and eccentricity measurements. From each tree, 11 discs were cut at every 60 cm along the stem. All discs, except one, contained compression wood. Compression wood and pith eccentricity was most pronounced near the stem base but not significantly correlated to basal sweep. Severe compression wood content was correlated to pith eccentricity and bow height. In general, correlations were better for the basal sections of the logs. Even though most trees were straight, they contained large amounts of compression wood. It is evident that eccentric growth and compression wood formation play major roles in the development of stem straightness. In several stems, a spiral compression wood distribution pattern was found. Reasons for this are discussed.

Warensjö, Department of Forest Products and Markets, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: mats.warensjo@spm.slu.se
Rune, Department of Forestry and Wood Technology, Dalarna University, SE-776 98 Garpenberg, Sweden E-mail: gr@nn.se

article id 481, category Research article

K. S. Wang. (2003). Relationship between empty seed and genetic factors in European beech (Fagus sylvatica L.). Silva Fennica vol. 37 no. 4 article id 481. https://doi.org/10.14214/sf.481

Keywords: Fagus sylvatica L.; allozyme; empty seeds; selfing; outcrossing rate; correlation

Abstract | View details | Full text in PDF | Author Info

The relationship between percentage of empty seed (Pes) and genetic factors was explored in an isolated stand of European beech (Fagus sylvatica L.). Nine allozyme loci (GOT-B, IDH-A, LAP-A, MDH-B, MDH-C, MNR-A, 6-PGDH-A, PGI-B and PGM-A) were used to estimate genetic factors. Pes ranged from 4.8% to 40.9% for seed samples of 91 trees within the stand and showed an approximate normal distribution. The average Pes was 21.4% and the repeatability of Pes was 43.4%. The multilocus estimate for outcrossing rate (tm) based on seed samples of 30 trees within the stand was 1.015 (SE = 0.011) and the mean single locus estimate was slightly higher at 1.061 (SE = 0.026). No evidence of biparental inbreeding was found. Weak positive correlation between Pes and maximum selfing rate as well as and significant negative correlation between Pes and multilocus outcrossing rate indicated that self-fertilization may be explained as one of the important causes of empty seeds in beech.

Wang, Program in Genetics and Genomic Biology, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada E-mail: kshengw@yahoo.ca

article id 507, category Research article

Tysk Staffan Ericsson, Lars Östlund, Rikard Andersson. (2003). Destroying a path to the past – the loss of culturally scarred trees and change in forest structure along Allmunvägen, in mid-west boreal Sweden. Silva Fennica vol. 37 no. 2 article id 507. https://doi.org/10.14214/sf.507

Keywords: forest history; dendroecology; blazed trees; culturally modified trees; forest trails; tree age structure

Abstract | View details | Full text in PDF | Author Info

The tradition to blaze trees to mark trails and boundaries is very old in northern Scandinavia. The disappearance of culturally modified trees (i.e. trees with trail blazes) and changes in forest structure along a section of an old bridle trail in boreal Sweden was analyzed using historical maps and forest surveys from the period 1876 to the year 2000. Remaining blazed trees were located during a field study and selected scars were dated. In total 104 scarred living and dead trees were found. The scars originated from the early 1500s to the early 1900s. Analysis of the forest surveys showed that the forest along the trail was dominated by older trees, and that the majority of the scarred trees probably were present, throughout the 19th century. By the mid 20th century logging had begun to affect the tree age along the trail and in 1974 no stands older than 180 years were present. A conservative estimate shows that around 90% of the original blazed trees have vanished. The trail was interpreted as have being lined for centuries with scarred trees which gradually have been destroyed during the 20th century. Culturally modified trees constitute an unique source of information for understanding pattern of old trails as well as of past human land use and movement in the landscape prior to the 20th century. This biological archive have to a large extent been destroyed by forestry activities and it is therefore very important to survey, recount and protect the trees that are still present.

Ericsson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden E-mail: staffan@delta.se
Östlund, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden E-mail: lo@nn.se
Andersson, SLU, Dept. of Forest Vegetation Ecology, S-901 83 Umeå, Sweden E-mail: ra@nn.se

article id 506, category Research article

Teijo Palander, Katja Turunen, Sanna Laukkanen. (2003). Attitude of Finnish timber buyers towards implementation of a forest computer visualisation. Silva Fennica vol. 37 no. 2 article id 506. https://doi.org/10.14214/sf.506

Keywords: change resistance; competence; forest computer visualisation; timber trade

Abstract | View details | Full text in PDF | Author Info

Timber buyers’ opinions as regards forest computer visualisation are studied. The results indicated that timber buyers are still rather conventional in their computer use since they mainly use only the information system of their own company. The majority of the buyers perceived computer visualisation to be slightly useful for their work, or they had no opinion concerning the usefulness of it. One third of the buyers considered computer visualisation to be a quality factor for timber trade, and the majority were willing to use it if a program is going to adopt by their company. In analysis, different personal characteristics were found for three timber buyer groups: qualified, neutral and reluctant. Qualified buyers were the largest one, about half of the buyers belonging to this group. The greatest barriers to adopting a positive attitude to computer visualisation turned out to be weak computer skills and a general lack of interest in computer use. On the other side, it was found that organisational factors did not influence the buyers’ computer skills or attitudes towards visualisation. The results of this study can be utilised by timber buying organisation in ensuring the successful adoption of a new computer system.

Palander, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: teijo.palander@joensuu.fi
Turunen, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: kt@nn.fi
Laukkanen, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: sl@nn.fi

article id 498, category Research article

Slobodan B. Mickovski, A. Roland Ennos. (2003). Anchorage and asymmetry in the root system of Pinus peuce. Silva Fennica vol. 37 no. 2 article id 498. https://doi.org/10.14214/sf.498

Keywords: Pinus sylvestris; eccentricity; root morphology; anchorage; asymmetry; Pinus peuce; clustering

Abstract | View details | Full text in PDF | Author Info

The relationship between the anchorage mechanics and root architecture of Pinus peuce was investigated by carrying out winching tests and examining excavated root systems of 20 mature trees. The root system was dominated by 6.1±1.3 lateral roots, more than 70% of the lateral root cross sectional area (CSA) being distributed in the uppermost 10 cm of soil. Anchorage strength was related to the size of the tree and CSA. The overturning moment of trees was proportional to the diameter at breast height (DBH) to the power of 1.6. The trees exhibited significant asymmetry in anchorage rigidity, but although there was clustering of lateral roots in a preferred direction the root asymmetry was not significantly correlated with the asymmetry in anchorage rigidity, suggesting that much of the anchorage is provided by tap and sinker roots, rather than the laterals. However, the major laterals showed dorsoventral eccentricity, the more eccentric ones being those that were distributed closer to the soil surface and which pointed perpendicular to the direction of greatest resistance. This suggests that this is a result of thigmomorphogenetic effects. These results are compared with those for the related P. sylvestris and suggest that the assimilation and anchorage characteristics of root systems are controlled independently of each other.

Mickovski, School of Biological Sciences, University of Manchester, 3.614 Stopford Building, Manchester M13 9PT, UK E-mail: sbm@nn.uk
Ennos, School of Biological Sciences, University of Manchester, 3.614 Stopford Building, Manchester M13 9PT, UK E-mail: roland.ennos@man.ac.uk

article id 526, category Research article

Matleena Kniivilä, Olli Saastamoinen. (2002). The opportunity costs of forest conservation in a local economy. Silva Fennica vol. 36 no. 4 article id 526. https://doi.org/10.14214/sf.526

Keywords: nature conservation; local economy; economic impacts; cost of conservation

Abstract | View details | Full text in PDF | Author Info

Costs generated by nature conservation are repeatedly under discussion. Most often the costs of conservation are estimated as aggregate figures at the national or regional level or alternatively, for a forest owner. In this study they were examined at the local level, in the forestry dependent municipality of Ilomantsi in Eastern Finland. The estimations of lost net revenues (stumpage income less silvicultural costs), wages, entrepreneurial income and profits, employment and value added were based on alternative forest management plans calculated for conservation areas. The annual losses as regards employment during the first decade were estimated to be 5.7–20.4 jobs. Later, the employment effects were estimated to be 2.4–6.3 lost jobs. Although the value added lost during the first decade was estimated to be at maximum only 3.4% of the present total value added of the municipality, the share of the value added of forestry was estimated to be higher than the mere protected forest land share would indicate. The use of conservation areas for forestry would create a moderate increase of employment in forestry, i.e. 3.8–14%, during the first decade, but it would later stabilise at a much lower level. Employment impacts at the municipal level were estimated as very small (at maximum 0.9%), but on the other hand, for some villages even single jobs may matter. The main reasons for the minor impacts were the high mechanisation rate of logging and the major flow of stumpage income outside the locality.

Kniivilä, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: matleena.kniivila@joensuu.fi
Saastamoinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: os@nn.fi

article id 521, category Research article

Gordon Nigh. (2002). Site index conversion equations for mixed trembling aspen and white spruce stands in northern British Columbia. Silva Fennica vol. 36 no. 4 article id 521. https://doi.org/10.14214/sf.521

Keywords: site index; mixed species; trembling aspen; white spruce

Abstract | View details | Full text in PDF | Author Info

White spruce and trembling aspen are two important commercial species in British Columbia. They often grow in association, particularly in the Boreal White and Black Spruce and Sub-Boreal Spruce biogeoclimatic zones. Site index conversion equations are useful for estimating the site index of one species from the site index of another species. This study fills a need for site index conversion equations for mixed spruce/aspen stands. Seventy 0.01 ha study plots were established in mixed spruce/aspen stands. One site tree of each species was selected from each plot. The height and breast height ages of the site trees were measured and the site index was estimated with these data. The correlation between the site index of spruce and aspen was 0.6. Geometric mean regression was used to estimate the parameters of a linear site index conversion equation. The analysis did not reveal any differences in the conversion equations across the three major biogeoclimatic units (BWBSmw1, BWBSmw2, and SBS) that were sampled. Therefore, only one conversion equation is required.

Nigh, Ministry of Forests, Research Branch, P.O. Box 9519, Stn. Prov. Govt., Victoria, BC, Canada V8W 9C2 E-mail: gordon.nigh@gems2.gov.bc.ca

article id 555, category Research article

Leena Karjalainen, Timo Kuuluvainen. (2002). Amount and diversity of coarse woody debris within a boreal forest landscape dominated by Pinus sylvestris in Vienansalo wilderness, eastern Fennoscandia. Silva Fennica vol. 36 no. 1 article id 555. https://doi.org/10.14214/sf.555

Keywords: forest dynamics; disturbances; dead wood; Scots pine; tree death

Abstract | View details | Full text in PDF | Author Info

The amount, variability, quality and spatial pattern of coarse woody debris (CWD) on mineral soil sites was studied within a natural Pinus sylvestris L. dominated boreal forest landscape in Russian Viena Karelia. Data on the total CWD was collected on 27 sample plots (20 m x 100 m) and data on large CWD was surveyed along four transects (40 m wide and up to 1000 m long). The mean volume of CWD (standing and down combined) was 69.5 m3 ha–1, ranging from 22.2 m3 ha–1 to 158.7 m3 ha–1 from plot to plot. On average, 26.9 m3 ha–1 (39%) of CWD was standing dead wood and 42.7 m3 ha–1 (61%) down dead wood. The CWD displayed a wide range of variation in tree species, tree size, stage of decay, dead tree type and structural characteristics, creating a high diversity of CWD habitats for saproxylic organisms. Large CWD was almost continuously present throughout the landscape and its overall spatial distribution was close to random, although a weak autocorrelation pattern was found at distances less than about 50 m. On small spatial scales total CWD showed wide variation up to a sample area of about 0.1 ha, beyond which the variation stabilized. The fire history variables of the sample plots were not related to the amount of CWD. This and the spatial pattern of CWD suggest that the CWD dynamics in this landscape was not driven by fire, but by more or less random mortality of trees due to autogenic causes of death.

Karjalainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland E-mail: lk@nn.fi
Kuuluvainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland E-mail: timo.kuuluvainen@helsinki.fi

article id 582, category Research article

Kari Kangas, Pasi Markkanen. (2001). Factors affecting participation in wild berry picking by rural and urban dwellers. Silva Fennica vol. 35 no. 4 article id 582. https://doi.org/10.14214/sf.582

Keywords: non-wood forest products; wild berries; participation; household behaviour

Abstract | View details | Full text in PDF | Author Info

The purpose of this study was to examine the participation of urban and rural dwellers in the activity of berry-picking. The respondents in the study lived in the city of Joensuu and in the municipality of Ilomantsi, in eastern Finland. 68% of Joensuu households compared with 82% of those in Ilomantsi participated in berry-picking. These evident differences in the participation rates may be largely due to the higher costs incurred by urban dwellers in picking, since the probability of participation was not significantly higher for Ilomantsi households compared with those in Joensuu who had access to a summer-cottage which was likely to be located near the berry resources. In both municipalities, the participants were divided into two groups according to the nature of their participation in the activity. The larger group – termed ordinary pickers – were characteristically younger families with children, while the other group, termed active pickers, were distinctly more advanced in age. The quantities picked for home consumption by the groups of pickers in Ilomantsi were twice as large as those picked by the corresponding groups in Joensuu. In Joensuu, households were not significantly involved in commercial picking.

Kangas, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: kari.kangas@joensuu.fi
Markkanen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: pm@nn.fi

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

Keywords: basal area growth model; mixed-model; uncertainty of predictions; Monte Carlo simulation

Abstract | View details | Full text in PDF | Author Info

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 E-mail: kenneth.nystrom@resgeom.slu.se
Ståhl, SLU, Department of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden E-mail: gs@nn.se

article id 594, category Research article

Walter Zucchini, Matthias Schmidt, Klaus von Gadow. (2001). A model for the diameter-height distribution in an uneven-aged beech forest and a method to assess the fit of such models. Silva Fennica vol. 35 no. 2 article id 594. https://doi.org/10.14214/sf.594

Keywords: diameter-height distribution; mixture models; bivariate normal distribution; SBB distribution; goodness-of-fit; pseudo-residuals; beech forest

Abstract | View details | Full text in PDF | Author Info

This paper illustrates the application of a mixture model to describe the bivariate diameter-height distribution of trees growing in a pure, uneven-aged beech forest. A mixture of two bivariate normal distributions is considered but the methodology is applicable to mixtures of other distributions. The model was fitted to diameter-height observations for 1242 beech trees in the protected forest Dreyberg (Solling, Germany). A considerable advantage of the model, apart from the fact that it happens to fit this large data set unusually well, is that the individual parameters all have familiar interpretations. The bivariate Johnson SBB distribution was also fitted to the data for the purpose of comparing the fits. A second issue discussed in this paper is concerned with the general question of assessing the fit of models for bivariate data. We show how a device called ‘pseudo-residual’ enables one to investigate the fit of a bivariate model in new ways and in considerable detail. Attractive features of pseudo-residuals include the fact that they are not difficult to interpret; they can be computed using generally available statistical software and, most important of all, they enable one to examine the fit of a model by means of simple graphs.

Zucchini, Georg-August-Universität Göttingen, Institute for Statistics and Econometrics E-mail: zucchini@wi-wiss.uni-goettingen.de
Schmidt, Forest Research Station of Lower Saxony E-mail: ms@nn.de
Gadow, Georg-August-Universität Göttingen, Institute for Forest Management and Yield Sciences E-mail: kvg@nn.de

article id 606, category Research article

Pekka Leskinen, Jyrki Kangas. (2001). Modelling future timber price development by using expert judgments and time series analysis. Silva Fennica vol. 35 no. 1 article id 606. https://doi.org/10.14214/sf.606

Keywords: forest planning; uncertainty; expert knowledge; forecasting; price peaks; price trend; price variation

Abstract | View details | Full text in PDF | Author Info

Timber prices belong to the most important variables affecting the optimality of forest management. On the other hand, forecasting of timber prices is very uncertain. One difficulty when using past time series data in forecasting future timber price development is the possibility of changes in the markets and in the society at large. Expert knowledge can be applied in forecasting of timber prices as information additional to that provided by time series modelling. This paper presents an approach utilising both time series data and expert judgments in modelling future timber prices. A time series model is used as the basis for the approach. Parameters describing future timber price trends, variation in future timber prices, and the probabilities of price peaks taking place in the future are estimated with expert judgments as the basis. A case study involving 12 experts was carried out in Finland, and models were estimated for all the six major timber assortments in the country. The model produced can be utilised in the optimisation calculations of forest planning.

Leskinen, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland E-mail: pekka.leskinen@metla.fi
Kangas, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland E-mail: jk@nn.fi

article id 604, category Research article

Dan Glöde, Ulf Sikström. (2001). Two felling methods in final cutting of shelterwood, single-grip harvester productivity and damage to the regeneration. Silva Fennica vol. 35 no. 1 article id 604. https://doi.org/10.14214/sf.604

Keywords: silviculture; time study; cost; forest operations; felling technique; logging-damage

Abstract | View details | Full text in PDF | Author Info

In order to find an efficient and careful way of final-cutting shelterwoods, two felling methods, in a single-grip harvester system, were compared with respect to productivity and damage caused to the regeneration. The shelterwood (140–165 m3/ha) consisted of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) and the natural regeneration (9530–11 780 seedlings/ha) mostly of Norway spruce. Treatments were: (i) conventional felling on both sides of the harvester striproad, preferably in blanks of the regeneration; (ii) felling of the trees top-end first into the striproad using a method named “tossing the caber”. Both treatments included forwarding after felling. Conventional felling had a non-significantly higher productivity (27.4 m3/E15–h) and lower cost (25.9 SEK/m3) than tossing the caber (26.1 m3/E15–h and 27.2 SEK/m3). However, tossing the caber was significantly more efficient in the felling and processing of pine trees compared with conventional felling. The mean proportions of the disappeared and damaged seedlings were approximately 40% after both treatments. The logging-related damage to the regeneration decreased with increased distance to the striproad in the tossing the caber treatment but not in conventional felling. The conclusions were that there were no differences between the treatments regarding productivity, cost and total damage to the regeneration in mixed conifer shelterwoods but that tossing the caber could be a more productive method than conventional felling in pine dominated stands. Tossing the caber could also be beneficial at a regeneration height of 2–3 m since at this height the damage to the regeneration seems less than at conventional felling.

Glöde, SkogForsk, Uppsala Science Park, S-751 83 Uppsala, Sweden E-mail: dan.glode@skogforsk.se
Sikström, SkogForsk, Uppsala Science Park, S-751 83 Uppsala, Sweden E-mail: us@nn.se

article id 617, category Research article

Jouni Siipilehto. (2000). A comparison of two parameter prediction methods for stand structure in Finland. Silva Fennica vol. 34 no. 4 article id 617. https://doi.org/10.14214/sf.617

Keywords: Pinus sylvestris; Picea abies; parameter prediction; dbh and height distribution; Johnson’s SBB distribution; Näslund’s height curve

Abstract | View details | Full text in PDF | Author Info

The objective of this paper was to predict a model for describing stand structure of tree heights (h) and diameters at breast height (dbh). The research material consisted of data collected from 64 stands of Norway spruce (Picea abies Karst.) and 91 stands of Scots pine (Pinus sylvestris L.) located in southern Finland. Both stand types contained birch (Betula pendula Roth and B. pubescent Ehrh.) admixtures. The traditional univariate approach (Model I) of using the dbh distribution (Johnson’s SB) together with a height curve (Näslund’s function) was compared against the bivariate approaches, Johnson’s SBB distribution (Model II) and Model Ie. In Model Ie within-dbh-class h-variation was included by transforming a normally distributed homogenous error of linearized Näslund’s function to concern real heights. Basal-area-weighted distributions were estimated using the maximum likelihood (ML) method. Species-specific prediction models were derived using linear regression analysis. The models were compared with Kolmogorov-Smirnov tests for marginal distributions, accuracy of stand variables and the dbh-h relationship of individual trees. The differences in the stand characteristics between the models were marginal. Model I gave a slightly better fit for spruce, but Model II was better for pine stands. The univariate Model I resulted in clearly too narrow marginal h-distribution for pine. It is recommended applying of a constrained ML method for reasonable dbh-h relationship instead of using a pure ML method when fitting the SBB model.

Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi

article id 628, category Research article

Stefan Daume, Dave Robertson. (2000). A heuristic approach to modelling thinnings. Silva Fennica vol. 34 no. 3 article id 628. https://doi.org/10.14214/sf.628

Keywords: thinning; heuristic model; rule-based; knowledge-based

Abstract | View details | Full text in PDF | Author Info

Thinnings play an important role in guiding forest development and are considered by many to be the most important influence on forests in Central Europe. Due to their importance, thinning models are a major part of any forest growth model for managed forests. Existing thinning model approaches have a number of problems associated with structure and model development that weaken their reliability and accuracy. To overcome some of these problems this paper proposes a heuristic approach to modelling thinnings, where the focus is on distance-dependent, single-tree models. This alternative approach tries to capture the information, strategies and deductive processes likely to be employed by a forester deciding on the removal of individual trees in a stand. Use of heuristics to represent thinning knowledge simplifies the construction and refinement of a thinning model and increases its plausibility. The representation of thinning heuristics in Prolog – a programming language based on formal logic – is a straightforward process without losing expressiveness of the original heuristics. Limited tests of the model implemented in Prolog indicate that the proposed model outperforms its competitors.

Daume, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: stefand@dai.ed.ac.uk
Robertson, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: dr@nn.uk

article id 637, category Research article

Hirofumi Kuboyama, Hiroyasu Oka. (2000). Climate risks and age-related damage probabilities – effects on the economically optimal rotation length for forest stand management in Japan. Silva Fennica vol. 34 no. 2 article id 637. https://doi.org/10.14214/sf.637

Keywords: simulation; climatic risks; damage probability; age class; optimal rotation period; land expectation value

Abstract | View details | Full text in PDF | Author Info

We estimated the damage probability according to age class and major climatic disasters based on ‘Statistical Yearbook of National Forest Insurance’ from 1960 to 1996. The probability of snow damage is high for young stands, then gradually decreases with age. On the other hand, the risk of wind damage gradually increases with age. Decisions about rotation age should be based on the distribution of damage probability with stand age. Risk of damage has two contradictory effects on the optimal rotation period; one is that the rotation-shortening effect caused by risk of damage around harvest age; another is the rotation-extending effect due to decrease of rent by the risk of damage through the raising period. Change of optimal rotation depends on the relative magnitude of these effects. We examine this by calculating land expectation value (LEV) using a simulation model with the empirical damage probability, price and cost. Change of the optimal rotation period obtained from the national average damage probability is not significant. However, the optimal rotation is shorter in high wind risk areas and is longer in high snow risk areas. It is because the damage probability for a mature stand is high in the case of wind and low in the case of snow. In addition, the extent of decrease in LEV is smaller for wind than for snow. The results of simulation based on empirical data confirm that the optimal rotation period can become either shorter or longer through incorporating risk in decision making, depending on the damage probability distribution with stand age.

Kuboyama, Forestry and Forest Products Research Institute Tohoku Center, Nabeyashiki 72, Shimo-Kuriyagawa, Morioka, Iwate, 020-0123 Japan E-mail: kuboyama@ffpri-thk.affrc.go.jp
Oka, Forestry and Forest Products Research Institute Tohoku Center, Nabeyashiki 72, Shimo-Kuriyagawa, Morioka, Iwate, 020-0123 Japan E-mail: ho@nn.jp

article id 640, category Research article

Jarkko Koskela. (2000). A process-based growth model for the grass stage pine seedlings. Silva Fennica vol. 34 no. 1 article id 640. https://doi.org/10.14214/sf.640

Keywords: allocation; Monte Carlo simulation; grass stage; Pinus merkusii; dynamic model

Abstract | View details | Full text in PDF | Author Info

A carbon- and nitrogen-balance model, applying pipe model theory and a modification of functional balance as growth-guiding rules, is presented for the grass stage pine seedlings. Three populations of Pinus merkusii Jungh. et de Vriese, originating from northern and northeastern Thailand, were grown under controlled environment for 47 weeks to obtain parameter information, to evaluate the model performance and to investigate genotypic variation in various characteristics among the populations. Monte Carlo simulations were used to evaluate the sensitivity of the model behaviour to varying parameter values and to calibrate the model for each population. With given sets of parameter values, the simulated biomass development fitted rather well the observed one during the experiment. The two most important parameters determining model performance were within-shoot shading and specific nitrogen uptake rate of fine roots. The fit of simulated versus measured fine roots had a major effect on acceptable model performance in Monte Carlo simulations. Significant variation in biomass growth, nitrogen use efficiency, height, stem diameter, total carbon concentrations of stem and fine roots, and total nitrogen concentrations of needles, transport roots and fine roots was found among the populations. The observed genotypic variation in seedling biomass and stem diameter was consistent with the geographical distribution of the populations while the variation in the rest of the measured characteristics was not. It seems that P. merkusii populations in Thailand are adapted to more site specific conditions rather than climatic conditions alone, and that the variation in biomass growth may result from variation in internal carbon and nitrogen dynamics among the populations.

Koskela, Department of Forest Ecology/Tropical Silviculture Unit, P.O. Box 28, FIN-00014 University of Helsinki, Finland E-mail: jarkko.koskela@helsinki.fi

article id 650, category Research article

Jouni Siipilehto. (1999). Improving the accuracy of predicted basal-area diameter distribution in advanced stands by determining stem number. Silva Fennica vol. 33 no. 4 article id 650. https://doi.org/10.14214/sf.650

Keywords: dbh distribution; parameter prediction; Johnson’s SB distribution; Weibull distribution

Abstract | View details | Full text in PDF | Author Info

The objective of this paper was to study to what extent the accuracy of predicted basal-area diameter distributions (DDG) could be improved by means of stem number observations in advanced (H > 10 m) stands. In the Finnish forest management planning (FMP) inventory practice, stem number is determined only in young stands; in older stands stand basal area is used. The study material consisted of sixty stands of Norway spruce (Picea abies Karst.) and ninety-one stands of Scots pine (Pinus sylvestris L.) with birch (Betula pendula Roth and B. pubescens Ehrh.) admixtures in southern and eastern Finland. For test data, 167–292 independent, National Forest Inventory-based, permanent sample plots were used. DDGs were estimated with the maximum likelihood method. Species-specific models for predicting the distribution parameters were derived using regression analysis. The two-parameter Weibull distribution was compared to the three-parameter Johnson’s SB distributions in predicting DDGs. The models were based on either predictors that are consistent with current FMP (model G), or assuming an additional stem number observation (model G+N). The predicted distributions were compared in terms of the derived stand variables: stem number, total and timber volumes. The results were similar in modelling and test data sets. Methods, based on the SB distribution obtained with model (G+N), proved to give the most accurate description of the stand structure. Differences were marginal in stand total volumes. However, the error variation in stem number was 20% to 80% lower than when applying model (G). SB and Weibull distributions gave very much the same results if model (G) was applied.

Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi

article id 649, category Research article

Tord Johansson. (1999). Biomass production of Norway spruce (Picea abies (L.) Karst.) growing on abandoned farmland. Silva Fennica vol. 33 no. 4 article id 649. https://doi.org/10.14214/sf.649

Keywords: Norway spruce; biomass production; Picea abies; thinning; LAI; abandoned farmland; basic density

Abstract | View details | Full text in PDF | Author Info

Biomass production of forests has been studied for at least a century. Tree biomass is used in Sweden both as industrial raw material and an energy source. Few studies dealing with biomass yield from Norway spruce (Picea abies (L.) Karst.) growing on farmland are published. Practical recommendations are sparsely. The aim of this study was to construct dry weight equations for Norway spruce growing on farmland. Dry weight equations for fractions of Norway spruce trees were made. Biomass production was estimated in 32 stands of Norway spruce growing on abandoned farmland. The stands were located in Sweden at latitudes ranging from 58° to 64° N, and their total age varied from 17 to 54 years. A modified ‘mean tree technique’ was used to estimate biomass production; i.e. the tallest tree was chosen for sampling. The actual mean total dry weight above stump level for the 32 stands was 116 ton ha–1, with a range of 6.0 to 237.4 ton d.w. ha–1. When previous thinning removals were included, the mean biomass value was 127 ton ha–1 (6.0–262.8). In addition to estimating conventional dry weights of trees and tree components, basic density, specific leaf area, total surface area and leaf area index, among other measures, were estimated. Norway spruce biomass yields on plots subjected to different thinning were compared. The total harvested biomass was 75–120 ton d.w. ha–1 in heavy thinnings from below. Stands were thinned four to five times, with the first thinning at 23–27 years and the last at 51–64 years. The harvested biomass obtained in the first thinning was 18–38 ton d.w. ha–1. Total biomass production was 178–305 ton d.w. ha–1. Stands thinned from above supplied 71–130 ton d.w. ha–1 in total and 17–42 ton d.w. ha–1 in the first thinning. The total biomass supply was 221–304 ton d.w. ha–1. Unthinned stands produced a total of 155–245 ton d.w. ha–1.

Johansson, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, S-750 07 Uppsala, Sweden E-mail: tord.johansson@sh.slu.se

article id 672, category Research article

Rimvydas Vasiliauskas, Jan Stenlid. (1998). Spread of Stereum sanguinolentum vegetative compatibility groups within a stand and within stems of Picea abies. Silva Fennica vol. 32 no. 4 article id 672. https://doi.org/10.14214/sf.672

Keywords: Picea abies; Stereum sanguinolentum; somatic incompatibility; decay; wounds

Abstract | View details | Full text in PDF | Author Info

A total of 57 naturally established Stereum sanguinolentum isolates was obtained from artificially wounded Picea abies stems in a forest area of 2 ha in Lithuania. Somatic incompatibility tests revealed 27 vegetative compatibility groups (VCGs) that contained 1–10 isolates. There was no spatial clustering of S. sanguinolentum VCGs within the forest area. The extent of S. sanguinolentum decay was analysed in 48 P. abies stems, 9–26 cm in diameter at breast height. Within 7 years of wounding, the length of S. sanguinolentum decay column in stems was 107–415 cm (291.5 ± 77.3 cm on average), lateral spread of the fungus at the butt was 38–307 cm2 (142.3 ± 66.8 cm2) and decayed proportion of the stem cross-section at the wound site (the butt) was 3–84% (36.8 ± 19.7%). In average, S. sanguinolentum VCG that infected 10 trees exhibited more slow growth inside the stem than VCGs that infected only one tree, and vertical growth varied to a greater extent within this VCG than among different VCGs. Correlation between stem diameter and vertical spread of S. sanguinolentum was not significant (r = –0.103). Despite uniformity of debarked area on all stems 7 years ago (300 cm2), open wound sizes on individual trees at the time of study were between 97–355 cm2 (215.1 ± 59.2 cm2) indicating large differences in wound healing capacity.

Vasiliauskas, Department of Plant Protection, Lithuanian University of Agriculture, LT-4324 Kaunas, Lithuania E-mail: rv@nn.lt
Stenlid, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, S-750 07 Uppsala, Sweden E-mail: js@nn.se

article id 701, category Research article

Antrei Lausti, Markku Penttinen. (1998). The analysis of return and its components of non-industrial private forest ownership by forestry board districts in Finland. Silva Fennica vol. 32 no. 1 article id 701. https://doi.org/10.14214/sf.701

Keywords: non-industrial private forests; risk; return; portfolio management; forestry board district; performance evaluation

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Non-industrial private forest ownership returns and risks in Finland are both estimated and disaggregated to local Forestry Board Districts (FBD) level. Additionally, the FBD level return is divided into price change, felling and change in the growing stock components, which are compared with the inflation rate. The results are based on a complete count of the stumpage prices, silvicultural costs and state subsidies as well as the National Forest Inventory (NFI) data. The influence of taxation is discussed as well. Although this database is excellent for economic studies as well, the estimation methodology is vitiated by a host of problems, the resolution of which is the major contribution of this study. The study period is 1972–1996. The results show that there have been fairly large differences in forest ownership returns and prices depending on the Forestry Board District. Results show that the price change component has been larger in Northern Forestry Board Districts, as much as 0.9% above the inflation rate in Lapland FBD, than in Southern Forestry Board Districts, 1.5% less than the inflation rate in southern Helsinki FBD. The net increase, however, has been larger in Southern Forestry Board Districts than in Northern Forestry Board Districts. Using the average net increment in Finland as a comparison base, the net increment in South Karelia exceeded it by 0.6%, but fell below it by 1.8% in Northeastern Finland. Finally, the return over the whole period is compared to the return on private housing and inflation in the case of North Savo. In all, the estimation methodology developed also serves as spin-off product development for the Forest Statistics Information Service (FSIS).

Lausti, Helsinki School of Economics and Business Administration, Centre for Doctoral Programme, Runeberginkatu 15 A, FIN-00100 Helsinki, Finland E-mail: al@nn.fi
Penttinen, Finnish Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, FIN-00170 Helsinki, Finland E-mail: markku.penttinen@metla.fi

article id 700, category Research article

Riitta H. Hänninen. (1998). Exchange rate changes and the Finnish sawnwood demand and price in the UK market. Silva Fennica vol. 32 no. 1 article id 700. https://doi.org/10.14214/sf.700

Keywords: exchange rate; export demand; Johansen’s cointegration method; pass-through; sawnwood price; United Kingdom

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This paper examines the long-run influence of exchange rate changes on the Finnish sawnwood price in the United Kingdom (UK) using quarterly data for the period 1978–1994. The degree of influence was measured by a pass-through coefficient (PT) obtained from a markup pricing relation of a system model. The model, which included export demand and price equations, was estimated with the cointegration method of Johansen. The results indicated a large PT, which means that exchange rate changes are reflected almost proportionately in Finnish export price expressed in pounds sterling. Thus, the Finnish price of sawnwood in pounds has lowered as a result of depreciation of the Finnish markka (FIM). This has improved Finnish competitiveness and market share in the UK. Appreciation of the FIM has had the opposite effect. It seems that Finnish exporters have made use of depreciations and devaluations of the FIM to maintain and increase their market shares but not necessarily their markups. For Finland, which is in the process of joining the European economic and monetary union (EMU), knowing the size of the PT is also important in assessing the economic impact of membership.

Hänninen, Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, 00170 Helsinki, Finland E-mail: riitta.hanninen@metla.fi

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

Keywords: risk; growth index; ARMA models; scenario approach

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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 E-mail: pasanen@gis.joensuu.fi

article id 10709, category Review article

Pavel Škvor, Martin Jankovský, Pavel Natov, Jiří Dvořák. (2023). Evaluation of stress loading for logging truck drivers by monitoring changes in muscle tension during a work shift. Silva Fennica vol. 57 no. 1 article id 10709. https://doi.org/10.14214/sf.10709

Keywords: timber transportation; biofeedback; driver; electromyography; physical load

Highlights: This study compared the workload of drivers when driving different types of vehicles; The combination of a truck and trailer exposes the driver to a significantly greater workload than trucks without trailers; The workload of drivers varied during a work shift i.e. drivers experienced significantly more workload in the middle of their work shifts.

Abstract | Full text in HTML | Full text in PDF | Author Info

Our research aimed to quantify and evaluate the stress loading of drivers by monitoring the loading of the radial extensor muscle at the wrist joint (musculus extensor carpi radialis) when they drove different types of timber trucks. We monitored changes in the electric potential of skeletal muscles with electromyographic measurements and measurements of changes of heart rate using the Biofeedback 2000 ^x-pert device. The drivers were observed throughout their work shifts during normal operation of logging trucks and logging trucks with trailers. As a reference, muscle load was measured when driving a passenger car. We evaluated the normality of the measured data and obtained descriptive statistics from the individual measurements. The differences in stress load associated with driving the different types of vehicles increased whilst driving on lower-class roads. Results showed a high stress load for drivers of loaded vehicles when driving on narrow roads. It was more challenging to control a loaded logging truck with a trailer than driving a logging truck, with the difference in muscular loading reaching 22.5%. Driving a logging truck with a trailer produced 46.5% more muscle loading compared to driving a loaded passenger car. For preventive health and safety reasons, it would be reasonable to alternate between drivers when operating various vehicles, thus minimizing the development of possible health issues.

Škvor, Department of Forestry Technologies and Construction, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6 - Suchdol, Czech Republic https://orcid.org/0000-0001-7540-4761 E-mail: skvorp@fld.czu.cz
Jankovský, Department of Forestry Technologies and Construction, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6 - Suchdol, Czech Republic E-mail: jankovskym@fld.czu.cz
Natov, Department of Forestry Technologies and Construction, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6 - Suchdol, Czech Republic E-mail: natov@fld.czu.cz
Dvořák, Department of Forestry Technologies and Construction, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6 - Suchdol, Czech Republic https://orcid.org/0000-0002-5986-8002 E-mail: dvorakj@fld.czu.cz

article id 10516, category Review article

Faujiah N. Ritonga, Jacob N. Ngatia, Run X. Song, Umar Farooq, Sonia Somadona, Andi T. Lestari, Su Chen. (2021). Abiotic stresses induced physiological, biochemical, and molecular changes in Betula platyphylla: a review. Silva Fennica vol. 55 no. 3 article id 10516. https://doi.org/10.14214/sf.10516

Keywords: antioxidant; cis-acting elements; gene; ROS production; transcription factor

Highlights: Abiotic stress influence Betula platyphylla growth, development, and yield production by impairing physiological, biochemical, and molecular functions; Overexpression or RNAi line of transcription factors enhance the abiotic stress tolerance of B. platyphylla; MYB and AP2/ERF are the most frequently transcription factor family that has been explored over the last two decades in B. platyphylla under abiotic stress.

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Abiotic stress is one of the major factors in reducing plant growth, development, and yield production by interfering with various physiological, biochemical, and molecular functions. In particular, abiotic stress such as salt, low temperature, heat, drought, UV-radiation, elevated CO2, ozone, and heavy metals stress is the most frequent study in Betula platyphylla Sukaczev. Betula platyphylla is one of the most valuable tree species in East Asia facing abiotic stress during its life cycle. Using transgenic plants is a powerful tool to increase the B. platyphylla abiotic stress tolerance. Generally, abiotic stress reduces leaves water content, plant height, fresh and dry weight, and enhances shed leaves as well. In the physiological aspect, salt, heavy metal, and osmotic stress disturbs seed germination, stomatal conductance, chlorophyll content, and photosynthesis. In the biochemical aspect, salt, drought, cold, heat, osmotic, UV-B radiation, and heavy metal stress increases the ROS production of B. platyphylla cells, resulting in the enhancement of enzymatic antioxidant (SOD and POD) and non-enzymatic antioxidant (proline and AsA) to reduce the ROS accumulation. Meanwhile, B. platyphylla upregulates various genes, as well as proteins to participate in abiotic stress tolerance. Based on recent studies, several transcription factors contribute to increasing abiotic stress tolerance in B. platyphylla, including BplMYB46, BpMYB102, BpERF13, BpERF2, BpHOX2, BpHMG6, BpHSP9, BpUVR8, BpBZR1, BplERD15, and BpNACs. These transcription factors bind to different cis-acting elements to upregulate abiotic stress-related genes, resulting in the enhancement of salt, drought, cold, heat, osmotic, UV-B radiation, and heavy metal tolerance. These genes along with phytohormones mitigate the abiotic stress. This review also highlights the candidate genes from another Betulacea family member that might be contributing to increasing B. platyphylla abiotic stress tolerance.

Ritonga, State Key Laboratory of Tree Genetics and Breeding, Forestry College, Northeast Forestry University, Harbin 150040, China E-mail: ritongafaujiah@ymail.com
Ngatia, College of Wildlife and Protected Areas, Northeast Forestry University, Harbin 150040, China E-mail: jacob.ngatia3@gmail.com
Song, State Key Laboratory of Tree Genetics and Breeding, Forestry College, Northeast Forestry University, Harbin 150040, China E-mail: 13359850710@163.com
Farooq, College of Life Science, Northeast Forestry University, Harbin 150040, China E-mail: uf@nn.ch
Somadona, College of Agriculture, Riau University, Pekanbaru 28293, Indonesia E-mail: sonia_hut@yahoo.co.id
Lestari, Forestry Major, College of Agriculture, Mataram University, Mataram 83125, Indonesia E-mail: atlestari@unram.ac.id
Chen, State Key Laboratory of Tree Genetics and Breeding, Forestry College, Northeast Forestry University, Harbin 150040, China E-mail: chensu@nefu.edu.cn

article id 10172, category Review article

Ulf Sikström, Karin Hjelm, Kjersti Holt Hanssen, Timo Saksa, Kristina Wallertz. (2020). Influence of mechanical site preparation on regeneration success of planted conifers in clearcuts in Fennoscandia – a review. Silva Fennica vol. 54 no. 2 article id 10172. https://doi.org/10.14214/sf.10172

Keywords: natural regeneration; regeneration chain; seedling growth; coniferous seedlings; disturbed soil surface; seedling survival

Highlights: Mechanical site preparation (MSP) increases seedling survival rates by 15–20%; Survival rates of 80–90% ca. 10 years after MSP and planting conifers are possible; MSP can increase tree height 10–15 years after planting by 10–25%; The increase in growth rate associated with MSP may be temporary, but the height enhancement probably persists.

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In the Nordic countries Finland, Norway and Sweden, the most common regeneration method is planting after clearcutting and, often, mechanical site preparation (MSP). The main focus of this study is to review quantitative effects that have been reported for the five main MSP methods in terms of survival and growth of manually planted coniferous seedlings of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and lodgepole pine (Pinus contorta var. latifolia Engelm.) in clearcuts in these three countries. Meta analyses are used to compare the effects of MSP methods to control areas where there was no MSP and identify any relationships with temperature sum and number of years after planting. In addition, the area of disturbed soil surface and the emergence of naturally regenerated seedlings are evaluated. The MSP methods considered are patch scarification, disc trenching, mounding, soil inversion and ploughing. Studies performed at sites with predominately mineral soils (with an organic topsoil no thicker than 0.30 m), in boreal, nemo-boreal and nemoral vegetation zones in the three Fenno-Scandinavian countries are included in the review. Data from 26 experimental and five survey studies in total were compiled and evaluated. The results show that survival rates of planted conifers at sites where seedlings are not strongly affected by pine weevil (Hylobius abietis L.) are generally 80–90% after MSP, and 15–20 percent units higher than after planting in non-prepared sites. The experimental data indicated that soil inversion and potentially ploughing (few studies) give marginally greater rates than the other methods in this respect. The effects of MSP on survival seem to be independent of the temperature sum. Below 800 degree days, however, the reported survival rates are more variable. MSP generally results in trees 10–25% taller 10–15 years after planting compared to no MSP. The strength of the growth effect appears to be inversely related to the temperature sum. The compiled data may assist in the design, evaluation and comparison of possible regeneration chains, i.e. analyses of the efficiency and cost-effectiveness of multiple combinations of reforestation measures.

Sikström, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: ulf.sikstrom@skogforsk.se
Hjelm, Skogforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden E-mail: karin.hjelm@skogforsk.se
Holt Hanssen, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: kjersti.hanssen@nibio.no
Saksa, Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@luke.fi
Wallertz, Swedish University of Agricultural Sciences (SLU), Asa Forest Research Station, SE-360 30 Lammhult, Sweden E-mail: kristina.wallertz@slu.se

article id 1650, category Review article

Uriel Safriel. (2017). Land Degradation Neutrality (LDN) in drylands and beyond – where has it come from and where does it go. Silva Fennica vol. 51 no. 1B article id 1650. https://doi.org/10.14214/sf.1650

Keywords: climate change; desertification; ecosystem services; offsetting mechanism; Rio Conventions

Highlights: LDN, a mechanism for offsetting new losses of land’s productivity by restoring productivity of already degraded lands, would maintain the balance of productive lands; As target of Sustainable Development Goal LDN highlights the significance of land whose biological productivity is critical to human survival; Commissioning UNCCD to oversee the implementation of LDN empowers the UNCCD and its impact on sustainability.

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The paper first reviews the desertification/land degradation syndrome, the shortcomings of attempts to control it and the consequences of this failure, including to climate change and biodiversity. It then examines the experience gained by carbon and biodiversity offsets that helped adapting the offsetting principle to the context of land degradation, by emphasizing the restoration of the many already degraded lands on earth, as major component of the Land Degradation Neutrality (LDN) mechanism. LDN is a new voluntary and aspirational target of a Sustainable Development Goal (SDG) under the UN 2030 Agenda for Sustainable Development, aimed at neutralizing the rate of lands coming under degrading use of their productivity. This by balancing the ongoing added degradation with similar rate of restoring equivalent lands whose productivity had been already degraded. If extensively implemented, LDN would stabilize the global amount of productive land by 2030. This would increase global food security and reduce poverty of land users, thus contributing to global sustainability. This review maintains that the failure of United Nations Convention to Combat Desertification (UNCCD) to reduce desertification triggered the emergence of LDN as a mechanism for addressing land degradation globally, rather than just desertification in the drylands. LDN accepted as target of a Sustainable Development Goal also legitimized UNCCD to lead and oversee the aspired process of achieving land degradation neutral world. This paper reviews the development of the LDN concept expressed in scientific deliberations and political advocacy, throughout the five years from inception in 2011 at the UNCCD Secretariat, to early 2016. It notes the fast and increasing acceptance of LDN, expressed in the initiation of implementation already in April 2015 by an increasing number of countries, and in the growing interest and engagement of scientists and policy-makers. But the paper also express concern regarding potential misuse of the concept.

Safriel, Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel E-mail: uriel36@gmail.com

article id 1095, category Review article

Jonas Fridman, Sören Holm, Mats Nilsson, Per Nilsson, Anna Hedström Ringvall, Göran Ståhl. (2014). Adapting National Forest Inventories to changing requirements – the case of the Swedish National Forest Inventory at the turn of the 20th century. Silva Fennica vol. 48 no. 3 article id 1095. https://doi.org/10.14214/sf.1095

Keywords: remote sensing; sampling; sample plot inventory; forest state; ENFIN; harmonization

Highlights: National Forest Inventories supply invaluable long term time series of forest state. Recent developments and international harmonization of modern NFIs widen the scope to even include ecosystem goods, e.g. biodiversity and carbon sequestration. The combination of NFI field data with remote sensing techniques can give good estimates for areas smaller than national and regional level.

Abstract | Full text in HTML | Full text in PDF | Author Info

National Forest Inventories (NFIs) are becoming increasingly important worldwide in order to provide information about the multiple functions of forests, e.g. their provision of raw materials to industry, biodiversity and their capacity to store carbon for mitigating climate change. In several countries the history of NFIs is very long. For these countries a specific challenge is to keep the inventories up-to-date without sacrificing the advantages associated with long time series. At the turn of the 20th century European NFIs faced some major challenges. In this article we describe the history and the recent developments of the Swedish NFI as an example from which general observations are made and discussed. The Swedish NFI started in 1923 and has evolved from an inventory with a narrow focus on wood resources to an inventory today which aims to provide information about all major forest ecosystem services. It can be concluded that the traditional approaches of most European NFIs, e.g. to collect data through sample plot field inventories, has proved to be applicable even for a wide range of new information requirements. Specifically, detailed data about land use, trees, vegetation, and soils has found new important uses in connection with biodiversity assessments and the estimation of greenhouse gas emissions. Though time-consuming and difficult, making NFI information comparable across countries through harmonization appears to be a useful approach. The European National Forest Inventory Network (ENFIN) was formed in 2003 and has been successful in pan-European NFI harmonization.

Fridman, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: jonas.fridman@slu.se
Holm, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: soren.holm@slu.se
Nilsson, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: mats.nilsson@slu.se
Nilsson, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: per.nilsson@slu.se
Ringvall, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: Anna.Ringvall@slu.se
Ståhl, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden E-mail: goran.stahl@slu.se

article id 446, category Review article

Guntis Brumelis, Bengt Gunnar Jonsson, Jari Kouki, Timo Kuuluvainen, Ekaterina Shorohova. (2011). Forest naturalness in northern Europe: perspectives on processes, structures and species diversity. Silva Fennica vol. 45 no. 5 article id 446. https://doi.org/10.14214/sf.446

Keywords: disturbances; dead wood; natural forest; biological diversity

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Saving the remaining natural forests in northern Europe has been one of the main goals to halt the ongoing decline of forest biodiversity. To facilitate the recognition, mapping and efficient conservation of natural forests, there is an urgent need for a general formulation, based on ecological patterns and processes, of the concept of “forest naturalness”. However, complexity, structural idiosyncracy and dynamical features of unmanaged forest ecosystems at various spatio-temporal scales pose major challenges for such a formulation. The definitions hitherto used for the concept of forest naturalness can be fruitfully grouped into three dimensions: 1) structure-based concepts of natural forest, 2) species-based concepts of natural forest and 3) process-based concepts of natural forest. We propose that explicit and simultaneous consideration of all these three dimensions of naturalness can better cope with the natural variability of forest states and also aid in developing strategies for forest conservation and management in different situations. To become operational, criteria and indicators of forest naturalness need to integrate the three dimensions by combining species (e.g. red-listed-, indicator- and umbrella species) with stand and landscape level structural features that are indicative of disturbance and succession processes.

Brumelis, Faculty of Biology, University of Latvia, Kronvalda bulv. 4, Riga, LV-1586, Latvia; E-mail: guntis.brumelis@lu.lv
Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: bgj@nn.se
Kouki, School of Forest Sciences, University of Eastern Finland, Joensuu, Joensuu E-mail: jk@nn.fi
Kuuluvainen, Department of Forest Sciences, University of Helsinki, Finland E-mail: tk@nn.fi
Shorohova, Saint-Petersburg State Forest Academy, Saint-Petersburg, Russia & Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: es@nn.ru

article id 36, category Review article

Tuomo Wallenius. (2011). Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause. Silva Fennica vol. 45 no. 1 article id 36. https://doi.org/10.14214/sf.36

Keywords: human influence; fire-history; fire suppression; forest dynamics; Pinus

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Steep decline in forest fires about a century ago occurred in coniferous forests over large areas in North America and Fennoscandia. This poorly understood phenomenon has been explained by different factors in different regions. The objective of this study is to evaluate the validity of the four most commonly suggested causes of the decrease in forest fires: fire fighting, over-grazing, climate change and human influence. I compiled the available dendrochronological data and estimated the annually burned proportions of Pinus-dominated forests in four subcontinental regions during the past 500 years. These data were compared to the development of fire suppression, grazing pressure, climate and human livelihoods. The annually burned proportions declined over 90% in all studied regions. In three out of the four regions fires decreased decades before fire suppression began. Available drought data are annually well correlated with fires but could not explain the decrease of the level in annually burned areas. A rapid increase in the number of livestock occurred at the same time with the decrease in fires in the Western US but not in Fennoscandia. Hence, fire suppression in Central Fennoscandia and over-grazing in the Western US may have locally contributed to the reduction of burned areas. More general explanation is offered by human influence hypothesis: the majority of the past forest fires were probably caused by humans and the decrease in the annually burned areas was because of a decrease in human caused fires. This is in accordance with the old written records and forest fire statistics. The decrease in annually burned areas, both in Fennoscandia and the United States coincides with an economic and cultural transition from traditional livelihoods that are associated with high fire use to modern agriculture and forestry.

Wallenius, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: tuomo.wallenius@metla.fi

article id 147, category Review article

Arja Lilja, Marja Poteri, Raija-Liisa Petäistö, Risto Rikala, Timo Kurkela, Risto Kasanen. (2010). Fungal diseases in forest nurseries in Finland. Silva Fennica vol. 44 no. 3 article id 147. https://doi.org/10.14214/sf.147

Keywords: damping-off; grey mold; root dieback; needle casts; snowblights; scleroderris canker; Sirococcus; pine twisting rust; stem lesions and top dying; leaf lesions; Venturia; powdery mildews

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Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver birch (Betula pendula) are the major tree species grown in Finnish forest nurseries where 99% of the seedlings are grown in containers first in plastic-covered greenhouses and later outdoors. The main diseases on conifer seedlings are Scleroderris canker (Gremmeniella abietina), Sirococcus blight and cankers (Sirococcus conigenum), snow blights (Herpotrichia juniperi and Phacidium infestans) and needle casts (Lophodermium seditiosum and Meria laricis). Also grey mould (Botrytis cinerea) and birch rust (Melampsoridium betulinum) are among the diseases to be controlled with fungicides. During last years Scleroderris canker has been a problem on Norway spruce, which has been since 2000 the most common species produced in Finnish nurseries. Root die-back (uninucleate Rhizoctonia sp.) on container-grown spruce and pine was a problem in the 1990s. Today the disease has become less common in modern nurseries due to improvements in hygiene and cultivation practice. Since 1991 stem lesions and top dying caused by Phytophthora cactorum has been a problem on birch. The ongoing climate change has already had effect on rusts and powdery mildews as well as other fungi infecting leaves. All diseases, which gain high precipitation and warm and long autumns. For same reasons winter stored seedlings need sprayings against grey mold. Fungal infections are also possible during short-day (SD) treatment, that is necessary for summer and autumn plantings and a beneficial step prior freezing temperatures outside or in freezer storage. Growers are encouraged to use cultural and integrated pest management techniques such as better nursery hygiene, including removing plant debris in nursery growing areas and hot water washing of containers plus removal of diseased, spore-producing seedlings and trees around the nursery.

Lilja, Finnish Forest Research Institute, Vantaa, Finland E-mail: arja.lilja@metla.fi
Poteri, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: mp@nn.fi
Petäistö, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: rlp@nn.fi
Rikala, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: rr@nn.fi
Kurkela, Finnish Forest Research Institute, Vantaa, Finland E-mail: tk@nn.fi
Kasanen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland E-mail: rk@nn.fi

article id 489, category Review article

Ralph J. Alig. (2003). U.S. landowner behavior, land use and land cover changes, and climate change mitigation. Silva Fennica vol. 37 no. 4 article id 489. https://doi.org/10.14214/sf.489

Keywords: adaptation; carbon sequestration; forest sector; mitigation

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Landowner behavior is a major determinant of land use and land cover changes, an important consideration for policy analysts concerned with global change. Study of landowner behavior aids in designing more effective incentives for inducing land use and land cover changes to help mitigate climate change by reducing net greenhouse gas emissions. Afforestation, deforestation, reforestation, and timber harvest are the most frequent land management practices that influence forest carbon stocks and flux. Research studies provide estimates of how private landowners respond to market signals and government programs and how they alter land management. For example, landowners have tended to retain subsidized afforested stands well beyond program life in the United States, suggesting that similar programs for climate change mitigation could result in high rates of retention. At the same time, policy makers need to be aware that unintended consequences of policies can lead to significantly different outcomes than envisioned, including leakage possibilities.

Alig, USDA Forest Service, Forestry Sciences Lab, 3200 SW Jefferson Way, Corvallis, Oregon 97331, USA E-mail: ralig@fs.fed.us

article id 497, category Review article

Oili Kiikkilä. (2003). Heavy-metal pollution and remediation of forest soil around the Harjavalta Cu-Ni smelter, in SW Finland. Silva Fennica vol. 37 no. 3 article id 497. https://doi.org/10.14214/sf.497

Keywords: mulch; copper; forest; ecosystem; Harjavalta; nutrient cycle; remediation; liming

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Heavy metals and sulphur have been emitted from the Cu-Ni smelter at Harjavalta since 1945. This article reviews the work that has been published in scientific journals after 1975 concerning heavy metal deposition and the effects of pollution on forest ecosystem around Harjavalta. The pollution has had diverse effects on boreal forest ecosystem, e.g. vegetation, nutrient cycle mediated by microbiota and soil animals, herbivorous insects and pathogens, resistance mechanisms of vegetation, and birds. The deposition of heavy metals has increased up to 30 km distance from the smelter. At 8 km distance the ecosystem began to approximate an undisturbed ecosystem where only slight changes in the understorey vegetation were observed. At 4 km distance the species composition of different ecosystem components (vegetation, insects, birds, soil microbiota) had changed and the growth of trees was retarded. At 0.5–1 km distance, where the nutrient cycling was disturbed and only the most resistant organisms were surviving, the ecosystem had ceased to carry out its essential functions. Remediation through liming or mulching with organic matter, of forest soil has had some positive effects on the ecosystem.

Kiikkilä, Vantaa Research Centre, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: oili.kiikkila@metla.fi

article id 551, category Review article

Anders Dahlberg. (2002). Effects of fire on ectomycorrhizal fungi in Fennoscandian boreal forests. Silva Fennica vol. 36 no. 1 article id 551. https://doi.org/10.14214/sf.551

Keywords: boreal forests; ectomycorrhizal fungi; fire; population; community

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Fire, the primary natural disturbance factor in Fennoscandian boreal forests, is considered to have exerted major selection pressure on most boreal forest organisms. However, recent studies show that few ectomycorrhizal (EM) fungi appear to have evolved post-fire adaptations, no succession of EM fungi following fire is apparent after low intensity fires, and only two EM fungal taxa exclusively fruit at post-fire conditions. In this paper I review the present knowledge of effects of forest fire on EM fungal communities in Fennscandian boreal forests, put into perspective by a comparison from other parts of the world. Characteristically, these boreal forests consist of less than a handful of tree species, e.g. Scots pine and Norway spruce, while the below ground communities of EM fungi is impressively species rich with presently more than 700 known taxa. Commonly, forest fires in Fennoscandia have been of low intensity, with a considerable portion of the trees surviving and the organic humus layer partly escaping combustion. Hence, EM fungi appear to largely have evolved under conditions characterised by a more or less continuous presence of their hosts. In fact, the composition of EM fungi within a forest appear be more variable due to spatial variation than due to wildfire. However, in areas with high intensity burns and high tree mortality, most EM fungi may locally be killed. Thus, the legacy of EM fungi following wildfire depends on the survival of trees, which determine the potential for mycorrhizal growth, and the combustion and heating of the organic soil, which directly correlate to mortality of mycorrhizas. The questions if and to what degree fires may be of significance for yet unidentified spatiotemporal dynamics of EM fungal populations and communities are discussed. Recent experiments indicate a few EM fungi are favoured by high intensity burn conditions whereas others disappear. The consequences of wildfires in temperate conifer forests differ considerably from those in boreal forests. Wildfires in temperate conifer forests are typically high intensity stand-replacing fires that cause a total combustion of organic layers. Subsequently, pre-fire EM fungal communities are largely eradicated and a succession of post-fire EM fungi is initiated.

Dahlberg, Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden E-mail: anders.dahlberg@artdata.slu.se

article id 548, category Review article

Kevin C. Ryan. (2002). Dynamic interactions between forest structure and fire behavior in boreal ecosystems. Silva Fennica vol. 36 no. 1 article id 548. https://doi.org/10.14214/sf.548

Keywords: boreal forest; disturbance dynamics; stand structure; fire behavior; fire severity

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This paper reviews and synthesizes literature on fire as a disturbance factor in boreal forests. Spatial and temporal variation in the biophysical environment, specifically, vegetative structure, terrain, and weather lead to variations in fire behavior. Changes in slope, aspect, elevation, and soil affect site energy and water budgets and the potential plant community. These terrain features also have a major influence on fire-caused disturbance through their role in determining moisture conditions and flammability of fuels on hourly, seasonal, and successional time-scales. On fine time scales (minutes to hours), changes in weather, specifically wind and relative humidity, significantly affect a fire’s intensity and aboveground effects. Normal seasonal changes in dryness and periodic drought influence fire intensity and severity principally by affecting the depth of burn and belowground effects. On decades-long time scales changes in vegetative structure affect the mass of fuel available for burning and therefore the potential energy that can be released during a fire. The severity of fire varies in time and space depending not only on the biophysical environment, but also on the location on the fire’s perimeter (head vs. flank vs. rear). Spatial and temporal variation in severity within a fire can have long-lasting impacts on the structure and species composition of post-fire communities and the potential for future disturbances. Characteristic temperature histories of ground, surface, and crown fires are used to illustrate variations in fire severity. A soil-heating model is used to illustrate the impact of varying depth of burn on the depth at which various fire effects occur in the soil profile. A conceptual model is presented for the effects of fire severity on fire-plant regeneration interactions. The conceptual model can be used by restoration ecologists to evaluate the differential effects of controlled or prescribed fires and wildfires and to plan and implement fire treatments to conserve biodiversity.

Ryan, USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, P.O. Box 8089, Missoula, Montana 59807, USA E-mail: kryan@fs.fed.us

article id 695, category Review article

Marja-Leena Päätalo. (1998). Factors influencing occurrence and impacts of fires in northern European forests. Silva Fennica vol. 32 no. 2 article id 695. https://doi.org/10.14214/sf.695

Keywords: tree species; fire; climate; risk assessment; site

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The return interval and number of fires vary, depending on the geographical location in interaction with climate, topography and amount of fuel. During recent decades, in northern Europe the number and severity of fires have been insignificant compared with Mediterranean region, in which fire return intervals may be 15–35 years, compared to the average of 60–120 years for boreal forests. This is partly due to the efficient system of fire protection in northern Europe, but is mainly due to the less favourable climate for fire and the smaller human impact on ignition of forest fires. The consequences of fire are related to both site and stand characteristics, site being the most important factor controlling the stability of stands. Dry sites being more flammable and likely to ignite are associated with high risk of fire. In northern Europe, due to the interaction between species and site, the role of species difference in risk of fire damage is not clear. In southern Europe, fire risk cannot be explained by differences between tree species. There, other vegetation (shrubs, etc.) is of major importance for the risk of fire. Management of forests can, to some degree, alter the risk and the occurrence of fire. In northern Europe, logging may have compensated for fire occurrence by decreasing the amount of fuel. In addition, forest roads act as fire-breaks and facilitate fire-fighting. On the contrary, in southern Europe the risk of fire has been found to increase because the traditional forest uses and management have decreased, which increases the accumulation of fuel. However, it is not yet possible to quantify and compare the effect of management in absolute terms. Currently, some tools, such as fire-risk indices, remote sensing and GIS-based techniques, are available for prediction of fire risk in some areas. For example, fire-risk indices are most suitable for areas, like northern Europe, which have a low fire risk. In high-risk areas, such as southern Europe, more sophisticated techniques are needed for assessment of the risk. In the future, assuming global warming at northern latitudes (2 x CO2 climate), the risk of fire damage could also increase in northern Europe. Therefore, to allow the various locational and silvicultural factors to be assessed on the European level, an integrated risk model is needed.

Päätalo, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: mlp@nn.fi

article id 24062, category Research note

Jussi Manner, Hagos Lundström. (2025). The effect of boom-tip control on harvester time consumption in Picea abies dominated final-felling stands: case study. Silva Fennica vol. 59 no. 1 article id 24062. https://doi.org/10.14214/sf.24062

Keywords: productivity; automation; cut-to-length logging; crane work; Intelligent Boom Control (IBC); Levels of Automation (LoA); operator assistance system

Highlights: Two experienced harvester operators (A and B) participated in the study; Operator A reduced time consumption by 10% with boom-tip control, while operator B neither saved nor lost time; Operator A’s time savings occurred exclusively during the work element felling-processing; Variation in the results between the operators emphasizes the need for further research involving a larger pool of operators.

Abstract | Full text in HTML | Full text in PDF | Author Info

Crane work accounts for the majority of a harvester’s productive working time. Boom-tip control assists operators by coordinating end-effector movements, offering the potential to improve productivity. With boom-tip control, the operator steers the boom-tip directly rather than controlling individual crane joints. Despite being commercially available for several years, research on boom-tip control’s impact on harvester work – particularly compared to forwarder work – is limited. Therefore, this study analysed the effect of boom-tip control on harvester time consumption (s m^-3) in final-felling stands, involving two experienced operators (A and B) driving a John Deere 1470G harvester. John Deere’s boom-tip control system, Intelligent Boom Control (IBC), was compared to a conventional boom-control system. Data were analysed separately for each operator. While operator A saved time using IBC, no statistically significant difference between IBC and the conventional boom-control system was observed for operator B. For operator A, IBC reduced total time consumption (s m^-3) by approximately 10%. The results indicate a need for further research, involving multiple machine manufacturers, operators, and work environments such as thinning and final-felling stands. Moreover, future studies should preferably utilise automated data recording to generate large follow-up datasets on harvester work.

Manner, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
Lundström, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: hagos.lundstrom@skogforsk.se

article id 10683, category Research note

Aarne Hovi, Petr Lukeš, Lucie Homolová, Jussi Juola, Miina Rautiainen. (2022). Small geographical variability observed in Norway spruce needle spectra across Europe. Silva Fennica vol. 56 no. 2 article id 10683. https://doi.org/10.14214/sf.10683

Keywords: albedo; remote sensing; reflectance; transmittance; land surface modeling; leaf optical properties; radiative transfer modeling

Highlights: Spectra of Norway spruce needles were collected from three sites in Europe (49°–62°N); The same acquisition and processing parameters were applied throughout the campaign; Geographical variability in the needle spectra was small; Comparison of the spectra of coniferous needles and broadleaved tree foliage is also presented.

Abstract | Full text in HTML | Full text in PDF | Author Info

Foliage spectra form an important input to physically-based forest reflectance models. However, little is known about geographical variability of coniferous needle spectra. In this research note, we present an assessment of the geographical variability of Norway spruce (Picea abies (L.) H. Karst.) needle albedo, reflectance, and transmittance spectra across three study sites covering latitudes of 49–62°N in Europe. All spectra were measured and processed using exactly the same methodology and parameters, which guarantees reliable conclusions about geographical variability. Small geographical variability in Norway spruce needle spectra was observed, when compared to variability observed between previous measurement campaigns (employing slightly varying measurement and processing parameters), or to variability between plant functional types (broadleaved vs. coniferous). Our results suggest that variability of needle spectra is not a major factor introducing geographical variability to forest reflectance. The results also highlight the importance of harmonizing measurement protocols when collecting needle spectral libraries. Furthermore, the data collected for this study can be useful in studies where accurate information on spectral differences between broadleaved and coniferous tree foliage is needed.

Hovi, Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland https://orcid.org/0000-0002-4384-5279 E-mail: aarne.hovi@aalto.fi
Lukeš, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic https://orcid.org/0000-0002-3707-6557 E-mail: lukes.p@czechglobe.cz
Homolová, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic https://orcid.org/0000-0001-7455-2834 E-mail: homolova.l@czechglobe.cz
Juola, Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland https://orcid.org/0000-0002-6050-7247 E-mail: jussi.juola@aalto.fi
Rautiainen, Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland; Aalto University, School of Electrical Engineering, Department of Electronics and Nanoengineering, P.O. Box 15500, FI-00760 Aalto, Finland https://orcid.org/0000-0002-6568-3258 E-mail: miina.a.rautiainen@aalto.fi

article id 10197, category Research note

Ville Kankare, Ville Luoma, Ninni Saarinen, Jussi Peuhkurinen, Markus Holopainen, Mikko Vastaranta. (2019). Assessing feasibility of the forest trafficability map for avoiding rutting – a case study. Silva Fennica vol. 53 no. 3 article id 10197. https://doi.org/10.14214/sf.10197

Keywords: remote sensing; open data; preharvest information; stand trafficability

Highlights: A static trafficability map was developed to provide information about suitable harvesting season; The majority (91.7%) of the evaluated thinning stands were harvested without causing rutting damage if operations were timed correctly in relation to the static trafficability map information; The static trafficability map provides reliable and slightly conservative estimation of the forest trafficability for supporting forest operations.

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Information on forest trafficability (i.e. carrying capacity of the forest floor) is required before harvesting operations in Southern Boreal forest conditions. It describes the seasons when harvesting operations may take place without causing substantial damage to the forest soil using standard logging machinery. The available trafficability information have been based on subjective observations made during the wood procurement planning. For supporting forest operations, an open access map product has been developed to provide information on trafficability of forests. The forest stands are distributed into classes that characterize different harvesting seasons based on topographic wetness index, amount of vegetation, ground water height and ditch depth. The main goal of this case study was to evaluate the information of the static forest trafficability map in relation to the detected rutting within logging tracks measured in the field. The analysis concentrated on thinning stands since the effect of rutting is significant on the growth of the remaining trees. The results showed that the static trafficability map provided reliable and slightly conservative estimation of the forest trafficability. The majority (91.7%) of the evaluated stands were harvested without causing significant damage if harvesting was timed correctly compared to the trafficability information. However, it should be pointed out that the weather history at small scale, the skills of a driver, and effects of used machinery are not considered in the map product although they can have a considerable impact on the rutting.

Kankare, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101, Finland; Department of Forest Sciences, University of Helsinki, FI-00014 University of Helsinki, Finland https://orcid.org/0000-0001-6038-1579 E-mail: ville.kankare@uef.fi
Luoma, Department of Forest Sciences, University of Helsinki, FI-00014 University of Helsinki, Finland E-mail: ville.luoma@helsinki.fi
Saarinen, Department of Forest Sciences, University of Helsinki, FI-00014 University of Helsinki, Finland; School of Forest Sciences, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101, Finland E-mail: ninni.saarinen@helsinki.fi
Peuhkurinen, Arbonaut Oy, Malminkaari 13–19, FI-00700 Helsinki, Finland E-mail: jussi.peuhkurinen@arbonaut.com
Holopainen, Department of Forest Sciences, University of Helsinki, FI-00014 University of Helsinki, Finland E-mail: markus.holopainen@helsinki.fi
Vastaranta, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101, Finland E-mail: mikko.vastaranta@uef.fi

article id 1717, category Research note

Jussi Manner, Olle Gelin, Anders Mörk, Martin Englund. (2017). Forwarder crane’s boom tip control system and beginner-level operators. Silva Fennica vol. 51 no. 2 article id 1717. https://doi.org/10.14214/sf.1717

Keywords: productivity; automation; cut-to-length logging; haulage; crane work; extraction; learning curve

Highlights: Boom tip control (BTC) allows the operator to control boom tip movements directly, instead of controlling each movement separately to achieve the desired boom tip movement; BTC eased boom control, so beginner-level operators using BTC achieved higher productivity than beginner-level operators using a conventional (reference) system; There were no significant differences in the slopes of learning curves between the systems.

Abstract | Full text in HTML | Full text in PDF | Author Info

The forwarder loads processed wood and transports it to a landing. Productivity of forwarding could be improved by increasing driving speed, but difficult forest terrain limits this. According to current literature, crane work is the most time-consuming work element of forwarding, so improving crane work productivity is essential for improving forwarding productivity. One way to do this is through automation of recurrent boom movement patterns, or alternatively automation can be used to ease crane work. When using conventional boom control (CBC), the operator manually controls each of the independent boom joint movements and combines them to achieve a desired boom tip movement, but boom tip control (BTC) allows the operator to control boom tip movements directly. The objective of the present study was to examine whether BTC facilitates crane work and affects the slopes of learning curves for beginner-level forwarder operators. The study was carried out using a standardised test routine to evaluate effects of two fixed factors, system (levels: CBC, BTC) and point of time (four levels), on five dependent variables. Four of the five dependent variables measured ease of boom control and the fifth measured crane work productivity. The results showed that there were no significant differences in the slopes of learning curves between the systems but the BTC did increase crane work productivity and made boom control easier.

Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
Gelin, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: olle.gelin@skogforsk.se
Mörk, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: anders.mork@skogforsk.se
Englund, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: martin.englund@skogforsk.se

article id 1549, category Research note

Francesco Chianucci, Luca Salvati, Tessa Giannini, Ugo Chiavetta, Piermaria Corona, Andrea Cutini. (2016). Long-term response to thinning in a beech (Fagus sylvatica L.) coppice stand under conversion to high forest in Central Italy. Silva Fennica vol. 50 no. 3 article id 1549. https://doi.org/10.14214/sf.1549

Keywords: continuous cover forestry; thinning; Leaf Area Index; coppice management; Plant Canopy Analyzer

Highlights: Canopy recovery after medium-heavy thinning reveals the prompt response of beech to intensive thinning cycles; Active management practices accelerate the transition from coppice to high forest.

Abstract | Full text in HTML | Full text in PDF | Author Info

European beech (Fagus sylvatica L.) forests have a long history of coppicing, but the majority of formerly managed coppices are currently under conversion to high forest. The long time required to achieve conversion requires a long-term perspective to fully understand the implication of the applied conversion practices. In this study, we showed results from a long-term (1992–2014) case-study comparing two management options (natural evolution and periodic thinning) in a beech coppice in conversion to high forest. Leaf area index, litter production, radiation transmittance and growth efficiency taken as relevant stand descriptors, were estimated using both direct and indirect optical methods. Overall, results indicated that beech coppice showed positive and prompt responses to active conversion practices based on periodic medium-heavy thinning. A growth efficiency index showed that tree growth increased as the cutting intensity increased. Results from the case study supported the effectiveness of active conversion management from an economic (timber harvesting) and ecological (higher growth efficiency) point of view.

Chianucci, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy http://orcid.org/0000-0002-5688-2060 E-mail: fchianucci@gmail.com
Salvati, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Research Centre for the Soil-Plant System, via della Navicella 2–4, 00184 Roma, Italy E-mail: bayes00@yahoo.it
Giannini, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: tessa.giannini@entecra.it
Chiavetta, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: ugo.chiavetta@entecra.it
Corona, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: piermaria.corona@unitus.it
Cutini, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: andrea.cutini@entecra.it

article id 1321, category Research note

Sofia Bäcklund, Mari T. Jönsson, Joachim Strengbom, Göran Thor. (2015). Composition of functional groups of ground vegetation differ between planted stands of non-native Pinus contorta and native Pinus sylvestris and Picea abies in northern Sweden. Silva Fennica vol. 49 no. 2 article id 1321. https://doi.org/10.14214/sf.1321

Keywords: boreal forests; bryophytes; managed forests; introduced species; exotics; lichens; vascular plants

Highlights: Differences in ground vegetation patterns can be linked to tree species, forest stand age and differences in canopy cover; Vascular plant cover was higher in stands of P. contorta than in stands of both native tree species; The overall differences and similarities between P. contorta and the two native conifers were not consistent over the different age classes.

Abstract | Full text in HTML | Full text in PDF | Author Info

Intensified forestry increases the interest in replacing native tree species with fast growing non-native species. However, consequences for native biodiversity and ecosystem functioning are poorly understood. We compared cover and composition of major functional groups of ground vegetation between planted stands of non-native Pinus contorta Dougl. var. latifolia Engelm. and native conifers Pinus sylvestris L. and Picea abies (L.) H. Karst. in northern boreal Sweden. We quantified the ground cover of lichens, bryophytes, vascular plants and ground without vegetation (bare ground) in 96 stands covering three different age classes (15, 30 and 85 years old). Our study revealed differences in ground vegetation patterns between non-native and native managed forests, and that these differences are linked to stand age and differences in canopy cover. Total vascular plant cover increased with increasing stand age for all tree species, with P. contorta stands having higher cover than both native conifers. The ground cover of lichens was, although generally low, highest in stands of Pinus sylvestris. P. abies stands had a lower cover of vascular plants, but bare ground was more common compared with P. contorta. Our results suggest that the use of P. contorta as an alternative tree species in Fennoscandian forestry will influence native ground vegetation patterns. This influence is likely to change with time and future research should consider both temporal and landscape-scale effects from shifting tree-species dominance to Pinus contorta and other non-native tree species.

Bäcklund, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: sofia.backlund@slu.se
Jönsson, The Swedish Species Information Centre, P.O. Box 7007, SE-750 07 Uppsala, Sweden E-mail: mari.jonsson@slu.se
Strengbom, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: joachim.strengbom@slu.se
Thor, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: goran.thor@slu.se

article id 60, category Research note

Dominik Röser, Blas Mola-Yudego, Robert Prinz, Beatrice Emer, Lauri Sikanen. (2012). Chipping operations and efficiency in different operational environments. Silva Fennica vol. 46 no. 2 article id 60. https://doi.org/10.14214/sf.60

Keywords: wood-fuel logistics; forest machinery; bioenergy supply

Abstract | View details | Full text in PDF | Author Info

This research analyses the productivity of energy wood chipping operations at several sites in Austria and Finland. The aim of the work is to examine the differences in productivity and the effects of the operational environment for the chipping of bioenergy at the roadside. Furthermore, the study quantifies the effects of different variables such as forest energy assortments, tree species, sieve size and machines on the overall productivity of chipping. The results revealed that there are significant differences in the chipping productivity in Austria and Finland which are largely based on the use of different sieve sizes. Furthermore, the different operational environments in both countries, as well as the characteristics of the raw material also seem to have an effect on productivity. In order to improve the chipping productivity, particularly in Central European conditions, all relevant stakeholders need to work jointly to find solutions that will allow a greater variation of chip size. Furthermore, in the future more consideration has to be given to the close interlinkage between the chipper, crane and grapple. As a result, investments costs can be optimized and operational costs and stress on the machines reduced.

Röser, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: dominik.roser@metla.fi
Mola-Yudego, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: bmy@nn.fi
Prinz, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: rp@nn.fi
Emer, University of Padova, Department of Land, Agriculture and Forest Systems, Legnaro (PD), Italy E-mail: be@nn.it
Sikanen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: ls@nn.fi

article id 92, category Research note

Adam Felton, Erik Andersson, David Ventorp, Matts Lindbladh. (2011). A comparison of avian diversity in spruce monocultures and spruce-birch polycultures in southern Sweden. Silva Fennica vol. 45 no. 5 article id 92. https://doi.org/10.14214/sf.92

Keywords: biodiversity; conservation; sustainable forestry

Abstract | View details | Full text in PDF | Author Info

The replacement of some spruce monocultures with stands composed of planted Norway spruce (Picea abies) and naturally regenerated birch (Betula spp.) has a range of potential benefits, but the implications for biodiversity are generally unknown. Here we conduct a paired replicated study in southern Sweden of the avian biodiversity found within Norway spruce monocultures, and within Norway spruce stands possessing approximately 20% birch. Our research leads us to three findings. First, avian diversity was significantly higher in the spruce–birch polycultures. Second, spruce–birch polycultures exclusively attracted broadleaf-associated bird species and retained the majority of conifer-associated bird species found in the spruce monocultures. Third, avian biodiversity within the spruce–birch polycultures did not incorporate threatened taxa. We suggest that in addition to the apparent benefits for stand level diversity, widespread use of spruce–birch polycultures could provide a means of softening the matrix for broadleaved-associated species, while concurrently providing an increased broadleaf base from which future conservation actions could be implemented. Our results are relevant to multi-use forestry, and recent policy initiatives by forest certification agencies which aim to increase broadleaf-associated biodiversity within conifer-dominated production forest landscapes.

Felton, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden E-mail: adam.felton@ess.slu.se
Andersson, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden E-mail: ea@nn.se
Ventorp, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden E-mail: dv@nn.se
Lindbladh, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden E-mail: ml@nn.se

article id 10350, category Discussion article

Maja Peteh. (2020). A synthesis of the characteristics of current national, regional and international forestry journals. Silva Fennica vol. 54 no. 3 article id 10350. https://doi.org/10.14214/sf.10350

Keywords: forestry; geographical coverage; journal title list; scientific publishing

Highlights: Currently, 451 forestry-related journals are published worldwide (41.7% in Europe, 37.3% in Asia) in 32 different languages (47.9% in English only); 6 categories have been defined for the geographical coverage of a journal (55.5% of which have been defined as national and 18.2% as international); The journals could increase their visibility and value by improving their websites and submitting relevant information to international indexing databases.

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One of the main objectives of the International Union of Forest Research Organization’s WP 9.01.06 (Forest Science Publishing) is to clarify the range of forestry-related journals in the context of the overall objective of supporting authors and readers to deepen their knowledge of forestry. This study extended an earlier list of forestry journals using the ISSN database and the CAB abstracts. The study included 451 journal titles, each categorized by ISSN, publisher, language of publication, website, and geographical coverage (i.e. national, regional, international, or three mixed intermediate categories), as well as information on indexing in Web of Science, Scopus, DOAJ, and SherpaRomeo. The included journals are published in 61 countries and in 32 different languages. Those categorized as international are mostly published in English. 21.7% of the journals are indexed in Web of Science and 34.1% in Scopus. 95.6% of the titles are published online or in the print+online publishing model, but only 57.0% of the titles are published in Open Access, of which only 33.7% are indexed in DOAJ.

Peteh, University of Ljubljana, Biotechnical Faculty, Večna pot 83, Ljubljana 1000, Slovenia; Slovenian Forestry Institute, Večna pot 2, Ljubljana 1000, Slovenia https://orcid.org/0000-0002-9636-1155 E-mail: maja.peteh@gozdis.si

article id 1304, category Discussion article

Annika Kangas, Teppo Hujala. (2015). Challenges in publishing: producing, assuring and communicating quality. Silva Fennica vol. 49 no. 4 article id 1304. https://doi.org/10.14214/sf.1304

Keywords: peer review; open access; altmetrics; citation index

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This paper is based on a session “How to make forest science available for all? Publishers’, editors’, and authors’ challenges” at the IUFRO XXIV world conference, organized by Pekka Nygren and Eeva Korpilahti from the Finnish Society of Forest Science. The presenters dealt with the topical problems of publishing scientific knowledge from different perspectives. The talks covered the development of journals, publications and submissions, benefits and drawbacks of open access publishing as well as electronic and traditional publishing, and possibilities to promote interesting papers either from the journal’s or from the author’s perspective, and the problems of disseminating the scientific results to the end users. In this paper, a few prevalent viewpoints, inspired by the session, are raised and discussed with some suggestions included.

Kangas, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: annika.kangas@luke.fi
Hujala, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: teppo.hujala@luke.fi

article id 528, category Commentary

Annikki Mäkelä, Thomas J. Givnish, Frank Berninger, Thomas N. Buckley, Graham D. Farquhar, Pertti Hari. (2002). Challenges and opportunities of the optimality approach in plant ecology. Silva Fennica vol. 36 no. 3 article id 528. https://doi.org/10.14214/sf.528

Keywords: models; acclimation; adaptation; optimisation; evolution; hypotheses; evaluation

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A meeting was held in Hyytiälä, Finland 10–12 April 2000 to assess critically the current challenges and limitations of the optimality approach in plant ecophysiology and botany. This article summarises the general discussions and views of the participants on the use of optimisation models as tools in plant ecophysiological research. A general framework of the evolutionary optimisation problem is sketched with a review of applications, typically involved with balanced regulation between parallel processes. The usefulness and limitations of the approach are discussed in terms of published examples, with special reference to model testing. We conclude that, regardless of inevitable problems of model formulation, wider application of the optimality approach could provide a step forward in plant ecophysiology. A major role of evolutionary theory in this process is simply the formulation of testable hypotheses, the evaluation of which can lead to important advances in our ecophysiological understanding and predictive ability.

Mäkelä, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: annikki.makela@helsinki.fi
Givnish, University of Wisconsin, Department of Botany, Madison, WI 53706 USA E-mail: tjg@nn.us
Berninger, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: fb@nn.fi
Buckley, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: tnb@nn.au
Farquhar, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: gdf@nn.au
Hari, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: ph@nn.fi

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Category : Special section

Category : Research article

Category : Review article

Category : Research note

Category : Discussion article

Category : Commentary