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Silva Fennica vol. 58 | 2024

Category : Editorial

article id 24058, category Editorial
Henrik Heräjärvi. (2024). Wood is much more than just carbon. Silva Fennica vol. 58 no. 4 article id 24058. https://doi.org/10.14214/sf.24058
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article id 24034, category Editorial
Hanne K. Sjølie. (2024). Normative bias in research. Silva Fennica vol. 58 no. 3 article id 24034. https://doi.org/10.14214/sf.24034
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  • Sjølie, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Department of Forestry and Wildlife Management, Campus Evenstad, Postboks 400, 2418 Elverum, Norway E-mail: sjoliehannek3@gmail.com
article id 24020, category Editorial
Matti Maltamo. (2024). What we pay attention to when we are in the forest? Silva Fennica vol. 58 no. 2 article id 24020. https://doi.org/10.14214/sf.24020
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article id 24016, category Editorial
Pekka Nygren. (2024). Advancing the Everyone’s Right to Forest Science: opening research data and computational codes in Silva Fennica. Silva Fennica vol. 58 no. 1 article id 24016. https://doi.org/10.14214/sf.24016
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Category : Climate resilient and sustainable forest management – Research article

article id 23067, category Climate resilient and sustainable forest management – Research article
Lucas N. López, Hanne K. Sjølie, Abbas Nabhani, Francisco X. Aguilar. (2024). Impacts of biodiversity and carbon policies on the management of Norwegian forest and its ecosystem services. Silva Fennica vol. 58 no. 4 article id 23067. https://doi.org/10.14214/sf.23067
Keywords: simulation; optimization; site productivity; bio-economic modeling; NorFor; regional impacts; TreeSim
Highlights: National-level biodiversity and carbon forest sector policies modelled in a simulation-optimization framework; Impacts of policies on management along site productivity gradients estimated; Policies vary in impact across productivity gradients with regional implications.
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Measures to enhance boreal forests’ biodiversity and climate change mitigation potential are high on the policy agenda. Site productivity influences management, ecological attributes, and economic outcomes. However, national-level analyses of management implementation in response to policies considering site productivity are lacking. We analyzed impacts of a carbon policy (Carb), a biodiversity policy (Bio) and a combined biodiversity and carbon policy (BioCarb) in Norway using a simulation-optimization framework, assessing impacts on forest management, timber harvest, ecological attributes, and carbon fluxes until year 2140. Management alternatives were simulated in the single-tree simulator TreeSim before being fed into a market model NorFor to compare policy outcomes to a business-as-usual (BAU) scenario. All policies led to decreased harvests. Old forests expanded from the current 3% to cover 21% or more of the productive forest area in all scenarios. Impacts of policies depended on site productivity. On low-productive land, management under Bio mirrored BAU, while the Carb and BioCarb policies yielded more set-asides. On high-productive land, management intensity under the Carb policy was similar to BAU but the Bio and BioCarb policies resulted in more set-asides and more old forest.  Thus, on low-productive land, the carbon policy showed to have the strongest impact on forest management, while on high-productive land, the biodiversity policy had the strongest impact. With geographical site-productivity gradients, the two policies exhibited different regional effects. The study shows that ex-ante analyses with appropriate tools can provide relevant information of multiple consequences beyond the stated aims which should be considered in policy design.
  • López, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway ORCID https://orcid.org/0009-0006-6860-3408 E-mail: lucas.lopez@inn.no (email)
  • Sjølie, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway ORCID https://orcid.org/0000-0001-8099-3521 E-mail: hanne.sjolie@inn.no
  • Nabhani, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway E-mail: abbas.nabhani@inn.no
  • Aguilar, Swedish University of Agricultural Sciences, Department of Forest Economics, SE-901 83 Umeå, Sweden E-mail: francisco.aguilar@slu.se
article id 23075, category Climate resilient and sustainable forest management – Research article
Lauri Männistö, Jari Miina, Saija Huuskonen. (2024). How to utilize natural regeneration of birch to establish mixed spruce-birch forests in Finland? Silva Fennica vol. 58 no. 3 article id 23075. https://doi.org/10.14214/sf.23075
Keywords: Betula pendula; Picea abies; Betula pubescens; mixed model; Chapman-Richards; mixed stands
Highlights: Naturally emerging birch admixture provides a sufficient starting point for mixed forest in young, planted spruce stands; Creating mixed forest is a time sensitive process, as different growth patterns among tree species might cause a situation where one tree species suppresses the other, leading to monoculture or two-storied mixed forest; Birch admixture should be retained during early cleaning.
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Mixed forests are known for their ability to provide a wide range of ecosystem services. Such forests have higher biodiversity compared to monocultures, are resilient against disturbances and may mitigate the effects of climate change. Despite well-known benefits, there is still little information on how these forests should be established and managed. The aim of this study was to describe the early growth dynamics of current boreal young mixed stands of planted Norway spruces (Picea abies (L.) Karst.) and naturally regenerated birches (Betula spp.). We collected data from 9  stands planted for spruce 8–14 years ago in Southern and Central Finland. Stem analysis was conducted to 144 spruces and to 144 birches to determine previous growth. We modelled the height and diameter development of individual trees in relation to tree age at stump height using non-linear mixed Chapman-Richards model. There were no significant differences between spruce and seed-origin birch in diameter growth at stump height, but the initial height increments of natural birches were larger than those of planted spruces. However, planted spruces were able to keep up with the height development of birches, if spruces received a head start over naturally regenerated seed-origin birch for two growing seasons. Thus, naturally regenerated birch admixture can be utilized to establish single-storied spruce-birch mixtures, and the admixture should be retained during the early cleaning of planted spruce stands.

  • Männistö, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0009-0009-0213-1972 E-mail: lauri.mannisto@luke.fi (email)
  • Miina, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-8639-4383 E-mail: jari.miina@luke.fi
  • Huuskonen, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0000-0001-8630-3982 E-mail: saija.huuskonen@luke.fi
article id 23069, category Climate resilient and sustainable forest management – Research article
John Alexander Pulgarin Diaz, Markus Melin, Tiina Ylioja, Päivi Lyytikäinen-Saarenmaa, Heli Peltola, Olli-Pekka Tikkanen. (2024). Relationship between stand and landscape attributes and Ips typographus salvage loggings in Finland. Silva Fennica vol. 58 no. 3 article id 23069. https://doi.org/10.14214/sf.23069
Keywords: Picea abies; wind damage; clear-cuts; European spruce bark beetle; stand attributes
Highlights: In Finland, the European spruce bark beetle (SBB) prefers mature stands (high age and mean diameter at breast hight), herb-rich heath forest sites and semi-coarse or coarse heath forest soil type, as well as a short distance to the closest wind damage from the previous-year, SBB damage from previous-year and particularly to clear-cuts; These stand types should be prioritised for monitoring SBB damage.
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Disturbances caused by the European spruce bark beetle (SBB; Ips typographus L.) on Norway spruce (Picea abies (L.) H. Karst.), have increased immensely across Central and Northern Europe, and are expected to increase further as a result of climate change. While this trend has been noted in Finland, so far limited research has been published. To support proper SBB risk management in Finland, we compared stand properties between salvage loggings due to SBB damage during 2012–2020 (4691 cases) and spruce stands free of SBB damage. Also, we explored the role of landscape attributes as drivers of SBB damage. We considered the forest stand attributes of site fertility class, stand development class, soil type, stand mean diameter at breast height and mean stand age. Considered forest landscape attributes were the distance from SBB-damaged stands to the closest clear-cut, to previous-year SBB-damaged stands and to the previous-year wind-damaged stand. We used nationwide forest logging and forest stock data, and analysed forest stand attributes using chi-squared and Mann-Whitney U tests and landscape attributes using generalised linear mixed models. Based on our findings, the SBB didn’t damage stands randomly, but prevailed in mature stands (high age and high mean diameter at breast height), in herb-rich heath forest site types and in semi-coarse or coarse heath forest soil soils. We found correlation between the landscape variables and the number of salvage loggings, with a higher number of loggings due to SBB damage close to clear-cuts. Our results help to find risk areas of SBB damage.

  • Pulgarin Diaz, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-0554-8254 E-mail: alexander.pulgarin.diaz@uef.fi (email)
  • Melin, Natural Resources Institute Finland (Luke), P.O. Box 68, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0001-7290-9203 E-mail: markus.melin@luke.fi
  • Ylioja, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-0079 Helsinki, Finland ORCID https://orcid.org/0000-0002-8840-7504 E-mail: tiina.ylioja@luke.fi
  • Lyytikäinen-Saarenmaa, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-1884-3084 E-mail: paivi.lyytikainen-saarenmaa@ef.fi
  • Peltola, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heli.peltola@uef.fi
  • Tikkanen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0002-3875-2772 E-mail: olli-pekka.tikkanen@uef.fi
article id 23061, category Climate resilient and sustainable forest management – Research article
Noora Tienaho, Ninni Saarinen, Tuomas Yrttimaa, Ville Kankare, Mikko Vastaranta. (2024). Quantifying fire-induced changes in ground vegetation using bitemporal terrestrial laser scanning. Silva Fennica vol. 58 no. 3 article id 23061. https://doi.org/10.14214/sf.23061
Keywords: forest fires; biomass; boreal forest; LIDAR; controlled burning; surface differencing; surface fires
Highlights: Bitemporal terrestrial laser scanning provided a means for identifying surface areas exposed to fire by utilizing a surface differencing method developed in this study; The developed method allowed for the quantification of fire-induced volumetric changes in ground vegetation at high resolution, facilitating the assessment of the impact of surface fires on forest ecosystems.
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Forest fires pose a significant threat to forest carbon storage and sinks, yet they also play a crucial role in the natural dynamics of boreal forests. Accurate quantification of biomass changes resulting from forest fires is essential for damage assessment and controlled burning evaluation. This study utilized terrestrial laser scanning (TLS) to quantify changes in ground vegetation resulting from low-intensity surface fires. TLS data were collected before and after controlled burnings at eight one-hectare test sites in Scots pine (Pinus sylvestris L.) dominated boreal forests in Finland. A surface differencing-based method was developed to identify areas exposed to fire. Validation, based on visual interpretation of 1 × 1 m surface patches (n = 320), showed a recall, precision, and F1-score of 0.9 for the accuracy of identifying burned surfaces. The developed method allowed the assessment of the magnitude of fire-induced vegetation changes within the test sites. The proportions of burned 1 × 1 m areas within the test sites varied between 51–96%. Total volumetric change in ground vegetation was on average –1200 m³ ha-1, with burning reducing the vegetation volume by 1700 m³ ha-1 and vegetation growth increasing it by 500 m³ ha-1. Substantial variations in the volumetric changes within and between the test sites were detected, highlighting the complex dynamics of surface fires, and emphasizing the importance of having observations from multiple sites. This study demonstrates that bitemporal TLS measurements provide a robust means for characterizing fire-induced changes, facilitating the assessment of the impact of surface fires on forest ecosystems.

article id 23042, category Climate resilient and sustainable forest management – Research article
Johanna Jääskeläinen, Lauri Korhonen, Mikko Kukkonen, Petteri Packalen, Matti Maltamo. (2024). Individual tree inventory based on uncrewed aerial vehicle data: how to utilise stand-wise field measurements of diameter for calibration? Silva Fennica vol. 58 no. 3 article id 23042. https://doi.org/10.14214/sf.23042
Keywords: laser scanning; calibration; mixed-effects model; single-tree detection
Highlights: A practical scheme to improve the accuracy of predicted tree and stand attributes in an uncrewed aerial vehicle based individual tree inventory; Accuracy was considerably improved with data from 2–4 sample trees from the target stand; Calibrated existing models and the construction of local models performed equally well; The laborious task of constructing a local model can be avoided by using a calibrated transferred model.
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Uncrewed aerial vehicles (UAV) have great potential for use in forest inventories, but in practice they can be expensive for relatively small inventory areas as a large number of field measurements are needed for model construction. One proposed solution is to transfer previously constructed models to a new inventory area and to calibrate these with a small number of local field measurements. Our objective was to compare calibration of general models and the construction of new models to determine the best approach for UAV-based forest inventories. Our material included field measurements and UAV-based laser scanning data, from which individual trees were automatically identified. A general mixed-effects model for diameter at breast height (DBH) had been formulated earlier based on data from a geographically wider area. It was calibrated to the study area with field measurements from 2–10 randomly selected calibration trees. The calibrated diameters were used to calculate the diameter of a basal area median tree (DGM), tree volumes, and the volume of all trees at plot-level. Next, new DBH-models were formulated based on the 2–10 randomly selected trees and calibrated with plot-level random effects estimated during model construction. Finally, plot-specific height-diameter regression models were formulated by randomly selecting 10 trees from each plot. Calibration reduced the prediction errors of all variables. An increase in the number of calibration trees decreased error rates by 1–6% depending on the variable. Calibrated predictions from the general mixed-effects model were similar to the separately formulated mixed-effects models and plot-specific regression models.

Category : Research article

article id 24047, category Research article
Kalle Kemppainen, Kalle Kärhä, Juha Laitila, Antti Sairanen, Ville Kankaanhuhta, Heli Viiri, Heli Peltola. (2024). Evaluation of the productivity and costs of excavator-based mechanized tree planting in Finland based on automated data collection. Silva Fennica vol. 58 no. 5 article id 24047. https://doi.org/10.14214/sf.24047
Keywords: site preparation; cost-efficiency; mechanization; forest regeneration; planting machine; site selection
Highlights: With proper site selection and competent machine operators, it is possible to achieve a higher productivity than 200 seedlings per operating hour in excavator-based mechanized planting; The hectare-based regeneration costs from excavator-based mechanized planting can be 5% lower than those of conventional manual planting chains; The most cost-efficient planting chain was a continuously advancing mounder combined with manual planting.
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The poor cost-effectiveness of mechanized planting (MECP) is the main reason for the low mechanization rate of planting. In this study, we investigated the productivity of the mechanized excavator-based planting of Norway spruce (Picea abies [L.] H. Karst.) seedlings based on data collected by the Risutec Asta documentation system. We also compared the costs of a MECP chain with two different manual planting (MAP) chains, where mounding was carried out by a crawler excavator (EXC) or a continuously advancing mounder (CONT). The MECP of seedlings was carried out using an EXC equipped with a Risutec PM-160 planting device. Generally, the nine study sites in western Finland contained few surface obstacles (e.g., the logging residues had mainly been harvested), which made the conditions very suitable for MECP. The average production time taken by the MECP was 9 h ha-1. The operating hour (G15-h) productivity averaged 215 seedlings G15-h-1 , with the mean planting time being 13.8 s seedling-1. Loading 160 seedlings into the seedling cassette took approximately 10 min (3.8 s seedling-1). Overall, the cost of the MECP was about 5% lower than for the EXC + MAP. However, when productivity was set at <200 seedlings G15-h-1 , the cost of the MECP was higher than that of the EXC + MAP. Based on our findings, the most cost-efficient planting chain was CONT + MAP. However, based on our results, the required level of productivity can be achieved if the sites are suitable for MECP and the machine operators are skilled.

  • Kemppainen, School of Forest Sciences, University of Eastern Finland (UEF), P.O. Box 111, FI-80101 Joensuu, Finland; Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0009-0000-6184-8812 E-mail: kalle.kemppainen@uef.fi (email)
  • Kärhä, School of Forest Sciences, University of Eastern Finland (UEF), P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0002-8455-2974 E-mail: kalle.karha@uef.fi
  • Laitila, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0003-4431-3319 E-mail: juha.laitila@luke.fi
  • Sairanen, School of Forest Sciences, University of Eastern Finland (UEF), P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0009-0008-8632-3797 E-mail: anttsair@student.uef.fi
  • Kankaanhuhta, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0001-5785-5972 E-mail: ville.kankaanhuhta@luke.fi
  • Viiri, UPM-Kymmene Plc, UPM Forest, Peltokatu 26 C 4, FI-33100 Tampere, Finland ORCID https://orcid.org/0000-0003-3952-9481 E-mail: heli.viiri@upm.com
  • Peltola, School of Forest Sciences, University of Eastern Finland (UEF), P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-1384-9153 E-mail: heli.peltola@uef.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.
Abstract | Full text in HTML | Full text in PDF | Author Info

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 ORCID https://orcid.org/0000-0002-6198-853X E-mail: kari.t.korhonen@luke.fi (email)
  • Räty, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland ORCID 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 ORCID 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 ORCID 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 ORCID https://orcid.org/0000-0002-7583-6297 E-mail: juho.pitkanen@luke.fi
article id 24042, category Research article
Han Ren, Xuezhen Chen, Xiaohong Qin, Suyang Zhang, Chengqun Lv, Jiangmin Zhou, Hualin Chen. (2024). Bacterial fertilizer and filtered sludge enhance soil fertility and plant growth in a eucalyptus plantation. Silva Fennica vol. 58 no. 5 article id 24042. https://doi.org/10.14214/sf.24042
Keywords: nutrient content; Bacillus megaterium; enzyme activity; PGPR; plant yield
Highlights: Filtered sludge significantly increased eucalyptus growth, particularly after six months of application; Bacterial fertilizer significantly improved soil enzyme activities, specifically urease and sucrase; Bacterial fertilizer influenced overall soil fertility, promoting sustainable eucalyptus cultivation practices; The study indicates the potential of biofertilizers as environmentally friendly alternatives to chemical fertilizers.
Abstract | Full text in HTML | Full text in PDF | Author Info

Plant growth-promoting rhizobacteria (PGPR) and filtered sludge are widely used to improve soil fertility and plant yields. In this study, we evaluated the impact of sludge and/or PGPR application on the nutrient contents and enzyme activities of the soil as well as on plant growth. We planted bare-root eucalyptus seedlings in (1) soil amended with filtered sludge from Nanning sugar factory (FS), (2) soil amended with filtered sludge + PGPR (BF), and (3) non-amended soil (control). Soil fertility and eucalyptus growth were determined after 3, 6, 9, and 12 months. Results demonstrated that FS treatment significantly increased eucalyptus growth compared to the control, particularly after six months. Bacterial fertilizer (BF) also increased soil urease and sucrase activities, although differences diminished over the study period. Our findings suggest that the integration of bacterial fertilizers and filtered sludge can serve as an effective and environmentally friendly strategy to improve soil health and promote sustainable eucalyptus cultivation. This research contributes to the growing body of evidence supporting the use of bio-fertilizers in forestry practices, highlighting their potential to reduce or replace the use of chemical fertilizers while increasing plant productivity.

  • Ren, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China; Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China ORCID https://orcid.org/0000-0002-0156-0726 E-mail: renhan1225@163.com (email)
  • Chen, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: 21211270104@stu.wzu.edu.cn
  • Qin, Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China E-mail: qinxiaohong186@163.com
  • Zhang, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: 00811091@wzu.edu.cn
  • Lv, Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China E-mail: lvchengqun8@163.com
  • Zhou, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: rosechl@wzu.edu.cn
  • Chen, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China ORCID https://orcid.org/0000-0002-3043-6919 E-mail: hualin2100@wzu.edu.cn (email)
article id 24031, category Research article
Jaakko Repola, Jaana Luoranen, Saija Huuskonen, Mikko Peltoniemi, Päivi Väänänen, Karri Uotila. (2024). Biomass models for young planted Norway spruce and naturally regenerated silver birch, aspen and rowan trees. Silva Fennica vol. 58 no. 5 article id 24031. https://doi.org/10.14214/sf.24031
Keywords: deciduous trees; Picea abies; tree biomass; model; multi-response
Highlights: Needle biomass was the greatest tree component of young spruce trees, and its proportion of whole biomass was 40-50%; The proportion of foliage biomass showed a decreasing tendency with tree height for all tree species; The existing models (Repola 2008, 2009) were not suitable for predicting spruce and birch biomass growing in young planted stands allocating too much biomass to roots and too little to crown.
Abstract | Full text in HTML | Full text in PDF | Author Info

We developed tree level biomass (dry weight) models for Norway spruce (Picea abies [L.] H. Karst.), silver birch (Betula pendula Roth), rowan (Sorbus aucuparia L.) and aspen (Populus tremula L.) growing in young spruce dominated seedling stands with high mixture of broadleaves. The study material was collected from three planted Norway spruce seedling stands located on mineral soil in southern Finland. Biomass models were estimated by individual tree component (stem, living branches, foliage, stump, and roots with diameter of 2 mm) by using a multi-response approach (seemingly unrelated regression), which estimated the parameters of the sub-models (tree component) simultaneously. Even though the application and generalization of the developed models can be restricted by the limited material, they provide new information of seedling biomass allocation and more reliable biomass predictions for spruce and birch growing in young seedling stand compared with those of the commonly applied biomass models (Repola 2008, 2009) in Finland. Repola’s models (2008, 2009) tended to produce biased predictions for crown and below-ground biomasses of seedlings by allocating too much biomass to roots and too little to needle and branches. In addition, this study provides biomass models for aspen and rowan, which were not previously available.

  • Repola, Natural Resources Institute Finland (Luke), Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID https://orcid.org/0000-0001-7086-0549 E-mail: jaakko.repola@luke.fi (email)
  • Luoranen, Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland ORCID https://orcid.org/0000-0002-6970-2030 E-mail: jaana.luoranen@luke.fi
  • Huuskonen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0000-0001-8630-3982 E-mail: saija.huuskonen@luke.fi
  • Peltoniemi, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0000-0003-2028-6969 E-mail: mikko.peltoniemi@luke.fi
  • Väänänen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: paivi.vaananen@luke.fi
  • Uotila, Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@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 ORCID https://orcid.org/0000-0002-1407-8349 E-mail: irene.a.kuhmonen@jyu.fi (email)
  • 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 ORCID https://orcid.org/0000-0002-5626-2929 E-mail: janne.keranen@vtt.fi
article id 23035, category Research article
Venla Wallius, Janni Kunttu, Elias Hurmekoski, Teppo Hujala, Anders Q. Nyrud, Hans F. Hoen. (2024). Attractiveness of wood-frame multi-storey buildings in seven European countries: consumer segmentation and the effect of fire safety information. Silva Fennica vol. 58 no. 5 article id 23035. https://doi.org/10.14214/sf.23035
Keywords: wood construction; consumer perceptions; consumer segmentation; fire safety
Highlights: There are significant differences in the perceived attractiveness of wooden multi-storey construction between consumer segments; According to the survey results, young consumers living in urban areas have the most interest in wooden multi-storey construction; Targeted marketing efforts are needed to inform potential consumers of wooden multi-storey construction.
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Wooden construction has the potential to contribute to climate change mitigation, and it is being promoted by the EU and national governments. However, several market barriers to wood-frame multi-storey building (WMSB), have been recognized, including obstacles in national building codes, lack of expertise in wood construction, and material durability concerns among end-users as well as other technical aspects. Given that increased wood construction is a target, understanding consumer perceptions of WMSB is crucial. In this study, consumer attitudes on WMSB were studied through consumer segmentation relying on demographic attributes. Further, the effect of providing fire safety information was explored. To this end, an online survey was deployed in seven European countries, with 7007 responses. The results show that in general, the awareness and attractiveness of WMSB is low amongst European consumers. Out of all respondents, 46% had not heard of WMSB before and only 12% stated that they are interested in the subject and know something about it, showing a clear lack of information and awareness within the general public. Significant differences in the perceived attractiveness of wooden multi-storey construction between consumer segments exist, with younger consumers and urban consumers being more attracted to living in WMSB than older or rural consumers. Fire safety was an important attribute affecting overall attractiveness, yet updated information regarding fire safety and control in WMSBs had a small but statistically significant negative effect on the perceived attractiveness. The results indicate that targeted marketing efforts are needed to inform potential consumers of WMSB and aspects related to fire safety effectively.
  • Wallius, European Forest Institute, Yliopistokatu 6 B, FI-80100, Joensuu, Finland; Jyväskylä University School of Business and Economics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID https://orcid.org/0000-0003-2576-9994 E-mail: venla.j.wallius@jyu.fi (email)
  • Kunttu, University of Helsinki, Department of Forest Sciences, P.O. Box 4, FI-00014 University of Helsinki, Finland ORCID https://orcid.org/0000-0002-7298-3363 E-mail: janni.kunttu@helsinki.fi
  • Hurmekoski, University of Helsinki, Department of Forest Sciences, P.O. Box 4, FI-00014 University of Helsinki, Finland ORCID https://orcid.org/0000-0001-8717-7287 E-mail: elias.hurmekoski@helsinki.fi
  • Hujala, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0002-7905-7602 E-mail: teppo.hujala@uef.fi
  • Nyrud, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway E-mail: anders.qvale.nyrud@nmbu.no
  • Hoen, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway E-mail: hans.hoen@nmbu.no
article id 24011, category Research article
Alexander Kaulen, Benjamin Engler, Thomas Purfürst. (2024). Net carbon storage of supplied timber in highly mechanized timber harvest. Silva Fennica vol. 58 no. 4 article id 24011. https://doi.org/10.14214/sf.24011
Keywords: carbon balance; emissions; forest machine data; forestry technique; timber supply chain; traceability
Highlights: CO2 emissions from timber supply comprise only 1.5–5% of the CO2 stored in wood; Distance to the mill has the greatest influence on CO2 emissions; Successful application by combining a few variable parameters from forest machine data with constant parameters to create a net carbon storage of the supplied timber; Simple presentation of the net CO2 storage capacity of wood can influence policy positively.
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Highly mechanized timber harvesting and timber logistics emit CO2. In turn, the provided timber stores CO2 from the atmosphere as biogenic carbon. This basic assumption resulted in the calculation of net carbon storage of supplied timber. For this, we first developed a formula that represents the carbon content of freshly harvested timber. Coniferous wood contains about 734 kg CO2 m-3 and deciduous wood about 1000 CO2 m-3. Contrary to this, CO2 emissions from trucks, harvesters, and forwarders were calculated using the variable parameters for actual diesel consumption and the distance to the sawmill and constant parameters for the transport of the machine to the stand, lubricants, transport of operators, loading, and fabrication, supply, and maintenance. The method was tested on an actual harvest. The principal findings are that the method is practical, the net carbon storage of the supplied timber is reduced by 1.5% to 5% by harvesting and transport activities, and timber logistics is the largest contributor to emissions. The CO2 emissions for harvesters and forwarders are about 4 kg CO2 m-3, and for downstream timber logistics across all assortments and distances is 11 kg CO2 m-3. We conclude that the emissions are low, vis-a-vis the storage capacity. Emissions and a standardized calculation model are imperative. The model developed here for mapping the net carbon storage of roundwood highlights the climate protection performance of timber and contributes to optimizing climate-friendly timber supply chains.

  • Kaulen, KWF - Kuratorium für Waldarbeit und Forsttechnik e.V., Spremberger Straße 1, 64823 Groß-Umstadt, Germany; University of Freiburg, Chair of Forest Operations, Werthmannstr. 6, 79085 Freiburg, Germany ORCID https://orcid.org/0009-0006-2633-8132 E-mail: alexander.kaulen@kwf-online.de (email)
  • Engler, University of Freiburg, Chair of Forest Operations, Werthmannstr. 6, 79085 Freiburg, Germany ORCID https://orcid.org/0000-0003-2104-8209 E-mail: benjamin.engler@foresteng.uni-freiburg.de
  • Purfürst, University of Freiburg, Chair of Forest Operations, Werthmannstr. 6, 79085 Freiburg, Germany ORCID https://orcid.org/0000-0001-9661-0193 E-mail: thomas.purfuerst@foresteng.uni-freiburg.de
article id 24007, category Research article
Heikki Manninen, Hanna Lehtimäki, Riitta Kilpeläinen, Eila Lautanen, Kalle Kärhä. (2024). The qualifications and competence in supervisory and management skills among recently graduated Finnish forestry professionals. Silva Fennica vol. 58 no. 4 article id 24007. https://doi.org/10.14214/sf.24007
Keywords: competence gap; forestry organizations; generic skills; higher forestry education; working life orientation; work requirements
Highlights: A remarkably large share of forestry professionals has supervisory or managerial duties soon after their graduation; Supervisory skills were considered important for all forestry professionals regardless of their position; The respondents recognized notable gaps in their competence in supervisory and management skills relative to work requirements, which higher forestry education must react to.
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In the past decade, research and several surveys have indicated that the competence of higher forestry education graduates does not meet the requirements of working life regarding supervisory and management skills. The aim of this study was to discover what kind of supervisory and management competence is required in the daily tasks of early-career forestry professionals, and to what extent the teaching of these skills would be advisable to include in higher forestry education. The study was implemented through a Webropol survey of the Master’s of Forestry graduates and forestry engineers graduated between 2018–2021, which mapped their supervisory and managerial duties and skills. The study population was 1046 people, of which 30.4% responded to the survey. The principal finding was of an apparent extensive need for the abovementioned skills, as supervisory duties are typical in the work of forestry professionals soon after their graduation. In this study, approximately one fifth of the employed respondents worked in a supervisory position, one third had supervisory or managerial duties, and half had an indirect network of subordinates. Supervisory skills were seen important for all forestry professionals regardless of their position. Moreover, self-management, team management, and well-being and occupational health management were regarded as important skills. However, there appeared to be notable gaps in all these skills. The study results contribute to improving working life orientation in higher forestry education. Based on these findings, we recommend that teaching of these subjects should be implemented by integrating the topics into field-specific courses.

  • Manninen, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland; South-Eastern  Finland University of Applied Sciences, P.O. Box 68, FI-50101 Mikkeli, Finland ORCID https://orcid.org/0009-0001-4234-7649 E-mail: heikki.manninen@xamk.fi (email)
  • Lehtimäki, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland ORCID https://orcid.org/0000-0002-9061-8984 E-mail: hanna.lehtimaki@uef.fi
  • Kilpeläinen, TTS Työtehoseura, P.O. Box 5, FI-05201 Rajamäki, Finland E-mail: riitta.kilpelainen@tts.fi
  • Lautanen, TTS Työtehoseura, P.O. Box 5, FI-05201 Rajamäki, Finland E-mail: eila.lautanen@tts.fi
  • Kärhä, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0002-8455-2974 E-mail: kalle.karha@uef.fi
article id 23077, category Research article
Timo Domisch, Saija Huuskonen, Juho Matala, Ari Nikula. (2024). Interactive effects of moose browsing and stand composition on the development of mixed species seedling stands. Silva Fennica vol. 58 no. 4 article id 23077. https://doi.org/10.14214/sf.23077
Keywords: boreal forest; tree species; Alces alces; ungulates; moose damage; mixed stands; meta-analysis
Highlights: We conducted meta-analyses assessing effect sizes of moose exclusion on seedling density and height, as well as regressions between stand density and deciduous seedling proportion and effect sizes; The more deciduous trees in a seedling stand, the smaller was the fencing effect, but at some point, the conifer seedling growth was impaired by too many deciduous seedlings. At the same time, the protective fencing effect increased with stand density; An appropriate deciduous admixture in conifer-dominated mixed seedling stands seems to improve moose damage tolerance.
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The moose (Alces alces L.), a common large herbivore in the boreal region, impairs forest regeneration by browsing on tree seedlings and saplings. Moose prefer deciduous species, but during winter more coniferous seedlings are used. We used meta-analyses, separately for deciduous and coniferous seedlings, for evaluating whether excluding moose browsing affected seedling density and height. In addition, we compared (1) deciduous seedling proportion, (2) stand density, (3) elapsed time from fencing and (4) estimated moose density with moose exclusion effect sizes. Fencing had a positive effect on coniferous seedling height. With more deciduous trees in a seedling stand, the fencing effect for both seedling height and density of coniferous seedlings decreased. On the other hand, the fencing effects increased with denser stands. At some point effect sizes turned to negative, and conifer species varied in their response to browsing. This implies that deciduous seedlings can protect conifers from browsing by moose up to some mixing ratio, but when deciduous seedling densities are too high, their negative effect increases, presumably through increased competition. Our results suggest that a moderate deciduous admixture in conifer-dominated mixed seedling stands can decrease moose damage but also underline the significance of timely silvicultural measures to minimize the negative effects of excessive deciduous seedlings and too dense stands. Due to differences in coniferous and deciduous species, as well as their compositions and amounts in studied experiments, more studies adjusted to local conditions are still needed to give exact measures for silvicultural recommendations.

  • Domisch, Natural Resources Institute Finland (Luke), Natural Resources, Yliopistokatu 6B, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0001-7026-1087 E-mail: timo.domisch@luke.fi (email)
  • Huuskonen, Natural Resources Institute Finland (Luke), Natural Resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: saija.huuskonen@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural Resources, Yliopistokatu 6B, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-5867-5057 E-mail: juho.matala@luke.fi
  • Nikula, Natural Resources Institute Finland (Luke), Natural Resources, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID https://orcid.org/0000-0001-8372-8440 E-mail: ari.nikula@luke.fi
article id 23068, category Research article
Anne Viljanen, Mikko Kurttila, Anne Toppinen. (2024). Retrofitting urban areas with wood: the origin of new projects in an emerging business ecosystem. Silva Fennica vol. 58 no. 4 article id 23068. https://doi.org/10.14214/sf.23068
Keywords: decision-making; business ecosystem; dynamic capabilities; project initiation; vertical building; wooden retrofits
Highlights: Decarbonizing building stock requires businesses to create new solutions for markets; Wood-material based retrofits offer new possibilities but are yet rare in urban context; The city-owned housing companies are found to be most aware of seizing opportunities of climate-benefits and facelifts in the less appealing suburban areas; Actors use dynamic capabilities in niche-level projects, yet the reconfiguring stage of business models is not visible.
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Nurturing a low-carbon residential building stock requires businesses to create new solutions for markets. Wood material-based retrofits would be one solution but have remained rare in the urban context. Our study explores the structure and dynamics of an emerging business ecosystem (BE) of wooden retrofits in Finland. We study wooden retrofit projects, from the perspective of the initial steps of local-level development. By applying the concepts of BE and dynamic capabilities, we aim to shed light on the role of actors and their early-stage decision-making and use actor mapping and qualitative analysis of 27 thematic interviews with retrofit businesses and municipal actors. Results show that project initiation has relied on individual champions seizing opportunities as a main base in building dynamic capabilities. Builders and customers are key actors of wooden retrofit projects in local BEs in Finland. The identified actors are further involved with future plans for wooden retrofits, some with ambitious deep renovation with wood. Motivations for projects are driven from urban densification strategies, improvement of suburban neighborhood attractiveness and from the efficiency of space utilization. Results further elaborate a certain degree of difficulty in the early-stage decision-making. This study contributes to the scientific knowledge of both the BE and the dynamic capability perspective by exploring a path to material-driven sustainable construction in the Finnish context. We provide new information on this emerging retrofit construction business with potentially significant international implications if scaled up more widely.
  • Viljanen, University of Helsinki, Faculty of Agriculture and Forestry, Latokartanonkaari 7, 00014 Helsingin yliopisto, Finland ORCID https://orcid.org/0000-0001-7166-8022 E-mail: anne.viljanen@helsinki.fi (email)
  • Kurttila, Natural Resources Institute Finland (Luke), Research and Customer Relationships, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0001-5290-4771 E-mail: mikko.kurttila@luke.fi
  • Toppinen, University of Helsinki, Faculty of Agriculture and Forestry, Latokartanonkaari 7, 00014 Helsingin yliopisto, Finland ORCID https://orcid.org/0000-0003-0910-1505 E-mail: anne.toppinen@helsinki.fi
article id 23044, category Research article
Kyle Eyvindson, Annika Kangas, Olha Nahorna, Juliette Hunault-Fontbonne, Maria Potterf. (2024). Integrating wind disturbances into forest planning: a stochastic programming approach. Silva Fennica vol. 58 no. 4 article id 23044. https://doi.org/10.14214/sf.23044
Keywords: forest planning; wind damage; risk mitigation; stochastic optimization
Highlights: Assessing risk should focus on the objectives of the decision maker, not simply to minimize wind damage; We explored timber income-oriented objectives, maximizing net profit and maintaining a high even-flow of timber related income; Integrating wind disturbances had limited advantages when prioritizing net profits, however, the impact was dramatic when striving to maintain a high even-flow of timber.
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Forest disturbances challenge our ability to carefully plan for sustainable use of forest resources. As forest disturbances are stochastic, we cannot plan for the disturbance at any specific time or location. However, we can prepare for the possibility of a disturbance by integrating its potential intensity range and frequency when developing forest management plans. This study uses stochastic programming to integrate wind intensity (wind speed) and wind event frequency (number of occurrences) into the forest planning process on a small coastal Finnish forest landscape. We used a mechanistic model to quantify the critical wind speed for tree felling, with a Monte Carlo approach to include wind damage and salvage logging into forest management alternatives. We apply a stochastic programming model to explore two objectives: maximizing the expected forest net present value or maximizing the even-flow of income. To assess the effects of improper wind risk assumptions in planning, we compare the results when optimizing for correct versus incorrect wind intensity and frequency assumptions. When maximizing for net present value, the impacts of misidentifying wind intensity and frequency are minor, likely due to harvests planned immediately as trees reach maturity. For the case when maximizing even-flow of income, incorrectly identifying wind intensity and frequency severely impacts the ability to meet the required harvest targets and reduces the expected net present value. The specific utility of risk mitigation therefore depends on the planning problem. Overall, we show that incorporating wind disturbances into forest planning can inform forest owners about how they can manage wind risk based on their specific risk preferences.
  • Eyvindson, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Campus Ås, Norway; Natural Resource Institute Finland (Luke), Bioeconomy and Environment, Laatokartanonkaari 9, 00790 Helsinki, Finland ORCID https://orcid.org/0000-0003-0647-1594 E-mail: kyle.eyvindson@nmbu.no (email)
  • Kangas, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Yliopistokatu 6, 80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-8637-5668 E-mail: annika.kangas@luke.fi
  • Nahorna, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Campus Ås, Norway ORCID https://orcid.org/0000-0002-5497-0315 E-mail: olha.nahorna@nmbu.no
  • Hunault-Fontbonne, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Campus Ås, Norway ORCID https://orcid.org/0009-0004-1864-5162 E-mail: juliette.hunault@nmbu.no
  • Potterf, Ecosystem Dynamics and Forest Management Group, Technical University of Munich, Hans Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany ORCID https://orcid.org/0000-0001-6763-1948 E-mail: maria.potterf@tum.de
article id 23073, category Research article
Curt Almqvist. (2024). High stand density improves seed production in seed orchards of the masting species Picea abies. Silva Fennica vol. 58 no. 3 article id 23073. https://doi.org/10.14214/sf.23073
Keywords: Norway spruce; thinning; cone production
Highlights: Cone production per tree in a Picea abies seed orchard is independent of stand density up to at least 800 stems ha–1; The higher the stand density, the higher per hectare cone production will be in the seed orchard.
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Reproduction in masting species is characterised by long intervals between good cone and seed production years, and only sparse reproduction between mast years. The physiological mechanisms behind masting, and how these are linked to internal resource status and external weather factors, is still a subject of scientific exploration and debate, as is the effect of climate change on masting. This study investigates cone production in one operational seed orchard in Sweden which was established with two different spacings and has since been subject to three tree thinning experiments. The spacings before thinning varied between 800 and 400 stems ha–1, and then thinning reduced the stand density in all trials to half, i.e. between 400 and 200 stems ha–1. In all three experiments cone production per tree was equal in un-thinned and thinned treatments, both in mast years and in non-mast years. Thus, the cone production per unit area was twice as high in the un-thinned areas. The conclusion from these experiments is that the establishment of Picea abies (L.) H. Karst. seed orchards with wide tree spacing is both a misuse of good orchard locations and bad economics.

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 ORCID https://orcid.org/0000-0002-9095-7986 E-mail: harri.silvennoinen@uef.fi (email)
  • Pikkarainen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID 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 ORCID 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 ORCID 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 ORCID 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 ORCID 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 ORCID https://orcid.org/0000-0003-1384-9153 E-mail: heli.peltola@uef.fi
article id 23018, category Research article
Anssi Ahtikoski, Kari Väätäinen, Perttu Anttila, Juha Laitila, Antti Mutanen, Jari Lindblad, Lauri Sikanen, Johanna Routa. (2024). The effects of the EU’s forest-related policies on harvesting costs in Finland. Silva Fennica vol. 58 no. 3 article id 23018. https://doi.org/10.14214/sf.23018
Keywords: forests; scenario approach; harvesting costs; directives and regulations; EU legislation; structural systems analysis
Highlights: The EU’s forest-related policies set direct and indirect limitations on the harvesting operations and operating environment; The effect on harvesting costs of Directives and Regulations depends on the magnitude of policy implementation; In a high-impact scenario, harvesting costs could increase by as much as 18% from the current level of costs.
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The EU’s influence on national forest policies is growing, and the implementation of forest-related policies proposed by the Commission will affect the practice of forestry in Europe. For instance, the Nature Restoration Law sets concrete areal goals for restoring forest ecosystems and for conservation, the Deforestation Regulation requires meticulous tracking of wood’s origin, and the renewed Renewable Energy Directive (RED III) sets new criteria to sustainable forest biomass procurement. So far there have been no studies that have looked into the impacts from the economic and operational point of view. In this study, structural systems analysis was first performed to discover the relevant variables (and their functioning) associated with the roundwood harvesting operations and the operating environment. A scenario approach was then applied to capture the potential levels of implementation of the EU’s forest-related policies. Finally, using different scenarios (low-, moderate- and high-impact) and a systems analysis framework, the impact of alternative levels of implementation was quantified in terms of harvesting costs, measured in € m–3. The results indicate that with the low- and moderate-impact scenarios the harvesting costs would increase by less than 10% from the current levels in three different regions in Finland. Such an increase (less than 10%) could be tolerated over a period of a few years, but a sudden increase is likely to lead to challenges to the running of businesses. With the high-impact scenario the harvesting costs would increase by between 15% and 18%, depending on the region. This magnitude of increase (of approximately a sixth) corresponds to a severe change in the roundwood harvesting operations and operating environment.

  • Ahtikoski, Natural Resources Institute Finland (Luke), Tekniikankatu 1, FI-33720 Tampere, Finland ORCID https://orcid.org/0000-0003-1658-3813 E-mail: anssi.ahtikoski@luke.fi (email)
  • Väätäinen, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-6886-0432 E-mail: kari.vaatainen@luke.fi
  • Anttila, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0000-0002-6131-392X E-mail: perttu.anttila@luke.fi
  • Laitila, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland E-mail: juha.laitila@luke.fi
  • Mutanen, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0003-0533-9356 E-mail: antti.mutanen@luke.fi
  • Lindblad, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0009-0003-6766-6587 E-mail: jari.lindblad@luke.fi
  • Sikanen, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland E-mail: lauri.sikanen@luke.fi
  • Routa, Natural Resources Institute Finland (Luke), Yliopistonkatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0001-7225-1798 E-mail: johanna.routa@luke.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.
Abstract | Full text in HTML | Full text in PDF | Author Info

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 ORCID 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 ORCID 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 ORCID https://orcid.org/0000-0003-3360-4444 E-mail: yrjo.nuutinen@luke.fi (email)
article id 23045, category Research article
Laura Pikkarainen, Harri Strandman, Eerik Vento, Aaron Petty, Olli-Pekka Tikkanen, Antti Kilpeläinen, Heli Peltola. (2024). Effects of forest conservation and management on timber, ecosystem carbon, dead wood and habitat suitability area in a boreal forest under climate change. Silva Fennica vol. 58 no. 2 article id 23045. https://doi.org/10.14214/sf.23045
Keywords: saproxylic species; simulation; carbon storage; forest fertilization; Fennoscandia; forest ecosystems services; improved regeneration material
Highlights: Increasing forest conservation areas increased all other ecosystem services except timber yield. Intensive forest management enhanced this increase; Increased conservation area decreased timber yield, but intensive forest management reduced this effect and even overcompensated it at the end of simulation period in the 10% conservation scenario with intensified forest management; Climate change increased all other ecosystem services, except carbon stocks.
Abstract | Full text in HTML | Full text in PDF | Author Info

We used forest ecosystem model simulations to study how forest conservation and management intensity affected timber yield, ecosystem carbon stocks, amount of dead wood, and habitat suitability area in a middle boreal forest region of Finland under changing climate over a 90-year simulation period. We used the following forest conservation and management scenarios: baseline forest management (BM), BM with 10 or 20% increase of conservation area with or without intensified forest management (i.e. improved forest regeneration material and forest fertilization). The simulations were done under current climate (reference period of 1981–2010), and Representative Concentration Pathway (RCP) climate change projections under the RCP2.6 and RCP4.5 forcing scenarios. Overall, increasing the forest conservation area decreased timber yield and increased the ecosystem carbon stock, the amount of dead wood and consequently the area of suitable habitat for saproxylic species. The use of intensified forest management reduced the loss of timber yield, increased ecosystem carbon stock, the amount of dead wood and area of suitable habitat for saproxylic species. At the end of simulation period, the use of intensified forest management even overcompensated (4–6% higher) the timber loss from 10% increase of conservation area. Under changing climate, timber yield, the amount of dead wood and the area of suitable habitats for saproxylic species increased. To conclude, with intensified forest management it is possible, in the short term, to decrease the loss of timber yield through increased forest conservation area and in the long term maintain or even increase it compared to baseline forest management.

  • Pikkarainen, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0001-5301-3639 E-mail: laura.pikkarainen@uef.fi (email)
  • Strandman, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-9400-6424 E-mail: harri.strandman@uef.fi
  • Vento, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland E-mail: eerik.vento@gmail.com
  • Petty, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0009-0006-6595-1386 E-mail: aaron.petty@uef.fi
  • Tikkanen, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-3875-2772 E-mail: olli-pekka.tikkanen@uef.fi
  • Kilpeläinen, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0003-4299-0578 E-mail: antti.kilpelainen@uef.fi
  • Peltola, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80100 Joensuu, Finland E-mail: heli.peltola@uef.fi
article id 23029, category Research article
Amira Fetouab, Nicole J. Fenton, Nelson Thiffault, Martin Barrette. (2024). Planting density and mechanical site preparation effects on understory composition, functional diversity and planted black spruce growth in boreal forests. Silva Fennica vol. 58 no. 2 article id 23029. https://doi.org/10.14214/sf.23029
Keywords: silviculture; paludification; reforestation; plantation establishment; community ecology; functional ecology
Highlights: Mechanical site preparation and planting density interacted to influence understory diversity and composition in plowed plots; Careful logging alone resulted in higher density of naturally established conifers; Planting density and site preparation alone had no effect on tree height and diameter; Findings provide insights for managing paludified forests and enhancing forest ecosystem functions.
Abstract | Full text in HTML | Full text in PDF | Author Info

Mechanical site preparation (MSP) is used prior to planting to control competing vegetation and enhance soil conditions, particularly in areas prone to paludification. Tree planting density can be adapted to the management context and objectives, as it influences yield and wood quality. However, the combined effects of MSP and planting density on understory vegetation composition, functional traits, and diversity remain uncertain. We thus conducted a study in the Clay Belt region of northwestern Quebec, Canada. After careful logging, the study area was divided into nine sites, each receiving one of three treatments: plowing, disc trenching, or no preparation. Sites were further divided into two, with black spruce (Picea mariana [Mill.] Britton, Sterns & Poggenb.) seedlings planted at either a low planting density of 1100 seedlings ha-1 or a high planting density of 2500 seedlings ha-1. After nine years, we assessed understory composition, diversity, key functional traits, sapling density and growth of planted trees. Careful logging alone led to a higher density of naturally established conifers compared to plowing or disc trenching. The interaction between planting density and MSP significantly influenced understory diversity and composition in plowed plots. Understory composition was affected by the soil C/N ratio, coniferous species, and deciduous species density. The growth of black spruce was notably enhanced with higher planting density in the plow treatment only. Neither planting density nor MSP alone affected tree height and diameter. Our results suggest that combining plowing with high-density planting can enhance stand growth and improve forest productivity. These findings guide future research on paludified forests.

  • Fetouab, Institute for Forest Research and Centre for Forest Research, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada E-mail: amira.fetouab@uqat.ca
  • Fenton, Institute for Forest Research and Centre for Forest Research, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada ORCID https://orcid.org/0000-0002-3782-2361 E-mail: nicole.fenton@uqat.ca
  • Thiffault, Institute for Forest Research and Centre for Forest Research, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada; Canadian Wood Fibre Centre, Natural Resources Canada, 1055 du P.E.P.S, P.O. Box 10380, Sainte-Foy Stn, Québec, QC G1V 4C7, Canada ORCID https://orcid.org/0000-0003-2017-6890 E-mail: nelson.thiffault@canada.ca (email)
  • Barrette, Institute for Forest Research and Centre for Forest Research, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada; Direction de la recherche forestière, Ministère des Ressources naturelles et des Forêts, 2700 rue Einstein, Québec, QC G1P 3W8, Canada ORCID https://orcid.org/0000-0001-5937-382X E-mail: martin.barrette@mffp.gouv.qc.ca
article id 23025, category Research article
Gundega Done, Jānis Ozoliņš, Guna Bagrade, Jurģis Jansons, Jānis Baumanis, Alekss Vecvanags, Dainis Jakovels. (2024). A case study for best suitable methods of monitoring demographic structure in cervid populations to predict increasing forest damages. Silva Fennica vol. 58 no. 2 article id 23025. https://doi.org/10.14214/sf.23025
Keywords: age structure; Alces alces; Cervus elaphus; camera trapping; damage to trees; pellet group counts; sex structure
Highlights: The study examines the interaction between sex-age structure of deer populations and forest damage throughout the country (Latvia); In pine stands, a higher female biased pellet group density index correlates with larger damage to pine trees through the browsing or debarking; Counting pellet groups and setting trail cameras both provide useful data on sex and age structure in moose and red deer populations that can be used for population monitoring.
Abstract | Full text in HTML | Full text in PDF | Author Info

The overall increase of ungulate populations in modern Europe has contributed to conflicts in national economies, particularly between game management and the forestry sector. This study assessed damage risks to young pine (Pinus sylvestris L.), spruce (Picea abies (L.) H. Karst.) and aspen (Populus tremula L.) stands at two spatial scales. One level assessed the interaction between sex-age structure of cervid populations, measured by pellet group density, and forest damages, measured as the percentage of heavily browsed trees in 2040 stand surveys distributed proportionally throughout the country. The second level compared pellet counts and trail-camera-based records of moose (Alces alces L.) and red deer (Cervus elaphus L.) presence in a pilot study area. We examined whether 1) there is a correlation between damage amount and ungulate population structure and 2) are the data from trail cameras suitable for wider use in monitoring ungulate population structure. The study confirmed significantly higher moose pellet group densities in pine than in spruce and aspen stands. Pine damages were greater in stands with higher moose pellet group density, especially with female moose prevailing over male moose density index. The red deer pellet group densities were significantly higher in heavily damaged pine and spruce stands, regardless of sex-age structure. In most cases, there were no statistically significant differences between the two survey methods of ungulate population structure by using pellet count transects and trail camera fixations. Both methods provide comparable data on sex-age structure in moose and red deer populations if seasonal and habitat-predicted biases are considered. However, trail cameras are more widely applicable and easier to use by hunters than pellet counts.

  • Done, Latvian State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0002-2122-7154 E-mail: gundega.done@silava.lv (email)
  • Ozoliņš, Latvian State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0002-6647-9128 E-mail: janis.ozolins@silava.lv
  • Bagrade, Latvian State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0002-1031-0665 E-mail: guna.bagrade@gmail.com
  • Jansons, Latvian State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, LV-2169, Latvia E-mail: jurgis.jansons@silava.lv
  • Baumanis, Latvian State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, LV-2169, Latvia E-mail: jbaumanis@inbox.lv
  • Vecvanags, Institute for Environmental Solutions ‘Lidlauks’, Cēsis, LV-4126, Latvia ORCID https://orcid.org/0000-0003-1233-764X E-mail: alekss.vecvanags@vri.lv
  • Jakovels, Institute for Environmental Solutions ‘Lidlauks’, Cēsis, LV-4126, Latvia ORCID https://orcid.org/0000-0002-2969-5972 E-mail: dainis.jakovels@vri.lv
article id 23014, category Research article
Hao Xiong, Yong Pang, Wen Jia, Yu Bai. (2024). Forest stand delineation using airborne LiDAR and hyperspectral data. Silva Fennica vol. 58 no. 2 article id 23014. https://doi.org/10.14214/sf.23014
Keywords: canopy height model; automatic delineation; merge rule; over-segmentation
Highlights: Delineate forest stands by the fusion of airborne LiDAR and hyperspectral data automatically; The forest height, canopy closure, and species information were taken into account during the delineation process, aligning with forest management in reality; The delineation accuracy was verified through comparison with three reference data sources commonly used in forest management.
Abstract | Full text in HTML | Full text in PDF | Author Info

Forest stands, crucial for inventory, planning, and management, traditionally rely on time-consuming visual analysis by forest managers. To enhance efficiency, there is a growing need for automated methods that take into account essential forest attributes. In response, we propose a novel approach utilizing airborne Light Detection and Ranging (LiDAR) and hyperspectral data for automated forest stand delineation. Our approach initiates with over-segmentation of the Canopy Height Model (CHM), followed by attribute calculation for each segment using both CHM and hyperspectral data. Two rules are applied to merge homogeneous segments and eliminate others based on calculated attributes. The effectiveness of our method was validated using three types of reference forest stands with two indices: the explained variance (R2) and Intersection over Union (IoU). Results from our study demonstrated notable accuracy, with a R2 of 97.35% and 97.86% for mean tree height and mean diameter at breast height (DBH), respectively. The R2 for mean canopy height is 81.80%, outperforming manual delineation by 7.31% and multi-scale segmentation results by 2.13%. Furthermore, our approach achieved high IoU values, which indicates a strong spatial agreement with manually delineated forest stands and leading to fewer manual adjustments when applied directly to forest management. In conclusion, our forest stand delineation method enhances both internal consistency and spatial accuracy. This method contributes to improving practical performance and forest management efficiency.

  • Xiong, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Forestry Remote Sensing and Information System, National Forestry and Grassland Administration, Beijing 100091, China; School of Geospatial Engineering and Science, Sun Yat-sen University, Zhuhai 519082, China ORCID https://orcid.org/0000-0003-4432-2485 E-mail: xiongh29@mail2.sysu.edu.cn
  • Pang, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Forestry Remote Sensing and Information System, National Forestry and Grassland Administration, Beijing 100091, China ORCID https://orcid.org/0000-0002-9760-6580 E-mail: pangy@ifrit.ac.cn (email)
  • Jia, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Forestry Remote Sensing and Information System, National Forestry and Grassland Administration, Beijing 100091, China E-mail: jiawen@ifrit.ac.cn
  • Bai, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Forestry Remote Sensing and Information System, National Forestry and Grassland Administration, Beijing 100091, China E-mail: baiyu9224@163.com
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.
Abstract | Full text in HTML | Full text in PDF | Author Info
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.
article id 23062, category Research article
Tobias Semberg, Anders Nilsson, Rolf Björheden, Linnea Hansson. (2024). Real-time target point identification and automated log grasping by a forwarder, using a single stereo camera for both object detection and boom-tip control. Silva Fennica vol. 58 no. 1 article id 23062. https://doi.org/10.14214/sf.23062
Keywords: vector analysis; forwarder; forest operations; loading; boom automation; object detection; stereo camera
Highlights: Simple target-point detection in real time using only a stereo camera; Sturdiness ensured through the simple feedback system based on the same camera; Automated boom-tip control and log grasping successfully tested on full-sized forwarder; A step toward semi-automation (operator support) or autonomous forwarding.
Abstract | Full text in HTML | Full text in PDF | Author Info
The forest industry is constantly striving to increase productivity and cut costs, and many research and innovation projects are currently focusing on semi-automated or autonomous systems. A key element, with several possible solutions, is automated log grasping, where researchers and manufacturers are looking for efficient and sturdy ways to solve the task in real-time forwarding operations. This study presents a simple method for automated log grasping using only a single stereo camera for object detection (log and grapple) and a simple controller moving the boom, with feedback from the camera as boom-tip control. The accuracy, precision, and repeatability of the method was tested on a full-scale forwarder. Boom movements were examined from two different start positions in relation to the target position, with the log placed at three different angles. The overall log-grasping success was also evaluated. The tests were performed in a full-scale, real-time operation, without hand-eye calibration or other sensor data from the machine. The method was precise, with high repeatability, but the grasping point showed a minor systematic offset, depending on log angle. However, the deviation in accuracy was too small to affect the success rate. In practice, the most difficult log angles can be avoided by moving the machine slightly. The log grasping method may become part of an autonomous forwarding system or could provide operator support in semi-automated systems.
  • Semberg, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: tobias.semberg@skogforsk.se
  • Nilsson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: anders.nilsson@skogforsk.se
  • Björheden, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-4158-102X E-mail: rolf.bjorheden@skogforsk.se
  • Hansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-9788-1734 E-mail: linnea.hansson@skogforsk.se (email)
article id 23058, category Research article
Johanna Jetsonen, Annamari Laurén, Heli Peltola, Olli Muhonen, Juha Nevalainen, Veli-Pekka Ikonen, Antti Kilpeläinen, Eeva-Stiina Tuittila, Elisa Männistö, Nicola Kokkonen, Marjo Palviainen. (2024). Effects of nitrogen fertilization on the ground vegetation cover and soil chemical properties in Scots pine and Norway spruce stands. Silva Fennica vol. 58 no. 1 article id 23058. https://doi.org/10.14214/sf.23058
Keywords: boreal forest; competition index; forest fertilization; upland forests; vegetation cover
Highlights: Nitrogen (N) fertilization decreased the total cover of ground vegetation; N fertilization decreased the cover of mosses and dwarf shrubs and increased the cover of herbaceous plants; N concentration of the mor humus layer increased with the N fertilization; The magnitude of these changes depended on the intensity of the N fertilization.
Abstract | Full text in HTML | Full text in PDF | Author Info
The aim of this study was to investigate the short-term effects of nitrogen (N) fertilization intensity on the ground vegetation cover and soil chemical properties  in two Scots pine (Pinus sylvestris L.)  and two Norway spruce (Picea abies (L.) Karst.) dominated stands on upland forest sites in Eastern Finland. The fertilizer was applied using a helicopter in the spruce stands and a forwarder in the pine stands. The distribution and the amount of fertilizer was measured with funnel traps. Cover of each species of ground vegetation was estimated  before fertilization and 3–4 years after it in pine and 2–3 years after it in spruce stands. Further, the cover observations were aggregated by plant types. Based on measurements, we analyzed the effects of the funnel-trap-observed amount of N fertilizer on the cover and plant type composition of ground vegetation and soil N and C concentration. In addition, we analyzed  the impacts of competition caused by trees on the ground vegetation cover based on competition indices. N fertilization increased the cover of herbaceous plants and decreased the cover of mosses and dwarf shrubs, and the total cover of ground vegetation. Further, it increased the N concentration of the mor humus layer. The magnitude of the changes increased with the intensity of the N fertilization. The competition caused by trees did not affect the cover of ground vegetation.
  • Jetsonen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014 University of Helsinki, Finland E-mail: johanna.jetsonen@helsinki.fi (email)
  • Laurén, Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014 University of Helsinki, Finland; Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0000-0002-6835-9568 E-mail: annamari.lauren@helsinki.fi
  • Peltola, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland E-mail: heli.peltola@uef.fi
  • Muhonen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0009-0007-4051-8567 E-mail: olli.muhonen@forestvital.com
  • Nevalainen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0009-0000-2972-4385 E-mail: juha.hs.nevalainen@gmail.com
  • Ikonen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-1732-2922 E-mail: veli-pekka.ikonen@uef.fi
  • Kilpeläinen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-4299-0578 E-mail: antti.kilpelainen@uef.fi
  • Tuittila, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland E-mail: eeva-stiina.tuittila@uef.fi
  • Männistö, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-3869-6739 E-mail: elisa.mannisto@uef.fi
  • Kokkonen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-0197-2672 E-mail: nicola.kokkonen@uef.fi
  • Palviainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014 University of Helsinki, Finland E-mail: marjo.palviainen@helsinki.fi
article id 23032, category Research article
Maria Anna Gartner, Matthias Kaltenbrunner, Manfred Gronalt. (2024). Dynamic box assignment planning in log yards. Silva Fennica vol. 58 no. 1 article id 23032. https://doi.org/10.14214/sf.23032
Keywords: storage assignment; seasonality; binary integer program; optimisation model; sawmill storage
Highlights: Seasonal change of assortments calls for dynamic box assignment planning in log yards; Multi-period planning better suited for dynamic problem, however period per period planning improves with decreasing capacity on the log yard; Rearrangement of assortment amounts to 8–11% of total transportation distance (loaded travelled distances of transportation vehicle); Considering separate box allocation (storage and ejection), which results in double stage planning of box allocation, benefits most if 10% additional volume may be cut in to clear the box.
Abstract | Full text in HTML | Full text in PDF | Author Info
The situation on the log yard changes seasonally and also over the years. The quantities of assortments to be stored, their number and also the type of wood can change. To respond to this, we have developed a dynamic log yard planning model for assigning roundwood to specific ejection boxes and storage areas in order to minimise the overall transport distances of the loaded transportation vehicles on the log yard, including any possible re-allocation of assortments. The study centres on the log yard of a medium-sized hardwood sawmill in Europe, with actual cutting data from a six-month period. We are comparing a multi-period binary integer program with a model that operates on a period per period basis and a solution approach that splits the problem into two subproblems and solves them sequentially. The models undergo testing with decreasing space capacities at the storage boxes on the log yard and are compared. If capacity is continuously decreasing from 100% to 80%, then period per period planning is on average 13% worse than multi-period planning. We also investigate how the solutions change when twice as many or half as many assortments are stored at the log yard. In addition, we study how much the solutions improve when logs can be removed from the storage boxes to clear them and release them for other material in the following period.
  • Gartner, University of Natural Resources and Life Sciences, Department of Economics and Social Sciences, Institute of Production and Logistics, Feistmantelstrasse 4, 1180 Vienna, Austria ORCID https://orcid.org/0000-0001-8547-718X E-mail: maria.gartner@boku.ac.at (email)
  • Kaltenbrunner, improvem GmbH, Holzinnovationszentrum 1a, 8740 Zeltweg, Austria ORCID https://orcid.org/0000-0002-1178-0087 E-mail: matthias.kaltenbrunner@improvem.at
  • Gronalt, University of Natural Resources and Life Sciences, Department of Economics and Social Sciences, Institute of Production and Logistics, Feistmantelstrasse 4, 1180 Vienna, Austria ORCID https://orcid.org/0000-0003-0944-4911 E-mail: manfred.gronalt@boku.ac.at
article id 22017, category Research article
Andis Lazdiņš, Ainārs Lupiķis, Kaspars Polmanis, Arta Bārdule, Aldis Butlers, Santa Kalēja. (2024). Carbon stock changes of drained nutrient-rich organic forest soils in Latvia. Silva Fennica vol. 58 no. 1 article id 22017. https://doi.org/10.14214/sf.22017
Keywords: drainage; hemiboreal forests; organic soil; peat compaction; peatland forests; subsidence of the peat layer
Highlights: In moderate nutrient-rich forest site type (Myrtillosa turf. mel.), a significant subsidence of peat layer after drainage is associated with compaction rather than decomposition of peat; In nutrient-rich forest site type (Oxalidosa turf. mel.), a contribution of soil C stock losses to subsidence of the peat layer is significant; In moderate nutrient-rich forest site type (Myrtillosa turf. mel.), type of dominant tree species has higher impact on changes in soil C stock after drainage than in nutrient-rich forest site type (Oxalidosa turf. mel.); Distribution of different forest site types involving soil nutrient status has to be taken into account when CO2 emissions from drained organic soil in forest land are estimated at national level.
Abstract | Full text in HTML | Full text in PDF | Author Info

Impact of drainage of organic soils in forest land on soil carbon (C) stock changes is of high interest not only to accurately estimate soil C stock changes, but also to provide scientifically based recommendations for forest land management in context of climate change mitigation. To improve knowledge about long-term impact of drainage on nutrient-rich organic soils in hemiboreal forests in Latvia, 50 research sites representing drained conditions (Oxalidosa turf. mel. (Kp) and Myrtillosa turf. mel. (Ks) forest site types) and undrained conditions as control areas (Caricoso-phragmitosa, Dryopterioso-caricosa and Filipendulosa forest site types) were selected. Soil C stock changes after drainage was evaluated by comparing current C stock in drained organic soils to theoretical C stock before drainage considering impact of soil subsidence. During the 53-years period after drainage, the peat subsidence was higher in nutrient-rich Kp forest site type compared to moderate nutrient-rich Ks forest site type (peat subsided by 37.0 ± 4.8 and 23.3 ± 4.8 cm, respectively). In nutrient-rich Kp forest site type, soil C stock decreased by 4.98 ± 1.58 Mg C ha-1 yr-1 after drainage, while no statistically significant changes in soil C stock (0.19 ± 1.31 Mg C ha-1 yr-1) were observed in moderate nutrient-rich soils in Ks forest site type. Thus, in Ks forest site type, the main driver of the peat subsidence was the physical compaction, while in Kp forest site type contribution of organic matter decomposition and consequent soil C losses to subsidence of the peat was significant.

  • Lazdiņš, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0002-7169-2011 E-mail: andis.lazdins@silava.lv
  • Lupiķis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: ainars.lupikis@inbox.lv
  • Polmanis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0003-2579-353X E-mail: kaspars.polmanis@silava.lv (email)
  • Bārdule, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0003-0961-5119 E-mail: arta.bardule@silava.lv
  • Butlers, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia ORCID https://orcid.org/0000-0003-3118-1716 E-mail: aldis.butlers@silava.lv
  • Kalēja, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: santa.kaleja@silava.lv

Category : Climate resilient and sustainable forest management – Review article

article id 23076, category Climate resilient and sustainable forest management – Review article
Joanne C. White. (2024). Characterizing forest recovery following stand-replacing disturbances in boreal forests: contributions of optical time series and airborne laser scanning data. Silva Fennica vol. 58 no. 2 article id 23076. https://doi.org/10.14214/sf.23076
Keywords: regeneration; fire; time series; Landsat; harvest; forest change
Highlights: Remote sensing contributions to monitoring of post-disturbance forest recovery in the boreal are synthesized; Definitions of forest recovery need to be clear and measurable and will vary by application; Landsat time series represent a significant innovation in recovery assessments, but the boreal biome is underrepresented in this research; Opportunities for future research directions and priorities are highlighted.
Abstract | Full text in HTML | Full text in PDF | Author Info
The success and rate of forest regeneration following disturbance has implications for sustainable forest management, climate change mitigation, and biodiversity, among others. Systematic monitoring of forest regeneration over large and often remote areas of the boreal forest is challenging. The use of remotely sensed data to characterize post-disturbance recovery in the boreal forest has been an active research topic for more than 30 years. Innovations in sensors, data policies, curated data archives, and increased computational power have enabled new insights into the characterization of post-disturbance forest recovery, particularly following stand-replacing disturbances. Landsat time series data have emerged as an important data source for post-disturbance forest recovery assessments, with Landsat’s 40-year archive of 30-m resolution data providing consistent observations on an annual time step and enabling retrospective capacity to establish spatially explicit recovery baselines. The application of remote sensing for monitoring post-disturbance forest recovery is a rapidly growing area of research globally; however, despite the large amount of disturbance and the disproportionate effects of climate change in the boreal, the boreal biome is relatively underrepresented in the remote sensing forest recovery literature. Herein, the past and present contributions of optical time series and airborne laser scanning data to the characterization of forest recovery in boreal forests are highlighted, and future research priorities are identified.
  • White, Canadian Forest Service, Pacific Forestry Centre, Natural Resources Canada, 506 West Burnside Road, Victoria, B.C., V8Z 1M5, Canada ORCID https://orcid.org/0000-0003-4674-0373 E-mail: joanne.white@nrcan-rncan.gc.ca (email)
article id 23057, category Climate resilient and sustainable forest management – Review article
Ane Christensen Tange, Hanne K. Sjølie, Gunnar Austrheim. (2024). Effectiveness of conservation measures to support biodiversity in boreal timber-production forests. Silva Fennica vol. 58 no. 2 article id 23057. https://doi.org/10.14214/sf.23057
Keywords: forestry; sustainable forest management; dead wood enhancement; forest certification; green tree retention; riparian buffer zone
Highlights: A systematic review of in-situ conservation measures displays that forest biodiversity levels are largely maintained upon harvest with conservation measures compared to unlogged forest; The type of control impacts the frequency of positive, not significant and negative observations; The relatively few significant results restrain distinct conclusions on the effectiveness of the assessed conservation measures to support biodiversity.
Abstract | Full text in HTML | Full text in PDF | Author Info

Large parts of the boreal forest ecosystems have been greatly affected by human use, and the current timber-oriented forest management practice that dominates boreal forests is proven to cause biodiversity and ecosystem services declines. These negative effects are mitigated in various ways, including in-situ measures implemented upon harvest. The measures comprise trade-offs between economic and ecological aims; thus, requiring solid knowledge of their effectiveness. However, comprehensive literature review of the effectiveness of such measures is scarce. We aim to fill part of this void by reviewing the scientific literature that have gauged effects of four in-situ conservation measures: green tree retention (GTR), patch retention (PR), dead wood retention (DW) and riparian buffer zones (RB). Two outcomes were considered, species richness and species abundance across taxa.

From a total of 3012 initial papers, 48 met our inclusion criteria that generated 238 unique results. Results were grouped according to control. 178 studies used mature, unlogged forest as control. Out of those, 68% of the findings were not significant, i.e., suggesting no significant impact of harvest with biodiversity measures on species richness and species abundance compared to no harvest. Eighteen percent of the observations showed negative effects and 14% of the observations showed positive effects compared to no harvest. Sixty studies used harvest with no measures as control, of which 45% showed significant positive effects, meaning that compared to harvest with no measures, harvest with conservation measures has positively effects on species richness and abundance. However, 43% of the studies found no significant effect of the implemented conservation measures compared to harvest with no measures taken.

The relatively few significant results reported restrain distinct conclusions on the effectiveness of the assessed conservation measures, but some degree of conservation measure is likely to have positive effects on biodiversity in timber-production forest. However, the scientific basis does not allow for pointing to threshold levels. Higher transparency of study design and statistical results would allow us to include more studies. There is a clear need for more research of effectiveness of common conservation measures in timber-production forests in order to strengthen the knowledge basis. In particular, there are few studies that employ harvest without any conservation measure as control. This is pivotal knowledge for forest managers as well as for policymakers for preserving biodiversity and the ecosystems in forest.

  • Tange, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Department of Forestry and Wildlife Management, Evenstad, Norway; Glommen Mjøsen Skog SA, Elverum, Norway ORCID https://orcid.org/0009-0001-3145-8159 E-mail: ane.tange@inn.no (email)
  • Sjølie, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Department of Forestry and Wildlife Management, Evenstad, Norway ORCID https://orcid.org/0000-0001-8099-3521 E-mail: hanne.sjolie@inn.no
  • Austrheim, University Museum Norwegian University of Science and Technology, Department of Natural History, Trondheim, Norway ORCID https://orcid.org/0000-0002-3909-6666 E-mail: gunnar.austrheim@ntnu.no

Category : Review article

article id 24021, category Review article
Eva Ring, Märtha Wallgren, Erland Mårald, Per Westerfelt, Line Djupström, Aron Davidsson, Johan Sonesson. (2024). Forest roads in Sweden – infrastructure with multiple uses and diverse impacts. Silva Fennica vol. 58 no. 4 article id 24021. https://doi.org/10.14214/sf.24021
Keywords: insects; forestry; recreation; reindeer; water; plants; wildlife
Highlights: The extensive network of forest roads in Sweden facilitates both forestry transportation and other activities including recreation, berry-picking, hunting, tourism, and firefighting; The multiple uses of roads can lead to conflicts when the interests between stakeholders and forest owners collide; Despite its extent, research into the social, ecological, and environmental consequences of Sweden’s forest road network is limited.
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Since the 1950s, more than 200 000 km of roads have been built in Sweden’s forests, making them easily accessible and open to multiple uses. The aim of this study was to review the impacts of forest roads in Sweden from a broad perspective encompassing social, ecological, and environmental factors. The Swedish case is interesting because it has an extensive network of permanent forest roads which were built primarily for forestry-related transportation but are currently used by many other stakeholders for many different purposes. Forest roads not only facilitate transportation of wood, machinery, personnel, and equipment into and out of the forest but also enable emergency response to wildfires and support berry and mushroom picking, hunting, recreation, tourism, and access to second homes. The roads increase the opportunities for members of the public to experience forests in various ways. Conflicts arise when different interests collide, for example when the interests of the forest owner clash with those of commercial berry-picking companies, tourism entrepreneurs, or reindeer (Rangifer tarandus L.) herding. Forest roads may have ecological impacts such as barrier and disturbance effects, fragmentation or loss of habitats, altering fauna movement patterns, and changing the composition of plant and insect species. The environmental impacts of forest roads relate to, among other things, hydrology, water quality, and erosion. Predicted changes in the climate are likely to place new demands on Swedish forest roads but, despite their extent, this review shows that there is only a small amount of rather fragmented research on their social, ecological, and environmental consequences. Overall, few studies appear to cover both social and ecological/environmental factors and their interactions, either in Sweden or elsewhere. This review provides examples of such interactions in the case of Sweden, and suggests that more research into these and the specific social, ecological, and environmental factors involved is warranted.

  • Ring, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-8962-9811 E-mail: eva.ring@skogforsk.se (email)
  • Wallgren, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden; Swedish University of Agricultural Sciences, Department of Wildlife, Fish, and Environmental Studies, 907 36 Umeå, Sweden ORCID https://orcid.org/0000-0002-3172-4496 E-mail: martha.wallgren@skogforsk.se
  • Mårald, Umeå University, Department of Historical. Philosophical and Religious Studies, 901 87 Umeå, Sweden ORCID https://orcid.org/0000-0002-2291-9910 E-mail: erland.marald@umu.se
  • Westerfelt, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0003-2040-8305 E-mail: per.westerfelt@skogforsk.se
  • Djupström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden; Swedish University of Agricultural Sciences, Department of Wildlife, Fish, and Environmental Studies, 907 36 Umeå, Sweden ORCID https://orcid.org/0000-0003-4536-7765 E-mail: line.djupstrom@skogforsk.se
  • Davidsson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0009-0007-2736-8656 E-mail: Aron.davidsson@skogforsk.se
  • Sonesson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-2018-7496 E-mail: Johan.sonesson@skogforsk.se
article id 23056, category Review article
Eva Ring, Ulf Sikström. (2024). Environmental impact of mechanical site preparation on mineral soils in Sweden and Finland — a review. Silva Fennica vol. 58 no. 1 article id 23056. https://doi.org/10.14214/sf.23056
Keywords: carbon; nitrogen; soil disturbance; vegetation; water; chemistry; greenhouse gas
Highlights: Mechanical site preparation is carried out on large areas, but limited research on its environmental impact has been undertaken; It affects nitrogen and carbon cycling over the first few years, and has a minor initial impact on CO2, CH4 and N2O fluxes; It increases tree carbon stores and possibly ecosystem carbon stores; Reducing its soil disturbance intensity is warranted.
Abstract | Full text in HTML | Full text in PDF | Author Info

Mechanical site preparation (MSP) is deliberate soil disturbance which is undertaken to improve the conditions for forest regeneration. Disc trenching and mounding are the dominant MSP practices currently used in Sweden and Finland. In this paper, the impacts of MSP on the soil, water quality, greenhouse gas (GHG) emissions and ground vegetation of mineral soil sites in Sweden and Finland are reviewed. The practices considered are patch scarification, mounding, inverting, disc trenching, and ploughing, which together represent a wide range of soil disturbance intensity. The environmental effects of MSP in this region have not been studied extensively. The environmental impact of MSP derives from the process of creating microsites which involves horizontal and/or vertical redistribution of soil and soil mixing. This typically affects decomposition, element circulation and leaching, vegetation coverage and uptake of nutrients and water, and possibly erosion and sediment exports. Following disc trenching or mounding the effects on GHG emissions appear to be minor over the first two years. For a few years after disc trenching concentrations in soil water collected below ridges are higher than that below furrows for some elements (e.g., NO3-, NH4+, Mg2+, and total or dissolved organic C). The physical and chemical effects of ploughing remain detectable for several decades. There is little evidence about how the effects of forestry activities in upland areas on soil-water chemistry are transferred to adjacent surface water bodies, including what role streamside discharge areas play. MSP increases the tree biomass C store and may increase the total ecosystem C store. The impact of MSP on the cover and abundance of ground vegetation species depends on the composition of the original plant community, MSP intensity, and the establishment rate of different species. Species cover generally seems to decline for late succession understory species, while pioneer and ruderal species can benefit from the microsites created. Areas containing lichens which are used for reindeer forage require special consideration. More research is needed on the environmental effects of MSP, particularly regarding its long-term effects. Further efforts should be made to develop efficient site-preparation practices which better balance the disturbance intensity with what is needed for successful regeneration.

  • Ring, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83, Uppsala, Sweden ORCID https://orcid.org/0000-0002-8962-9811 E-mail: eva.ring@skogforsk.se (email)
  • Sikström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83, Uppsala, Sweden E-mail: ulf.sikstrom@skogforsk.se

Category : Research note

article id 24039, category Research note
Jussi Manner, Hagos Lundström. (2024). The effect of forked trees on harvester time consumption in a Pinus contorta final-felling stand. Silva Fennica vol. 58 no. 4 article id 24039. https://doi.org/10.14214/sf.24039
Keywords: productivity; stem quality; stem defect; lodgepole pine; cut-to-length logging; double stem; forking
Highlights: For forked trees, codominant stems double harvester time consumption per tree, while double crowns have only minor impacts on harvester time consumption; Forked trees should be removed during thinning when they can still be time-efficiently multi-tree handled; Dealing with forked trees at a later rotation age, when they are too large for multi-tree handling, becomes excessively time-consuming.
Abstract | Full text in HTML | Full text in PDF | Author Info

The consensus on the factors affecting harvester productivity is generally widely acknowledged in the discipline. However, research results regarding the effect of forking on productivity are diverse. Some studies show that harvester productivity is halved when harvesting double stems compared to single-stem trees, while other studies indicate that forking does not necessarily decrease harvester productivity. These differences in study results can depend on what is considered forking. In our study, the forking occurred above the breast-height level. We defined codominant stems as forked trees too large to be multi-tree handled. In contrast, we defined double crowns as forked trees that could be multi-tree handled. The objective of our study was to analyse how the presence of codominant stems and/or double crowns affects harvester time consumption. The study was conducted in Sweden in 2022, involving two operators and two large harvesters. The 45-year-old Pinus contorta Douglas ex Loudon-dominated stand was clearcut during the study. We found that the presence of codominant stems doubles harvester time consumption per tree, while double crowns had only a minor impact on harvester time consumption. Additionally, total time consumption increased linearly with increasing diameter at breast height. Based on these findings, we recommend that forked trees be removed already during thinning when they can still be time-efficiently multi-tree handled. Dealing with forked trees later during the rotation cycle, when they are too large for multi-tree handling, is excessively time-consuming.

  • Manner, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se (email)
  • Lundström, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: hagos.lundstrom@skogforsk.se
article id 23064, category Research note
Henrik Lindberg, Tuomas Aakala, Ilkka Vanha-Majamaa. (2024). Ignition probability and fuel consumption of boreal ground vegetation fuels – an experimental study in Finland. Silva Fennica vol. 58 no. 3 article id 23064. https://doi.org/10.14214/sf.23064
Keywords: forest fires; ground vegetation; prescribed burning; flammability; fuel moisture content; mass loss rate
Highlights: Ignition probability and mass loss rates clearly differed in experimental burnings among four common circumboreal moss and lichen species; Cladonia rangiferina was the most flammable, Dicranum spp. the least flammable and Pleurozium schreberi and Hylocomium splendens intermediate.
Abstract | Full text in HTML | Full text in PDF | Author Info

In boreal forests fires often ignite and spread within the dominant moss and lichen cover of the ground layer vegetation, which thus greatly influences fire hazard. We used an experimental set-up in greenhouse conditions to study the differences in how (1) fuel moisture and (2) wind velocity influence the ignition probability and fuel consumption among four common circumboreal ground vegetation fuels, Pleurozium schreberi (Willd. ex Brid.) Mitt., Hylocomium splendens Schimp., Dicranum spp. and Cladonia rangiferina (L.) F. H. Wigg. Our results show that the reindeer lichen C. rangiferina was clearly the most flammable species, with high ignition probability even at high moisture contents and low wind velocities. Of the mosses, Dicranum was the least flammable, with low ignition probability and mass loss at low wind velocities regardless of moisture content. P. schreberi and H. splendens behaved somewhat similarly with wind velocities quickly increasing the initially low ignition probability and mass loss observed in the absence of wind. However, especially for mass loss, among-species differences tended to disappear with stronger winds. The observed differences can be explained by the different structures and growth forms of the studied species and open a potential avenue for improving forest fire risk predictions.

  • Lindberg, Häme University of Applied Sciences, School of Bioeconomy, Visamäentie 35 A, P.O. Box 230, FI-13100 Hämeenlinna, Finland ORCID https://orcid.org/0000-0001-9045-2673 E-mail: henrik.lindberg@hamk.fi (email)
  • Aakala, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID https://orcid.org/0000-0003-0160-6410 E-mail: tuomas.aakala@uef.fi
  • Vanha-Majamaa, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: ilkka.vanha-majamaa@luke.fi
article id 23050, category Research note
Anne Carolina, Rita K. Sari, Deded S. Nawawi, Effendi T. Bahtiar, Dai Kusumoto. (2024). Mechanical-chemical induction of balsam from Liquidambar excelsa trees. Silva Fennica vol. 58 no. 2 article id 23050. https://doi.org/10.14214/sf.23050
Keywords: Liquidambar excelsa; balsam; ethylene; methyl jasmonate; sustainable tapping
Highlights: The combination of mechanical and chemical induction on Rasamala branches offers an easy and efficient method for balsam exudation; Balsam exudation is chemically stimulated by methyl jasmonate and ethephon; Stimulant concentration increased the amount of balsam exuded in a dose-dependent manner.
Abstract | Full text in HTML | Full text in PDF | Author Info

Rasamala (Liquidambar excelsa (Noronha) Oken) is an endemic plant in Indonesia. Apart from its use as wood, Rasamala also produces an exudate, known as balsam. Rasamala balsam has the potential to be a substitute for other true balsams derived from Altingiaceae, namely Storax. However, local communities have not used Rasamala balsam to its full potential owing to a lack of knowledge about the tapping method and processing. Therefore, an easy and efficient induction method for plant exudates is required to boost productivity. The use of exogenous hormones as stimulants and less damaging tapping techniques for plant stems requires further investigation. In this study, mechanical and chemical inductions were conducted using 0.1%, 1%, 2%, 5%, and 10% (w/w) methyl jasmonate and ethephon as stimuli. These chemical compounds were applied to young twigs without incision (TW), by incision (TI), to branches perforated with an electric bore (BB), and by incision (BI). After exogenous application for 21 days, Rasamala balsam exuded in all induction techniques, except for the TW treatment. BI treatment showed the highest effective induction, as indicated by the highest balsam exudation. Furthermore, methyl jasmonate was a better chemical stimulant than ethephon. In addition, the induced balsam Rasamala exudate showed a physical characteristic of a clear, thick, sticky colorless to white liquid with a distinctive balsamic odor.

  • Carolina, Department of Forest Products, Faculty of Forestry and Environment, IPB University, Jl. Lingkar Kampus IPB Dramaga, Bogor, 16680, Indonesia ORCID https://orcid.org/0000-0002-2129-8665 E-mail: a_caroline@apps.ipb.ac.id (email)
  • Sari, Department of Forest Products, Faculty of Forestry and Environment, IPB University, Jl. Lingkar Kampus IPB Dramaga, Bogor, 16680, Indonesia ORCID https://orcid.org/0000-0001-5377-1384 E-mail: rita_kartikasari@apps.ipb.ac.id
  • Nawawi, Department of Forest Products, Faculty of Forestry and Environment, IPB University, Jl. Lingkar Kampus IPB Dramaga, Bogor, 16680, Indonesia ORCID https://orcid.org/0000-0001-8367-0349 E-mail: dnawawi@apps.ipb.ac.id
  • Bahtiar, Department of Forest Products, Faculty of Forestry and Environment, IPB University, Jl. Lingkar Kampus IPB Dramaga, Bogor, 16680, Indonesia ORCID https://orcid.org/0000-0003-0003-5855 E-mail: bahtiar_et@apps.ipb.ac.id
  • Kusumoto, The University of Tokyo Chiba Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 770 Amatsu, Kamogawa, Chiba 299-5503, Japan ORCID https://orcid.org/0000-0002-4250-2469 E-mail: kusumoto@uf.a.u-tokyo.ac.jp
article id 23071, category Research note
Mattias Finndin, Per Milberg. (2024). The population development of small trees and shrubs after 100 years of free succession of a wooded meadow in southern Sweden. Silva Fennica vol. 58 no. 1 article id 23071. https://doi.org/10.14214/sf.23071
Keywords: conservation; land-use change; nemoral forest; plants; regrowth; wooded grassland
Highlights: Using a unique map of trees and shrubs from 1937, we estimated the mortality of woody species typical of wooded meadows after management ceased in 1923; Both population size and canopy cover of the studied species had decreased during the past 86 years; On the other hand, several tree and shrub specimens endured for a century, pointing to the slow changes involved as well as the potential for restoration.
Abstract | Full text in HTML | Full text in PDF | Author Info
Wooded meadows are characterised by traditional-historic human use. Deliberate selection of species, pollarding and haymaking has created a complex and biodiverse habitat where small trees and shrubs were prevalent. This study set out to document what happens to such trees and shrubs during succession to forest, the normal fate when wooded meadows are abandoned but also when other open to semi-open patches revert to forest. The study was conducted at a site in southern Sweden where traditional management was abandoned by 1923 when the area was protected for research and allowed to follow natural succession. The current study is a follow-up of a 1937-inventory of small trees and shrubs. The results show a decrease in both population size and canopy cover in the selected species during the past 86 years. Hence, we can expect a loss of these species when wooded meadow are abandoned and left to developed into forests. On the other hand, several tree and shrub specimens endured for a century, pointing to the slow changes involved as well as the potential for restoration.

Category : Discussion article

article id 24053, category Discussion article
Francisco X. Aguilar, Marie Lautrup, Dohun Kim, Ane C. Tangen, Aapo Rautiainen, Huntley Brownell, Lucas N. López, Andrew D. H. Stratton, Sebastian Glasenapp, Silvia M. Korth, Hanne K. Sjølie, Jette Bredahl Jacobsen. (2024). Inherently spatial: data and analytical insights for the identification of forest socio-ecological hotspots. Silva Fennica vol. 58 no. 5 article id 24053. https://doi.org/10.14214/sf.24053
Keywords: forest sector; spatial analyses; adaptive interventions; ecological-social systems; robustness; spatial data
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We draw insights regarding intricacies with spatially explicit data and analyses when studying the vulnerability of forest socio-ecological systems to disruptive abiotic and biotic factors. Common issues associated with data include location precision, spatial delimitation, methodological comparability, and measurement consistency. Spatial data analyses are challenged by issues of interpolation and extrapolation, inferences using data at different spatial scales, and assessment of disruption impacts at detectable spatial scales. The inextricable empirical nature of spatial data and analyses requires carefully conducting and disclosing the sensitivity of findings, and including robustness tests to openly inform decision-makers on issues of uncertainty associated with possible interventions. These considerations might be central to identifying forest socio-ecological hotspots as forest-dominated geographic areas encompassing social and ecological systems vulnerable to disruptions caused by abiotic and biotic factors, but where risks to human wellbeing may be considerably reduced through adaptive interventions.

  • Aguilar, Swedish University of Agricultural Sciences (SLU), Department of Forest Economics, SE-901 83 Umeå, Sweden ORCID https://orcid.org/0000-0003-0226-4467 E-mail: francisco.aguilar@slu.se (email)
  • Lautrup, University of Copenhagen, Department of Food and Resource Economics, Rolighedsvej 23, 1958 Frederiksberg C, Denmark E-mail: ml@ifro.ku.dk
  • Kim, Swedish University of Agricultural Sciences (SLU), Department of Forest Economics, SE-901 83 Umeå, Sweden ORCID https://orcid.org/0000-0002-1919-3346 E-mail: dohun.kim@slu.se
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article id 24004, category Discussion article
Jussi Manner. (2024). Automatic work-element detection: the missing piece in developing intelligent coaching systems for cut-to-length logging machinery. Silva Fennica vol. 58 no. 1 article id 24004. https://doi.org/10.14214/sf.24004
Keywords: forwarder; harvester; work method; operator effect; assistance system; instructor; trainer
Highlights: Next-generation logging systems will crucially impact the future demand for automatic data gathering and work guidance; Artificial intelligence emerges as a gamechanger, prompting re-evaluation of traditional approaches to automatically gather data, especially for forwarders; Industry-wide, interdisciplinary discussions are vital for charting alternative future paths for automatic data gathering and work guidance.
Abstract | Full text in HTML | Full text in PDF | Author Info

The productivity of cut-to-length machine operators exhibits a significant disparity, with the most productive individuals demonstrating twice the efficiency of their less productive counterparts. This discrepancy is largely attributed to variations in work methods. While supervised training has proven effective in streamlining work methods and enhancing productivity, the availability of forest-machine instructors for supervision is limited. Intelligent coaching systems (ICS) are periodically proposed to address this constraint. ICS are computer-based aids that offer machine operators real-time feedback on their work and guide them on how to rationalize their work. The successful implementation of ICS initially requires the development of systems for automatic work-element detection (AWED). Therefore, this article explores the history, current status, and technological possibilities of AWED. Additionally, key features of ICS are briefly reviewed. Lastly, a broader, interdisciplinary discussion is initiated on how to strategically allocate limited research resources. Questions surrounding the feasible ambition level for ICS and AWED are raised, prompting considerations for the next steps in research and development.


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