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Silva Fennica vol. 58 | 2024

Category : Editorial

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 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

Category : Research article

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

  • Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland 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.
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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.
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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.
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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 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 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 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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