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| 2. |
- Andersson, Gert, et al.
(författare)
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RuttOpt : a decision support system for routing of logging trucks
- 2008
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Ingår i: Canadian Journal of Forest Research. - 0045-5067 .- 1208-6037. ; 38:7, s. 1784-1796
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Tidskriftsartikel (refereegranskat)abstract
- We describe the decision support system RuttOpt, which is developed for scheduling logging trucks in the forest industry. The system is made up of a number of modules. One module is the Swedish road database NVDB, which consists of detailed information of all of the roads in Sweden. This also includes a tool to compute distances between locations. A second module is an optimization routine that finds a schedule, i.e., set of routes for all trucks. This is based on a two-phase algorithm where linear programming and a standard tabu search method are used. A third module is a database storing all relevant information. At the center of the system is a user interface where information and results can be viewed on maps, Gantt schedules, and result reports. The RuttOpt system has been used in a number of case studies and we describe four of these. The case studies have been made in both forest companies and hauling companies. The cases range from 10 to 110 trucks and with a planning horizon ranging between 1 and 5 days. The results show that the system can be used to solve large case studies and that the potential savings are in the range 5%–30%.
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| 3. |
- Arhipova, Natalija, et al.
(författare)
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Bark stripping of Pinus contorta caused by moose and deer: wounding patterns, discoloration of wood, and associated fungi
- 2015
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 45, s. 1434-1438
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to assess the extent of bark stripping wounds, subsequent wood discoloration, and associated fungi in 30-year-old Pinus contorta Douglas ex Loudon stems damaged by large game. In total, 90 trees were evaluated, and 170 bark stripping wounds of different ages (1-20 years) were measured. From each wound, wood samples were collected for subsequent fungal isolation. Thirty trees were cut to evaluate the length of the discoloration column. Of 170 injuries, 16 of them represented closed scars and 154 of them represented open wounds that exposed 4-4355 cm(2) of sapwood. The wound length had a strong impact on the length of decay (r = 0.716); however, the spread of discoloration beyond the wound margin was limited (0-20 cm). The most commonly isolated fungus was Sarea difformis (Fr.) Fr. and, among the Basidiomycetes, Peniophora pini (Schleich.) Boidin. The results suggest that when planning to grow P. contorta in areas of Europe, the population size of large game animals needs to be considered, in view of potential risk of bark stripping damage.
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| 4. |
- Aurangojeb, Mohammad, et al.
(författare)
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Nitrous oxide emissions from Norway spruce forests on drained organic and mineral soil
- 2017
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 47:11, s. 1482-1487
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Tidskriftsartikel (refereegranskat)abstract
- Nitrous oxide (N2O) emissions from drained organic (Histosol) and mineral (Umbrisol) soils having a 60 year old Norway spruce (Picea abies (L.) Karst.) forest in a catchment in southwest Sweden were measured using static closed chambers every other week over 3 years (August 2010 - July 2013). High emissions were observed during the summer months for both sites, which were significantly higher for the drained organic soils compared to the mineral soils: average emissions of 49.0 +/- 3.3 and 8.0 +/- 3.3 mu g N2O.m(-2).h(-1), respectively. As the experiment was designed to have similar forest and weather conditions for both sites, these were omitted as explanatory factors for the emission difference. Initially, the soil organic matter concentration (percent by mass) difference was thought to be the cause. However, the results found that the soil organic matter amount per square metre of top soil was similar at both sites, suggesting other possible explanations. We propose that the most plausible explanation is that higher tree growth and mycorrhizal nitrogen demand reduce nitrogen availability contributing to the lower N2O emissions from the mineral soil site.
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| 5. |
- Bansal, Sheel, et al.
(författare)
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The interactive effects of surface-burn severity and canopy cover on conifer and broadleaf tree seedling ecophysiology
- 2014
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 44, s. 1032-1041
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Tidskriftsartikel (refereegranskat)abstract
- Fire has an important role for regeneration of many boreal forest tree species, and this includes both wildfire and prescribed burning following clear-cutting. Depending on the severity, fire can have a variety of effects on above-and below-ground properties that impact tree seedling establishment. Very little is known about the impacts of ground fire severity on post-fire seedling performance, or how the effects of fire severity interact with those of canopy structure. We conducted a full-factorial experiment that manipulated surface-burn severity (no burn; light, medium, or heavy burn; or scarification) and canopy (closed forest or open clear-cut) to reveal their interactive effects on ecophysiological traits of establishing broadleaf and conifer seedlings in a Swedish boreal forest. Medium and heavy surface burns increased seedling growth, photosynthesis, respiration, and foliar N and P concentrations, and these effects were most apparent in open clear-cuts. Growth rates of all species responded similarly to surface-burn treatments, although photosynthesis, foliar P, and specific leaf area were more responsive to burning treatments for broadleaf species than for conifers. Our study demonstrates that the positive impacts of fire on tree seedling physiology are dependent on a minimum severity threshold and are more effective when combined with clear-cutting.
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| 6. |
- Barbeito, Ignacio
(författare)
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Pan-European sustainable forest management indicators for assessing Climate-Smart Forestry in Europe
- 2021
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 51, s. 1741-1750
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Tidskriftsartikel (refereegranskat)abstract
- The increasing demand for innovative forest management strategies to adapt to and mitigate climate change and benefit forest production, the so-called Climate-Smart Forestry, calls for a tool to monitor and evaluate their implementation and their effects on forest development over time. The pan-European set of criteria and indicators for sustainable forest management is considered one of the most important tools for assessing many aspects of forest management and sustainability. This study offers an analytical approach to selecting a subset of indicators to support the implementation of Climate-Smart Forestry. Based on a literature review and the analytical hierarchical approach, 10 indicators were selected to assess, in particular, mitigation and adaptation. These indicators were used to assess the state of the Climate-Smart Forestry trend in Europe from 1990 to 2015 using data from the reports on the State of Europe's Forests. Forest damage, tree species composition, and carbon stock were the most important indicators. Though the trend was overall positive with regard to adaptation and mitigation, its evaluation was partly hindered by the lack of data. We advocate for increased efforts to harmonize international reporting and for further integrating the goals of Climate-Smart Forestry into national-and European-level forest policy making.
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| 7. |
- Becs, Artis, et al.
(författare)
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How do different thinning methods influence spatial tree diversity in mixed forest stands of planted Norway spruce (Picea abies L.) and naturally regenerated birch (Betula spp.) in southern Sweden?
- 2024
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Ingår i: Canadian Journal of Forest Research. - 0045-5067 .- 1208-6037.
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Tidskriftsartikel (refereegranskat)abstract
- Forest biomass has become a viable alternative energy source for replacing fossil fuels, particularly after the European Union acknowledged its sustainability status. To reach zero net greenhouse gas emissions by 2045 in Sweden, new efficient methods of biomass extraction, such as geometrical biomass thinnings, are being explored and tested. These machine-based methods involve the extraction of above-ground biomass in narrow, 1-2 m-wide strips between extraction racks. While evidence-based optimization of biomass extraction mostly focuses on time- and cost-efficiency and on stand growth, criteria such as tree diversity are often overlooked. However, with ongoing climate change, tree diversity is crucial to strengthening the resilience and productivity of future forests, which also enhance the provision of ecosystem services and overall biological diversity. Therefore, we studied the effects of different biomass thinning strategies on spatial tree diversity in southern Sweden using nearest-neighbour summary statistics. We found scientific evidence that different geometrical designs of biomass thinning, especially in 1 or 2 m-wide strips, resulted in higher spatial tree diversity compared to conventional biomass thinning. Hence, in mixed conifer-broadleaved forests, biomass thinning in 1 or 2 m-wide strips is recommended for maintaining spatial tree diversity.
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| 8. |
- Berg, Björn, et al.
(författare)
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Manganese dynamics in decomposing needle and leaf litter : a synthesis
- 2013
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 43:12, s. 1127-1136
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present synthesis paper was to determine whether concentration changes and net release of manganese (Mn), as related to accumulated litter mass loss, are related to initial Mn concentration, mean annual temperature (MAT), mean annual precipitation (MAP), and tree genus or species. We also examined whether limit values for decomposition are related to initial litter Mn concentration, MAT, and MAP. We compiled 84 foliar litter decomposition studies, conducted mainly in boreal and temperate forest ecosystems, for which Mn dynamics had been well documented. Manganese concentration and amount were related to accumulated litter mass loss at each sampling time for each single study, as well as for (i) all studies combined (n = 748) and (ii) for species groups viz. Norway spruce (Picea abies (L.) Karst.) (n = 284), pine (Pinus) species (n = 330), and deciduous species (n = 214). The changes in Mn concentration with accumulated mass loss followed quadratic functions showing significantly higher Mn concentrations for Norway spruce vs. Scots pine (Pinus sylvestris L.) (p < 0.0001) and vs. deciduous species (p < 0.01), as well as significantly higher for deciduous species vs. Scots pine (p < 0.0001). Manganese release rates were different among the three species groups (p < 0.001). Still, rates were related to initial Mn concentrations (p < 0.001) for all litter types combined and for the three species groups. Norway spruce released Mn more slowly than pine and deciduous species. Rates were related to climatic factors for litter of Norway spruce and deciduous species. Limit values for all litter and for pine species separately were related to Mn (p < 0.001) and MAT (p < 0.001). For Norway spruce, limit values were related to MAT (p < 0.001) and MAP (p < 0.01). It appears that Norway spruce litter retains Mn more strongly in the litter structure, producing humus richer in Mn than does litter of pine and deciduous species.
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| 9. |
- Berg, Björn, et al.
(författare)
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Sequestration of carbon in the humus layer of Swedish forests - direct measurements
- 2009
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Ingår i: Canadian Journal of Forest Research. - 0045-5067 .- 1208-6037. ; 39:5, s. 962-975
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Tidskriftsartikel (refereegranskat)abstract
- To determine sequestration rates of carbon dioxide (CO2) we calculated the carbon (C) storage rate in humus layers of Swedish forests with Podsolic soils, which account for 14.2 x 106 ha of the 22.7 x 106 ha of forested land in Sweden. Our data set covered 41 years of humus inventories and mean humus layer thickness in 82513 plots. We analysed three forest types: (i) all combinations of tree species, (ii) forests dominated (>70%) by Norway spruce (Picea abies (L.) Karst.), and (Ui) forests dominated (>70%) by Scots pine (Pinus sylvestris L.). To relate changes in humus layer thickness to land area we used the intersections in 25 km x 25 km grids and used kriging interpolation, permitting calculations for each forest type. For each intersection mean humus thickness for each year was calculated and regressed against time to obtain the rate of change. This rate, humus bulk density, and humus C concentration were used, to calculate sequestration rates. The mean sequestration rate was 251 kg C-ha-1'year1, which is higher than theoretical values. The sequestration rate was positively related to temperature sum, albeit including effects of forest management. The pine-dominated forest type had a mean rate of 283 kgCha⁁year-1, and. the spruce-dominated had a mean rate of 239 kg Cha-1-year1. Under similar site conditions, pine sequestered more C than spruce (difference of 71 kg Cha-1'year-1; p < 0.0001), showing the importance of this type of ecosystem for C sequestration.
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| 10. |
- Bergsten, Urban
(författare)
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Effects of overstory tree density, site preparation, and ground vegetation on natural Scots pine seedling emergence and survival in northern boreal pine forests
- 2022
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 52
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Tidskriftsartikel (refereegranskat)abstract
- Natural regeneration is a commonly used forest regeneration method in northern Finland. It is not known, however, what would be the optimal overstory density and ground vegetation composition for seedling emergence and survival, and if site preparation is needed to accompany overstory density manipulation. We studied the effects of overstory density (unthinned control and thinning to 50,150, and 250 trees.ha(-1)) and ground vegetation removal (mechanical site preparation with disc trenching) on the number of naturally germinated pine seedlings and survival of individual seedlings over a period of 8 to 11 years. Bare mineral soil was a superior seedbed compared to intact vegetation cover, even though the mortality rate was high on mineral soil. Greater cover of lingonberry, crowberry, and slash had a negative effect on seedling number. Seedling mortality was initially high (60% died during the first 2 years) but decreased throughout the first 5 years. The survival rate of seedlings located in the mineral soil of the upper part of the disc trencher track was twice as high as that of seedlings located in the lower part of the track. High coverage of hair mosses (Polytrichum spp.) was associated with poorer seedling survival. An overstory density of 50-150 trees.ha(-1) with site preparation seems to be an efficient treatment to promote regeneration under these circumstances.
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