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1.	Akselsson, Cecilia, et al. (author) Critical biomass harvesting - Applying a new concept for Swedish forest soils 2018 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 409, s. 67-73 Journal article (peer-reviewed)abstract The contribution of forest harvesting to base cation losses and soil acidification has increased in recent years in Sweden, as the demand for bioenergy has increased and the sulphur deposition has decreased. Thus, new policy tools are required to evaluate the progress of the recovery from acidification, and as a basis for forest management recommendations. In this study we introduce and test a concept, Critical biomass harvesting. The concept builds on the concept Critical loads, which has been used world-wide for several decades as a bridge between science and policies related to transboundary air pollution and acidification. The basis for the concept is an acidity mass balance, with sources and sinks of acidity. A critical limit defines the highest acceptable acidification status of the water leaving the root zone. Based on the critical limit, the highest allowed biomass harvesting can be calculated, keeping the other parameters constant. In this study the critical limit was set to ANC (Acid Neutralizing Capacity) = 0. Nitrogen was assumed to be affecting acidity only if it leaches from the root zone. The critical biomass harvesting was calculated for almost 12000 National Forest Inventory sites with spruce and pine forest, using the best available data on deposition, weathering and nitrogen leaching. The exceedance of critical biomass harvesting was calculated as the difference between the estimated harvest losses and the critical biomass harvesting. The results were presented as median values in merged catchments in a catchment database, with totally 2079 merged catchments in Sweden. According to the calculations, critical biomass harvesting was exceeded in the southern half of Sweden already at stem harvesting in spruce forests. Whole-tree harvesting expanded the exceedance area, and increased the exceedance levels in southern Sweden. The exceedance in pine forest was lower and affected smaller areas. It was concluded that the concept of critical biomass harvesting can be successfully applied on the same database that has been used for critical load calculations in Sweden, using basically the same approach as has been extensively applied, evaluated and discussed in a critical load context. The results from the calculations in Sweden indicate that whole-tree harvesting, without wood ash recycling, can be expected to further slow down recovery, especially in the most acidified parts of the country, in the southwest.
2.	Andersson, Jon, et al. (author) Defining stump harvesting retention targets required to maintain saproxylic beetle biodiversity 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 371, s. 90-102 Journal article (peer-reviewed)abstract Stumps comprise up to 80% of the residual deadwood following clear cutting and are a significant source of biomass for bioenergetic applications. However, stump harvesting may pose significant conservation risks for saproxylic organisms that occur in residual deadwood. To define retention targets for stump harvesting operations, we compared abundance and species richness of saproxylic beetles within individual stumps as well as species accumulation curves in replicated pairs of clear cuts with and without stump harvesting in northern Sweden. Using 20 stands, we sampled 1049 stumps using eclector traps and collected 9821 beetles representing 253 species with known saproxylic biology. Nineteen of these species were red-listed in Sweden. We hypothesized that individual stumps left following stump harvesting would contain higher densities and species richness than in clear cuts without stump removal due to crowding of beetles into increasingly limited habitats. However, we found no difference in density or richness within individual stumps between control clear cuts and stumped stands. We also compared species richness between control and stumped treatments using rarefaction within individual stands and across all stands and found no difference. As with density and richness, beetle composition at the stand-level did not differ between control and stumped stands. Thus, the density of surrounding stumps within a stand had very little effect on beetle assemblages in residual stumps. We estimated the effect of stump harvest on species richness at the stand level by combining all samples and extrapolating a rarefaction curve derived from the landscape-level species pool to an accumulated sample volume of 48 m(3) which corresponds to the total volume of stumps on average-sized clear cuts in Northern Sweden. Using this curve, we compared differences in species richness in average-sized clear cuts with 100% (48 m(3)) and 25% (12 m(3)) stump retention and found that stump harvest resulted in a 26% (95% C.I. 7-41%) loss of species. While the absolute scaling of the landscape-derived rarefaction does not reflect species loss at the stand-level because the combined curve reflects all rare species in the landscape, the relative species loss derived from this curve may serve as credible benchmark for species loss at the stand level following current stump harvesting practices. This benchmark may be further calibrated with additional information on number of singleton species and estimates of maximum species richness. (C) 2016 Elsevier B.V. All rights reserved.
3.	Berg, Björn, et al. (author) Calcium in decomposing foliar litter – A synthesis for boreal and temperate coniferous forests 2017 In: Forest Ecology and Management. - : Elsevier B.V.. - 0378-1127 .- 1872-7042. ; 403, s. 137-144 Journal article (peer-reviewed)abstract We have synthesized available data for calcium (Ca) dynamics in decomposing foliar litter of mainly pine (Pinus), spruce (Picea), and birch (Betula) species to determine patterns of Ca concentration with climate in newly shed litter and its dynamics in decomposing litter as well as a possible role for Ca as regards limit values. Initial Ca concentration was negatively related to mean annual precipitation (MAP) with different relationships among genera. A limited data set showed a positive relationship across species (p < 0.05) to extractable Ca in soil. In paired stands, litter of both Norway spruce (Picea abies) and lodgepole pine (Pinus contorta) had higher Ca concentrations than Scots pine (Pinus silvestris), Norway spruce litter even twice as high. Relationships between initial concentrations of Ca and those of other nutrients appeared to be dominated by the positive ones to potassium (K) and magnesium (Mg) and specifically for deciduous litter there was a negative relationship to nitrogen (N). In decomposing litter, Ca concentration followed a negative quadratic (Ca = a + t − t2) function and had a maximum, which was variable. The Ca maximum concentration during decomposition was positively related to initial Ca concentration both within and among species. Separate linear relationships based on species were combined into one, in common for all investigated species and genera (R2 = 0.914, n = 63, p < 0.001). Limit values for decomposition were positively related to maximum Ca concentration at p < 0.05 with separate functions for pine and spruce litter. Calcium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient for each study. The net release rates were linear to initial Ca concentration both within and across species/genera. All studies combined gave a negative linear relationship (R2 = 0.894, n = 67, p < 0.001).
4.	Berg, Björn, et al. (author) Late stage pine litter decomposition : Relationship to litter N, Mn, and acid unhydrolyzable residue (AUR) concentrations and climatic factors 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 358, s. 41-47 Journal article (peer-reviewed)abstract The aim of this paper is to evaluate relationships between decomposition rates of Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta var. contorta) needle litter in the late stage of decomposition (>30% accumulated mass loss), and the progressively changing concentrations of manganese (Mn), nitrogen (N), and acid unhydrolyzable residue (AUR), as well as mean annual temperature (MAT) and mean annual precipitation (MAP). Using available long-term decomposition studies on pine needle litter in a climate gradient in Sweden, we calculated annual mass loss and related to concentrations of Mn, N, and AUR at the start of each one-year period as well as to MAT and MAP. We investigated these relationships for (i) all data on annual mass loss combined and (ii) annual mass loss for five different decomposition categories as defined by accumulated mass loss. We found highly significant, negative, and dominant relationships between annual mass loss and N (R2=0.39) and AUR (R2=0.39), a slight but significant positive relationship to Mn (R2=0.08) and a significant negative relationship to MAT (R2=0.06). The relationships were dynamic, and changed with accumulated mass loss. The rate-dampening effect of N decreased to be a rate-enhancing effect at c. 60-80% accumulated mass loss. A similar trend was found for AUR, becoming rate-enhancing at 70-80% accumulated mass loss. For Scots pine needle litter the effect of MAT on mass loss decreased with increasing accumulated mass loss and changed to a rate-dampening effect at c. 50-70% accumulated mass loss. Mn showed a stimulating effect on mass loss rate in all categories whereas MAP showed no effect in this mainly boreal climatic gradient. The current approach indicates a method for detailed studies of rate-regulating factors for litter decomposition.
5.	Berg, Björn, et al. (author) Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems : a review 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 358, s. 248-260 Research review (peer-reviewed)abstract We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO2) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.
6.	Bergholm, Johan, et al. (author) Nitrogen fluxes after clear-cutting. Ground vegetation uptake and stump/root immobilisation reduce N leaching after experimental liming, acidification and N fertilisation 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 342, s. 64-75 Journal article (peer-reviewed)abstract Clear-cutting often results in a dramatic change in the soil nitrogen (N) balance. This study analysed the fate of inorganic soil N over four years (1992-1995) in a new clear-cut containing three replicate blocks. Treatments comprised control (0), 6000 kg CaCO3 ha(-1) (Ca), 600 kg sulphur powder ha(-1) (S) and 600 kg urea-N ha(-1) (U), applied during 1976-1987 to a Norway spruce (Picea abies) forest. Trees were cut in March 1992, after which stems, tops and branches were removed from the 12 experimental plots. Spruce seedlings were planted in May 1992. Clear-cutting resulted in accumulation of approx. 50 kg inorganic N ha(-1) in the 30 cm deep topsoil of the 0, S and U treatments and 25 kg N ha(-1) in the Ca treatment by October of 1992. During the next two years, the inorganic pools increased (S), stabilised (0 and U) or declined (Ca), but from the end of the third year all inorganic pools decreased. Plant cover gradually increased with dominance of Deschampsia flexuosa. Mean plant N uptake in grasses, forbs and spruce seedlings was estimated at 95 (0), 139 (Ca), 52 (S) and 121 (U) kg N ha(-1) for the four-year period. Nitrogen leaching at 50 cm depth was dominated by NO3-N and culminated during the second (Ca and U) and third (0 and S) years. Cumulative N leaching for the four-year period was lower for U and Ca (28 and 31 kg N ha(-1)) than for 0 and S (53 and 81 kg N ha(-1)), and was inversely correlated with plant N uptake. Nitrogen immobilisation in stumps and root necromass (including spruce and grass roots) was calculated to be 35-45 kg N ha(-1) during this period. The four-year N balance showed 5-17% higher inputs (net mineralisation and deposition) than outputs (plant uptake, leaching, immobilisation in dead stumps/roots and accumulation of inorganic N). Gaseous N losses were not studied, but high pH and high NO3--N formation in the organic layers of the Ca treatment in 1992 might have favoured denitrification, which can partly explain the lower amount of inorganic N remaining in this treatment. A novel finding was that stump and dead root immobilisation of N was quantitatively important. A second novel finding was that lime application, although stimulating nitrification, also stimulated plant N uptake so much that nitrate leaching was reduced in comparison with the control and sulphur treatments. (C) 2015 Elsevier B.V. All rights reserved.
7.	Bergner, Adam, et al. (author) Influences of forest type and habitat structure on bird assemblagesof oak (Quercus spp.) and pine (Pinus spp.) stands in southwesternTurkey 2015 In: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 336, s. 137-147 Journal article (peer-reviewed)abstract The Mediterranean basin exhibits a multitude of forest habitats affected by former and current exploitation and management. Recent afforestation programs have resulted in an increase in the proportion of coniferous trees, while oak stands, formerly utilized for coppicing and grazing, are abandoned or converted into coniferous plantations. The loss of oak stands might negatively affect birds dependent upon broadleaved forests. Studies confirming or rejecting that statement are scarce, particularly in the eastern part of the region. Using a study area in southwestern Turkey we applied a guild-based approach to investigate how pine and oak stands across a chronosequence differ in their capacity to support forest bird assemblages. Variables describing the vegetation were sampled to characterize the stands and relate bird assemblages to stand structure. Bird abundance and species richness was positively associated with age for both stand types. Richness and diversity was highest in oak stands, while there were no differences in bird abundance between the two forest types. Pine stands supported a different bird species composition compared to oak stands of the same age. Stand age and structure, rather than forest type, held the highest explanatory powers for bird assembly structure. Primary cavity-nesters and ground-nesters were more abundant in oak stands, possibly reflecting differences in stand structure and resource distribution. To support these birds with suitable habitats, oaks stands need conservation. Management practices in pine stands should strive for increasing the amount of old trees and retain vegetation in the understory to benefit breeding birds.
8.	Bergqvist, Göran, et al. (author) Forage availability and moose winter browsing in forest landscapes 2018 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 419-420, s. 170-178 Journal article (peer-reviewed)abstract In a large-scale survey, comprising 38 landscapes throughout Sweden, we measured winter forage availability and use by moose within different forest- and land types, and also at three different spatial scales: plot, tract and area.Measured as percent cover of browse species within moose browsing range, young forests contained significantly more browse (16.5 +/- 1.20%: mean +/- SE) compared with older forests (6.7 +/- 0.57%) or non-forest land (5.9 +/- 0.67%). Total cover of browse species increased with increasing mean tree height in forests, and peaked at around 22% when the trees were 3-5 m. The relative consumption was highest in young forests (9.2 +/- 0.98%) compared with non-forest land (7.8 +/- 1.40%) or older forests (5.8 +/- 0.78%). The selection order did not vary much among forest- or land types, with aspen, willows, rowan and oak being the most selected species.A multiple regression, including four independent variables (moose index, cover of Scots pine, cover of other species and temperature sum) explained 45% (young forests), 18% (older forests) and 36% (non-forest land) of the variation in relative consumption. In young forests, moose index and cover of Scots pine accounted for 40 and 44%, respectively, of the explained variation. Model selection, using AICc, further emphasized the importance of moose index and cover of Scots pine, as these variables were included in the most parsimonious models for all forest- and land types.At the tract level, we recorded a proportional relationship between total cover of browse species and absolute consumption, suggesting an ideal free distribution. Taking into account the availability of forage, the degree of browsing and the proportion of each land type in the landscape, we calculated that 44.3% of the total forage consumption occurred in young forests, 42.3% in older forests and 13.4% in non-forest land.Our main conclusions are that moose conform to an ideal free distribution based on availability of forage within the landscape, and that all forest- and land types, not just young forests, are important as sources of browse for moose. Thus, it may be possible to release the browsing pressure on damage-sensitive young forests by increasing the food supply in other forest- and land types. Furthermore, managers needs to consider both the size of the moose population and the amounts of browse in the landscape when deciding on prudent management actions.
9.	Bernhardsson, Carolina, et al. (author) Present genetic structure is congruent with the common origin of distant Scots pine populations in its Romanian distribution 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 361, s. 131-143 Journal article (peer-reviewed)abstract Owing to the fact that mitochondrial, chloroplast and nuclear genomes are differently affected by evolutionary forces, the comparative study of all three genomes in combination with paleobotanical evidences allows for a more accurate interpretation of present genetic make-up. In this study, we analyzed the nad1-nad7 mitotype, 14 cpSSR loci and 10 nSSR loci in 13 Romanian Scots pine (Pious sylvestris L.) populations from the Romanian Carpathians and two Hungarian populations. Previous analysis of the macro fossil records supports the presence of Scots pine and Swiss stone pine (Pinus cembra L.) during the glacial period in Hungary and Romania. For a better image into the population structure in the studied area we also included in the data analysis two outgroup populations (north and south of Sweden) of known post glacial origin, which resulted in a more defined genetic structure. Our study reveals that relatively high genetic diversity is preserved at all the Romanian and Hungarian populations, with no distinction among naturally regenerated, managed autochthonous and introduced populations. Furthermore, genetic differentiation analysis fails to distinguish the two introduced populations from the Romanian ones. AMOVA clustering is congruent with the paleobotanical-based evidences of contraction of Scots pine range since the Holocene to its present fragmented distribution. (C) 2015 Elsevier B.V. All rights reserved.
10.	Binkley, Dan (author) Bark beetle effects on seven-century chronosequence of Engelmann spruce and subalpine fir in Colorado, USA 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 361, s. 154-162 Journal article (peer-reviewed)abstract Many important trends in forest development across landscapes and centuries are difficult to measure directly, and a space-for-time substitution in a chronosequence may provide useful insight at these scales. The value of chronosequences for forest ecology and management depends on a number of sources of variation, including geographic differences in site productivity, differences in climate over long periods, and the presence or absence of rapid events such as fire, windthrow, and insect outbreaks. Confidence in the value of a chronosequence may be increased if later resampling shows that each site followed the predominant trajectory expected from the chronosequence pattern. We resampled a 700-year chronosequence of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) three decades after the initial sampling. The original chronosequence suggested long-term stasis in both biomass and production after about 200 years of stand developments in the absence of major fire, beetle outbreaks, and windstorms. Three decades later, a spruce beetle (Dendroctonus rufipennis) outbreak had reduced spruce biomass by 68% and total stand biomass by 44% across the chronosequence (to an average of 7.8 kg m(-2)). There remained no trend in total stem biomass with stand age, averaging 13.9 kg m(-2) of stemwood across all ages. Stem production averaged 0.15 kg m(-2) yr(-1) between 1984 and 2013, higher than the 0.09 kg m(-2) yr(-1) estimated in 1984. Over the three decades, stand biomass shifted from about 2/3 spruce to 2/3 fir. Stands may be selected for chronosequences based on an absence of rapid events that substantially change stand structure, but this may limit the ability of a chronosequence to represent real long-term patterns across landscapes. (C) 2015 Elsevier B.V. All rights reserved.
11.	Binkley, Dan (author) Eucalyptus plantation effects on soil carbon after 20 years and three rotations in Brazil 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 359, s. 92-98 Journal article (peer-reviewed)abstract How will shifting land use from row crops and pasture to intensively managed forests alter soil carbon storage? Demand and profitability has led to a dramatic increase in Eucalyptus production with a total planted area over 20 million hectares worldwide. The impacts of these short-rotation (6- to 8-year harvest cycle) Eucalyptus plantations on soil carbon appear to be variable, and the available case studies are typically too short term to support generalization. Spatial heterogeneity of soils across landscapes requires repeated sampling for reliable documentation of soil carbon changes over multiple rotations. We characterized soil carbon stocks and change over two decades in 306 operational Eucalyptus plantations across a 1200-km gradient. Across all sites, soil C (0-30 cm depth) in 2010 averaged 29 Mg ha(-1) (0.70 Mg ha(-1)), tending to increase with increasing soil clay content, precipitation, and mean annual temperature. Average soil C from the original sampling to 2010 (ranging from 18 to 26 years or approximately 3 to 4 rotations) showed a slight decrease (-0.22 0.05 Mg ha(-1) yr(-1), P < 0.0001). Tropical sites in Region 1 (Bahia state) showed no net change (-0.11 Mg ha(-1) yr(-1), P = 0.1874, whereas tropical and subtropical sites in Region 2 (Espirito Santo state) lost soil carbon stocks (-0.87 Mg ha(-1) yr(-1), P <0.0001), and subtropical sites in Region 3 (Sao Paulo state) also remained the same (0.06 Mg ha(-1) yr(-1), P = 0.3969). Soil carbon change tended to increase with precipitation during the dry season, and had weaker associations with soil order and mean annual temperature. (C) 2015 Elsevier B.V. All rights reserved.
12.	Binkley, Dan, et al. (author) Tamm Review: Revisiting the influence of nitrogen deposition on Swedish forests 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 368, s. 222-239 Research review (peer-reviewed)abstract Are the health and productivity of Sweden's forests at risk from too much nitrogen (N) from acid deposition? Twenty years ago we assessed the evidence available for several aspects of this question (Binkley and Hogberg, 1997). We found little evidence for risks other than potential shifts in ground flora, but concerns continued to arise across Europe and elsewhere. We took advantage of two decades of accumulated evidence to re-evaluate whether Swedish forests are threatened by N deposition. During this time, N deposition declined by about 25% across the southern half of Sweden, and sulfur deposition declined by more than half. The growth rates of forests across the country continued the long-term trend of increasing by about 1-1.5% annually; average growth rates are now about 20-25% greater than in the mid-1990s. Forest soils often acidify by about 0.5-1.5 pH units during a rotation, but some evidence indicated that acidification may have occurred beyond this age-related pattern. Any average change in soil pH across the country appeared to relate more strongly to increases in carbon concentrations rather than cation leaching and declining base saturation. No evidence of N saturation (with outputs matching inputs) has been reported in Sweden, and nitrogen-limitation remains widespread. Fertilization with elements other than N generally does not increase growth unless N is also added, especially on mineral soils. Long-term fertilization experiments demonstrated that growth responses depended heavily on the dose rate of N application, not just cumulative totals. Repeated low rates of addition (20-50 kg N ha(-1) yr(-1)) provided greater growth increases per kg N added than higher rates, illustrating that the possible impacts of N deposition could not be reliably gauged by shorter-term experiments with unrealistically high dose rates. The composition of ground flora appeared to be sensitive to N additions, in studies across geographic gradients of N deposition and with high rates of N fertilization. Any long-term effects of N deposition on ground flora may be difficult to separate from long-term changes in stand structure and growth. Aluminum toxicity concerns do not appear to be supported by evidence, and liming generally does not increase forest growth. We discuss broader implications that arise from this assessment, including approaches to evaluating support for assumptions, the varying quality of types of evidence, and in some cases the irreducibility of uncertainty about elucidating cause-and-effect responses in complex forest systems.
13.	Binkley, Dan (author) The interactions of climate, spacing and genetics on clonal Eucalyptus plantations across Brazil and Uruguay 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 405, s. 271-283 Journal article (peer-reviewed)abstract Intensively managed plantations account for 1.5% of the world's forests, but they meet one-third of the demand for wood products. Eucalyptus plantations are among the most productive, with rates of growth depending heavily on genetics, silviculture, and climate. The TECHS Project examines productivity at 36 locations across a 3500 km gradient from Brazil to Uruguay, testing the interacting influences of genetics, temperature and precipitation on stemwood production. Across all sites and genotypes, stemwood production in the middle of the 6 year rotation (the peak period of growth) averaged 22 Mg ha(-1) yr(-1). Production varied by fivefold across sites, and by about 2-fold among genotypes within each site. The best clones at each location grew 1.5-4 Mg ha(-1) yr(-1) more than the average for all clones, underscoring the importance of matching genotypes to local site conditions. Contrary to patterns for natural forests across geographic gradients, Eucalyptus production declined with increasing temperature, dropping by 2.5 Mg ha(-1) yr(-1) for a 1 degrees C temperature increase. The temperature effect was likely driven in part by the geographic covariance of temperature and rainfall, as rainfall tended to decline by 78 mm yr(-1) for each 1 degrees C increase in temperature. Stemwood production increased an average of 1.5 Mg ha(-1) yr(-1) for each 100 mm yr(-1) increase in precipitation, but when the covariation of temperature and precipitation were included the apparent influence of precipitation declined to 0.4 Mg ha(-1) yr(-1) for each 100 mm yr(-1) increase in precipitation. Future results will determine if within-site reductions in ambient rainfall have the same apparent influences as the rainfall pattern across the geographic gradient, as well as quantifying the importance of insects and pests in affecting growth. The supply of wood from intensively managed plantations will be strongly influenced by both temperature and precipitation at plantation locations, and with changing climates.
14.	Boberg, Johanna, et al. (author) Life after tree death: Does restored dead wood host different fungal communities to natural woody substrates? 2018 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 409, s. 863-871 Journal article (peer-reviewed)abstract In Europe, enhancing the amount of dead wood, and thereby promoting habitats for saproxylic species, is one of the most commonly applied restorative treatments in intensively managed forests. This study examines whether the different tree-level treatments utilized to increase the amount of dead wood (girdling, chainsaw felling, and uprooting) have an effect on the wood-inhabiting fungi in the logs of Scots pine (Pinus sylvestris). We also investigate whether the structure (diversity and composition) of these communities differ from those that occur in pine wood substrates that have been uprooted naturally. The study was conducted within currently protected forests that have been previously managed for timber production. Both fungal DNA (for sequence-based identification) and the presence of sporocarps of polypore fungi were surveyed from the logs. Based on the results, greater number of species were associated with the girdled logs compared to the other types of dead wood. The method of felling the trees (uprooting vs. chainsaw-felling) also resulted in differences in community composition, but this mainly concerned the sporocarp occurrence of polypore fungi. Fungal communities on naturally uprooted dead wood had more variation to the restored logs. Overall, our results suggest that restoration of dead wood can provide substrates for many fungi, including Red Listed polypores, and successfully contribute to achieving some of the restoration targets. However, to capture most of the variation in natural fungal communities, several methods should be used together when artificially increasing the amount of dead wood in forest ecosystems.
15.	Bohlin, Inka (author) Usability of citizen science observations together with airborne laser scanning data in determining the habitat preferences of forest birds 2018 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 430, s. 498-508 Journal article (peer-reviewed)abstract Citizens' field observations are increasingly stored in accessible databases, which makes it possible to use them in research. Citizen science (CS) complements the field work that must necessarily be carried out to gain an understanding of any of bird species' ecology. However, CS data holds multiple biases (e.g. presence only data, location error of bird observations, spatial data coverage) that should be paid attention before using the data in scientific research.The use of Airborne Laser Scanning (ALS) enables investigating forest bird species' habitat preferences in detail and over large areas. In this study the breeding time habitat preferences of 25 forest bird species were investigated by coupling CS observations together with nine forest structure parameters that were computed using ALS data and field plot measurements. Habitat preferences were derived by comparing surroundings of presence-only observations against the full landscape. Also, in order to account for bird observation location errors, we analysed several buffering alternatives.The results correspond well with the known ecology of the selected forest bird species. The size of a bird species' territory as well as some behavioural traits affecting detectability (song volume, mobility etc.) seemed to determine which bird species' CS data could be analysed with this approach. Especially the habitats of specialised species with small or medium sized territories differed from the whole forest landscape in the light of several forest structure parameters. Further research is needed to tackle issues related to the behaviour of the observers (e.g. birdwatchers' preference for roads) and characteristics of the observed species (e.g. preference for edge habitats), which may be the reasons for few unexpected results.Our study shows that coupling CS data with ALS yield meaningful results that can be presented with distribution figures easy to understand and, more importantly, that can cover areas larger than what is normally possible by means of purpose-designed research projects. However, the use of CS data requires an understanding of the process of data collection by volunteers. Some of the biases in the data call for further thinking in terms of how the data is collected and analysed.
16.	Brunet, Jörg (author) Litter quality, land-use history, and nitrogen deposition effects on topsoil conditions across European temperate deciduous forests 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 433, s. 405-418 Journal article (peer-reviewed)abstract Topsoil conditions in temperate forests are influenced by several soil-forming factors, such as canopy composition (e.g. through litter quality), land-use history, atmospheric deposition, and the parent material. Many studies have evaluated the effects of single factors on physicochemical topsoil conditions, but few have assessed the simultaneous effects of multiple drivers. Here, we evaluate the combined effects of litter quality, land-use history (past land cover as well as past forest management), and atmospheric deposition on several physicochemical topsoil conditions of European temperate deciduous forest soils: bulk density, proportion of exchangeable base cations, carbon/nitrogen-ratio (C/N), litter mass, bio-available and total phosphorus, pH(KCI)and soil organic matter. We collected mineral soil and litter layer samples, and measured site characteristics for 190 20 x 20 m European mixed forest plots across gradients of litter quality (derived from the canopy species composition) and atmospheric deposition, and for different categories of past land cover and past forest management. We accounted for the effects of parent material on topsoil conditions by clustering our plots into three soil type groups based on texture and carbonate concentration. We found that litter quality was a stronger driver of topsoil conditions compared to land-use history or atmospheric deposition, while the soil type also affected several topsoil conditions here. Plots with higher litter quality had soils with a higher proportion of exchangeable base cations, and total phosphorus, and lower C/N-ratios and litter mass. Furthermore, the observed litter quality effects on the topsoil were independent from the regional nitrogen deposition or the soil type, although the soil type likely (co)-determined canopy composition and thus litter quality to some extent in the investigated plots. Litter quality effects on topsoil phosphorus concentrations did interact with past land cover, highlighting the need to consider land-use history when evaluating canopy effects on soil conditions. We conclude that forest managers can use the canopy composition as an important tool for influencing topsoil conditions, although soil type remains an important factor to consider.
17.	Börjesson, Pål, et al. (author) Future demand for forest-based biomass for energy purposes in Sweden 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383:January, s. 17-26 Journal article (peer-reviewed)abstract This paper assesses the potential changes in the demand for forest-based biomass for various energy purposes in Sweden in 2030 and 2050, respectively. The assessment is based on a review of scenarios and predictions of how the Swedish energy system may develop, taking into account techno-economical conditions. It includes potential changes in district heating, electricity production in combined heat and power plants, industrial process energy, and production of biofuel for road transportation. In addition, the potential demand for forest-based feedstock in the chemical and petrochemical sector, replacing current use of fossil feedstock, is analysed. The assessment suggests that Sweden may see an additional demand for forest fuels at about 30 TW h in 2030 and 35–40 TW h in 2050. This can be compared with the current use of biomass for energy in Sweden at 130 TW h per year, and the estimated potential increase of sustainable harvest of logging residues (slash and stumps) at some additional 20 TW h per year, based on current conditions. If also potential demand for forest-based feedstock in the chemical and petrochemical industry is included, another 10–15 and 25–30 TW h of biomass per year may be needed in 2030 and 2050, respectively. The future demand is sensitive to the pace and magnitude of energy efficiency improvements and electrification in the various sectors. If far-reaching energy efficiency improvements and electrification are realised, the total additional demand for biomass as energy and industry feedstock may be about 20 and 30 TW h per year in 2030 and 2050, respectively, thus roughly corresponding to the sustainable harvests of logging residues. If, however, efficiency improvements and electrification are only marginal, then the additional demand for biomass as industry and energy feedstock may reach 70 TW h and 100 TW h per year in 2030 and 2050, respectively. In these cases, the use of logging residues will not suffice and additional biomass would be needed. A combination of regulations and incentives is recommended to accelerate the fuel and feedstock switch, especially in the transportation and industrial sectors, and incentives promoting a substantial improvement in energy efficiency and electrification in all sectors.
18.	Caron, M. M., et al. (author) Divergent regeneration responses of two closely related tree species to direct abiotic and indirect biotic effects of climate change 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 342, s. 21-29 Journal article (peer-reviewed)abstract Changing temperature and precipitation can strongly influence plant reproduction. However, also biotic interactions might indirectly affect the reproduction and recruitment success of plants in the context of climate change. Information about the interactive effects of changes in abiotic and biotic factors is essential, but still largely lacking, to better understand the potential effects of a changing climate on plant populations. Here we analyze the regeneration from seeds of Acer platanoides and Acer pseudoplatanus, two currently secondary forest tree species from seven regions along a 2200 km-wide latitudinal gradient in Europe. We assessed the germination, seedling survival and growth during two years in a common garden experiment where temperature, precipitation and competition with the understory vegetation were manipulated. A. platanoides was more sensitive to changes in biotic conditions while A. pseudoplatanus was affected by both abiotic and biotic changes. In general, competition reduced (in A. platanoides) and warming enhanced (in A. pseudoplatanus) germination and survival, respectively. Reduced competition strongly increased the growth of A. platanoides seedlings. Seedling responses were independent of the conditions experienced by the mother tree during seed production and maturation. Our results indicate that, due to the negative effects of competition on the regeneration of A. platanoides, it is likely that under stronger competition (projected under future climatic conditions) this species will be negatively affected in terms of germination, survival and seedling biomass. Climate-change experiments including both abiotic and biotic factors constitute a key step forward to better understand the response of tree species' regeneration to climate change.
19.	Castaño Soler, Carles (author) Temporal dynamics of soil fungal communities after partial and total clear-cutting in a managed Pinus sylvestris stand 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 449 Journal article (peer-reviewed)abstract Forest management aimed to maximize timber production might impact soil fungi, especially those symbioti-cally associated to tree roots. In this study, we analyse the temporal dynamics of soil fungi along five sampling years after tree removal in a managed Pinus sylvestris stand in northern Spain, where timber production is combined with regular mushroom harvesting. Two management methods were tested: total and partial clearcutting leaving retention trees for seedling regeneration. Undisturbed, uncut plots were also included in the experiment as a control treatment. The whole fungal community (phylotypes and ecological guilds) were analysed by high-throughput Illumina MiSeq sequencing of fungal ITS1 amplicons. We hypothesized that (1) ectomycorrhizal fungal communities will decrease after both clear-cutting treatments with a concurrent increase in the abundance of saprotrophs, (2) the abundance and diversity of the ectomycorrhizal guild will be more preserved in partially clear-cut than in total clear-cut plots, and (3) the overall fungal diversity will decrease in the cut plots leading to major losses of ectomycorrhizal species. Our results show that soil fungal composition changed across the five years after clear-cutting by decreasing ectomycorrhizal fungi and increasing saprotrophs. However, these changes did not significantly affect fungal diversity and there were taxa-specific responses to tree harvest treatments. Boletus edulis, the most abundant ectomycorrhizal species fruiting in the study area and a valuable local non-forest resource, was negatively affected by either clear-cutting treatments. Soil fungal community composition in partially clear-cut areas was not different from that of total clear-cut areas. Our results indicate a strong effect of tree harvest on the relative abundance of ectomycorrhizal fungi along the first years after clear-cutting. However, levels of fungal diversity were comparable to the undisturbed forest, thus suggesting a potential further recovery of ectomycorrhizal fungi through the colonization of the regenerated seedlings.
20.	Cavard, Xavier (author) The influence of boreal tree species mixtures on ecosystem carbon storage and fluxes 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 354, s. 119-129 Journal article (peer-reviewed)abstract Plant species mixtures are often seen as being able to achieve higher productivity and carbon (C) sequestration than their single-species counterparts, but it is unclear whether this is true in natural forests. Here, we investigated whether naturally-regenerated mixtures of common North American boreal tree species were more productive and stored more C than single-species stands. We also examined how closely the different C pools and fluxes were interrelated and whether these relationships varied with species composition. Single- and mixed-species stands of trembling aspen, black spruce and jack pine on mesic sites were selected in two regions of the Canadian boreal forest to assess aboveground and belowground productivity and C storage. Although previous studies conducted in these stands found synergistic effects of tree species mixtures on specific C pools and fluxes, such as higher organic layer C stocks and higher fine root productivity in some mixtures, no effects were detected on combined C pools or fluxes at the ecosystem level in the current study. Aspen abundance was linked with higher aboveground tree productivity, higher aboveground living biomass and higher soil heterotrophic respiration, indicating that aspen acts as a key driver of ecosystem C storage and fluxes in these natural forest ecosystems, more so than species richness. However, our results do not rule out the possibility of increased productivity and C storage in mixed stands under environmental conditions or stand developmental stages that are different from the ones studied here. Furthermore, when the entire forest ecosystem is considered (not only tree parts), synergistic effects of tree species mixtures may be more difficult to observe because the beneficial effect of species mixing on one specific C pool may be counterbalanced by a negative effect on another pool. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.
21.	Cintas Sanchez, Olivia, 1982, et al. (author) The potential role of forest management in Swedish scenarios towards climate neutrality by mid century 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383:January, s. 73-84 Journal article (peer-reviewed)abstract Swedish climate policy targets net zero greenhouse gases (GHG) by mid-century, with road transport independent of fossil fuels by 2030, requiring far-reaching changes in the way energy is used. Forest management is expected to support carbon sequestration and provide biomass for various uses, including energy. In this paper, we combine two energy scenarios with four forest scenarios and quantify GHG balances associated with energy-use for heat, electricity, and road transport, and with forest management and production, use, and end-of-life management of various forest products, including products for export. The aggregated GHG balances are evaluated in relation to the 2-degree target and an allocated Swedish CO2 budget. The production of biofuels in the agriculture sector is considered but not analyzed in detail.The results suggest that Swedish forestry can make an important contribution by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The GHG neutrality goal is not met in any of the scenarios without factoring in carbon sequestration. Measures to enhance forest productivity can increase output of forest products (including biofuels for export) and also enhance carbon sequestration. The Swedish forest sector can let Sweden reach net negative emissions, and avoid “using up” its allocated CO2 budget, thereby increasing the associated emissions space for the rest of the world.
22.	Cromsigt, Joris (author) Elephant effects on treefall and logfall highlight the absence of megaherbivores in coarse woody debris conceptual frameworks 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 438, s. 57-62 Journal article (peer-reviewed)abstract Despite the importance of coarse woody debris (CWD) in woody ecosystems, conceptual frameworks of its dynamics currently exclude the role of the megaherbivores, focusing instead on the role of insects, disease, fire, wind and droughts. However, recognizing the ecological roles of the megaherbivores is one of the most urgent contemporary issues, particularly as their decline will likely have unanticipated outcomes at the ecosystem-level. Here we used sites with and without elephants in a semi-arid woodland ecosystem in South Africa to test whether elephants changed the quantitative and qualitative features of the CWD profile in relation to other wood producers. We show that elephants increased the abundance of CWD, influenced its quality by toppling mostly maturing trees, and changed the distribution of large woody items along gentle hillslopes. Surprisingly, and despite the recognized importance of both CWD and elephants for biodiversity, there is almost no published data on the role of elephants in shaping wood-living communities by changing fallen woody debris dynamics. Our study contributes towards developing a broader conceptual framework of CWD dynamics that includes the role of megaherbivores and provides a novel view of the ecological consequences of the loss of the Pleistocene megaherbivores. Our findings have important implications for CWD restoration efforts in transformed systems that previously supported megaherbivores.
23.	Cromsigt, Joris, et al. (author) The blame game: Using eDNA to identify species-specific tree browsing by red deer (Cervus elaphus) and roe deer (Capreolus capreolus) in a temperate forest 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 451 Journal article (peer-reviewed)abstract Increasing deer populations in many temperate regions can affect tree regeneration, resulting in severe long-term impacts on forest structure, composition and diversity. Of the most common deer species in Europe - red deer (Cervus elaphus) and roe deer (Capreolus capreolus) - roe deer are generally thought to have the highest impact on palatable tree species owing to their feeding niche. Although browsing and its potential consequences are well researched, less is known about the influence of specific deer species within multi-species ungulate communities on specific tree species. Environmental DNA (eDNA) allows the determination of species-specific browsing habits without the need for direct observations, facilitating effective targeting of management interventions. In this study eDNA was used to elucidate the browsing patterns of these two deer species in the temperate forest of the Bavarian Forest National Park, Germany and analysed the influence of tree species, management type and height of browsing, on the success rate of the method. Samples were collected from twigs used in feeding trials from enclosures containing red deer or roe deer and from naturally browsed twigs in three different management types within the national park. eDNA was successfully amplified from 98% of the feeding trial samples, and the correct deer species was identified for all samples. eDNA was successfully amplified from approximately 50% of the naturally browsed samples. Neither management type, tree species, nor height of browsing had any significant influence on the success of the method. For silver fir and rowan, no significant difference was found in the proportion of browsing events attributable to roe or red deer, when the two deer species occur at similar densities. These results indicate that roe deer might not always be disproportionately responsible for the browsing of palatable tree species as expected from its food niche. Roe deer were significantly more responsible for browsing at lower heights than red deer. Although not statistically significant, roe deer were more responsible for browsing in intact forest compared to bark-beetle-impact forest, with the opposite relationship for red deer.
24.	de Jong, Johnny, et al. (author) Impact on species of conservation interest of forest harvesting for bioenergy purposes 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 37-48 Journal article (peer-reviewed)abstract Wood harvested from logging residues, pre-commercial and conservation thinnings is increasingly being used as biofuel as a substitute for fossil fuels. Here, we review the additional impact that wood harvesting for energy purposes has on species of conservation interest (SCI) in Swedish forests compared with the effects of conventional management, a perspective that largely has not been taken into consideration. We compiled data from 122 studies of forest fuel extraction with short- and long-term perspectives at the stand and landscape level to examine whether the effects on SCI are due to an additional loss of bio-diversity as a result of cutting old forest or owing to competition from species that are favoured by the habitats formed by clearcutting. We also consider whether forest bioenergy extractions can be used to favour conservation values. The amount of logging residues has, in parallel to the amount of annually harvested trees, doubled during the past 50 years in Sweden and constitutes the major source of dead wood for biodiversity in managed forests. Common wood-inhabiting species, predominantly fungi, beetles and other insects, and to some extent lichens, are the main species affected by wood harvesting for energy purposes. The main cause for the decline of SCI is the impact already imposed by conventional forest management: clearcutting old forest stands with subsequent soil scarification. Few SCI survive clear-felling because these species typically require other types of conditions and substrates than the new dead-wood substrate created after clear-felling. We conclude that the logging residues of conifers could potentially be harvested with small to negligible impacts on SCI. However, owing to the limited number of landscape level analyses that have been performed and the inherent difficulties of assessing the effects of wood harvesting on rare SCI, we suggest that these findings need to be treated with caution and that further studies should be undertaken. Hardwood conservation thinnings and brushwood harvest may improve conservation values. Developing operational guidelines to help to mitigate ecological damage to biodiversity should be based on cautionary principles and requires further large-scale and long-term research. (C) 2016 Elsevier B.V. All rights reserved.
25.	de Jong, Johnny, et al. (author) Realizing the energy potential of forest biomass in Sweden – How much is environmentally sustainable? 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 3-16 Journal article (peer-reviewed)abstract Harvesting of wood for bioenergy purpose will probably increase in importance in the future, in order to replace fossil fuel. However, the environmental impact of increased harvesting might be considerable, e.g. on soil and water chemistry, biodiversity and long-term productivity, and in this study we investigate thresholds for sustainable harvesting volumes. The study is based on scientific reviews of the impact of harvesting of logging residues (slash and stumps) on forest production, biodiversity, acidification, eutrophication and toxic substances. We define sustainability by using environmental objectives decided by the Swedish parliament (which are based on the Aichi targets), and relate the harvesting impact to these objectives within different harvesting scenarios, by using expert judgment. We demonstrate that an increase in harvesting of logging residues by 2.5 times might be sustainable. However, we also identify a number of risks and the sustainability depends on a number of requirements that should be fulfilled, such as ash-recycling. It was found that factors related to biodiversity conservation (defined in the goals ‘Sustainable Forests’ and ‘A Rich Diversity of Plant and Animal Life’) were limiting factors both for slash- and stump harvesting, and that risk of acidification (defined in the goal ‘Natural Acidification Only’) also limit slash harvesting. We also include harvesting of brushwood and energy wood from conservation cutting in the discussion, since these assortments might be important in the future.
26.	de Jong, Johnny, et al. (author) Special Issue: Sustainability of increased forest biomass harvest from a Swedish perspective Preface 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 21- Journal article (peer-reviewed)
27.	Dimitriou, Ioannis, et al. (author) Poplar and willow plantations on agricultural land in Sweden: Area, yield, groundwater quality and soil organic carbon 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 99-107 Journal article (peer-reviewed)abstract Poplars (Populus spp.) and Willows (Salix spp.) are predominantly grown in plantations on arable land in southern and central parts of Sweden to produce biomass for energy and other purposes. The present study aims at characterizing their present situation with special emphasis on the current extension of the cultivation, expected yield levels as well as on their effects on soil and water. The data sources combine own measurements with existing data, trials and records from previous studies. The results show that poplar and willow currently entail 1322 and 9830 ha in Sweden, respectively, being distributed in similar areas in central and south parts of the country, with an average plantation size of 2.59 and 3.87 ha. Productivity varies depending on the measurement methods, being 6.90 and 7.7 Mg-1 ha(-1) year for poplar and willow, respectively, when estimating standing biomass based on small plots but being about half this value when based on harvesting records from commercial experience. Concerning the impact on groundwater quality, poplar plantations presented higher values of NO3-N and lower values of PO4-P than willow. These differences were consistent along seasons in case of NO3-N, and were only observed in autumn in the case of PO4-P. The results showed no differences between the plantations systems concerning the organic carbon on soil, although in the subsoil (>40 cm) there were slight higher values in case of willow plantations. (C) 2016 Elsevier B.V. All rights reserved.
28.	Drobyshev, Igor, et al. (author) A mixture of human and climatic effects shapes the 250-year long fire history of a semi-natural pine dominated landscape of Northern Latvia 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 441, s. 192-201 Journal article (peer-reviewed)abstract Fire has been shown to shape successional pathways and dynamics of forest vegetation. However, its role in European hemiboreal forests remains poorly understood. Here we provide the first annually resolved reconstruction of fire history from the Eastern Baltic Sea region, developed in the pine-dominated landscape of Slitere National Park (SNP), northwestern Latvia, over the last 250 years. Our results suggest that forest fires have been a common disturbance factor in the studied landscape. In total, we dated 62 single fire years, with the mean-point scale fire return interval of 46 years and the length of the fire cycle ranging from 45 to 80 years. We identified periods of high (1750-1950) and low (1960-2000) fire activity, with the corresponding lengths of fire cycles being 45-68 and 58-80 years, respectively. Although both long-term (century and decade-long) and annual dynamics of fire activity in SNP was closely linked to socio-political changes in Latvia, fire activity in SNP was also affected by climate, as indicated by the close positive association of years with increased area burned and positive SST anomalies in the Baltic and North Seas. Future management of SNP should make fire an important element of natural forest dynamics and consider using prescribed fires of various spatial extent and severity.
29.	Drössler, Lars, et al. (author) Mixing of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) enhances structural heterogeneity, and the effect increases with water availability 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 373, s. 149-166 Journal article (peer-reviewed)abstract The mixing of tree species with complementary ecological traits may modify forest functioning regarding productivity, stability, or resilience against disturbances. This may be achieved by a higher heterogeneity in stand structure which is often addressed but rarely quantified. Here, we use 32 triplets of mature and fully stocked monocultures and mixed stands of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) located along a productivity and water availability gradient through Europe to examine how mixing modifies the stand structure in terms of stand density, horizontal tree distribution pattern, vertical stand structure, size distribution pattern, and variation in tree morphology. We further analyze how site conditions modify these aspects of stand structure. For this typical mixture of a light demanding and shade tolerant species we show that (i) mixing significantly increases many aspects of structural heterogeneity compared with monocultures, (ii) mixing effects such as an increase of stand density and diversification of vertical structure and tree morphology are caused by species identity (additive effects) but also by species interactions (multiplicative effects), and (iii) superior heterogeneity of mixed stands over monocultures can increase from dry to moist sites. We discuss the implications for analyzing the productivity, for modelling and for the management of mixed species stands. (C) 2016 Elsevier B.V. All rights reserved.
30.	Drössler, Lars, et al. (author) Predicting the spatial and temporal dynamics of species interactions in Fagus sylvatica and Pinus sylvestris forests across Europe 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 405, s. 112-133 Journal article (peer-reviewed)abstract The productivity and functioning of mixed-species forests often differs from that of monocultures. However, the magnitude and direction of these differences are difficult to predict because species interactions can be modified by many potentially interacting climatic and edaphic conditions, stand structure and previous management. Process-based forest growth models could potentially be used to disentangle the effects of these factors and thereby improve our understanding of mixed forest functioning while facilitating their design and silvicultural management. However, to date, the predicted mixing effects of forest growth models have not been compared with measured mixing effects. In this study, 26 sites across Europe, each containing a mixture and monocultures of Fagus sylvatica and Pinus sylvestris, were used to calculate mixing effects on growth and yield and compare them with the mixing effects predicted by the forest growth model 3-PG(mix). The climate and edaphic conditions, stand structures and ages varied greatly between sites. The model performed well when predicting the stem mass and total mass (and mixing effects on these components), with model efficiency that was usually > 0.7. The model efficiency was lower for growth or smaller components such as foliage mass and root mass. The model was also used to predict how mixing effects would change along gradients in precipitation, temperature, potential available soil water, age, thinning intensity and soil fertility. The predicted patterns were consistent with measurements of mixing effects from published studies. The 3-PG model is a widely used management tool for monospecific stands and this study shows that 3-PGmb, can be used to examine the dynamics of mixed-species stands and determine how they may need to be managed.
31.	Drössler, Lars, et al. (author) Terrestrial laser scanning reveals differences in crown structure of Fagus sylvatica in mixed vs. pure European forests. 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 405, s. 381-390 Journal article (peer-reviewed)abstract Competition with neighboring trees of different species can affect crown size and shape. However, whether intra-specific differences in crown characteristics in mixed stands compared to pure stands are dependent on site conditions remains poorly understood. We used terrestrial laser scanning (TLS) to examine the differences in Fagus sylvatica crown characteristics at four sites, each of which contained pure stands of F. sylvatica and their mixture with Pinus sylvestris. These sites covered the area where the mixture occurs in Europe from south to north, representing a gradient of F. sylvatica productivity, defined as the mean increment of annual volume growth in pure F. sylvatica stands. Despite the large range in productivity, F. sylvatica trees in mixtures had larger crowns regardless of site conditions, with a higher proportion of their crown volume in the lower canopy compared to trees in pure stands. Larger crown volumes were related to higher live crown ratios and greater crown expansion, depending on the site. The magnitude of the mixing effect was variable among the crown characteristics evaluated, but overall our findings provide evidence that for a given species combination and density, the effect of mixture increased in the two most productive sites. TLS-derived novel crown metrics revealed that the mixing effect was affected by productivity, which was not captured by traditionally measured crown variables.
32.	Ebenhard, Torbjörn, et al. (author) Environmental effects of brushwood harvesting for bioenergy 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 85-98 Journal article (peer-reviewed)abstract Sweden aims to increase the proportion of renewable energy sources, ultimately to be able to phase out fossil fuels. To achieve this, new energy sources need to be explored. In this multi-disciplinary article, we examine the technical, economical, ecological and legal possibilities to commercially and sustainably harvest brushwood for bioenergy, while simultaneously gaining positive environmental effects, both for biological diversity, the cultural heritage, and the climate. The Swedish open landscape is becoming covered with secondary brushwood regrowth through natural succession, except where it is kept open. Brushwood is spreading along roads, railway lines, edge zones, in power line corridors, abandoned semi-natural grasslands, nature reserves, and in marginal land in urban areas. Such brushwood consists of saplings, bushes and young trees of a range of deciduous plant species, e.g. birch, aspen, alder and goat willow, sometimes mixed with conifers, often forming dense thickets. Such secondary brushwood regrowth could be systematically utilised as a new source of renewable bioenergy. Commercial brushwood harvesting in Sweden may contribute 26 PJ of energy annually, which may be a small but significant contribution, considering the favourable energy ratio (E-r = 28), indicating that large emission reductions can be achieved, if fossil fuels are replaced. Growing brushwood does not require fertilizers or pesticides, soil tillage or crop management, and it does not compete with any other potential land use. Many brushwood habitats are already being managed to clear brushwood, for other purposes, minimizing the added harvesting cost. Apart from providing bioenergy, it has also been suggested that brushwood harvesting would benefit biological diversity. A large number of nationally redlisted species are dependent on the active management of open habitats, including semi-natural grasslands, and man-made habitats such as road verges and power line corridors. Our literature review shows that brushwood harvesting could benefit both biological diversity and the cultural heritage, and contribute to the management of the open cultural landscape. There are however certain limitations. Brushwood harvesting would favour a certain set of species, including many redlisted, but it may also threaten another set of species, especially species associated with early successional stages of forest regeneration, as well as forest edge species, depending on how and where it is applied. Harvesting may be affected by legislation imposing limitations regarding habitats of particular importance for biodiversity. The environmental and legal constraints would probably reduce the profitability of brushwood harvesting in certain areas, as well as the annual production of bioenergy.
33.	Edman, Mattias, et al. (author) The importance of large-tree retention for the persistence of old-growth epiphytic bryophyte Neckera pennata in selection harvest systems 2016 In: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 372, s. 143-148 Journal article (peer-reviewed)abstract Partial harvesting methods are generally more similar to the natural dynamics of broad-leaved forests than clear cutting. However, their effects on biodiversity are still poorly understood. We investigated the effects of selection cutting on the occurrence of a large epiphytic bryophyte, Neckera pennata, in a northern hardwood forest of New Brunswick, Canada. Twenty-eight forest stands were selected, repre- senting two contrasting forest management practices: 5–9 years old, first-entry selection cuts and untreated stands that had been subjected to low-intensity single-tree cutting at least 35 years earlier. Within each stand, we quantified the presence–absence of N. pennata on 36 trees and measured selected forest stand variables. Although N. pennata had persisted in post-harvest stands, its frequency of occur- rence on maple trees was only 7% there, compared to 39% in untreated stands. The density of large- diameter sugar maple trees and crown cover were the most important factors predicting the frequency of N. pennata at the stand level. Tree diameter was also a strong predictor of N. pennata’s presence at the tree level and the occupancy of large-diameter maples was almost twice as high in untreated stands as in selection cuts. However, the occupancy of large-diameter maples relative to smaller maple trees was much higher in selection cuts, possibly due to dispersal limitations resulting from reduced connectivity of large-diameter host trees. Taken together, our findings suggest that (1) large trees from older seral stages are a prerequisite for the long-term persistence of N. pennata in managed forests and that (2) they are therefore particularly important for managers to retain in selection cuts. Further, since our results indi- cate that reduced crown cover in selection cuts has a negative effect on N. pennata, the benefit of retaining large host trees would probably increase if buffered within retention patches of maturing trees. Finally, since host tree diameter clearly is a very important factor for the presence of N. pennata, any extension of the harvest rotation would be beneficial.
34.	Eggers, Sönke, et al. (author) Ecological restoration in boreal forest modifies the structure of bird assemblages 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 401, s. 75-88 Journal article (peer-reviewed)abstract Ecological restoration is increasingly recognised as a useful tool for biodiversity conservation in boreal forests. Most restoration methods in this environment aim to emulate natural disturbances, and thereby promote the development of key ecological structures. However, research about forest ecosystem restoration is still in its infancy and the responses of many boreal species groups remain to be described. We established a large-scale field experiment to evaluate the short-term effects of two restoration treatments - prescribed burning and gap cutting involving the creation of dead wood - on breeding bird assemblages in boreal Sweden. We censused breeding birds using territory mapping during two years in forest stands subjected to the two restoration treatments, in untreated controls and in old-growth references (nature reserves) (n = 10 per treatment). Averaged over the two census years, we found 1145 territories of 36 bird species. Total bird species richness and abundance did not differ among treatments. However, prescribed burning led to clear changes in the structure of the bird assemblages. When dividing species according to four functional categorizations (migration, foraging, nesting and successional stage), we found that the abundance of long-distance migrants, ground breeders, strong cavity excavators and species preferring early-successional habitat was higher in burned stands than in untreated controls and gap-cut stands, as was the species richness of bark feeders and strong cavity excavators. In contrast, abundance of off-ground breeders and species richness of crown feeders were lower following prescribed burning than in the controls. The gap cutting treatment did not have any significant effects on the bird assemblages. Ecological restoration through prescribed burning can be a useful tool for the conservation of boreal forest birds, including the ecologically important strong cavity excavators (i.e. woodpeckers (Picidae)). Forest managers should therefore be encouraged to use prescribed burning as a restoration tool to quickly provide habitat for bird species adapted to natural disturbances in boreal forest. (C) 2017 Elsevier B.V. All rights reserved.
35.	Egnell, Gustaf (author) A review of Nordic trials studying effects of biomass harvest intensity on subsequent forest production 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 27-36 Research review (peer-reviewed)abstract In the Nordic countries, emerging markets for renewable energy have resulted in increased harvest intensity, i.e., branches, tops, and stumps are now also harvested. This increased harvest intensity changes site conditions in a way that may impact future forest production. In this review published results are compiled from long-term field experiments in the Nordic countries. The objectives are to identify general patterns or inconsistences, to identify possible causes, and to discuss the practical implications of the results. I summarize 16 publications where short to medium-term forest production data were presented from 72 experimental sites. Data on growth of the subsequent stand following slash harvest in final felling indicate a moderate negative growth effect in Norway spruce, whereas growth in Scots pine appears unaffected, as compared to stem-only harvested control plots. Spruce data also showed a trend suggesting that poorer sites are more sensitive. Stump harvest in final felling did not have a negative effect on growth - rather the opposite - particularly on poor Scots pine sites. Trends in the data suggest that the positive growth effect in pine is stronger on poorer sites at higher latitudes. Slash harvest in thinnings resulted in more consistent growth reductions in the residual stand in both pine and spruce. There was a weak trend suggesting that poorer spruce sites are more susceptible. Seedling survival rates or stem numbers following slash and stump harvest were either unaffected or positively affected by the treatments - particularly by stump harvest. Trends in data suggest a stronger positive effect on more fertile sites. High relative survival or stem numbers coincided with high relative growth. Thus, survival rates or stem number may partly explain the lack of consistency in growth responses in field experiments. Management of natural regeneration in the experiments is discussed as potentially critical. Both short- and medium-term growth responses have been reported in individual studies. It is therefore recommended that a final evaluation should be based on longer-term data. The recommended next step is to combine all available data into a formal meta-analysis. (C) 2016 Elsevier B.V. All rights reserved.
36.	Egnell, Gustaf (author) Effects of slash and stump harvesting after final felling on stand and site productivity in Scots pine and Norway spruce 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 371, s. 42-49 Journal article (peer-reviewed)abstract As a response to the increased market for biomass for energy in Sweden logging residues such as slash and stumps, previously left in the forest at stemwood harvest, have been targeted as a resource. Negative effects on site and stand productivity have been suggested as unwanted effects of this increased harvest intensity. Slash with its high nutrient content has the potential to impact forest production on nutrient limited northern forest sites. Stumps, with a lower nutrient content, may therefore be more favourable from a production point of view and the additional soil disturbance caused by the harvest may counteract the nutrient loss as a result of stimulated mineralization and reduced competition from the ground vegetation. Seedling survival is another critical factor that could be affected with potential effect on future stand productivity. Here stand and site productivity data from four long-term field experiments planted with, Scots pine (2 sites) and Norway spruce (2 sites) seedlings following (i) conventional stemwood harvest (5), (ii) stem and stump harvest (SS), and (iii) stem, stump, and slash harvest (SSS) is analysed and presented.The statistical analyses based on data from all sites did not reveal any general treatment effects on seedling survival, standing volume (after 24-27 years), basal area growth (between the last two revisions), upper quartile mean height (25% highest trees) after 10 years or top height (after 24-27 years).Analyses at the species level revealed a significant main treatment effect on top height for the spruce sites, with lower top height following SSS (11.6 m) as compared to S (12.9 m). No main treatment effect was detected for the pine sites.Analyses at the site level gave significant but inconsistent results for the least productive site in both pine and spruce, suggesting site and possibly also species-specific responses. Response variables affected by treatments at the pine site were survival rate after 15 years (S < SS), standing volume after 24 years (S < SS and SSS), and upper quartile mean height after 10 years (S < SS and SSS). Response variables affected at the spruce site were standing volume after 27 years (SSS < S and SS), upper quartile mean height after 10 years (SSS < S and SS), and top height after 27 years (SSS < S and SS). Thus, responses on increased harvest intensity were from a forest production perspective positive in pine, whereas the spruce responded negatively - primarily on slash harvest. From a forest production perspective these results suggest that pine forests should be targeted before spruce forests and that stumps should be targeted before slash in spruce forests. (C) 2016 Published by Elsevier B.V.
37.	Egnell, Gustaf, et al. (author) Negative effects of stem and stump harvest and deep soil cultivation on the soil carbon and nitrogen pools are mitigated by enhanced tree growth 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 338, s. 57-67 Journal article (peer-reviewed)abstract New energy policies in many forest rich countries have promoted the utilization of industrial and logging residues for energy purposes. This practice is, however, questioned from a climate change mitigation point of view, particularly when it comes to the harvest of coarse woody biomass like stem wood and stumps.Stump harvest removes slowly decomposing biomass with its carbon (C) and nutrients. The harvest operations also cause soil disturbance that may stimulate mineralization of the soil organic pool, and thereby further increase the C and nutrient loss from the site. However, increased mineralization and expected decrease in amount of competing vegetation could make more nutrients available that stimulates growth of the new tree generation and thereby compensates for the soil C loss.Based on two field experiments, located in southern and northern Sweden, we present C and nitrogen (N) pool data in soil (0-70 cm depth) and tree biomass 22 and 24 years after stem and stump harvest and deep soil cultivation (SS-DSC) in comparison to conventional stem-only harvest and a manual patch scarification (S-PS). The SS-DSC management practice represents a "worst case" in terms of potential C and N loss.We tested the hypotheses that SS-DSC (i) will reduce C and N pools in the soil; (ii) will increase C and N pools in the planted trees; (iii) will not have any effect on the total C and N pools (soil and tree biomass) as compared to S-PS.Soil C and N pools were lower following SS-DSC in line with hypothesis (i) but only statistically different for C at the northern site. Tree biomass C and N pools were significantly increased by the SS-DSC treatment in line with hypothesis (ii). As a result, the total C and N pools were not significantly affected by SS-DSC in line with hypothesis (iii).The main conclusion from these results is that judgments on the effects of silvicultural measures on the forest C and N balances or net greenhouse gas emissions cannot be based on measurements of single C or N pool changes (i.e. in the soil or in the trees only) it has to be based on changes in the total C or N pool. The trade-off between soil and tree biomass C and N pools is discussed in terms of possible causes, current forestry practices, and the climate change mitigation potential of soil vs. tree, biomass C. (C) 2014 Elsevier B.V. All rights reserved.
38.	Egnell, Gustaf, et al. (author) Stand productivity following whole-tree harvesting in early thinning of Scots pine stands in Sweden 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 340, s. 40-45 Journal article (peer-reviewed)abstract Swedish energy policy and the introduction of targets concerning the proportion of renewable energy used within Europe have increased the demand for forest biomass that can be used for energy generation. This includes industrial forest residues, residues from logging operations, and whole trees harvested during early thinnings. However, the sustainability of utilizing the nutrient-rich parts of the trees, such as needles and twigs, may be questionable. It is therefore important to assess the impact of whole-tree harvesting (WTH) in thinnings on the growth of the remaining trees in the stand, particularly in boreal forests where growth is normally limited by the availability of nutrients. Here we present data on 22years of volume growth following WTH practiced in early thinning compared with the alternative, a late pre-commercial thinning, in which all of the biomass including the stem is left on site, from four Scots pine (Pinus sylvestris L.) dominated experimental sites in Sweden. WTH caused a statistically significant 4% growth reduction over the entire duration of the experiment. Analyses of volume growth at three different points in time following the experiments' establishment suggested that this growth reduction occurred largely during the first growth period (0-8years), when there was a significant negative growth effect. No statistically significant treatment effect on volume growth was detected for the second and third periods. The results for the two treatments are compared and discussed in relation to previously published findings concerning stand growth following WTH during thinning.
39.	Felton, Adam, et al. (author) The biodiversity contribution of wood plantations: Contrasting the bird communities of Sweden's protected and production oak forests 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 365, s. 51-60 Journal article (peer-reviewed)abstract The oak-dominated woodlands and forests of northern Europe have experienced dramatic declines due to agriculture, urbanization, and conifer-dominated production forestry. These losses have had a substantial negative impact on biodiversity due to the large number of forest species which depend on oak and the environments oak-dominated forests provide. Production oak stands may serve as a means of supplementing or complementing the habitat provided by the limited remaining natural oak remnants in this region. Here we evaluate the extent to which oak plantations in temperate southern Sweden provide habitat and resources for bird communities, by surveying and contrasting the bird species composition and diversity found in mature and young production oak stands (5 and 8 replicates respectively) and protected oak-dominated remnant forests (5 replicates). The mature production stands possessed a bird community partially overlapping in bird species composition, and comparable in species richness (34 species) to that found within protected oak forests (39 species). Furthermore, the production oak forests surveyed hosted threatened or near threatened bird species, including black woodpecker (Dryocopus martius), goldcrest (Regulus regulus), starling (Sturnus vulgaris), and yellowhammer (Emberiza citrinella). Though production oak forests cannot replace the habitat provided by protected oak forests, these stands do appear to provide conditions consistent with the habitat and resource requirements of a diverse cross-section of bird species in this region, including species of substantial conservation concern. Production oak forests thus have the capacity to make a positive contribution to biodiversity conservation, as well as providing a diverse range of goods and services to society. (C) 2016 Elsevier B.V. All rights reserved.
40.	Filyushkina, Anna, et al. (author) Applying the Delphi method to assess impacts of forest management on biodiversity and habitat preservation 2018 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 409, s. 179-189 Journal article (peer-reviewed)abstract This study applied a structured expert elicitation technique, the Delphi method, to identify the impacts of five forest management alternatives and several forest characteristics on the preservation of biodiversity and habitats in the boreal zone of the Nordic countries. The panel of experts consisted of a number of scientists in the field. The data was collected using a semi-structured questionnaire distributed via e-mail in two rounds. Our findings demonstrated that an increase in management intensity for timber production is likely to have a negative effect on the biodiversity and habitats with intense management alternatives such as a "clear-cutting system" resulting in the strongest adverse impact. The presence of deadwood, mixture of trees of different sizes and increase in stand age were expected to promote preservation of biodiversity and habitats. However, there was little agreement between experts regarding the functional form that relationships between preservation of biodiversity and forest characteristics take. The Delphi method was found useful in investigating the existing knowledge base and capable of contributing to a more comprehensive assessment for decision support as a valuable addition to on-going empirical and modeling efforts. The findings could assist forest managers in developing forest management strategies that generate benefits from timber production while taking into account the trade-offs with biodiversity goals.
41.	Goodman, Rosa (author) Carbon emissions and potential emissions reductions from low-intensity selective logging in southwestern Amazonia 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 439, s. 18-27 Journal article (peer-reviewed)abstract Forests in southwestern Amazonia are increasingly being converted for agriculture, mining, and infrastructure development; subjected to low-intensity selective logging of high value timber species; and designated as conservation areas and indigenous reserves. To understand the impacts of forestry in this region, we evaluated carbon emissions from felling, skidding, and hauling in five FSC-certified concessions where workers were trained in reduced-impact logging (RIL) and in four non-certified concessions where workers were not trained in RIL in Madre de Dios, Peru. Emissions estimates did not differ by certification status, so we established a single baseline for selective logging emissions. Total carbon emissions from selective logging were low per hectare (4.9-11.6 Mg ha(-1)) due to low logging intensities (2.9-8.1 m(3) ha(-1)). Despite the unique architecture of trees in the southwestern Amazon (short stems and large crowns), emissions per volume and per ton carbon in the extracted timber were also relatively low (1.55 Mg m(-3) and 4.04 Mg Mg-1, respectively). Only emissions per area scaled with logging intensity. Emissions were dominated by the felled tree itself (in extracted logs and residuals), whereas hauling infrastructure (roads and log landings) contributed comparatively little. Unintended emissions could be reduced by 46% if concessions were able to achieve the best demonstrated outcomes in each source category and by 54% with additional improvements. Less than 5% of timber was lost due to hollow sections. We determined that it would be overly cautious to avoid cutting all trees with any hollow sections, and it would actually increase emissions per unit timber extracted if no other trees were cut in place of the hollow trees. At the tree level, certified concessions had higher log recovery and damaged fewer commercial species during felling, which should increase their current and future timber yields. It is important to both understand and improve carbon dynamics in managed forests in this emerging hotspot for greenhouse gas emissions from deforestation and forest degradation.
42.	Goodman, Rosa (author) Reduced-impact logging for climate change mitigation (RIL-C) can halve selective logging emissions from tropical forests 2019 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 438, s. 255-266 Journal article (peer-reviewed)abstract Selective logging causes at least half of the emissions from tropical forest degradation. Reduced-impact logging for climate (RIL-C) is proposed as a way to maintain timber production while minimizing forest damage. Here we synthesize data from 61 coordinated field-based surveys of logging impacts in seven countries across the tropics. We estimate that tropical selective logging emitted 834 Tg CO2 in 2015, 6% of total tropical greenhouse gas emissions. Felling, hauling, and skidding caused 59%, 31%, and 10% of these emissions, respectively. We suggest that RIL-C incentive programs consider a feasible target carbon impact factor of 2.3 Mg emitted per Mg of timber extracted. Operational modifications are needed to achieve this target, such as reduced wood waste, narrower haul roads, and lower impact skidding equipment. Full implementation would reduce logging emissions by 44% (366 Tg CO2 year(-1)) and deliver 4% of the nationally determined contributions to the Paris Climate Agreement from tropical countries, while maintaining timber supplies.
43.	Granath, Gustaf, et al. (author) Nitrogen fertilization reduces wild berry production in boreal forests 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 390, s. 119-126 Journal article (peer-reviewed)abstract Nitrogen is the main limiting nutrient in temperate and boreal forests. Large-scale nitrogen fertilization has been suggested as a potential tool to enhance production and meet the increasing demand for wood products and biofuels. Here, we test the effect of N fertilization and thinning on berry (i.e., fruit) production and incidence of fungal pathogens along a latitudinal gradient in Sweden. We used an N fertilization (100-150 kg ha(-1)) and thinning experiment that was established between 1970 and 1980 in 30 pine forests, covering a latitudinal gradient stretching from southern to northern Sweden. We measured fruit production and disease incidence of fungal pathogens in bilberry and cowberry in the experimental plots (30 x 30 m), over two years (2014 and 2015), when the stands were between 67 and 85 years old. Nitrogen fertilization reduced fruit production for both species, while thinning had a positive effect. For cowberry, treatment effects on fruit production were mainly associated with changes in plant cover, while direct treatment effects altered fruit production in bilberry. Furthermore, N application increased disease incidence of the parasitic fungus Valdensia heterodoxa in bilberry and contributed to the reduced fruit production in the N treatment. In contrast, disease incidence of the main parasitic fungus in cow berry (snow-mold disease) was negatively affected by N. Thinning decreased disease incidence in bilberry, but tended to increase incidence in cowberry. For cowberry, disease incidence increased with latitude. Overall, our results suggest that the N-induced effect on fruit production in bilberry is partly associated with presence of the parasitic fungus, and largely due to unknown direct effects. For cowberry, reduction in fruit production is correlated with N-induced negative effects on plant cover. Large-scale fertilization will have an overall negative impact on fruit production, and given that fruit production is considered highly valuable in the context of ecosystem services and functioning, this reduction should be considered when forest management scenarios that include N fertilization are evaluated. Thinning on the other hand, can promote fruit production and may be used as a management tool to generate berry-rich forests. ( C) 2017 Elsevier B.V. All rights reserved.
44.	Gundale, Michael (author) Combined effects of anthropogenic fires and land-use change on soil properties and processes in Patagonia, Chile 2015 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 357, s. 60-67 Journal article (peer-reviewed)abstract Fire and land-use change are two major types of disturbances that strongly affect the structure and function of forest ecosystems around the world, although their impacts can be difficult to quantify due to concomitant changes in climate or other land-use change factors. In this study we examined how fire and subsequent land-use conversion impacted soil properties (i.e. organic matter (OM), total available pools of carbon (C), nitrogen (N), and phosphorous (P)), and processes (i.e. N cycling inferred through delta N-15) in each of six different land cover types, including old- and second-growth native Nothofagus pumilio, similar to 50 year old exotic conifer plantations, and grassland pastures. We selected six land cover types, including unburned old-growth (MF), and post-fire second-growth (SG) forests of N. pumilio, post-fire afforestations of Pinus contorta (PC), P. ponderosa (PP) and P. sylvestris (PS), and post-fire grassland (GR), in three watersheds in the Aysen Region, Chilean Patagonia. In one growing season, at each of 5-7 sampling locations within each site, two 10 cm deep soil cores were removed using a 12.4 cm diameter PVC soil-corer. From each soil core, organic matter content, total C and N concentrations, availability of NH4+, NO3-, and PO4-, and delta N-15 were determined. Additionally, we collected foliage of Osmorhiza chilensis, a forb that was present in every tree-cover condition, for delta N-15 determination. Unburned old-growth Nothofagus forests showed significantly higher stocks of OM, C, N and P than the P. contorta and P. sylvestris afforestations but not higher than Nothofagus second-growth forests and P. ponderosa afforestations. Conifer afforestations showed significantly lower NH4+ values than unburned Nothofagus forests, whereas no differences in NO3- were found among the land cover types. Contrary to expectations, conifer afforestations showed significantly higher plant and soil delta N-15 values than the unburned Nothofagus forests. Although most land cover types resulted in significant alteration of soil properties and processes relative to the mature, unburned N. pumilio forests, we highlight that P. ponderosa afforestations generated the most similar characteristics, suggesting a utility of this species to restore some ecosystem properties. (C) 2015 Elsevier B.V. All rights reserved.
45.	Gustafsson, Malin, et al. (author) Life history traits predict the response to increased light among 33 tropical rainforest tree species 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 362, s. 20-28 Journal article (peer-reviewed)
46.	Hadden, David, et al. (author) Net CO2 emissions from a primary boreo-nemoral forest over a 10 year period 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 398, s. 164-173 Journal article (peer-reviewed)abstract Primary forests play an important role in the global carbon balance. With little to no human intervention, primary forests are shaped and characterised by disturbances such as weather extremes, fire, insect and pathogen attacks. Such disturbances have a direct impact on the volume of coarse woody debris (CWD) which contributes to the total ecosystem respiration (Re). There are currently few studies that present continuous long term measurements of the carbon balance of northern primary forests. We used the eddy covariance method to measure continuous carbon dioxide (CO2) fluxes from a Swedish primary boreo-nemoral forest over a ten year period. By mapping the measured CO2 fluxes to the forest ecosystem we could indicate that small areas that had some form of disturbance and areas with significant levels of CWD within the eddy covariance footprint contributed to the total Re resulting in the forest being a net carbon source. A weighing algorithm, was used to account for directional ecosystem heterogeneity and to estimate a representative carbon balance for the ecosystem. The forest ecosystem was a continuous source of CO2 to the atmosphere, losing around 25 Mg per hectare of CO2 over a ten year period. (C) 2017 Elsevier B.V. All rights reserved.
47.	Hallinger, Martin, et al. (author) Factors driving tree mortality in retained forest fragments 2016 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 368, s. 163-172 Journal article (peer-reviewed)abstract Green tree retention is often applied in forests otherwise harvested by clearcutting. Its aim is to support biodiversity by contributing to a continuity of living trees and large-diameter dead wood in the new generation of a forest. However, high levels of mortality can undermine the aims of tree retention and pose a concern for forest managers. Therefore, knowledge about the mortality of retention trees over the long term is needed. We calculated cumulative tree mortality for the seven most common tree species up to 20 years after clearcutting based on a chronosequence of dead and living trees in 583 tree groups on 206 clearcuts distributed over a wide area in boreal central Sweden. For all tree taxa combined and for the three most common tree taxa (Scots pine, Norway spruce and two birch species) we modeled tree mortality based on structural and environmental variables measured for each tree group and characteristics of the clearcut using generalized linear mixed effects models. The cumulative mortality averaged over all clearcut ages was 12% for Scots pine, 25% for Norway spruce and 16% for birch. Only 10% of all retention tree groups had a mortality >50%. Key factors reducing mortality for all tree taxa combined were tree density, tree volume of a retention group and the position at a former stand edge abutting open habitat, while a high wind exposure increased tree mortality. For the three most common species (pine, spruce, birch), the same factors as for all taxa combined were of importance, except tree density that resulted in species specific responses. For pine and spruce, the presence of seed trees on the clearcut reduced mortality. Increased mortality was additionally observed on wet soils. Mortality increased with tree height in birch and with diameter and slenderness ratio in spruce. Generally, a focus on retaining trees in groups with large tree volumes and tree density in less wind exposed positions and on forest edges will decrease the mortality after clearcutting and thus also reduce dead wood input. (C) 2016 Elsevier B.V. All rights reserved.
48.	Hellsten, Sofie, et al. (author) Increased concentrations of nitrate in forest soil water after windthrow in southern Sweden 2015 In: Forest Ecology and Management. - : Elsevier BV. - 1872-7042 .- 0378-1127. ; 356, s. 234-242 Journal article (peer-reviewed)abstract In January 2005, south-west Sweden was hit by a severe storm that caused large damage to the forests through massive windthrow. The aim of this study was to assess the effect of this windthrow on nitrate concentrations in the soil water below the root zone on 33 forest monitoring plots within the Swedish Throughfall Monitoring Network (SWETHRO). These sites were damaged to different extents by the storm. The analysis showed increased levels of nitrate concentrations in the soil water as a consequence of storm damaged forest. The present study concerned forest ecosystems with relatively low levels of nitrogen deposition, as compared with forests analysed in previous studies. The maximum soil water nitrate concentrations occurred 1-4 years after the storm. After 5-6 years, the concentrations were back at the same levels as before the storm event. It was not possible to demonstrate a significant correlation between increased nitrate concentrations in the soil water after the storm and the level of nitrogen deposition at the site. The potential impact on ground- and surface waters due to elevated nitrate concentrations in soil water after storm events is discussed. (C) 2015 Elsevier B.V. All rights reserved.
49.	Hellsten, Sofie (author) Stump harvesting in Picea abies stands: Soil surface disturbance and biomass distribution of the harvested stumps and roots 2018 In: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 425, s. 27-34 Journal article (peer-reviewed)abstract Finland has a long tradition of utilizing forest-based biomass for energy and industry purposes and the use has steadily increased in the past decade due to changes in international and regional energy policies. Intensive harvesting practices, in which a larger proportion of the woody biomass is removed from the forest stand, are becoming more common. The objectives of this study were to evaluate the spatial and temporal extent of soil surface disturbance caused by stump-root system harvesting and to quantify how much biomass and nitrogen is removed from the stand in stump and coarse root harvesting. The extent of surface disturbance was assessed in three clear-cut Norway spruce stands in southern and central Finland, differing in time since harvest. To determine the biomass distribution of the stump-root system, stumps and coarse roots were excavated at one of the experimental stands. Across all age classes (time since harvest) less soil surface had remained undisturbed at the stump harvesting sites (52%) than at the sites where only mechanical site preparation (28%) had been carried out. Thus, the findings of this study indicate that soil disturbance caused by stump harvesting can exist on forest soil surface for more than a decade following harvest. The total biomass of the stump-root system in the stand was estimated to 39.3 Mg ha−1 and 79% of this biomass was removed during stump harvesting and consequently, 8.3 Mg ha−1 of stump-root biomass remained in soil. The stump-root system accounted for 17% of the whole-tree biomass, and coarse roots and fine coarse roots represented a significant portion of it (73%). Thus, the stump-root system represents a large biomass component in boreal forest stands. However, forest management utilizing stumps may result in carbon losses from the stand. Download the article here: https://www.sciencedirect.com/science/article/pii/S0378112718304432
50.	Hjältén, Joakim, et al. (author) Biodiversity benefits for saproxylic beetles with uneven-aged silviculture 2017 In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 402, s. 37-50 Journal article (peer-reviewed)abstract Large scale use of even-aged silviculture (clear-cutting) commencing in the mid-20th century has had negative impacts on forest biodiversity. As a consequence, uneven-aged silviculture is currently being considered to help meet the ecological and social criteria required for sustainable forest management. Uneven-aged silviculture (e.g. selective felling) involves selective removal of some older trees in a stand which may to some extent mimics natural small scale stand dynamics and thus potentially benefit species associated with old forests. Here we test whether selective felling benefits beetle biodiversity by producing beetle assemblages that better resemble those of old growth stands than those found in uncut production stands. We conducted a field study in northern Sweden, comparing beetles assemblages collected with window traps in three spruce dominated stand types: (1) Stands recently (on average 7 years prior to the study) subjected to selective felling (Selective felling), (2) mature uneven-aged stands without recent history of management, resembling selective felling stands prior to management (Uncut), and (3) old-growth stands with high conservation values (Old growth). As predicted, we found that assemblage composition was similar in selective felling and old growth stands, and that assemblages of cambivores and obligate saproxylics (marginally significant) differed between these two stand types and uncut stands. The differences were largely explained by a higher abundance of saproxylic species presumably associated with old growth conditions and large volumes of deadwood. Thus, although overall assemblage composition did not differ between stand types, part of the beetle community seemingly benefited from selective felling. We therefore recommend that selective felling is considered as an alternative to clear-felling to maintain biodiversity values. (C) 2017 Elsevier B.V. All rights reserved.

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