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Peter B Reich - One of the best experts on this subject based on the ideXlab platform.
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species rich Boreal Forests grew more and suffered less mortality than species poor Forests under the environmental change of the past half century
Ecology Letters, 2019Co-Authors: Masumi Hisano, Han Y. H. Chen, Peter B Reich, Eric B SearleAbstract:Climate and other global environmental changes are major threats to ecosystem functioning and biodiversity. However, the importance of plant diversity in mitigating the responses of functioning of natural ecosystems to long-term environmental change remains unclear. Using inventory data of Boreal Forests of western Canada from 1958 to 2011, we found that aboveground biomass growth increased over time in species-rich Forests but decreased in species-poor Forests, and importantly, aboveground biomass loss from tree mortality was smaller in species-rich than species-poor Forests. A further analysis indicated that growth of species-rich (but not species-poor) Forests was statistically positively associated with rising CO2 , and that mortality in species-poor Forests increased more as climate moisture availability decreased than it did in species-rich Forests. In contrast, growth decreased and mortality increased as the climate warmed regardless of species diversity. Our results suggest that promoting high tree diversity may help reduce the climate and environmental change vulnerability of Boreal Forests.
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climate and interrelated tree regeneration drivers in mixed temperate Boreal Forests
Landscape Ecology, 2013Co-Authors: Lee E Frelich, Peter B Reich, Nicholas A FisichelliAbstract:Forest compositional shifts in response to climate change are likely to be initially detectable in the understory tree regeneration layer near species range limits. Because many factors in addition to climate, such as seedbed and soil characteristics, overstory composi- tion, and interactions with other understory biota, drive tree regeneration trends, a thorough understanding of the relative importance of all variables as well as their interrelationships is needed. The range limits of several widespread temperate and Boreal tree species overlap in the upper Great Lakes region, USA, thus facilitating an observational study over relatively short regional climate gradients. We used redundancy analysis and variation partitioning to quantify the unique, shared, and total explanatory power of four sets of explanatory variables. The results showed that all four variable sets (climate 9.5 %, understory environment 13.7 %, over- story composition 26.3 %, and understory biota 13.8 %) were significantly associated with tree regeneration compositional variation in mixed temperate-Boreal Forests. Partitioning also revealed high confounded or shared explanatory power, but also that each set contributed significant unique explanatory power not shared with other sets. Spatial patterning in regeneration composition was strongly related to broad scale envi- ronmental patterns, while the large majority of unex- plained variation did not have a detectable spatial structure, suggesting factors with local scale variability. Future forest shifts across the landscape will depend not only on the rate and direction of climate change but also on how the strengths and interrelationships among other explanatory variables, such as overstory composition and understory biota, shift with a changing climate.
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understorey diversity in southern Boreal Forests is regulated by productivity and its indirect impacts on resource availability and heterogeneity
Journal of Ecology, 2012Co-Authors: Peter B Reich, Lee E Frelich, Richard A Voldseth, Peter Bakken, Carol E AdairAbstract:Summary 1. Understanding the relationship between species diversity and productivity is central to linking compositional and functional aspects of terrestrial ecosystems, and little is known about such issues in Boreal Forests. We used structural equation modelling (SEM) to test several hypotheses about direct and indirect influences of productivity, its correlate basal area, and resources on understorey vascular plant diversity on 2025 plots in 81 southern Boreal Forests in Minnesota, USA. 2. We first examined the hypothesis that increasing basal area reduces plot-scale species richness due to competitive exclusion from the most limiting resource, light. As expected, light pre-emption increased with total basal area, which directly reduced understorey species richness. However, complex relations between basal area, dominant understorey species, and resource supply to the understorey can also influence understorey communities. Hence, we addressed whether plots with low light availability in the understorey were associated with low abundance of dominant understorey species and alleviation of competitive exclusion of other understorey species. SEM results showed that low light decreased total understorey cover, alleviating resource competition from this stratum and thus increasing understorey species richness. Furthermore, the cover of four dominant understorey species was positively correlated with light availability and negatively correlated with plotscale species richness. 3. Aggregating data for the 25 plots at each stand, SEM showed that stand-scale species richness was positively influenced by light heterogeneity, which in turn increased with annual above-ground productivity. 4. Species richness was positively influenced by litter %N, considered an index of nitrogen availability at the plot and stand scale. 5. Synthesis. These results suggest that understorey species richness in Boreal Forests is regulated by productivity, but is primarily mediated by the indirect effects of productivity of the dominant producers on resource availability and heterogeneity.
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earthworm invasion into previously earthworm free temperate and Boreal Forests
Biological Invasions, 2006Co-Authors: Lee E Frelich, Cindy M Hale, Stefan Scheu, Andrew R Holdsworth, Liam Heneghan, Patrick J Bohlen, Peter B ReichAbstract:Earthworms are keystone detritivores that can influence primary producers by changing seedbed conditions, soil characteristics, flow of water, nutrients and carbon, and plant-herbivore interactions. The invasion of European earth- worms into previously earthworm-free temperate and Boreal Forests of North America dominated
Pasi Kolari - One of the best experts on this subject based on the ideXlab platform.
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the human footprint in the carbon cycle of temperate and Boreal Forests
Nature, 2007Co-Authors: Federico Magnani, Achim Grelle, P G Jarvis, Marco Borghetti, Sylvain Delzon, Maurizio Mencuccini, Frank Berninger, Pertti Hari, Paul Berbigier, Pasi KolariAbstract:A study of forest ecosystems from across western Europe and the United States has settled a long-running controversy — and raised many new questions. At issue is the influence of nitrogen deposition on the global carbon cycle, particularly the part played by human activity. The new study demonstrates that via the direct effects of forest management and indirectly via the use of nitrogen fertilizers and nitrogen oxide production by cars and industry, human activities have had a profound and largely positive effect on the carbon balance or net ecosystem production. (That's the balance between ecosystem carbon fixation through photosynthesis and its subsequent release through plant and soil respiration.) The implications of these findings for practical questions such as the merits of fertilizing Forests with nitrogen, are considered in the accompanying News and Views by Peter Hogberg. The profound, overwhelming effects of human activities on the carbon balance of temperate and Boreal Forests are demonstrated. Apart from the direct effects of forest management, they show that carbon sequestration by this important component of the biosphere is driven by the imbalance in the global nitrogen cycle determined by human activities. Temperate and Boreal Forests in the Northern Hemisphere cover an area of about 2 × 107 square kilometres and act as a substantial carbon sink (0.6–0.7 petagrams of carbon per year)1. Although forest expansion following agricultural abandonment is certainly responsible for an important fraction of this carbon sink activity, the additional effects on the carbon balance of established Forests of increased atmospheric carbon dioxide, increasing temperatures, changes in management practices and nitrogen deposition are difficult to disentangle, despite an extensive network of measurement stations2,3. The relevance of this measurement effort has also been questioned4, because spot measurements fail to take into account the role of disturbances, either natural (fire, pests, windstorms) or anthropogenic (forest harvesting). Here we show that the temporal dynamics following stand-replacing disturbances do indeed account for a very large fraction of the overall variability in forest carbon sequestration. After the confounding effects of disturbance have been factored out, however, forest net carbon sequestration is found to be overwhelmingly driven by nitrogen deposition, largely the result of anthropogenic activities5. The effect is always positive over the range of nitrogen deposition covered by currently available data sets, casting doubts on the risk of widespread ecosystem nitrogen saturation6 under natural conditions. The results demonstrate that mankind is ultimately controlling the carbon balance of temperate and Boreal Forests, either directly (through forest management) or indirectly (through nitrogen deposition).
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the human footprint in the carbon cycle of temperate and Boreal Forests
Nature, 2007Co-Authors: Federico Magnani, Achim Grelle, P G Jarvis, Marco Borghetti, Sylvain Delzon, Maurizio Mencuccini, Frank Berninger, Pertti Hari, Paul Berbigier, Pasi KolariAbstract:The profound, overwhelming effects of human activities on the carbon balance of temperate and Boreal Forests are demonstrated. Apart from the direct effects of forest management, they show that carbon sequestration by this important component of the biosphere is driven by the imbalance in the global nitrogen cycle determined by human activities.
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The human footprint in the carbon cycle of temperate and Boreal Forests
Nature, 2007Co-Authors: Federico Magnani, Achim Grelle, Marco Borghetti, Sylvain Delzon, Maurizio Mencuccini, Frank Berninger, Pertti Hari, Paul Berbigier, Paul G. Jarvis, Pasi KolariAbstract:Temperate and Boreal Forests in the Northern Hemisphere cover an area of about 2 x 10(7) square kilometres and act as a substantial carbon sink (0.6 - 0.7 petagrams of carbon per year)(1). Although forest expansion following agricultural abandonment is certainly responsible for an important fraction of this carbon sink activity, the additional effects on the carbon balance of established Forests of increased atmospheric carbon dioxide, increasing temperatures, changes in management practices and nitrogen deposition are difficult to disentangle, despite an extensive network of measurement stations(2,3). The relevance of this measurement effort has also been questioned(4), because spot measurements fail to take into account the role of disturbances, either natural ( fire, pests, windstorms) or anthropogenic ( forest harvesting). Here we show that the temporal dynamics following stand-replacing disturbances do indeed account for a very large fraction of the overall variability in forest carbon sequestration. After the confounding effects of disturbance have been factored out, however, forest net carbon sequestration is found to be overwhelmingly driven by nitrogen deposition, largely the result of anthropogenic activities(5). The effect is always positive over the range of nitrogen deposition covered by currently available data sets, casting doubts on the risk of widespread ecosystem nitrogen saturation(6) under natural conditions. The results demonstrate that mankind is ultimately controlling the carbon balance of temperate and Boreal Forests, either directly ( through forest management) or indirectly ( through nitrogen deposition).
Ekaterina Shorohova - One of the best experts on this subject based on the ideXlab platform.
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variable retention forestry in european Boreal Forests in russia
Ecological processes, 2019Co-Authors: Ekaterina Shorohova, Sergey Sinkevich, Aleksandr Kryshen, Ilkka VanhamajamaaAbstract:We explored whether, and to what extent, variable retention (VR) forestry has been applied in European Boreal Forests in northwestern Russia. Our survey revealed VR since 1910. Between 1910 and the 1960s, the statistics showing how much was retained are largely missing. However, for example, in the 1950s, on a large scale in the Republic of Karelia, up to 200-ha-sized harvesting areas, 18–33%, were retention patches with a mean growing stock of 30–40 m3 ha−1. In the fellings defined as “incomplete clear fellings,” which were the most common final felling type at that time, 11–40% of the growing stock was left. Between the 1960s and the early 1990s, with more efficient harvesting and skidding techniques, conventional clear fellings with a much lower amount of retention were practiced. Concern about the regeneration of harvested areas gradually led to smaller (maximum 50 ha) harvesting areas and the increase of silvicultural activities. Until now, to ensure natural regeneration, patches of understory and 20–25 seed trees (i.e., ca. 15–25 m3) per ha have been left permanently in harvesting areas. Landscape-scale retention for protecting ecosystem functions and biodiversity was legislated in 1978 by preserving key biotopes up to 1000 ha in size. Since 2001, promoted by forest certification, the key biotopes, such as paludified forest patches, buffers around water bodies, and habitats of red-listed species, have also been retained in harvesting areas, together with a dispersed retention of different elements. Quantitative estimates of the amount of key biotopes are largely missing. However, estimates of 1–13% in harvesting areas and 23% in whole managed landscapes have been given. VR applied during the last century has emulated natural disturbances and created diverse uneven-aged forest structures with high amounts of diverse coarse woody debris. We conclude that an analysis of past and current retention practices is essential for estimating the global role of Russian forestry. Further decisions on the general direction of Russian forestry and, specifically, retention practices are important to address the global challenges of biodiversity loss and climate change.
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the decomposition rate of non stem components of coarse woody debris cwd in european Boreal Forests mainly depends on site moisture and tree species
European Journal of Forest Research, 2016Co-Authors: Ekaterina Shorohova, Ekaterina KapitsaAbstract:The decomposition rate of CWD is a key missing link for a quantitative understanding of forest ecosystem functioning. We examined factors influencing decomposition rates of bark, roots and branches from aspen (Populus tremula), birch (Betula pendula, B. pubescens), fir (Abies sibirica), spruce (Picea abies, P. obovata), Scots pine (Pinus sylvestris) and Siberian pine (Pinus sibirica) CWD in three primeval European Boreal Forests. The chronosequence approach with estimates of single exponential decomposition rate (k) based on calculation of mass loss was used. The k of non-stem parts increased in the order: branches (0.006 year−1 for P. sibirica and 0.020 year−1 for other species), roots in poorly drained sites (0.025 year−1), roots in well-drained sites (0.034 year−1) and bark (0.110 and 0.138 year−1 and 0.147 and 0.255 year−1 under poorly and well-drained conditions and from 1 to 3 m and >3 m above the root collar, respectively). Our results predict that the rate of decomposition of whole CWD pieces in European Boreal Forests is a function of vegetation zone, site conditions, tree species and size.
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Stand and landscape scale variability in the amount and diversity of coarse woody debris in primeval European Boreal Forests
Forest Ecology and Management, 2015Co-Authors: Ekaterina Shorohova, Ekaterina KapitsaAbstract:Abstract Factors influencing natural variability in coarse woody debris (CWD) as an indicator of ecosystem services in Boreal Forests need to be better defined. We analysed the CWD characteristics in 194 dynamic primeval Boreal forest stands and 3 landscapes under different disturbance regimes. The volume of CWD in the spruce dominated Forests linearly increased with increasing annual temperature. The CWD amount and species diversity were higher in spruce than in pine dominated stands. The CWD volume increased in relationship to the types of forest stand dynamics in the order: ‘even-aged’, ‘cohort’, ‘fine-scale gap’. The CWD volumes were 52.3; 207.0 and 146.8 m3 ha−1 and the dead:live wood volume ratios were 29%, 102% and 60% in the landscapes with disturbance regimes driven by periodic surface fires, cohort-replacing windthrow, and fine-scale gap dynamics, respectively. Mean dead:live wood volume ratios exceeded 100% in spruce stands with even-aged and cohort dynamics and in pine stands with even-aged and fine-scale gap dynamics. The CWD decay class diversity was higher in pine than in spruce dominated stands. The CWD volume distribution by decay class was the most even in forest stands driven by fine-scale gap dynamics in both spruce and pine dominated stands. The CWD position diversity was higher in spruce than in pine dominated Forests. Fallen logs dominated among other CWD position types in the spruce dominated stands with cohort and fine-scale gap dynamics and in pine stands with cohort and even-aged dynamics. Pine Forests with fine-scale gap dynamics stored the greatest volume of snags. In the spruce dominated stands, the proportion of leaning logs decreased and the proportion of snags and stumps increased among forest dynamic types in the following order: even-aged, cohort, fine-scale gap. The CWD diameter distribution had peaks in small-sized CWD in even-aged spruce stands and pine stands with fine-scale gap dynamics. Mid-sized CWD dominated in spruce stands driven by cohort and fine-scale gap dynamics and pine stands with even-aged and cohort dynamics. The large quantity of CWD that encompassed a wide range of variation in tree species, decay class, position type and size creates a diversity of CWD habitats for saproxylic organisms and ensures functional resilience in Boreal forest ecosystems. Our results stress that mean annual temperatures and natural site-specific disturbance regimes should be taken into account when setting targets for CWD volumes and dead:live wood volume ratios for management and restoration of CWD in Boreal Forests.
Ekaterina Kapitsa - One of the best experts on this subject based on the ideXlab platform.
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the decomposition rate of non stem components of coarse woody debris cwd in european Boreal Forests mainly depends on site moisture and tree species
European Journal of Forest Research, 2016Co-Authors: Ekaterina Shorohova, Ekaterina KapitsaAbstract:The decomposition rate of CWD is a key missing link for a quantitative understanding of forest ecosystem functioning. We examined factors influencing decomposition rates of bark, roots and branches from aspen (Populus tremula), birch (Betula pendula, B. pubescens), fir (Abies sibirica), spruce (Picea abies, P. obovata), Scots pine (Pinus sylvestris) and Siberian pine (Pinus sibirica) CWD in three primeval European Boreal Forests. The chronosequence approach with estimates of single exponential decomposition rate (k) based on calculation of mass loss was used. The k of non-stem parts increased in the order: branches (0.006 year−1 for P. sibirica and 0.020 year−1 for other species), roots in poorly drained sites (0.025 year−1), roots in well-drained sites (0.034 year−1) and bark (0.110 and 0.138 year−1 and 0.147 and 0.255 year−1 under poorly and well-drained conditions and from 1 to 3 m and >3 m above the root collar, respectively). Our results predict that the rate of decomposition of whole CWD pieces in European Boreal Forests is a function of vegetation zone, site conditions, tree species and size.
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Stand and landscape scale variability in the amount and diversity of coarse woody debris in primeval European Boreal Forests
Forest Ecology and Management, 2015Co-Authors: Ekaterina Shorohova, Ekaterina KapitsaAbstract:Abstract Factors influencing natural variability in coarse woody debris (CWD) as an indicator of ecosystem services in Boreal Forests need to be better defined. We analysed the CWD characteristics in 194 dynamic primeval Boreal forest stands and 3 landscapes under different disturbance regimes. The volume of CWD in the spruce dominated Forests linearly increased with increasing annual temperature. The CWD amount and species diversity were higher in spruce than in pine dominated stands. The CWD volume increased in relationship to the types of forest stand dynamics in the order: ‘even-aged’, ‘cohort’, ‘fine-scale gap’. The CWD volumes were 52.3; 207.0 and 146.8 m3 ha−1 and the dead:live wood volume ratios were 29%, 102% and 60% in the landscapes with disturbance regimes driven by periodic surface fires, cohort-replacing windthrow, and fine-scale gap dynamics, respectively. Mean dead:live wood volume ratios exceeded 100% in spruce stands with even-aged and cohort dynamics and in pine stands with even-aged and fine-scale gap dynamics. The CWD decay class diversity was higher in pine than in spruce dominated stands. The CWD volume distribution by decay class was the most even in forest stands driven by fine-scale gap dynamics in both spruce and pine dominated stands. The CWD position diversity was higher in spruce than in pine dominated Forests. Fallen logs dominated among other CWD position types in the spruce dominated stands with cohort and fine-scale gap dynamics and in pine stands with cohort and even-aged dynamics. Pine Forests with fine-scale gap dynamics stored the greatest volume of snags. In the spruce dominated stands, the proportion of leaning logs decreased and the proportion of snags and stumps increased among forest dynamic types in the following order: even-aged, cohort, fine-scale gap. The CWD diameter distribution had peaks in small-sized CWD in even-aged spruce stands and pine stands with fine-scale gap dynamics. Mid-sized CWD dominated in spruce stands driven by cohort and fine-scale gap dynamics and pine stands with even-aged and cohort dynamics. The large quantity of CWD that encompassed a wide range of variation in tree species, decay class, position type and size creates a diversity of CWD habitats for saproxylic organisms and ensures functional resilience in Boreal forest ecosystems. Our results stress that mean annual temperatures and natural site-specific disturbance regimes should be taken into account when setting targets for CWD volumes and dead:live wood volume ratios for management and restoration of CWD in Boreal Forests.
Han Y. H. Chen - One of the best experts on this subject based on the ideXlab platform.
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species rich Boreal Forests grew more and suffered less mortality than species poor Forests under the environmental change of the past half century
Ecology Letters, 2019Co-Authors: Masumi Hisano, Han Y. H. Chen, Peter B Reich, Eric B SearleAbstract:Climate and other global environmental changes are major threats to ecosystem functioning and biodiversity. However, the importance of plant diversity in mitigating the responses of functioning of natural ecosystems to long-term environmental change remains unclear. Using inventory data of Boreal Forests of western Canada from 1958 to 2011, we found that aboveground biomass growth increased over time in species-rich Forests but decreased in species-poor Forests, and importantly, aboveground biomass loss from tree mortality was smaller in species-rich than species-poor Forests. A further analysis indicated that growth of species-rich (but not species-poor) Forests was statistically positively associated with rising CO2 , and that mortality in species-poor Forests increased more as climate moisture availability decreased than it did in species-rich Forests. In contrast, growth decreased and mortality increased as the climate warmed regardless of species diversity. Our results suggest that promoting high tree diversity may help reduce the climate and environmental change vulnerability of Boreal Forests.
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stand age fire and clearcutting affect soil organic carbon and aggregation of mineral soils in Boreal Forests
Soil Biology & Biochemistry, 2012Co-Authors: Han Y. H. Chen, Bharat M ShresthaAbstract:Abstract Soil organic carbon (SOC) in mineral soil accounts for a large portion of total ecosystem carbon (C) in Boreal Forests. We evaluated the effects of stand age and disturbance origin on SOC, soil aggregate stability, and aggregate-associated SOC in the Boreal Forests of Ontario, Canada. Mineral soils at 0–15 cm depth were sampled in 27 stands of six post-fire age classes (2- to 203-year-old) and three post-clearcut age classes (2- to 29-year-old), each with three replications. In post-fire stands, the SOC pool increased from 2- and 10-year-old to 29-, 85- and 140-year-old, and then decreased in 203-year-old stands. Aggregate-associated SOC showed a similar trend. Abundance of water stable aggregates (>0.25 mm in diameter) was the highest in 2-year-old stands. Compared with the same-aged post-fire stands, the SOC pool and aggregate-associated SOC were higher, and aggregate stability was lower in 2- and 10-year-old post-clearcut stands. But the differences in SOC pool, aggregate-associated SOC, and aggregate stability between the two stand origins diminished or became less dramatic in 29-year-old stands. Our results indicate that aggregate stability is more dependent on thermal modification of SOC by fire than on aggregate-associated SOC. Our results also show higher SOC pool and aggregate-associated SOC but lower aggregate stability in post-clearcut than post-fire stands shortly after disturbance; however, differences between the two stand origins diminish when stands become older.
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understory vegetation dynamics of north american Boreal Forests
Critical Reviews in Plant Sciences, 2006Co-Authors: Stephen A Hart, Han Y. H. ChenAbstract:Understory vegetation is the most diverse and least understood component of North American Boreal Forests. Understory communities are important as they act as drivers of overstory succession and nutrient cycling. The objective of this review was to examine how understory vegetation abundance, composition, and diversity change with stand development after a major stand replacing disturbance. Understory vegetation abundance and diversity increase rapidly after fire, in response to abundant resources and an influx of disturbance adapted species. The highest diversity occurs within the first 40 years following fire, and declines indefinitely thereafter as a result of decreasing productivity and increased dominance of a small number of late successional feather mosses and woody plant species. Vascular plant and bryophyte/lichen communities undergo very different successional changes. Vascular plant communities are dynamic and change more dramatically with time after fire, whereas bryophyte and lichen communiti...