Changes in clearcut management over time were evaluated using aerial photographs taken between 1960 and 2010. Temporal changes were analysed in two different climatic zones in Sweden: a typical boreal forest zone (the...Changes in clearcut management over time were evaluated using aerial photographs taken between 1960 and 2010. Temporal changes were analysed in two different climatic zones in Sweden: a typical boreal forest zone (the coast of Västerbotten County), and the hemi-boreal zone of southern Sweden (represented by Kronoberg County). The study covers the periods before and after the paradigm shift in Swedish forestry caused by the equalization of the production and nature conservation objectives specified in the first paragraph of the Swedish Forestry Act. Photographs were processed to determine clearcut size and shape and to register solitary retention trees and groups of retention trees. Small but significant changes in clearcut size were detected over time. The number of retention trees increased over time, a result that was also found in other studies using different methodologies. The results demonstrate that measurable structural changes have occurred in Swedish forests over the 25 years since the paradigm shift. Results from this study also show that digital detection of green tree retention could be a future complement to field inventory and monitoring.展开更多
The influence of edge effect on ground-dwelling beetles （Coleoptera） across a forest-clearcut ecotone was studied in Wolong Natural Reserve, southwestern China. During the field research, a total of 30 739 beetles w...The influence of edge effect on ground-dwelling beetles （Coleoptera） across a forest-clearcut ecotone was studied in Wolong Natural Reserve, southwestern China. During the field research, a total of 30 739 beetles were collected with pitfall traps along transects, which extending 100 m from the edge into the forest interior and 100 m into the clearcut. Of the collection, Carabidae comprised 92%, Staphylinidae 3%, Curculionidae 2%, and Tenebrionidae 2%, and these four families can be considered as abundant groups. Family richness, Shannon diversity and equitability display a significant decrease from forest interior, edge to clearcut. Based on the family composition and abundance, ground-dwelling beetles of the forest interior can be separated from those in the clearcut by Principal coordinate analysis ordination, and beetle assemblages in the forest edge were more similar to forest assemblages than to those found in the clearcut by cluster analysis. Seasonal dynamics of family richness showed a monotone peak in the middle season, with a highest value in the forest interior and a lowest value in the clearcut. Family abundance showed two peaks in the middle season, always with more individuals in the clearcut than in the forest interior or in the edge. Multiple linear regression analyses showed that the cover of shrub and litter were the two most important factors in determining family richness, Shannon diversity, equitability and abundance. Our results show that the forest edge and clearcut have obviously different composition and diversity of ground-dwelling beetles from forest interior at the family level. However, more edges have been formed due to increasing forest fragmentation （clearcutting or logging）, so it is necessary to preserve large and intact forest to protect the diversity of ground-dwelling beetles in Wolong Natural Reserve.We are indebted to Dr Jari Niemel^i and Dr Tibor Magura for constructive suggestions on the experiment and provid- ing important references. We are grateful to Mrs Xiao-Ping Zhou, Jin-Yan Huang, Shi-Qiang Zhou, Yuan-Jun Jiang, Shu-Ming Fan, Guo-You Li and You-Qian Yang （Wolong Natural Reserve, Wenchuan County, Sichuan Province） for assistance in field experiments. This study was supported in part by a State Key Basic Research and Development Plan from the Ministry of Science and Technology of China （G2000046800）, National Natural Science Foundation of China （No. 30570215）, a grant to the senior author （No. D/3684-1） of International Foundation for Sciences展开更多
Canada’s boreal forest represents an important contributor of the world’s wood supply industry. However,maintaining or increasing productivity of the boreal forest may be challenging in areas dominated by forested p...Canada’s boreal forest represents an important contributor of the world’s wood supply industry. However,maintaining or increasing productivity of the boreal forest may be challenging in areas dominated by forested peatlands. Moreover, sustainable management of these forests must also consider other important aspects of the forest ecosystem such as biodiversity and carbon sequestration. To address these concerns, ecosystem-based management has been implemented in some Canadian jurisdictions, such as in regions where a large portion of the boreal forest is dominated by forested peatlands. The objectives of this paper are(1) to summarize our current understanding of how natural disturbances influence stand dynamics and biodiversity in forested peatlands, and(2) to review the main differences between natural and managed forest stands with respect to soil properties, stand productivity, understory plant communities. We also discuss how even-age management regime succeeds or fails to preserve old forests and how this loss affects both forest structure and habitat diversity at the landscape level.We conclude by showing how, in boreal forested peatlands, forest management could contribute to carbon sequestration and mitigate projected climate change.展开更多
Stand-level retention is an important component of sustainable forest management which aims to balance ecological,social and economic objectives.Long-term retention of mature forest structures at the time of harvestin...Stand-level retention is an important component of sustainable forest management which aims to balance ecological,social and economic objectives.Long-term retention of mature forest structures at the time of harvesting(variable retention)is intended to produce future forest stands that more closely resemble conditions that develop after natural disturbances,thereby maintaining greater diversity of habitats for a variety of organisms.Structure includes features such as live and dead trees representing multiple canopy layers,undisturbed understory vegetation and coarse woody debris.Over the past two decades,variable retention has become common on forest lands in the temperate rainforests of coastal British Columbia(BC)and has been applied to a lesser extent in inland forest types.Our review of studies in BC and in similar forest types in our region indicates that both aggregated and dispersed retention can contribute to biodiversity conservation by providing short-term‘life-boating’habitat for some species and by enhancing the structural characteristics of future stands.For example,greater abundance of species present in the pre-harvest forest have been documented for vegetation,birds,carabid beetles,gastropods,ectomycorrhizal fungi and soil fauna in retention cutblocks compared to clearcuts.There are,however,some negative consequences for timber production such as wind damage to retained trees and reduced growth rates of tree regeneration compared to clearcuts.The authors suggest an adaptive management approach for balancing competing objectives when faced with uncertainty.This includes monitoring the implementation and effectiveness of various strategies for achieving goals.Over two decades of experience applying variable retention harvesting to industrial-scale management of forest lands in BC suggests that it is possible to balance production of wood with biodiversity conservation.展开更多
文摘Changes in clearcut management over time were evaluated using aerial photographs taken between 1960 and 2010. Temporal changes were analysed in two different climatic zones in Sweden: a typical boreal forest zone (the coast of Västerbotten County), and the hemi-boreal zone of southern Sweden (represented by Kronoberg County). The study covers the periods before and after the paradigm shift in Swedish forestry caused by the equalization of the production and nature conservation objectives specified in the first paragraph of the Swedish Forestry Act. Photographs were processed to determine clearcut size and shape and to register solitary retention trees and groups of retention trees. Small but significant changes in clearcut size were detected over time. The number of retention trees increased over time, a result that was also found in other studies using different methodologies. The results demonstrate that measurable structural changes have occurred in Swedish forests over the 25 years since the paradigm shift. Results from this study also show that digital detection of green tree retention could be a future complement to field inventory and monitoring.
基金We are indebted to Dr Jari Niemela and Dr Tibor Magura for constructive suggestions on the experiment and providing important references. We are grateful to Mrs Xiao-Ping Zhou, Jin-Yan Huang, Shi-Qiang Zhou, Yuan-Jun Jiang, Shu-Ming Fan, Guo-You Li and You-Qian Yang （Wolong Natural Reserve, Wenchuan County, Sichuan Province） for assistance in field experiments. This study was supported in part by a State Key Basic Research and Development Plan from the Ministry of Science and Technology of China （G2000046800）, National Natural Science Foundation of China （No. 30570215）, a grant to the senior author （No. D/3684-1） of International Foundation for Sciences （IFS, Stockholm, Sweden）, and National Science Fund for Fostering Talents in Basic Research （NSFC-J0030092）.
文摘The influence of edge effect on ground-dwelling beetles （Coleoptera） across a forest-clearcut ecotone was studied in Wolong Natural Reserve, southwestern China. During the field research, a total of 30 739 beetles were collected with pitfall traps along transects, which extending 100 m from the edge into the forest interior and 100 m into the clearcut. Of the collection, Carabidae comprised 92%, Staphylinidae 3%, Curculionidae 2%, and Tenebrionidae 2%, and these four families can be considered as abundant groups. Family richness, Shannon diversity and equitability display a significant decrease from forest interior, edge to clearcut. Based on the family composition and abundance, ground-dwelling beetles of the forest interior can be separated from those in the clearcut by Principal coordinate analysis ordination, and beetle assemblages in the forest edge were more similar to forest assemblages than to those found in the clearcut by cluster analysis. Seasonal dynamics of family richness showed a monotone peak in the middle season, with a highest value in the forest interior and a lowest value in the clearcut. Family abundance showed two peaks in the middle season, always with more individuals in the clearcut than in the forest interior or in the edge. Multiple linear regression analyses showed that the cover of shrub and litter were the two most important factors in determining family richness, Shannon diversity, equitability and abundance. Our results show that the forest edge and clearcut have obviously different composition and diversity of ground-dwelling beetles from forest interior at the family level. However, more edges have been formed due to increasing forest fragmentation （clearcutting or logging）, so it is necessary to preserve large and intact forest to protect the diversity of ground-dwelling beetles in Wolong Natural Reserve.We are indebted to Dr Jari Niemel^i and Dr Tibor Magura for constructive suggestions on the experiment and provid- ing important references. We are grateful to Mrs Xiao-Ping Zhou, Jin-Yan Huang, Shi-Qiang Zhou, Yuan-Jun Jiang, Shu-Ming Fan, Guo-You Li and You-Qian Yang （Wolong Natural Reserve, Wenchuan County, Sichuan Province） for assistance in field experiments. This study was supported in part by a State Key Basic Research and Development Plan from the Ministry of Science and Technology of China （G2000046800）, National Natural Science Foundation of China （No. 30570215）, a grant to the senior author （No. D/3684-1） of International Foundation for Sciences
文摘Canada’s boreal forest represents an important contributor of the world’s wood supply industry. However,maintaining or increasing productivity of the boreal forest may be challenging in areas dominated by forested peatlands. Moreover, sustainable management of these forests must also consider other important aspects of the forest ecosystem such as biodiversity and carbon sequestration. To address these concerns, ecosystem-based management has been implemented in some Canadian jurisdictions, such as in regions where a large portion of the boreal forest is dominated by forested peatlands. The objectives of this paper are(1) to summarize our current understanding of how natural disturbances influence stand dynamics and biodiversity in forested peatlands, and(2) to review the main differences between natural and managed forest stands with respect to soil properties, stand productivity, understory plant communities. We also discuss how even-age management regime succeeds or fails to preserve old forests and how this loss affects both forest structure and habitat diversity at the landscape level.We conclude by showing how, in boreal forested peatlands, forest management could contribute to carbon sequestration and mitigate projected climate change.
基金by the Province of British Columbia(BC Ministry of Forests,Lands,Natural Resource Operations and Rural DevelopmentBC Forest Investment Account,Land Based Investment ProgramBC Forest Science Program),the University of British Columbia and forest companies(Cascadia Forest Products,MacMillan Bloedel Limited,Western Forest Products Inc.,Weyerhaeuser Company).Other than the scientists and field personnel directly involved in the research,the funding bodies did not have a role in the design of the studies,in the collection,analysis,and interpretation of data,and in writing the manuscript.
文摘Stand-level retention is an important component of sustainable forest management which aims to balance ecological,social and economic objectives.Long-term retention of mature forest structures at the time of harvesting(variable retention)is intended to produce future forest stands that more closely resemble conditions that develop after natural disturbances,thereby maintaining greater diversity of habitats for a variety of organisms.Structure includes features such as live and dead trees representing multiple canopy layers,undisturbed understory vegetation and coarse woody debris.Over the past two decades,variable retention has become common on forest lands in the temperate rainforests of coastal British Columbia(BC)and has been applied to a lesser extent in inland forest types.Our review of studies in BC and in similar forest types in our region indicates that both aggregated and dispersed retention can contribute to biodiversity conservation by providing short-term‘life-boating’habitat for some species and by enhancing the structural characteristics of future stands.For example,greater abundance of species present in the pre-harvest forest have been documented for vegetation,birds,carabid beetles,gastropods,ectomycorrhizal fungi and soil fauna in retention cutblocks compared to clearcuts.There are,however,some negative consequences for timber production such as wind damage to retained trees and reduced growth rates of tree regeneration compared to clearcuts.The authors suggest an adaptive management approach for balancing competing objectives when faced with uncertainty.This includes monitoring the implementation and effectiveness of various strategies for achieving goals.Over two decades of experience applying variable retention harvesting to industrial-scale management of forest lands in BC suggests that it is possible to balance production of wood with biodiversity conservation.
