Variable retention harvesting is a silvicultural system that focuses on retaining key elements of stand structure at the time of logging and is increasingly being used worldwide.We describe the design and establishmen...Variable retention harvesting is a silvicultural system that focuses on retaining key elements of stand structure at the time of logging and is increasingly being used worldwide.We describe the design and establishment of a variable retention harvesting experiment established in the Mountain Ash(Eucalyptus regnans)forests of the Central Highlands of Victoria,south-eastern Australia.The experiment was instigated in 2003,and the work to date has shown that it has environmental benefits for certain groups of small mammals,birds,and vascular plants.The experiment has been integrated with an ongoing long-term monitoring program as well as other experiments such as those in post-fire salvage-logged areas.Collectively,the results of various studies suggest that the potential value of variable retention harvesting extends beyond green-tree logging to post-fire salvage logging environments.We outline some of the challenges in,and new perspectives derived from,implementing and maintaining our experiment.This included difficulties protecting islands from high-intensity post-harvest regeneration burns and threat of declining funding undermining ongoing project viability.A critically important perspective concerns the ecological and economic context in which variable retention harvesting is implemented.In the particular case of Mountain Ash forests,assessments using formal IUCN criteria classify the ecosystem as being Critically Endangered under the Red Listed Ecosystem approach.As a result,Mountain Ash forests are at a high risk of ecosystem collapse.Further logging will increase that risk,making the basis for continued harvesting questionable.In addition,economic analyses suggest that the value of natural assets,like water production,far outweigh the value of the wood products harvested from the Mountain Ash ecosystem,again leading to questions about the viability of ongoing harvesting.We therefore conclude that whilst variable retention harvesting has the potential to contribute to biodiversity conservation in Mountain Ash展开更多
Forest management such as timber harvesting shapes fire regimes and landscape patterns, and these patterns often differ significantly from those under natural disturbances. Our objective was to examine the effects of ...Forest management such as timber harvesting shapes fire regimes and landscape patterns, and these patterns often differ significantly from those under natural disturbances. Our objective was to examine the effects of timber harvesting modes on fire regimes and landscape patterns in a boreal forest of Northeast China. We used a spatially explicit landscape model, LANDIS, to simulate the changes of forest landscape in the Huzhong forest region of the Great Khingan Mountains under no-cutting, clear-cutting, gradual-cutting and selective-cutting modes. Results showed that：（1） the fine fuel loadings generally decreased while the coarse fuel loadings increased with the increase of timber harvesting intensity;（2） the potential burn area significantly varied among different cutting modes, but the potential fire frequency had no obvious difference. Moreover, timber harvesting generally increased the potential fire risk;（3） clear-cutting mode significantly decreased the mean patch size and the aggregation of larch forests and increased the mean patch size and the aggregation of white birch forests. Therefore, clear-cutting mode should be abandoned, and selective-cutting mode be recommended for the sustainable forest management in the Great Khingan Mountains.展开更多
Aims Clear-cutting is a common forest management practice,especially in subtropical China.However,the potential ecological consequences of clear-cutting remain unclear.In particular,the effect of clear-cutting on soil...Aims Clear-cutting is a common forest management practice,especially in subtropical China.However,the potential ecological consequences of clear-cutting remain unclear.In particular,the effect of clear-cutting on soil processes,such as the carbon cycle,has not been quantified in subtropical forests.Here,we investigated the response of soil respiration(Rs)to clear-cutting during a 12-month period in a subtropical forest in eastern China.Methods We randomly selected four clear-cut(CC)plots and four corresponding undisturbed forest(UF)plots.Measurements of Rs were made at monthly time points and were combined with continuous climatic measurements in both CC and UF.Daily Rs was estimated by interpolating data with an exponential model dependent on soil temperature.Daily Rs was cumulated to annual Rs estimates.Important Findings In the first year after clear-cutting,annual estimates of Rs in CC(508±23g C m^(−2) yr^(−1))showed no significant difference to UF plots(480±12g C m^(−2) yr^(−1)).During the summer,soil temperatures were usually higher,whereas the soil volumetric water content was lower in CC than in UF plots.The long-term effects of clear-cutting on Rs are not significant,although there might be effects during the first several months after clear-cutting.Compared with previous work,this pattern was more pronounced in our subtropical forest than in the temperate and boreal forests that have been studied by others.With aboveground residuals off-site after clear-cutting,our results indicate that the stimulation of increasing root debris,as well as environmental changes,will not lead to a significant increase in Rs.In addition,long-term Rs will not show a significant decrease from the termination of root respiration,and this observation might be because of the influence of fast-growing vegetation after clear-cutting in situ.展开更多
In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic chara...In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has th展开更多
文摘Variable retention harvesting is a silvicultural system that focuses on retaining key elements of stand structure at the time of logging and is increasingly being used worldwide.We describe the design and establishment of a variable retention harvesting experiment established in the Mountain Ash(Eucalyptus regnans)forests of the Central Highlands of Victoria,south-eastern Australia.The experiment was instigated in 2003,and the work to date has shown that it has environmental benefits for certain groups of small mammals,birds,and vascular plants.The experiment has been integrated with an ongoing long-term monitoring program as well as other experiments such as those in post-fire salvage-logged areas.Collectively,the results of various studies suggest that the potential value of variable retention harvesting extends beyond green-tree logging to post-fire salvage logging environments.We outline some of the challenges in,and new perspectives derived from,implementing and maintaining our experiment.This included difficulties protecting islands from high-intensity post-harvest regeneration burns and threat of declining funding undermining ongoing project viability.A critically important perspective concerns the ecological and economic context in which variable retention harvesting is implemented.In the particular case of Mountain Ash forests,assessments using formal IUCN criteria classify the ecosystem as being Critically Endangered under the Red Listed Ecosystem approach.As a result,Mountain Ash forests are at a high risk of ecosystem collapse.Further logging will increase that risk,making the basis for continued harvesting questionable.In addition,economic analyses suggest that the value of natural assets,like water production,far outweigh the value of the wood products harvested from the Mountain Ash ecosystem,again leading to questions about the viability of ongoing harvesting.We therefore conclude that whilst variable retention harvesting has the potential to contribute to biodiversity conservation in Mountain Ash
基金supported by the National Natural Science Foundation of China (41201185, 31070422, 41271201)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050201)the Agricultural Science and Technology Research Projects Foundation of Shenyang (F13-146-3-00)
文摘Forest management such as timber harvesting shapes fire regimes and landscape patterns, and these patterns often differ significantly from those under natural disturbances. Our objective was to examine the effects of timber harvesting modes on fire regimes and landscape patterns in a boreal forest of Northeast China. We used a spatially explicit landscape model, LANDIS, to simulate the changes of forest landscape in the Huzhong forest region of the Great Khingan Mountains under no-cutting, clear-cutting, gradual-cutting and selective-cutting modes. Results showed that：（1） the fine fuel loadings generally decreased while the coarse fuel loadings increased with the increase of timber harvesting intensity;（2） the potential burn area significantly varied among different cutting modes, but the potential fire frequency had no obvious difference. Moreover, timber harvesting generally increased the potential fire risk;（3） clear-cutting mode significantly decreased the mean patch size and the aggregation of larch forests and increased the mean patch size and the aggregation of white birch forests. Therefore, clear-cutting mode should be abandoned, and selective-cutting mode be recommended for the sustainable forest management in the Great Khingan Mountains.
基金This study was supported by the EU 7th FP Project BACCARA(Contract No.226299)the MOST Sino-EU Cooperation Program(Contract No.Sino-EU 0916)the National Natural Science Foundation of China(Grant No.31025005 and 31021001).
文摘Aims Clear-cutting is a common forest management practice,especially in subtropical China.However,the potential ecological consequences of clear-cutting remain unclear.In particular,the effect of clear-cutting on soil processes,such as the carbon cycle,has not been quantified in subtropical forests.Here,we investigated the response of soil respiration(Rs)to clear-cutting during a 12-month period in a subtropical forest in eastern China.Methods We randomly selected four clear-cut(CC)plots and four corresponding undisturbed forest(UF)plots.Measurements of Rs were made at monthly time points and were combined with continuous climatic measurements in both CC and UF.Daily Rs was estimated by interpolating data with an exponential model dependent on soil temperature.Daily Rs was cumulated to annual Rs estimates.Important Findings In the first year after clear-cutting,annual estimates of Rs in CC(508±23g C m^(−2) yr^(−1))showed no significant difference to UF plots(480±12g C m^(−2) yr^(−1)).During the summer,soil temperatures were usually higher,whereas the soil volumetric water content was lower in CC than in UF plots.The long-term effects of clear-cutting on Rs are not significant,although there might be effects during the first several months after clear-cutting.Compared with previous work,this pattern was more pronounced in our subtropical forest than in the temperate and boreal forests that have been studied by others.With aboveground residuals off-site after clear-cutting,our results indicate that the stimulation of increasing root debris,as well as environmental changes,will not lead to a significant increase in Rs.In addition,long-term Rs will not show a significant decrease from the termination of root respiration,and this observation might be because of the influence of fast-growing vegetation after clear-cutting in situ.
基金supported by the National Key R&D Program of China (2017YFD0600501)the Fundamental Research Funds for the Central Universities of China (TD2011-08)
文摘In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has th
