Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within wate...Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within watersheds leads to varied hydrological responses across spatiotemporal scales,challenging comprehensive assessment of logging impacts at the watershed scale.Here,we developed multiple forest logging scenarios using the soil and water assessment tool(SWAT)model for the Le'an River watershed,a 5,837 km2 subtropical watershed in China,to quantify the hydrological effects of forest logging across different spatiotemporal scales.Our results demonstrate that increasing forest logging ratios from 1.54% to 9.25% consistently enhanced ecohydrological sensitivity.However,sensitivity varied across spatiotemporal scales,with the rainy season(15.30%-15.81%)showing higher sensitivity than annual(11.56%-12.07%)and dry season(3.38%-5.57%)periods.Additionally,the ecohydrological sensitivity of logging varied significantly across the watershed,with midstream areas exhibiting the highest sensitivity(13.13%-13.25%),followed by downstream(11.87%-11.98%)and upstream regions(9.96%-10.05%).Furthermore,the whole watershed exhibited greater hydrological resilience to logging compared to upstream areas,with attenuated runoff changes due to scale effects.Scale effects were more pronounced during dry seasons((-8.13 to -42.13)×10^(4) m^(3)·month^(-1))than in the rainy season((-11.11 to -26.65)×10^(4) m^(3)·month^(-1)).These findings advance understanding of logging impacts on hydrology across different spatiotemporal scales in subtropical regions,providing valuable insights for forest management under increasing anthropogenic activities and climate change.展开更多
Forest logging in the Congo Basin has led to forest fragmentation due to logging infrastructures and felling gaps. In the same vein, forest concessions in the Congo Basin have increasing interest in the REDD＋ mechani...Forest logging in the Congo Basin has led to forest fragmentation due to logging infrastructures and felling gaps. In the same vein, forest concessions in the Congo Basin have increasing interest in the REDD＋ mechanism. However, there is little information or field data on carbon emissions from forest degradation caused by logging. To help fill this gap, Landsat 7 and 8 and SPOT 4 images of the East Region of Cameroon were processed and combined with field measurements （measurement of forest roads widths, felling gaps and log yards） to assess all disturbed areas. Also, measurements of different types of forest infrastructures helped to highlight emission factors. Forest contributes to 5.18 % of the degradation of the annual allowable cut （AAC） （84.53 ha） corresponding to 4.09 % of forest carbon stock （6.92 t ha^-1）. Felling gaps constitute the primary source of degradation, represented an estimated area of 32.41 ha （2 % of the cutting area） far ahead of primary roads （18.44ha） and skid trails （16.36 ha）. Assessment of the impact of degradation under the canopy requires the use of high resolution satellite images and field surveys.展开更多
Understanding foraging strategies of birds is essential to understanding mechanisms of their community assembly. To provide such information on a key Southeast Asian rainforest family, the babblers （Timaliidae）, we ...Understanding foraging strategies of birds is essential to understanding mechanisms of their community assembly. To provide such information on a key Southeast Asian rainforest family, the babblers （Timaliidae）, we evaluated foraging behavior and abundance in 7 morphologically and behaviorally similar sympatric species （Cyanoderma erythropterum, C. rufifrons, Stachyris maculata, S. nigricollis, S. poliocephala, Macronus ptilosus, and Mixornis gularis） in 5 habitats defined by structural complexity： （1） continuous native rainforest, （2） logged native rainforest fragments, （3） mature industrial tree plantation, （4） young industrial plantation, and （5） oil palm plantation. Enough data were obtained to compare abundance in all 7 species and foraging behavior in 5. All species were common in forest fragments and mature industrial tree plantations and less so in continuous rainforest and young industrial plantations; only M. gularis occurred in oil palm. In terms of foraging, M. gularis was the greatest generalist; C. rufifrons foraged mainly on live leaves in the forest midstory; and S. maculata, C. eryth- ropterum, and M. ptilosus foraged mainly on dead leaves suspended in understory vegetation at sig- nificantly different heights. The dead-leaf substrate depends on a rich supply of falling leaves and ex- tensive understory structure, conditions most common in native forest and old industrial plantations, and less so in mature forest, young plantations, and oil palm. Because of the importance of foraging data to understanding and managing biodiversity, we encourage the development of foraging fields in eBird （ebird.org）, so that birdwatchers may help collect these relatively rare data.展开更多
Subalpine dark coniferous forests in the western Sichuan Province of China play an important role in the hydrological processes in the upper reaches of the Yangtze River. Second-growth forests, with different stand su...Subalpine dark coniferous forests in the western Sichuan Province of China play an important role in the hydrological processes in the upper reaches of the Yangtze River. Second-growth forests, with different stand successional stages, have developed as a result of logging over the past 50 years. Forest cover and stand structure changed greatly with concomitant degradation of forest ecosystem functions. To understand how the stand structures of the second-growth forests change during the stand succession process, we analyzed stand structure characteristics and an old-growth state index of the bamboo and moss-forest types. We found that stand structure at the young successional stage featured one-third of the structure characteristics of the old-growth dark coniferous forests,while the structure of the medium-aged stage had reached half the structure of the old-growth state. The two forest types were similar in the rate of development at the young successional stage but differed at the medium-aged stage;the moss-forest type had more advanced development than the bamboo-forest type at the medium-aged successional stage.展开更多
In a tropical wet montane evergreen forest in the southern peninsular India, the estimated stocking of dead wood is 90 ± 3 stems·ha-1 and the total dead wood volume is 70.7 m3·ha-1. When the logs (downe...In a tropical wet montane evergreen forest in the southern peninsular India, the estimated stocking of dead wood is 90 ± 3 stems·ha-1 and the total dead wood volume is 70.7 m3·ha-1. When the logs (downed dead trees more than 10.1 cm in diameter) constitute about 80% of the total deadwood stocking and volume, the rest is by snags (sound and rotting standing dead trees). Since the shola forest trees are characterized by their short stature with low to medium girth, about 89% of the total number of deadwood is of the size ranging from 10.1 cm to 40.0 cm in diameter. The estimated standing dead wood/standing live tree ratio is 0.16 indicating that the forest represents an old stand. Variations observed between logs and snags to change from a given decay class to the higher decay classes in two year period could be attributed to the facts that the logs would be in contact with soil for a relatively longer time and in turn would be in more contact with microorganisms and other decomposing agents.展开更多
Tropical forests have large carbon stocks and their conservation is a very important mitigation measure against global warming.However,this carbon pool is the most vulnerable to anthropogenic activities like selective...Tropical forests have large carbon stocks and their conservation is a very important mitigation measure against global warming.However,this carbon pool is the most vulnerable to anthropogenic activities like selective logging and little is known about its recovery.This study aimed to determine the carbon stock recovery after selectively logging using different allometric equations in six 1 ha permanent monitoring plots established in logged and unlogged forest types.Each 1 ha was divided into 25,20×20 m and the DBH of all trees≥2 cm was measured in 2005/2006 and re-measured in 2011/2012.The logged forests had the highest%change in the species richness indicating the impacts of logging.The presence of exploitable commercial trees in both forest types suggests their recruitment after logging.The insignificant difference in the AGB using different allometric equations is an indication that the Pan tropical equation is a good reference for the calculations of AGB in moist tropical forests.The 59.4%recovery rate in forests of 21 YAL indicates that 30 years is not enough for the recovery of the Carbon timber stock as the unlogged forests had a 77.7%.This calls for a review of forest management silvicultural activities for sustainable forest management.展开更多
基金supported by the National Natural Science Foundation of China(No.31660234).
文摘Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within watersheds leads to varied hydrological responses across spatiotemporal scales,challenging comprehensive assessment of logging impacts at the watershed scale.Here,we developed multiple forest logging scenarios using the soil and water assessment tool(SWAT)model for the Le'an River watershed,a 5,837 km2 subtropical watershed in China,to quantify the hydrological effects of forest logging across different spatiotemporal scales.Our results demonstrate that increasing forest logging ratios from 1.54% to 9.25% consistently enhanced ecohydrological sensitivity.However,sensitivity varied across spatiotemporal scales,with the rainy season(15.30%-15.81%)showing higher sensitivity than annual(11.56%-12.07%)and dry season(3.38%-5.57%)periods.Additionally,the ecohydrological sensitivity of logging varied significantly across the watershed,with midstream areas exhibiting the highest sensitivity(13.13%-13.25%),followed by downstream(11.87%-11.98%)and upstream regions(9.96%-10.05%).Furthermore,the whole watershed exhibited greater hydrological resilience to logging compared to upstream areas,with attenuated runoff changes due to scale effects.Scale effects were more pronounced during dry seasons((-8.13 to -42.13)×10^(4) m^(3)·month^(-1))than in the rainy season((-11.11 to -26.65)×10^(4) m^(3)·month^(-1)).These findings advance understanding of logging impacts on hydrology across different spatiotemporal scales in subtropical regions,providing valuable insights for forest management under increasing anthropogenic activities and climate change.
基金financially supported by FORAFAMA and COBAM project
文摘Forest logging in the Congo Basin has led to forest fragmentation due to logging infrastructures and felling gaps. In the same vein, forest concessions in the Congo Basin have increasing interest in the REDD＋ mechanism. However, there is little information or field data on carbon emissions from forest degradation caused by logging. To help fill this gap, Landsat 7 and 8 and SPOT 4 images of the East Region of Cameroon were processed and combined with field measurements （measurement of forest roads widths, felling gaps and log yards） to assess all disturbed areas. Also, measurements of different types of forest infrastructures helped to highlight emission factors. Forest contributes to 5.18 % of the degradation of the annual allowable cut （AAC） （84.53 ha） corresponding to 4.09 % of forest carbon stock （6.92 t ha^-1）. Felling gaps constitute the primary source of degradation, represented an estimated area of 32.41 ha （2 % of the cutting area） far ahead of primary roads （18.44ha） and skid trails （16.36 ha）. Assessment of the impact of degradation under the canopy requires the use of high resolution satellite images and field surveys.
文摘Understanding foraging strategies of birds is essential to understanding mechanisms of their community assembly. To provide such information on a key Southeast Asian rainforest family, the babblers （Timaliidae）, we evaluated foraging behavior and abundance in 7 morphologically and behaviorally similar sympatric species （Cyanoderma erythropterum, C. rufifrons, Stachyris maculata, S. nigricollis, S. poliocephala, Macronus ptilosus, and Mixornis gularis） in 5 habitats defined by structural complexity： （1） continuous native rainforest, （2） logged native rainforest fragments, （3） mature industrial tree plantation, （4） young industrial plantation, and （5） oil palm plantation. Enough data were obtained to compare abundance in all 7 species and foraging behavior in 5. All species were common in forest fragments and mature industrial tree plantations and less so in continuous rainforest and young industrial plantations; only M. gularis occurred in oil palm. In terms of foraging, M. gularis was the greatest generalist; C. rufifrons foraged mainly on live leaves in the forest midstory; and S. maculata, C. eryth- ropterum, and M. ptilosus foraged mainly on dead leaves suspended in understory vegetation at sig- nificantly different heights. The dead-leaf substrate depends on a rich supply of falling leaves and ex- tensive understory structure, conditions most common in native forest and old industrial plantations, and less so in mature forest, young plantations, and oil palm. Because of the importance of foraging data to understanding and managing biodiversity, we encourage the development of foraging fields in eBird （ebird.org）, so that birdwatchers may help collect these relatively rare data.
基金supported by the grants from the Chinese National Natural Science Foundation(31160156)the Ministry of Science and Technology(2006BAD03A042012BAD22B01)
文摘Subalpine dark coniferous forests in the western Sichuan Province of China play an important role in the hydrological processes in the upper reaches of the Yangtze River. Second-growth forests, with different stand successional stages, have developed as a result of logging over the past 50 years. Forest cover and stand structure changed greatly with concomitant degradation of forest ecosystem functions. To understand how the stand structures of the second-growth forests change during the stand succession process, we analyzed stand structure characteristics and an old-growth state index of the bamboo and moss-forest types. We found that stand structure at the young successional stage featured one-third of the structure characteristics of the old-growth dark coniferous forests,while the structure of the medium-aged stage had reached half the structure of the old-growth state. The two forest types were similar in the rate of development at the young successional stage but differed at the medium-aged stage;the moss-forest type had more advanced development than the bamboo-forest type at the medium-aged successional stage.
文摘In a tropical wet montane evergreen forest in the southern peninsular India, the estimated stocking of dead wood is 90 ± 3 stems·ha-1 and the total dead wood volume is 70.7 m3·ha-1. When the logs (downed dead trees more than 10.1 cm in diameter) constitute about 80% of the total deadwood stocking and volume, the rest is by snags (sound and rotting standing dead trees). Since the shola forest trees are characterized by their short stature with low to medium girth, about 89% of the total number of deadwood is of the size ranging from 10.1 cm to 40.0 cm in diameter. The estimated standing dead wood/standing live tree ratio is 0.16 indicating that the forest represents an old stand. Variations observed between logs and snags to change from a given decay class to the higher decay classes in two year period could be attributed to the facts that the logs would be in contact with soil for a relatively longer time and in turn would be in more contact with microorganisms and other decomposing agents.
基金supported by the International Tropical Timber Organisation(ITTO)grantthe equipment grant was provided by IDEA WILD+2 种基金the Carnegie Corporation of New York through the Future Africa Research Leadership(FAR-LeaF)grant of the University of Pretoriasupported the fieldwork and data analyses,the mobility grant and research modernization allowance of the Ministry of Higher Education(MINESUP)Cameroonthe Fako America Scholarship.
文摘Tropical forests have large carbon stocks and their conservation is a very important mitigation measure against global warming.However,this carbon pool is the most vulnerable to anthropogenic activities like selective logging and little is known about its recovery.This study aimed to determine the carbon stock recovery after selectively logging using different allometric equations in six 1 ha permanent monitoring plots established in logged and unlogged forest types.Each 1 ha was divided into 25,20×20 m and the DBH of all trees≥2 cm was measured in 2005/2006 and re-measured in 2011/2012.The logged forests had the highest%change in the species richness indicating the impacts of logging.The presence of exploitable commercial trees in both forest types suggests their recruitment after logging.The insignificant difference in the AGB using different allometric equations is an indication that the Pan tropical equation is a good reference for the calculations of AGB in moist tropical forests.The 59.4%recovery rate in forests of 21 YAL indicates that 30 years is not enough for the recovery of the Carbon timber stock as the unlogged forests had a 77.7%.This calls for a review of forest management silvicultural activities for sustainable forest management.
