With the rapid economic development and continuous expansion of human activities,forest degradation—characterized by reduced forest stock within the forest including declining carbon storage—poses significant threat...With the rapid economic development and continuous expansion of human activities,forest degradation—characterized by reduced forest stock within the forest including declining carbon storage—poses significant threats to ecosystem stability.Understanding the current status of forest degradation and assessing potential carbon stocks in China are of strategic importance for making forest restoration efforts and enhancing carbon sequestration capacity.In this study,we used the national forest inventory data from 2009 to 2018 to develop a set of standard measures for assessing degraded forests across China,based on five key indicators:forest accumulation growth rate(FAGR),forest recruitment rate(FRR),tree species reduction rate(TSRR),forest canopy cover reduction rate(FCCRR),and forest disaster level(FDL).Additionally,we estimated standing carbon stock,potential carbon stock,and theoretical space to grow by developing a stand growth model,which accounts for stand density across different site classes,to evaluate the restoration potential of degraded forests.The results indicate that degraded forest area in China is 36.15 million hectares,accounting for 20.10% of a total forest area.Standing carbon stock and potential carbon stock of degraded forests in China are 23.93 million tons and 61.90 million tons,respectively.Overall,degraded forest varies significantly across different regions.The results highlight the important trade-offs among environmental factors,policy decisions,and forest conditions,providing a robust foundation for developing measures to enhance forest quality.展开更多
The Tibetan forest is one of the most important national forest zones in China. Despite the potentially important role that Tibetan forest will play in the Earth?s future carbon balance and climate regulation, few all...The Tibetan forest is one of the most important national forest zones in China. Despite the potentially important role that Tibetan forest will play in the Earth?s future carbon balance and climate regulation, few allometric equations exist for accurately estimating biomass and carbon budgets of this forest. In the present study, allometric equations,both species-specific and generic, were developed relating component biomass(DW) to diameter at breast height(DBH) and tree height(H) for six most common tree species in Tibetan forest. The 6 species were Abies georgei Orr., Picea spinulosa(Griff.)Henry, Pinus densata Mast., Pinus yunnanensis Franch., Cypresses funebris Endl. and Quercus semecarpifilia Smith.. The results showed that, both DBH-only and DBH2 H based species-specific equations showed a significant fit(P<0.05) for all tree species and biomass components. The DBH-only equations explained more than 80% variability of the component biomass and total biomass, adding H as a second independent variable increased the goodness of fit, while incorporating H into the term DBH2 H decreased the goodness of fit. However, not all DBH-H combined equations showed a significant fit(P<0.05) for all tree species and biomass components. Hence, the suggested species-specific allometric equations for the six most common tree species are of the form ln(DW) = c + αln(DBH). The generalized equations of mixed coniferous component biomass against DBH, DBH2 H and DBH-H also showed a significant fit(P<0.05) for all biomass components. However, due to significant species effect, the relative errors of the estimates were very high. Hence, generalized equations should only be used when there are too many different tree species, or there is no species-specific model of the same species or similar growth form in adjacent area.展开更多
Evaluating forest ecosystem services(FES)is crucial for comprehensively recognizing forest value and for formulating targeted forest management plans.However,hurdles persist in traditional FES evaluations that are bas...Evaluating forest ecosystem services(FES)is crucial for comprehensively recognizing forest value and for formulating targeted forest management plans.However,hurdles persist in traditional FES evaluations that are based on conventional data(e.g.,statistical yearbooks and survey data),such as a coarse evaluation scale and difficulty in formulating refined and spatially continuous evaluation results.Forest canopy cover,canopy height,and forest aboveground biomass(AGB)are the core fundamental inputs of a robust FES evaluation.Their accuracy and degree of refinement will influence the final evaluation results obtained.To overcome the above issues,this study first explored accurate estimation methods for all 3 parameters above and then evaluated FES multidimensionally,by using these results combined with other remote sensing products and applying various principles and algorithms.Our results show that a high estimation accuracy(>80%)of the 3 key parameters is achievable for coniferous to broad-leaved forest stands and that FES evaluation results are obtainable with a high resolution and spatial continuity.The service functions,such as nutrient retention,carbon sequestration and oxygen release,and product supply are stronger while others relatively are weaker.It is worth noting that carbon storage by the AGB carbon pool surpasses that of other carbon pools.Finally,the potential of FES varies according to forest type.Compared with broad-leaved forest,coniferous forest has a greater capacity for product supply,windbreak,and sand fixation services.This study offers a methodological reference for the formulation of policies related to the paid use of FES.展开更多
Accurate quantification of tree populations within regions is critical for evaluating forest ecosystem conditions and developing effective forest management strategies[1].High-quality tree census data,collected throug...Accurate quantification of tree populations within regions is critical for evaluating forest ecosystem conditions and developing effective forest management strategies[1].High-quality tree census data,collected through field surveys and remote sensing technologies,is fundamental to China's sustainable development and environmental conservation initiatives.This data facilitates the monitoring of forest structural changes,carbon sequestration dynamics,and ecosystem health evaluations.Notably,China maintains the world's largest managed forest area,achieved through comprehensive national afforestation and reforestation programs[2,3].Consequently,precise tree enumeration is crucial for formulating effective forest management policies,monitoring and protecting wildlife habitats,and preventing natural disasters in China.展开更多
基金supported by National Key Research and Development Program of China(No.2021YFD2200405(S.R.L.))Natural Science Foundation of China(Grant No.31971653).
文摘With the rapid economic development and continuous expansion of human activities,forest degradation—characterized by reduced forest stock within the forest including declining carbon storage—poses significant threats to ecosystem stability.Understanding the current status of forest degradation and assessing potential carbon stocks in China are of strategic importance for making forest restoration efforts and enhancing carbon sequestration capacity.In this study,we used the national forest inventory data from 2009 to 2018 to develop a set of standard measures for assessing degraded forests across China,based on five key indicators:forest accumulation growth rate(FAGR),forest recruitment rate(FRR),tree species reduction rate(TSRR),forest canopy cover reduction rate(FCCRR),and forest disaster level(FDL).Additionally,we estimated standing carbon stock,potential carbon stock,and theoretical space to grow by developing a stand growth model,which accounts for stand density across different site classes,to evaluate the restoration potential of degraded forests.The results indicate that degraded forest area in China is 36.15 million hectares,accounting for 20.10% of a total forest area.Standing carbon stock and potential carbon stock of degraded forests in China are 23.93 million tons and 61.90 million tons,respectively.Overall,degraded forest varies significantly across different regions.The results highlight the important trade-offs among environmental factors,policy decisions,and forest conditions,providing a robust foundation for developing measures to enhance forest quality.
基金supported by the “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant No. XDA05050207)the National Natural Science Foundation of China (Grant No. 31300416)
文摘The Tibetan forest is one of the most important national forest zones in China. Despite the potentially important role that Tibetan forest will play in the Earth?s future carbon balance and climate regulation, few allometric equations exist for accurately estimating biomass and carbon budgets of this forest. In the present study, allometric equations,both species-specific and generic, were developed relating component biomass(DW) to diameter at breast height(DBH) and tree height(H) for six most common tree species in Tibetan forest. The 6 species were Abies georgei Orr., Picea spinulosa(Griff.)Henry, Pinus densata Mast., Pinus yunnanensis Franch., Cypresses funebris Endl. and Quercus semecarpifilia Smith.. The results showed that, both DBH-only and DBH2 H based species-specific equations showed a significant fit(P<0.05) for all tree species and biomass components. The DBH-only equations explained more than 80% variability of the component biomass and total biomass, adding H as a second independent variable increased the goodness of fit, while incorporating H into the term DBH2 H decreased the goodness of fit. However, not all DBH-H combined equations showed a significant fit(P<0.05) for all tree species and biomass components. Hence, the suggested species-specific allometric equations for the six most common tree species are of the form ln(DW) = c + αln(DBH). The generalized equations of mixed coniferous component biomass against DBH, DBH2 H and DBH-H also showed a significant fit(P<0.05) for all biomass components. However, due to significant species effect, the relative errors of the estimates were very high. Hence, generalized equations should only be used when there are too many different tree species, or there is no species-specific model of the same species or similar growth form in adjacent area.
基金funded by the Fundamental Research Funds for the Central Non-profit Research Institution of CAF,grant number"CAFYBB2019ZB004"the National Science and Technology Major Project of China’s High Resolution Earth Observation System,grant number"21-Y30B02-9001-19/22-3"+1 种基金the ESA-MOST China Dragon 5 Cooperation,grant number"59313"the special fund for Science and Technology Innovation Teams of Shanxi Province,grant number"202204051001010"
文摘Evaluating forest ecosystem services(FES)is crucial for comprehensively recognizing forest value and for formulating targeted forest management plans.However,hurdles persist in traditional FES evaluations that are based on conventional data(e.g.,statistical yearbooks and survey data),such as a coarse evaluation scale and difficulty in formulating refined and spatially continuous evaluation results.Forest canopy cover,canopy height,and forest aboveground biomass(AGB)are the core fundamental inputs of a robust FES evaluation.Their accuracy and degree of refinement will influence the final evaluation results obtained.To overcome the above issues,this study first explored accurate estimation methods for all 3 parameters above and then evaluated FES multidimensionally,by using these results combined with other remote sensing products and applying various principles and algorithms.Our results show that a high estimation accuracy(>80%)of the 3 key parameters is achievable for coniferous to broad-leaved forest stands and that FES evaluation results are obtainable with a high resolution and spatial continuity.The service functions,such as nutrient retention,carbon sequestration and oxygen release,and product supply are stronger while others relatively are weaker.It is worth noting that carbon storage by the AGB carbon pool surpasses that of other carbon pools.Finally,the potential of FES varies according to forest type.Compared with broad-leaved forest,coniferous forest has a greater capacity for product supply,windbreak,and sand fixation services.This study offers a methodological reference for the formulation of policies related to the paid use of FES.
基金supported by the National Key Research and Development Program of China(2022YFF1300203)the National Natural Science Foundation of China(42371329 and 32301285)。
文摘Accurate quantification of tree populations within regions is critical for evaluating forest ecosystem conditions and developing effective forest management strategies[1].High-quality tree census data,collected through field surveys and remote sensing technologies,is fundamental to China's sustainable development and environmental conservation initiatives.This data facilitates the monitoring of forest structural changes,carbon sequestration dynamics,and ecosystem health evaluations.Notably,China maintains the world's largest managed forest area,achieved through comprehensive national afforestation and reforestation programs[2,3].Consequently,precise tree enumeration is crucial for formulating effective forest management policies,monitoring and protecting wildlife habitats,and preventing natural disasters in China.
