[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promo...[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promote the development of green low-carbon economy in China.[Methods]Based on the data of six forest resource inventories from 1989 to 2018 and related studies,the comprehensive evaluation model of forest carbon sink and forestry economic development,the coupling degree model of forest carbon sink and forestry economic development,and the coupling coordination degree model of forest carbon sink and forestry economic development were adopted.The coupling degree of forest carbon sink and forestry economic development from 1992 to 2018 was analyzed.Stepwise regression and ARIMA model were used to analyze the influencing factors and lagging characteristics of forest carbon sink.The coupling degree between forest carbon sink and forestry economic development in China from 2019 to 2030 was predicted by autoregression and ADF test.The coupling between forest carbon sink and forestry economic development in China and its long-term change characteristics were also discussed in this study.[Results](i)The investment of ecological construction and protection,the actual investment of forestry key ecological projects,GDP and the import of forest products had a significant impact on forest resources carbon stock.The total output value of forestry industry,the actually completed investment of forestry key ecological projects and the export volume of forest products had a significant impact on the forest carbon sink,and the actually completed investment of forestry key ecological projects has the greatest impact on the two.(ii)The impact of actually completed investment of forestry key ecological projects had a lag of 2 years on the forest resources carbon stock and a lag of 1 year on the forest carbon sink.When investing in forest carbon sink,it is necessary to make a good plan in advance,and do a good job in forest resources management and time optimization.(iii)From 1992 to 2018,the coupling degree of forest resources carbon stock,forest carbon sink and long-term development of forestry economy in China was gradually increasing.Although there were some fluctuations in the middle time,the coupling degree of forest resources carbon stock and the long-term development of forestry economy increased by 9.24%annually,and the degree of coupling coordination increased from"serious imbalance"in 1992 to"high-quality coordination"in 2018.From 1993 to 2018,the coupling degree of forest carbon sink and long-term development of forestry economy increased by 9.63%annually,slightly faster than the coupling coordination degree of forest resources carbon stock and long-term development of forestry economy.The coordination level also rose from level 2 in 1993 to level 10 in 2018.(iv)The prediction shows that the coupling coordination degree of forest resources carbon stock,forest carbon sink and the long-term development of forestry economy would increase from 2019 to 2030.The coupling coordination degree(D)values of both were close to 1,the coordination level was also 10 for a long time,and the degree of coupling coordination was also maintained at the"high-quality coordination"level for a long time.[Conclusions]Forest has multiple benefits of society,economy and ecology,and forest carbon sink is only a benefit output.The long-term coupling analysis of forest carbon sink and forestry economic development is a key point to multiple benefit analysis.The analysis shows that the spillover effect and co-evolution effect of forest carbon sink in China are significant.From 1992 to 2018,the coupling coordination degree of forest carbon sink and forestry economic development was gradually rising.The prediction analysis also indicate that the coupling coordination degree between the forest carbon sink and the long-term development of forestry economy will remain at the level of"high-quality coordination"for a long time from 2019 to 2030.Therefore,improving the level of forest management and maintaining the current trend of increasing forest resources are the key to achieving the goal of carbon peaking and carbon neutrality in China.展开更多
The Natural Forest Protection Program(NFPP)is one of the key ecological forestry programs in China.It not only facilitates the improvement of forest ecological quality in NFPP areas,but also plays a significant role i...The Natural Forest Protection Program(NFPP)is one of the key ecological forestry programs in China.It not only facilitates the improvement of forest ecological quality in NFPP areas,but also plays a significant role in increasing the carbon storage of forest ecosystems.The program covers 17 provinces,autonomous regions,and municipalities with correspondingly diverse forest resources and environments,ecological features,engineering measures and forest management regimes,all of which affect regional carbon storage.In this study,volume of timber harvest,tending area,pest-infested forest,firedamaged forest,reforestation,and average annual precipitation,and temperature were evaluated as factors that influence carbon storage.We developed a vector autoregression model for these seven indicators and we studied the dominant factors of carbon storage in the areas covered by NFPP.Timber harvest was the dominant factorinfluencing carbon storage in the Yellow and Yangtze River basins.Reforestation contributed most to carbon storage in the state-owned forest region in Xinjiang.In state-owned forest regions of Heilongjiang and Jilin Provinces,the dominant factors were forest fires and forest cultivation,respectively.For the enhancement of carbon sequestration capacity,a longer rotation period and a smaller timber harvest are recommended for the Yellow and Yangtze River basins.Trees should be planted in stateowned forests in Xinjiang.Forest fires should be prevented in state-owned forests in Heilongjiang,and greater forest tending efforts should be made in the state-owned forests in Jilin.展开更多
The interannual variation characteristics of NPP and carbon emission of Liaoning forest in recent 50 years (from 1961 to 2008) were analyzed based on the hydrothermal optimized NPP model and soil respiration Q10 model...The interannual variation characteristics of NPP and carbon emission of Liaoning forest in recent 50 years (from 1961 to 2008) were analyzed based on the hydrothermal optimized NPP model and soil respiration Q10 model.The results showed that the total amount of annual NPP was increased in recent 50 years,in which the amount of NPP (83.9 Mt) in 2008 was 2.8 times as high as that in 1961.Amount of NPP per unit area changed with different years,and the maximum value was 36.5% more than the minimum one.The net carbon budget of Liaoning forest was carbon sink,with annual 2.1 t CO2/hm2.展开更多
Forest carbon offset(FCO)projects play an increasingly important role in mitigating climate change through market mechanisms in both compliance and voluntary markets.However,there are challenges and barriers to develo...Forest carbon offset(FCO)projects play an increasingly important role in mitigating climate change through market mechanisms in both compliance and voluntary markets.However,there are challenges and barriers to developing an FCO project,such as carbon leakage and cost-eff ectiveness.There have been few attempts to summarize and synthesize all types and aspects of existing challenges and possible solutions for FCO projects.This paper systematically reviews and discusses the current challenges involved in developing FCO projects,and then draws on the experience and lessons of existing projects to show how those challenges were addressed in world-leading voluntary carbon standards,namely the Verifi ed Carbon Standard,the American Carbon Registry,the Climate Action Reserve,and Plan Vivo.These voluntary markets have rich experience in FCO projects and are responsible for a signifi cant share of the market.From the 53 publications used in this analysis,three broad thematic categories of challenges emerged.These were related to methodology,socio-economic implications,and implementation.Methodological challenges,particularly additionality,permanence,and leakage,were the focus of 46%of the selected research papers,while socio-economic challenges,including transaction,social,and opportunity costs,were addressed by 35%.The remaining 19%of the research articles focused on implementational challenges related to monitoring,reporting,and verifi cation.Major voluntary standards adequately addressed most of the methodological and implementational barriers by adopting various approaches.However,the standards did not adequately address socio-economic issues,despite these being the second most frequently discussed theme in the papers analyzed.More research is clearly needed on the socio-economic challenges involved in the development of FCO projects.For the development of high-quality forestry carbon off set projects,there are many challenges and no simple,universal recipe for addressing them.However,it is crucial to build upon the current science and move forward with carbon projects which ensure eff ective,long-term carbon sinks and maximize benefi ts for biodiversity and people;this is particularly important with a growing public and private interest in this fi eld.展开更多
Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in ...Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in economic environment and practical experience,weaknesses in social participation,project scale and carbon sink talents,opportunities in international climate environment,domestic policies,etc.,and threats in project crediting period and forest resource protection,etc.In view of these,Yunnan Province can change the participation mode of forest carbon sink projects,adopt appropriate trading methods,get familiar with the relevant rules of forest carbon sink projects,strengthen the publicity and research of forest carbon sink theory,strengthen the management of carbon sink forests and expand forest carbon sink projects to enhance the market competitiveness of the Yunnan forest carbon sink projects.展开更多
The paper analyzes the basis of forest carbon trade including the feasibility of carbon absorption trade,main body,platform and standard.The purposes of capital of carbon absorption trade is introduced.Caron absorptio...The paper analyzes the basis of forest carbon trade including the feasibility of carbon absorption trade,main body,platform and standard.The purposes of capital of carbon absorption trade is introduced.Caron absorption trade capital can be used to resettle ecological migrants,absorb employment,build forest and increase fund,increase local income,enhance forest science and technology development and launch environmental proportion.The perspective of developing forest carbon absorption trade is pointed out and the practical problems of developing forest carbon trade need to be solved.For example,the property problem of forest resources,value calculation problem of forest resources and sustainable development of forest.展开更多
Community forest management helps in mitigating deforestation and forest degradation by addressing the negative aspects of rural livelihoods such as poverty and social exclusion.It is important in regulating global cl...Community forest management helps in mitigating deforestation and forest degradation by addressing the negative aspects of rural livelihoods such as poverty and social exclusion.It is important in regulating global climate by encouraging sequestration of carbon in shoots,roots and soils.We studied the status of community forest management,forest resource harvest and carbon stocks in two community forests of the mid hill region of central and western Nepal.The study was based on primary and secondary data collected through carbon stock measurement from field visits and allometric equations,household surveys,focus group discussions,key informant interviews,and review of past studies.Socioeconomic variables such as gender,age group,livestock and landholding status were related to resource utilization,conservation,and management of community forest.Forest resources such as timber,firewood,fodder and leaf litter were harvested in sustainable ways.People were involved in forest thinning,co-management meetings,guarding and planting trees for forest conservation and management.Density and carbon stock of trees increased gradually in comparison to a previous study.We recommend further research on other community forests for more accurate and better results.展开更多
Accurate estimation of forest carbon storage is crucial in understanding global and regional carbon cycles and projecting future ecological and economic scenarios.Guizhou is the largest karst landform province in Chin...Accurate estimation of forest carbon storage is crucial in understanding global and regional carbon cycles and projecting future ecological and economic scenarios.Guizhou is the largest karst landform province in China;61.9% of its land area is characterized as karst. However,monitoring its field biomass and carbon storage is difficult.This study synthesized and analyzed a comprehensive database of direct field observations of forest vegetation and soil carbon storage in Guizhou Province by using data from existing literature. The total vegetation carbon storage in Guizhou Province was 488.170 TgC, the average vegetation carbon density(VCD) was 27.866 MgC hm^(-2), the total amount of soil organic carbon(SOC)(20 cm) was 1017.364 TgC, and the average SOC density was 58.074 MgC hm^(-2). Among all vegetation types, needleleaf forest had the highest vegetation carbon stocks, and scrub presented the highest SOC storage. The vegetation and SOC storage values of the karst landform were 282.352 and 614.825 TgC, respectively, which were higher than thoseof the non-karst landform. VCD was concentrated at 10–40 MgC hm^(-2), and SOC density was concentrated at 40–60, 60–80, and 80–100 MgC hm^(-2). This comprehensive regional data synthesis and analysis based on direct field measurement of vegetation and soil will improve our understanding of the forest carbon cycle in karst landforms under a changing climate.展开更多
Through designing questionnaires for farmers in the project area,the understanding and utilization of carbon sink forests were surveyed. In the form of stratified sampling,150 representative forest farmers were select...Through designing questionnaires for farmers in the project area,the understanding and utilization of carbon sink forests were surveyed. In the form of stratified sampling,150 representative forest farmers were selected from the project area. Through the survey,it found that many factors hindered the progress of forest carbon sequestration project in Guangdong Province. Besides,the implementation of this project was influenced by both natural and social factors. As to the natural factors,natural disasters for the forest carbon sequestration project in Guangdong Province mainly include typhoons,rainstorms,landslides and mudslides. The social factors of the forest carbon sequestration project in Guangdong Province mainly include the weak willingness of forest farmers to participate,the low awareness of forest farmers for forest carbon sinks,the single and insufficient source of afforestation funds,and the single afforestation model. In order to better implement the forest carbon sequestration project,Guangdong Province can take measures such as strengthening the publicity on forest carbon sinks,expanding channels of funds,organizing forest carbon exchange training courses,and diversifying the afforestation models.展开更多
This paper investigates modalities required to design and implement community monitoring of forest carbon stock changes and safeguards implementation in Kenya. General principles and elements were drawn from the UNFCC...This paper investigates modalities required to design and implement community monitoring of forest carbon stock changes and safeguards implementation in Kenya. General principles and elements were drawn from the UNFCCC REDD+ policy frameworks for developing modalities and procedures for designing community forest monitoring system. The paper utilised policy analysis approach used to derive monitoring goals and objectives by assessing the compatibility of Kenya’s policy and legislative framework with monitoring elements provided in the UNFCCC REDD+ policy mechanism. The elements included monitoring goals, objectives, questions, indicators, and methods and tools. Two goals were identified which included, reduction of forest carbon emissions (ER) and monitoring of multiple social and environmental safeguards (SG). Five ER related objectives were identified to include: forest reference emission levels or forest reference levels, drivers of deforestation and forest degradation, Land use activities, eligible ER actions and estimation of forest emissions. Six objectives guiding SG were identified to include: policy, governance, human rights, socio-economic, biodiversity and environmental concerns. Corresponding questions to the goals and objectives were systematically designed. In turns, indicators, depicting quantitative and qualitative measurements, which best provided answers to questions were identified. The various methods and tools used by communities around the world in providing data and information required to satisfy the indictors were identified through literature review. The review identified four methods and tools that included: Remote Sensing and GIS, GPS survey, smartphone survey and Ground trothing. Smartphone and cloud-based server technology were found to be the recent emergent tools in aiding community monitoring of REDD+ projects. The paper argues that local communities and indigenous peoples have the capability and capacity to monitor and undertake forest carbon monitoring and tracking of implementation of safeguards if supported with relevant training;compensated for the time, labour and knowledge they contribute to the process;provided with feedback and involved decision making process.展开更多
Based on the sub-forest management inventory, volume-derived biomass and mean biomass, carbon storage and its spatial distribution of forest vegetation in Kanas National Nature Reserve(hereinafter referred to as the R...Based on the sub-forest management inventory, volume-derived biomass and mean biomass, carbon storage and its spatial distribution of forest vegetation in Kanas National Nature Reserve(hereinafter referred to as the Reserve) were calculated. The results showed that carbon storage of forest vegetation in the Reserve was 3.004 7 Tg C, mean carbon density was 49.58 Mg C/hm^2; carbon storage of different vegetation types: forest land >shrubbery > open forest > scattered trees, among which carbon storage of forest land accounted for 90.18% of the total carbon storage of the forest vegetation, and mean carbon density of forest land was 68.87 Mg C/hm^2; in terms of regional distribution, spatial distribution of carbon storage and carbon density declined from southwest to northeast; in the Reserve, carbon storage of mature and over-mature forest stands accounted for 79.89% of carbon storage of forest land. If scientifi c management is applied, carbon sequestration capacity of forest will be improved.展开更多
Background： Forests are a key component of the global carbon cycle, and research is needed into the effects of human-driven and natural processes on their carbon pools. Airborne laser scanning （ALS） produces detail...Background： Forests are a key component of the global carbon cycle, and research is needed into the effects of human-driven and natural processes on their carbon pools. Airborne laser scanning （ALS） produces detailed 3D maps of forest canopy structure from which aboveground carbon density can be estimated. Working with a ALS dataset collected over the 8049-km2 Wellington Region of New Zealand we create maps of indigenous forest carbon and evaluate the influence of wind by examining how carbon storage varies with aspect. Storms flowing from the west are a common cause of disturbance in this region, and we hypothesised that west-facing forests exposed to these winds would be shorter than those in sheltered east-facing sites. Methods： The aboveground carbon density of 31 forest inventory plots located within the ALS survey region were used to develop estimation models relating carbon density to ALS information. Power-law models using rasters of top-of-the-canopy height were compared with models using tree-level information extracted from the ALS dataset. A forest carbon map with spatial resolution of 25 m was generated from ALS maps of forest height and the estimation models. The map was used to evaluate the influences of wind on forests. Results： Power-law models were slightly less accurate than tree-centric models （RMSE 35% vs 32%） but were selected for map generation for computational efficiency. The carbon map comprised 4.5 million natural forest pixels within which canopy height had been measured by ALS, providing an unprecedented dataset with which to examine drivers of carbon density. Forests facing in the direction of westerly storms stored less carbon, as hypothesised. They had much greater above-ground carbon density for a given height than any of 14 tropical forests previously analysed by the same approach, and had exceptionally high basal areas for their height. We speculate that strong winds have kept forests short without impeding basal area growth. Conclusion： Simple estimation models based on top-of-the canopy height are almost as accurate as state-of-the-art tree-centric approaches, which require more computing power. High-resolution carbon maps produced by ALS provide powerful datasets for evaluating the environmental drivers of forest structure, such as wind.展开更多
Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear...Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha<sup>−</sup><sup>1</sup>. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha<sup>−</sup><sup>1</sup>) than upper layers (55.42 ± 25.37 MgC ha<sup>−</sup><sup>1</sup>). The study highlights that low deforestation rate have led to less CO<sub>2</sub> (705.3 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup> - 922.62 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup>) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha<sup>−</sup><sup>1</sup>) than primary (20.33 ± 12.7 MgC ha<sup>−</sup><sup>1</sup>), savanna and cropland (21.71 ± 15.10 MgC ha<sup>−</sup><sup>1</sup>). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.展开更多
In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was construc...In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was constructed to evaluate the carbon emission risks of the construction industry in Hebei Province,China from 2005 to 2020.The results are shown as follows:(1)The overall carbon emissions of the construction industry in Hebei Province of China showed an inverted"V"-shaped evolution trend during the past 16 years.Tangshan and Shijiazhuang maintained high carbon emissions,while Langfang,Hengshui and Baoding saw rapid increases in carbon emissions.(2)The environmental safety threshold of carbon emission from the construction industry in Hebei Province,China,has been continuously improved,and the provincial environmental safety threshold is between 9475080-23144760 tons;The environmental safety threshold was the highest in Baoding and Langfang,and the lowest in Xingtai.(3)In the past 16 years,the carbon emission risk of the construction industry in Hebei Province of China has been in a state of extremely serious risk,and the risk index generally presents an inverted"V"type trend.(4)The carbon emission risk of Hebei city in China presents a spatial pattern of"high in the south and low in the north",which goes through two stages:risk increase period and risk reduction period.展开更多
In most Sub-Saharan African countries such as Togo, people’s heavy dependence on ecosystem services is a major factor in accelerating the degradation of natural resources, which are already suffering as a result of c...In most Sub-Saharan African countries such as Togo, people’s heavy dependence on ecosystem services is a major factor in accelerating the degradation of natural resources, which are already suffering as a result of climatic factors. This study was initiated to contribute to the sustainable and rational management of forest resources in the south-east of the Mono Biosphere Reserve in Togo. It specifically aims to identify and characterize the flora of the residual forest ecosystems within the reserve through their specific diversity, demographic structure, and carbon sequestration potential. The study was carried out in the forest ecosystems of Avévé. The methodology used was based on the analysis of phytosociological, forestry, ecological, and regeneration inventory data. Overall, the study revealed that the RBMT still has floristically viable habitats, despite the anthropogenic pressures it is subject to revealed a floristic diversity of 160 plant species divided into 52 families and 135 genera. The most represented families are Rubiaceae (29.09%), followed by Fabaceae (27.94%). The most represented species are Mitragyna inermis (Willd.) Kuntze (24.38%), Lecaniodiscus cupanioides Planch. Ex Benth (X) and Lonchocarpus sericeus (Poir.) Kunth (10.93%). The high presence of Mitragyna inermis observed in all the ecological groups identified makes it the characteristic species of the flooded marshy areas of southeast Togo and contributes to the resilience of the ecosystems and populations in the study area. The Shannon index for the formation groups varies between (3.03 and 5.16) bits. Pielou’s equitability varies between (0.43 and 0.63) bits. The overall average density is estimated at 210 stems/ha, with an average diameter of 25.57 ± 21.77 m and an average height of 7.93 ± 3.83 m. The adjustment of the diameter classes of the plant groups to the Weibull distribution gave an “inverted J” shape with coefficient values of less than 1 overall, reflecting the existence of multispecific or uneven-aged stands. Assessment of the horizontal and vertical structure shows a predominance of the shrub layer in all the groups identified. The carbon sequestration potential is 41.89 T/Ha. Despite ongoing anthropogenic pressures, the Mono Biosphere Reserve abounds in a relatively rich diversity of flora, the preservation of which is essential for the survival of biodiversity and even for the riparian population. The data provided by this study would form the basis for sustainable management planning of the forest islands in the biosphere reserve.展开更多
Background: In recent decades the future of global forests has been a matter of increasing concern, particularly in relation to the threat of forest ecosystem responses under potential climate change. To the future pr...Background: In recent decades the future of global forests has been a matter of increasing concern, particularly in relation to the threat of forest ecosystem responses under potential climate change. To the future predictions of these responses, the current forest biomass carbon storage(FCS) should first be clarified as much as possible,especially at national scales. However, few studies have introduced how to verify an FCS estimate by delimiting the reasonable ranges. This paper addresses an estimation of national FCS and its verification using two-step process to narrow the uncertainty. Our study focuses on a methodology for reducing the uncertainty resulted by converting from growing stock volume to above-and below-ground biomass(AB biomass), so as to eliminate the significant bias in national scale estimations.Methods: We recommend splitting the estimation into two parts, one part for stem and the other part for AB biomass to preclude possible significant bias. Our method estimates the stem biomass from volume and wood density(WD), and converts the AB biomass from stem biomass by using allometric relationships.Results: Based on the presented two-step process, the estimation of China’s FCS is performed as an example to explicate how to infer the ranges of national FCS. The experimental results demonstrate a national FCS estimation within the reasonable ranges(relative errors: + 4.46% and-4.44%), e.g., 5.6–6.1 PgC for China’s forest ecosystem at the beginning of the 2010 s. These ranges are less than 0.52 PgC for confirming each FCS estimate of different periods during the last 40 years. In addition, our results suggest the upper-limits by specifying a highly impractical value of WD(0.7 t·m-3) on the national scale. As a control reference, this value decides what estimate is impossible to achieve for the FCS estimates.Conclusions: Presented methodological analysis highlights the possibility to determine a range that the true value could be located in. The two-step process will help to verify national FCS and also to reduce uncertainty in related studies. While the true value of national FCS is immeasurable, our work should motivate future studies that explore new estimations to approach the true value by narrowing the uncertainty in FCS estimations on national and global scales.展开更多
Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contrib...Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contribute to the large fraction of tree biomass,the canonical value of 50%or other simplified values of stem C concentration are widely used to represent the values of tree C concentration in the estimations of forest C stocks at different scales.However,C concentration variations between tree organs and within tree size and their impacts on forest C stocks are still unclear.Methods We conducted a global analysis of organ C concentration in age-specific trees based on 576 records of tree age,size(diameter at breast height and biomass)and C concentration data to evaluate the relationships between organ C concentrations and the changes of stem C concentration with tree age and size.Important Findings Tree C concentration varied significantly with organs.Stem C concentration of trees was significantly correlated with that of other tree organs,except for barks and reproductive organs.The stem C concentration increased significantly with tree size and age,which contributed to the increases in C contents of stems and trees.Using the C concentration in stems to represent the C concentrations of other organs and the whole tree could produce considerable errors in the estimations of forest C stocks(−8.6%to 25.6%and−2.5%to 5.9%,respectively).Our findings suggest that tree C accumulation in forests is related to the size-and age-dependent increases in stem C concentration and using specific C concentration values of tree organs can improve the estimations of forest C stocks.展开更多
Rapid urbanization has led to dramatic changes in urban forest structures and functions, and consequently affects carbon(C) storage in cities. In this study, field surveys were combined with high resolution images to ...Rapid urbanization has led to dramatic changes in urban forest structures and functions, and consequently affects carbon(C) storage in cities. In this study, field surveys were combined with high resolution images to investigate the variability of C storage of urban forests in Changchun, Northeast China. The main objectives of this study were to quantify the C storage of urban forests in Changchun City, Northeast China and understand the effects of forest type and urbanization on C storage of urban forests. The results showed that the mean C density and the total C storage of urban forests in Changchun were 4.41 kg/m2 and 4.74 × 108 kg, respectively. There were significant differences in C density among urban forest types. Landscape and relaxation forest(LF) had the highest C density with 5.41 kg/m2, while production and management forest(PF) had the lowest C density with 1.46 kg/m2. These differences demonstrate that urban forest type is an important factor needed to be considered when the C storage is accurately estimated. Further findings revealed significant differences in different gradients of urbanization, and the mean C density decreased from the first ring(6.99 kg/m2) to the fourth ring(2.87 kg/m2). The total C storage increased from the first ring to the third ring. These results indicate that C storage by urban forests will be significantly changed during the process of urbanization. The results can provide insights for decision-makers and urban planners to better understand the effects of forest type and urbanization on C storage of urban forests in Changchun, and make better management plans for urban forests.展开更多
Forests have long life cycles of up to several hundred years and longer.They also have very different growth rates at different stages of their life cycles.Therefore the carbon cycle in forest ecosystems has long time...Forests have long life cycles of up to several hundred years and longer.They also have very different growth rates at different stages of their life cycles.Therefore the carbon cycle in forest ecosystems has long time scales,making it necessary to consider forest age in estimating the spatiotemporal dynamics of carbon sinks in forests.The focus of this article is to review methods for combining recent remote sensing data with historical climate data for estimating the forest carbon source and sink distribution.Satellite remote sensing provides useful data for the land surface in recent decades. The information derived from remote sensing data can be used for short-term forest growth estimation and for mapping forest stand age for longterm simulations.For short-term forest growth estimation, remote sensing can provide forest structural parameters as inputs to process-based models,including big-leaf,two-leaf,and multi-layered models. These models use different strategies to upscale from leaf to canopy,and their reliability and suitability for remote sensing applications will be examined here.For long-term forest carbon cycle estimation, the spatial distribution of the forest growth rate（net primary productivity,NPP） modeled using remote sensing data in recent years is a critical input.This input can be combined with a forest age map to simulate the historical variation of NPP under the influence of climate and atmospheric changes. Another important component of the forest carbon cycle is heterotrophic respiration in the soil,which depends on the sizes of soil carbon pools as well as climate conditions.Methods for estimating the soil carbon spatial distribution and its separation into pools are described.The emphasis is placed on how to derive the soil carbon pools from NPP estimation in current years with consideration of forest carbon dynamics associated with stand age variation and climate and atmospheric changes.The role of disturbance in the forest carbon cycle and the effects of forest regrowth after disturbance are also considered in this review.An example of national forest carbon budget estimation in Canada is given at the end.It illustrates the importance of forest stand age structure in estimating the national forest carbon budgets and the effects of climate and atmospheric changes on the forest carbon cycle.展开更多
Background： Capturing the response of forest ecosystems to inter-annual climate variability is a great challenge.In this study, we tested the capability of an individual-based forest gap model to display carbon fluxe...Background： Capturing the response of forest ecosystems to inter-annual climate variability is a great challenge.In this study, we tested the capability of an individual-based forest gap model to display carbon fluxes at yearly and daily time scales.The forest model was applied to a spruce forest to simulate the gross primary production（GPP）, respiration and net ecosystem exchange（NEE）.We analyzed how the variability in climate affected simulated carbon fluxes at the scale of the forest model.Results： Six years were simulated at a daily time scale and compared to the observed eddy covariance（EC） data.In general, the seasonal cycle of the individual carbon fluxes was correctly described by the forest model.However, the estimated GPP differed from the observed data on the days of extreme climatic conditions.Two new parameterizations were developed： one resulting from a numerical calibration, and the other resulting from a filtering method.We suggest new parameter values and even a new function for the temperature limitation of photosynthesis.Conclusions： The forest model reproduced the observed carbon fluxes of a forest ecosystem quite wel.Of the three parameterizations, the calibrated model version performed best.However, the filtering approach showed that calibrated parameter values do not necessarily correctly display the individual functional relations.The concept of simulating forest dynamics at the individual base is a valuable tool for simulating the NEE, GPP and respiration of forest ecosystems.展开更多
基金Supported by National Natural Science Foundation of China(72173011).
文摘[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promote the development of green low-carbon economy in China.[Methods]Based on the data of six forest resource inventories from 1989 to 2018 and related studies,the comprehensive evaluation model of forest carbon sink and forestry economic development,the coupling degree model of forest carbon sink and forestry economic development,and the coupling coordination degree model of forest carbon sink and forestry economic development were adopted.The coupling degree of forest carbon sink and forestry economic development from 1992 to 2018 was analyzed.Stepwise regression and ARIMA model were used to analyze the influencing factors and lagging characteristics of forest carbon sink.The coupling degree between forest carbon sink and forestry economic development in China from 2019 to 2030 was predicted by autoregression and ADF test.The coupling between forest carbon sink and forestry economic development in China and its long-term change characteristics were also discussed in this study.[Results](i)The investment of ecological construction and protection,the actual investment of forestry key ecological projects,GDP and the import of forest products had a significant impact on forest resources carbon stock.The total output value of forestry industry,the actually completed investment of forestry key ecological projects and the export volume of forest products had a significant impact on the forest carbon sink,and the actually completed investment of forestry key ecological projects has the greatest impact on the two.(ii)The impact of actually completed investment of forestry key ecological projects had a lag of 2 years on the forest resources carbon stock and a lag of 1 year on the forest carbon sink.When investing in forest carbon sink,it is necessary to make a good plan in advance,and do a good job in forest resources management and time optimization.(iii)From 1992 to 2018,the coupling degree of forest resources carbon stock,forest carbon sink and long-term development of forestry economy in China was gradually increasing.Although there were some fluctuations in the middle time,the coupling degree of forest resources carbon stock and the long-term development of forestry economy increased by 9.24%annually,and the degree of coupling coordination increased from"serious imbalance"in 1992 to"high-quality coordination"in 2018.From 1993 to 2018,the coupling degree of forest carbon sink and long-term development of forestry economy increased by 9.63%annually,slightly faster than the coupling coordination degree of forest resources carbon stock and long-term development of forestry economy.The coordination level also rose from level 2 in 1993 to level 10 in 2018.(iv)The prediction shows that the coupling coordination degree of forest resources carbon stock,forest carbon sink and the long-term development of forestry economy would increase from 2019 to 2030.The coupling coordination degree(D)values of both were close to 1,the coordination level was also 10 for a long time,and the degree of coupling coordination was also maintained at the"high-quality coordination"level for a long time.[Conclusions]Forest has multiple benefits of society,economy and ecology,and forest carbon sink is only a benefit output.The long-term coupling analysis of forest carbon sink and forestry economic development is a key point to multiple benefit analysis.The analysis shows that the spillover effect and co-evolution effect of forest carbon sink in China are significant.From 1992 to 2018,the coupling coordination degree of forest carbon sink and forestry economic development was gradually rising.The prediction analysis also indicate that the coupling coordination degree between the forest carbon sink and the long-term development of forestry economy will remain at the level of"high-quality coordination"for a long time from 2019 to 2030.Therefore,improving the level of forest management and maintaining the current trend of increasing forest resources are the key to achieving the goal of carbon peaking and carbon neutrality in China.
基金funded by Special Research Project of Institute of Applied Ecology,CAS(No.Y5YZX151YD)Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,CAS(No.LFEM2016-05)
文摘The Natural Forest Protection Program(NFPP)is one of the key ecological forestry programs in China.It not only facilitates the improvement of forest ecological quality in NFPP areas,but also plays a significant role in increasing the carbon storage of forest ecosystems.The program covers 17 provinces,autonomous regions,and municipalities with correspondingly diverse forest resources and environments,ecological features,engineering measures and forest management regimes,all of which affect regional carbon storage.In this study,volume of timber harvest,tending area,pest-infested forest,firedamaged forest,reforestation,and average annual precipitation,and temperature were evaluated as factors that influence carbon storage.We developed a vector autoregression model for these seven indicators and we studied the dominant factors of carbon storage in the areas covered by NFPP.Timber harvest was the dominant factorinfluencing carbon storage in the Yellow and Yangtze River basins.Reforestation contributed most to carbon storage in the state-owned forest region in Xinjiang.In state-owned forest regions of Heilongjiang and Jilin Provinces,the dominant factors were forest fires and forest cultivation,respectively.For the enhancement of carbon sequestration capacity,a longer rotation period and a smaller timber harvest are recommended for the Yellow and Yangtze River basins.Trees should be planted in stateowned forests in Xinjiang.Forest fires should be prevented in state-owned forests in Heilongjiang,and greater forest tending efforts should be made in the state-owned forests in Jilin.
基金Supported by Public Industry of Science and Technology Ministry (SYKYYW200903)National Natural Science Foundation (40605007)
文摘The interannual variation characteristics of NPP and carbon emission of Liaoning forest in recent 50 years (from 1961 to 2008) were analyzed based on the hydrothermal optimized NPP model and soil respiration Q10 model.The results showed that the total amount of annual NPP was increased in recent 50 years,in which the amount of NPP (83.9 Mt) in 2008 was 2.8 times as high as that in 1961.Amount of NPP per unit area changed with different years,and the maximum value was 36.5% more than the minimum one.The net carbon budget of Liaoning forest was carbon sink,with annual 2.1 t CO2/hm2.
基金funded by Zhejiang A&F University(POAU GR022067)China Green Carbon Foundation(PAFD GR015155)。
文摘Forest carbon offset(FCO)projects play an increasingly important role in mitigating climate change through market mechanisms in both compliance and voluntary markets.However,there are challenges and barriers to developing an FCO project,such as carbon leakage and cost-eff ectiveness.There have been few attempts to summarize and synthesize all types and aspects of existing challenges and possible solutions for FCO projects.This paper systematically reviews and discusses the current challenges involved in developing FCO projects,and then draws on the experience and lessons of existing projects to show how those challenges were addressed in world-leading voluntary carbon standards,namely the Verifi ed Carbon Standard,the American Carbon Registry,the Climate Action Reserve,and Plan Vivo.These voluntary markets have rich experience in FCO projects and are responsible for a signifi cant share of the market.From the 53 publications used in this analysis,three broad thematic categories of challenges emerged.These were related to methodology,socio-economic implications,and implementation.Methodological challenges,particularly additionality,permanence,and leakage,were the focus of 46%of the selected research papers,while socio-economic challenges,including transaction,social,and opportunity costs,were addressed by 35%.The remaining 19%of the research articles focused on implementational challenges related to monitoring,reporting,and verifi cation.Major voluntary standards adequately addressed most of the methodological and implementational barriers by adopting various approaches.However,the standards did not adequately address socio-economic issues,despite these being the second most frequently discussed theme in the papers analyzed.More research is clearly needed on the socio-economic challenges involved in the development of FCO projects.For the development of high-quality forestry carbon off set projects,there are many challenges and no simple,universal recipe for addressing them.However,it is crucial to build upon the current science and move forward with carbon projects which ensure eff ective,long-term carbon sinks and maximize benefi ts for biodiversity and people;this is particularly important with a growing public and private interest in this fi eld.
文摘Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in economic environment and practical experience,weaknesses in social participation,project scale and carbon sink talents,opportunities in international climate environment,domestic policies,etc.,and threats in project crediting period and forest resource protection,etc.In view of these,Yunnan Province can change the participation mode of forest carbon sink projects,adopt appropriate trading methods,get familiar with the relevant rules of forest carbon sink projects,strengthen the publicity and research of forest carbon sink theory,strengthen the management of carbon sink forests and expand forest carbon sink projects to enhance the market competitiveness of the Yunnan forest carbon sink projects.
基金Supported by The Research Projects in Tenth Five-Year Plan of Education Science and Research in Guangdong Province (2010tjk220)
文摘The paper analyzes the basis of forest carbon trade including the feasibility of carbon absorption trade,main body,platform and standard.The purposes of capital of carbon absorption trade is introduced.Caron absorption trade capital can be used to resettle ecological migrants,absorb employment,build forest and increase fund,increase local income,enhance forest science and technology development and launch environmental proportion.The perspective of developing forest carbon absorption trade is pointed out and the practical problems of developing forest carbon trade need to be solved.For example,the property problem of forest resources,value calculation problem of forest resources and sustainable development of forest.
基金supported by the University Grants Commission-NepalInstitute of Science and Technology+1 种基金Central Department of Environmental ScienceMinistry of Science Technology and Environment
文摘Community forest management helps in mitigating deforestation and forest degradation by addressing the negative aspects of rural livelihoods such as poverty and social exclusion.It is important in regulating global climate by encouraging sequestration of carbon in shoots,roots and soils.We studied the status of community forest management,forest resource harvest and carbon stocks in two community forests of the mid hill region of central and western Nepal.The study was based on primary and secondary data collected through carbon stock measurement from field visits and allometric equations,household surveys,focus group discussions,key informant interviews,and review of past studies.Socioeconomic variables such as gender,age group,livestock and landholding status were related to resource utilization,conservation,and management of community forest.Forest resources such as timber,firewood,fodder and leaf litter were harvested in sustainable ways.People were involved in forest thinning,co-management meetings,guarding and planting trees for forest conservation and management.Density and carbon stock of trees increased gradually in comparison to a previous study.We recommend further research on other community forests for more accurate and better results.
基金financially supported by National Natural Science Foundation of China (Nos. 41471049 and 31870462)
文摘Accurate estimation of forest carbon storage is crucial in understanding global and regional carbon cycles and projecting future ecological and economic scenarios.Guizhou is the largest karst landform province in China;61.9% of its land area is characterized as karst. However,monitoring its field biomass and carbon storage is difficult.This study synthesized and analyzed a comprehensive database of direct field observations of forest vegetation and soil carbon storage in Guizhou Province by using data from existing literature. The total vegetation carbon storage in Guizhou Province was 488.170 TgC, the average vegetation carbon density(VCD) was 27.866 MgC hm^(-2), the total amount of soil organic carbon(SOC)(20 cm) was 1017.364 TgC, and the average SOC density was 58.074 MgC hm^(-2). Among all vegetation types, needleleaf forest had the highest vegetation carbon stocks, and scrub presented the highest SOC storage. The vegetation and SOC storage values of the karst landform were 282.352 and 614.825 TgC, respectively, which were higher than thoseof the non-karst landform. VCD was concentrated at 10–40 MgC hm^(-2), and SOC density was concentrated at 40–60, 60–80, and 80–100 MgC hm^(-2). This comprehensive regional data synthesis and analysis based on direct field measurement of vegetation and soil will improve our understanding of the forest carbon cycle in karst landforms under a changing climate.
基金Project for Philosophy and Social Science of Zhaoqing City(18YB-03)Key Project of Humanities and Social Science Research Base of Guangdong Provincial Department of Education(09JDXM79004)Special Fund for Low Carbon Development of Guangdong Province(0C18)
文摘Through designing questionnaires for farmers in the project area,the understanding and utilization of carbon sink forests were surveyed. In the form of stratified sampling,150 representative forest farmers were selected from the project area. Through the survey,it found that many factors hindered the progress of forest carbon sequestration project in Guangdong Province. Besides,the implementation of this project was influenced by both natural and social factors. As to the natural factors,natural disasters for the forest carbon sequestration project in Guangdong Province mainly include typhoons,rainstorms,landslides and mudslides. The social factors of the forest carbon sequestration project in Guangdong Province mainly include the weak willingness of forest farmers to participate,the low awareness of forest farmers for forest carbon sinks,the single and insufficient source of afforestation funds,and the single afforestation model. In order to better implement the forest carbon sequestration project,Guangdong Province can take measures such as strengthening the publicity on forest carbon sinks,expanding channels of funds,organizing forest carbon exchange training courses,and diversifying the afforestation models.
文摘This paper investigates modalities required to design and implement community monitoring of forest carbon stock changes and safeguards implementation in Kenya. General principles and elements were drawn from the UNFCCC REDD+ policy frameworks for developing modalities and procedures for designing community forest monitoring system. The paper utilised policy analysis approach used to derive monitoring goals and objectives by assessing the compatibility of Kenya’s policy and legislative framework with monitoring elements provided in the UNFCCC REDD+ policy mechanism. The elements included monitoring goals, objectives, questions, indicators, and methods and tools. Two goals were identified which included, reduction of forest carbon emissions (ER) and monitoring of multiple social and environmental safeguards (SG). Five ER related objectives were identified to include: forest reference emission levels or forest reference levels, drivers of deforestation and forest degradation, Land use activities, eligible ER actions and estimation of forest emissions. Six objectives guiding SG were identified to include: policy, governance, human rights, socio-economic, biodiversity and environmental concerns. Corresponding questions to the goals and objectives were systematically designed. In turns, indicators, depicting quantitative and qualitative measurements, which best provided answers to questions were identified. The various methods and tools used by communities around the world in providing data and information required to satisfy the indictors were identified through literature review. The review identified four methods and tools that included: Remote Sensing and GIS, GPS survey, smartphone survey and Ground trothing. Smartphone and cloud-based server technology were found to be the recent emergent tools in aiding community monitoring of REDD+ projects. The paper argues that local communities and indigenous peoples have the capability and capacity to monitor and undertake forest carbon monitoring and tracking of implementation of safeguards if supported with relevant training;compensated for the time, labour and knowledge they contribute to the process;provided with feedback and involved decision making process.
基金Sponsored by"Twelfth Five-year Plan"of National Science&Technology Support Program in Rural Areas(2012BAD22B0301)Xinjiang Science & Technology Program(xjlk(2013)001)Open Fund of Xinjiang Aertai Mountain Forest Ecosystem Positioning Research Station
文摘Based on the sub-forest management inventory, volume-derived biomass and mean biomass, carbon storage and its spatial distribution of forest vegetation in Kanas National Nature Reserve(hereinafter referred to as the Reserve) were calculated. The results showed that carbon storage of forest vegetation in the Reserve was 3.004 7 Tg C, mean carbon density was 49.58 Mg C/hm^2; carbon storage of different vegetation types: forest land >shrubbery > open forest > scattered trees, among which carbon storage of forest land accounted for 90.18% of the total carbon storage of the forest vegetation, and mean carbon density of forest land was 68.87 Mg C/hm^2; in terms of regional distribution, spatial distribution of carbon storage and carbon density declined from southwest to northeast; in the Reserve, carbon storage of mature and over-mature forest stands accounted for 79.89% of carbon storage of forest land. If scientifi c management is applied, carbon sequestration capacity of forest will be improved.
基金supported by Ministry of Business, Innovation and Employment core funding to Crown Research Institutes
文摘Background： Forests are a key component of the global carbon cycle, and research is needed into the effects of human-driven and natural processes on their carbon pools. Airborne laser scanning （ALS） produces detailed 3D maps of forest canopy structure from which aboveground carbon density can be estimated. Working with a ALS dataset collected over the 8049-km2 Wellington Region of New Zealand we create maps of indigenous forest carbon and evaluate the influence of wind by examining how carbon storage varies with aspect. Storms flowing from the west are a common cause of disturbance in this region, and we hypothesised that west-facing forests exposed to these winds would be shorter than those in sheltered east-facing sites. Methods： The aboveground carbon density of 31 forest inventory plots located within the ALS survey region were used to develop estimation models relating carbon density to ALS information. Power-law models using rasters of top-of-the-canopy height were compared with models using tree-level information extracted from the ALS dataset. A forest carbon map with spatial resolution of 25 m was generated from ALS maps of forest height and the estimation models. The map was used to evaluate the influences of wind on forests. Results： Power-law models were slightly less accurate than tree-centric models （RMSE 35% vs 32%） but were selected for map generation for computational efficiency. The carbon map comprised 4.5 million natural forest pixels within which canopy height had been measured by ALS, providing an unprecedented dataset with which to examine drivers of carbon density. Forests facing in the direction of westerly storms stored less carbon, as hypothesised. They had much greater above-ground carbon density for a given height than any of 14 tropical forests previously analysed by the same approach, and had exceptionally high basal areas for their height. We speculate that strong winds have kept forests short without impeding basal area growth. Conclusion： Simple estimation models based on top-of-the canopy height are almost as accurate as state-of-the-art tree-centric approaches, which require more computing power. High-resolution carbon maps produced by ALS provide powerful datasets for evaluating the environmental drivers of forest structure, such as wind.
文摘Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha<sup>−</sup><sup>1</sup>. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha<sup>−</sup><sup>1</sup>) than upper layers (55.42 ± 25.37 MgC ha<sup>−</sup><sup>1</sup>). The study highlights that low deforestation rate have led to less CO<sub>2</sub> (705.3 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup> - 922.62 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup>) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha<sup>−</sup><sup>1</sup>) than primary (20.33 ± 12.7 MgC ha<sup>−</sup><sup>1</sup>), savanna and cropland (21.71 ± 15.10 MgC ha<sup>−</sup><sup>1</sup>). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.
基金supported by the Hebei Social Science Foundation Project(Grant No.HB20YJ018)2023 Hebei Province Social Science Development Research Project(Grant No.20230103005)Education Department of Hebei Province Graduate Student Innovation Ability Training Funding Project(Grant No.CXZZSS2023130).
文摘In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was constructed to evaluate the carbon emission risks of the construction industry in Hebei Province,China from 2005 to 2020.The results are shown as follows:(1)The overall carbon emissions of the construction industry in Hebei Province of China showed an inverted"V"-shaped evolution trend during the past 16 years.Tangshan and Shijiazhuang maintained high carbon emissions,while Langfang,Hengshui and Baoding saw rapid increases in carbon emissions.(2)The environmental safety threshold of carbon emission from the construction industry in Hebei Province,China,has been continuously improved,and the provincial environmental safety threshold is between 9475080-23144760 tons;The environmental safety threshold was the highest in Baoding and Langfang,and the lowest in Xingtai.(3)In the past 16 years,the carbon emission risk of the construction industry in Hebei Province of China has been in a state of extremely serious risk,and the risk index generally presents an inverted"V"type trend.(4)The carbon emission risk of Hebei city in China presents a spatial pattern of"high in the south and low in the north",which goes through two stages:risk increase period and risk reduction period.
文摘In most Sub-Saharan African countries such as Togo, people’s heavy dependence on ecosystem services is a major factor in accelerating the degradation of natural resources, which are already suffering as a result of climatic factors. This study was initiated to contribute to the sustainable and rational management of forest resources in the south-east of the Mono Biosphere Reserve in Togo. It specifically aims to identify and characterize the flora of the residual forest ecosystems within the reserve through their specific diversity, demographic structure, and carbon sequestration potential. The study was carried out in the forest ecosystems of Avévé. The methodology used was based on the analysis of phytosociological, forestry, ecological, and regeneration inventory data. Overall, the study revealed that the RBMT still has floristically viable habitats, despite the anthropogenic pressures it is subject to revealed a floristic diversity of 160 plant species divided into 52 families and 135 genera. The most represented families are Rubiaceae (29.09%), followed by Fabaceae (27.94%). The most represented species are Mitragyna inermis (Willd.) Kuntze (24.38%), Lecaniodiscus cupanioides Planch. Ex Benth (X) and Lonchocarpus sericeus (Poir.) Kunth (10.93%). The high presence of Mitragyna inermis observed in all the ecological groups identified makes it the characteristic species of the flooded marshy areas of southeast Togo and contributes to the resilience of the ecosystems and populations in the study area. The Shannon index for the formation groups varies between (3.03 and 5.16) bits. Pielou’s equitability varies between (0.43 and 0.63) bits. The overall average density is estimated at 210 stems/ha, with an average diameter of 25.57 ± 21.77 m and an average height of 7.93 ± 3.83 m. The adjustment of the diameter classes of the plant groups to the Weibull distribution gave an “inverted J” shape with coefficient values of less than 1 overall, reflecting the existence of multispecific or uneven-aged stands. Assessment of the horizontal and vertical structure shows a predominance of the shrub layer in all the groups identified. The carbon sequestration potential is 41.89 T/Ha. Despite ongoing anthropogenic pressures, the Mono Biosphere Reserve abounds in a relatively rich diversity of flora, the preservation of which is essential for the survival of biodiversity and even for the riparian population. The data provided by this study would form the basis for sustainable management planning of the forest islands in the biosphere reserve.
基金supported by the National Key Research and Development Program of China(Grant Nos:2017YFA0604401,2016YFC0501101)the Open Fund of State Key Laboratory of Remote Sensing Science(No.OFSLRSS201704)+1 种基金the Meteorology Scientific Research Fund in the Public Welfare of China(No.GYHY201506010)partly supported by the National Basic Research Program in China(No.2013CB956602)
文摘Background: In recent decades the future of global forests has been a matter of increasing concern, particularly in relation to the threat of forest ecosystem responses under potential climate change. To the future predictions of these responses, the current forest biomass carbon storage(FCS) should first be clarified as much as possible,especially at national scales. However, few studies have introduced how to verify an FCS estimate by delimiting the reasonable ranges. This paper addresses an estimation of national FCS and its verification using two-step process to narrow the uncertainty. Our study focuses on a methodology for reducing the uncertainty resulted by converting from growing stock volume to above-and below-ground biomass(AB biomass), so as to eliminate the significant bias in national scale estimations.Methods: We recommend splitting the estimation into two parts, one part for stem and the other part for AB biomass to preclude possible significant bias. Our method estimates the stem biomass from volume and wood density(WD), and converts the AB biomass from stem biomass by using allometric relationships.Results: Based on the presented two-step process, the estimation of China’s FCS is performed as an example to explicate how to infer the ranges of national FCS. The experimental results demonstrate a national FCS estimation within the reasonable ranges(relative errors: + 4.46% and-4.44%), e.g., 5.6–6.1 PgC for China’s forest ecosystem at the beginning of the 2010 s. These ranges are less than 0.52 PgC for confirming each FCS estimate of different periods during the last 40 years. In addition, our results suggest the upper-limits by specifying a highly impractical value of WD(0.7 t·m-3) on the national scale. As a control reference, this value decides what estimate is impossible to achieve for the FCS estimates.Conclusions: Presented methodological analysis highlights the possibility to determine a range that the true value could be located in. The two-step process will help to verify national FCS and also to reduce uncertainty in related studies. While the true value of national FCS is immeasurable, our work should motivate future studies that explore new estimations to approach the true value by narrowing the uncertainty in FCS estimations on national and global scales.
基金supported by the National Key Research and Development Program of China(grant no.2017YFC0503903)National Natural Science Foundation of China(grant no.31621091).
文摘Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contribute to the large fraction of tree biomass,the canonical value of 50%or other simplified values of stem C concentration are widely used to represent the values of tree C concentration in the estimations of forest C stocks at different scales.However,C concentration variations between tree organs and within tree size and their impacts on forest C stocks are still unclear.Methods We conducted a global analysis of organ C concentration in age-specific trees based on 576 records of tree age,size(diameter at breast height and biomass)and C concentration data to evaluate the relationships between organ C concentrations and the changes of stem C concentration with tree age and size.Important Findings Tree C concentration varied significantly with organs.Stem C concentration of trees was significantly correlated with that of other tree organs,except for barks and reproductive organs.The stem C concentration increased significantly with tree size and age,which contributed to the increases in C contents of stems and trees.Using the C concentration in stems to represent the C concentrations of other organs and the whole tree could produce considerable errors in the estimations of forest C stocks(−8.6%to 25.6%and−2.5%to 5.9%,respectively).Our findings suggest that tree C accumulation in forests is related to the size-and age-dependent increases in stem C concentration and using specific C concentration values of tree organs can improve the estimations of forest C stocks.
基金Under the auspices of Excellent Young Scholars of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.DLSYQ13004)Chinese Academy of Sciences/State Administration of Foreign Experts Affairs International Partnership Program for Creative Research Teams(No.KZZD-EW-TZ-07-09)
文摘Rapid urbanization has led to dramatic changes in urban forest structures and functions, and consequently affects carbon(C) storage in cities. In this study, field surveys were combined with high resolution images to investigate the variability of C storage of urban forests in Changchun, Northeast China. The main objectives of this study were to quantify the C storage of urban forests in Changchun City, Northeast China and understand the effects of forest type and urbanization on C storage of urban forests. The results showed that the mean C density and the total C storage of urban forests in Changchun were 4.41 kg/m2 and 4.74 × 108 kg, respectively. There were significant differences in C density among urban forest types. Landscape and relaxation forest(LF) had the highest C density with 5.41 kg/m2, while production and management forest(PF) had the lowest C density with 1.46 kg/m2. These differences demonstrate that urban forest type is an important factor needed to be considered when the C storage is accurately estimated. Further findings revealed significant differences in different gradients of urbanization, and the mean C density decreased from the first ring(6.99 kg/m2) to the fourth ring(2.87 kg/m2). The total C storage increased from the first ring to the third ring. These results indicate that C storage by urban forests will be significantly changed during the process of urbanization. The results can provide insights for decision-makers and urban planners to better understand the effects of forest type and urbanization on C storage of urban forests in Changchun, and make better management plans for urban forests.
文摘Forests have long life cycles of up to several hundred years and longer.They also have very different growth rates at different stages of their life cycles.Therefore the carbon cycle in forest ecosystems has long time scales,making it necessary to consider forest age in estimating the spatiotemporal dynamics of carbon sinks in forests.The focus of this article is to review methods for combining recent remote sensing data with historical climate data for estimating the forest carbon source and sink distribution.Satellite remote sensing provides useful data for the land surface in recent decades. The information derived from remote sensing data can be used for short-term forest growth estimation and for mapping forest stand age for longterm simulations.For short-term forest growth estimation, remote sensing can provide forest structural parameters as inputs to process-based models,including big-leaf,two-leaf,and multi-layered models. These models use different strategies to upscale from leaf to canopy,and their reliability and suitability for remote sensing applications will be examined here.For long-term forest carbon cycle estimation, the spatial distribution of the forest growth rate（net primary productivity,NPP） modeled using remote sensing data in recent years is a critical input.This input can be combined with a forest age map to simulate the historical variation of NPP under the influence of climate and atmospheric changes. Another important component of the forest carbon cycle is heterotrophic respiration in the soil,which depends on the sizes of soil carbon pools as well as climate conditions.Methods for estimating the soil carbon spatial distribution and its separation into pools are described.The emphasis is placed on how to derive the soil carbon pools from NPP estimation in current years with consideration of forest carbon dynamics associated with stand age variation and climate and atmospheric changes.The role of disturbance in the forest carbon cycle and the effects of forest regrowth after disturbance are also considered in this review.An example of national forest carbon budget estimation in Canada is given at the end.It illustrates the importance of forest stand age structure in estimating the national forest carbon budgets and the effects of climate and atmospheric changes on the forest carbon cycle.
基金supported by the Helmholtz-Alliance Remote Sensing and Earth System Dynamicssupported by the Helmholtz Impulse and Networking Fund through the Helmholtz Interdisciplinary Graduate School for Environmental Research(HIGRADE)
文摘Background： Capturing the response of forest ecosystems to inter-annual climate variability is a great challenge.In this study, we tested the capability of an individual-based forest gap model to display carbon fluxes at yearly and daily time scales.The forest model was applied to a spruce forest to simulate the gross primary production（GPP）, respiration and net ecosystem exchange（NEE）.We analyzed how the variability in climate affected simulated carbon fluxes at the scale of the forest model.Results： Six years were simulated at a daily time scale and compared to the observed eddy covariance（EC） data.In general, the seasonal cycle of the individual carbon fluxes was correctly described by the forest model.However, the estimated GPP differed from the observed data on the days of extreme climatic conditions.Two new parameterizations were developed： one resulting from a numerical calibration, and the other resulting from a filtering method.We suggest new parameter values and even a new function for the temperature limitation of photosynthesis.Conclusions： The forest model reproduced the observed carbon fluxes of a forest ecosystem quite wel.Of the three parameterizations, the calibrated model version performed best.However, the filtering approach showed that calibrated parameter values do not necessarily correctly display the individual functional relations.The concept of simulating forest dynamics at the individual base is a valuable tool for simulating the NEE, GPP and respiration of forest ecosystems.
