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1.
We developed a volume-to-biomass method based on age groups representative of forest development stages to estimate live tree biomass, C, and biomass and C accumulation rates of Chinas forests between 1973 and 1993. The data were from plot-level forest inventory, national-level inventory statistics, and ecological site studies specified to estimate biomass in different tree components. Our results indicate that carbon storage in Chinas forests was 4.34 Pg C in the early 1990s, an increase of 13% since the early 1970s. The annual forest C sequestration rate from the late 1980s to early 1990s was 0.068 Pg C/yr and approximately four- to five-times higher than in the 1970s and 1980s. The large C sink in Chinas forests in the early 1990s was likely related to age structure changes that had developed to more productive stages, a consequence of reforestation and afforestation programs from the 1960s. The results were compared with other C store estimates, which were based on the same inventory data. Various methods can produce estimates that differ in the direction of C flux as well as its magnitude. Separating age groups with the volume–biomass method could cause a 27% difference in estimated carbon pools but an 89% difference in C sequestration rates whereas the biomass density method would provide an estimate that differs by 65% in the C pools.  相似文献   

2.
We developed a volume-to-biomass method based on age groups representative of forest development stages to estimate live tree biomass, C, and biomass and C accumulation rates of Chinas forests between 1973 and 1993. The data were from plot-level forest inventory, national-level inventory statistics, and ecological site studies specified to estimate biomass in different tree components. Our results indicate that carbon storage in Chinas forests was 4.34 Pg C in the early 1990s, an increase of 13% since the early 1970s. The annual forest C sequestration rate from the late 1980s to early 1990s was 0.068 Pg C/yr and approximately four- to five-times higher than in the 1970s and 1980s. The large C sink in Chinas forests in the early 1990s was likely related to age structure changes that had developed to more productive stages, a consequence of reforestation and afforestation programs from the 1960s. The results were compared with other C store estimates, which were based on the same inventory data. Various methods can produce estimates that differ in the direction of C flux as well as its magnitude. Separating age groups with the volume–biomass method could cause a 27% difference in estimated carbon pools but an 89% difference in C sequestration rates whereas the biomass density method would provide an estimate that differs by 65% in the C pools.  相似文献   

3.
We studied forest land-use and carbon storage over a 40-year period in the Middle Zavolgie region of Russia, an area of approximately 287,000 km2. Data were obtained from state forest inventories for 1958 and 1995. In spite of the effects of disturbances and uncontrolled harvesting between 1958 and 1990, the forests of the Middle Zavolgie Region remained a considerable pool of ecosystem carbon (C). Over the study period the total area of forest lands decreased by approximately 2%, while the growing stock increased by 8%. There were significant changes in the age class structure of these forest ecosystems toward a larger proportion of young and middle aged stands. The total amount of carbon in the stem biomass of forests in all regions of Middle Zavolgie increased over the 40-year period and was equal to about 307 TgC in 1995. A regional approach for estimating the C dynamics of forest ecosystems in response to land use in the Middle Zavolgie region can contribute to understanding the potential role of Russian forests in C sequestration. This information is important for implementation of international conventions concerning national carbon budgets and reducing the potential negative impacts of climate change.  相似文献   

4.
Jian Ni 《Climatic change》2013,119(3-4):905-917
China is an important region for the global study of carbon because of its vast territory with various climate regimes, diverse ecosystems, and long-term human disturbances and land-use history. Carbon storage in ecosystems in China has been estimated using inventory and modeling methods in the past two decades. However, different methods may result in varied magnitudes and forms of carbon storage. In this study, the current status of carbon storage in terrestrial ecosystems in China, including the impacts of land use, is summarized in the national, regional, and biome scales. Significant differences in data have existed among studies. Such differences are mainly attributed to variations in estimation methods, data availability, and periods. According to available national-scale information on Chinese terrestrial ecosystems, vegetation carbon in China is 6.1 Pg C to 76.2 Pg C (mean 36.98 Pg C) and soil carbon is 43.6 Pg C to 185.7 Pg C (mean 100.75 Pg C). The forest sector has vegetation carbon of 3.26 Pg C to 9.11 Pg C (mean 5.49 Pg C), whereas the grassland sector has 0.13 Pg C to 3.06 Pg C (mean 1.41 Pg C). Soil carbon in the forest and grassland sectors exhibits more significant regional variations. Further studies need a comprehensive methodology, which combines national inventory, field measurement, eddy covariance technique, remote sensing, and model simulation in a single framework, as well as all available data at different temporal and spatial scales, to fully account for the carbon budget in China.  相似文献   

5.
At a national scale, the carbon (C) balance of numerous forest ecosystem C pools can be monitored using a stock change approach based on national forest inventory data. Given the potential influence of disturbance events and/or climate change processes, the statistical detection of changes in forest C stocks is paramount to maintaining the net sequestration status of these stocks. To inform the monitoring of forest C balances across large areas, a power analysis of a forest inventory of live/dead standing trees and downed dead wood C stocks (and components thereof) was performed in states of the Great Lakes region, U.S. Using data from the Forest Inventory and Analysis (FIA) program of the U.S. Forest Service, it was found that a decrease in downed wood C stocks (?1.87 Mg/ha) was nearly offset by an increase in standing C stocks (1.77 Mg/ha) across the study region over a 5-year period. Carbon stock change estimates for downed dead wood and standing pools were statistically different from zero (α?=?0.10), while the net change in total woody C (?0.10 Mg/ha) was not statistically different from zero. To obtain a statistical power to detect change of 0.80 (α?=?0.10), standing live C stocks must change by at least 0.7 %. Similarly, standing dead C stocks would need to change by 3.8 %; while downed dead C stocks require a change of 6.9 %. While the U.S.’s current forest inventory design and sample intensity may not be able to statistically detect slight changes (<1 %) in forest woody C stocks at sub-national scales, large disturbance events (>3 % stock change) would almost surely be detected. Understanding these relationships among change detection thresholds, sampling effort, and Type I (α) error rates allows analysts to evaluate the efficacy of forest inventory data for C pool change detection at various spatial scales and levels of risk for drawing erroneous conclusions.  相似文献   

6.
The dynamics of terrestrial ecosystems depends on interactions between carbon, nutrient and hydrological cycles. Terrestrial ecosystems retain carbon in live biomass (aboveground and belowground), decomposing organic matter, and soil. Carbon is exchanged naturally between these systems and the atmosphere through photosynthesis, respiration, decomposition, and combustion. Human activities change carbon stock in these pools and exchanges between them and the atmosphere through land-use, land-use change, and forestry.In the present study we estimated the wood (stem) biomass, growing stock (GS) and carbon stock of Indian forests for 1984 and 1994. The forest area, wood biomass, GS, and carbon stock were 63.86 Mha, 4327.99 Mm3, 2398.19 Mt and 1085.06 Mt respectively in 1984 and with the reduction in forest area, 63.34 Mha, in 1994, wood biomass (2395.12 Mt) and carbon stock (1083.69 Mt) also reduced subsequently. The Conifers, of temperate region, stocked maximum carbon in their woods, 28.88 to 65.21 t C ha−1, followed by Mangrove forests, 28.24 t C ha−1, Dipterocarp forests, 28.00 t C ha−1, and Shorea robusta forests, 24.07 t C ha−1. Boswellia serrata, with 0.22 Mha forest area, stocked only 3.91 t C ha−1. To have an idea of rate of carbon loss the negative changes (loss of forest area) in forest area occurred during 1984–1994 (10yrs) and 1991–1994 (4yrs) were also estimated. In India, land-use changes and fuelwood requirements are the main cause of negative change. Total 24.75 Mt C was lost during 1984–1994 and 21.35 Mt C during 1991–94 at a rate of 2.48 Mt C yr−1 and 5.35 Mt C yr−1 respectively. While in other parts of India negative change is due to multiple reasons like fuelwood, extraction of non-wood forest products (NWFPs), illicit felling etc., but in the northeastern region of the country shifting cultivation is the only reason for deforestation. Decrease in forest area due to shifting cultivation accounts for 23.0% of the total deforestation in India, with an annual loss of 0.93 Mt C yr−1.  相似文献   

7.
Using Remote Sensing to Assess Russian Forest Fire Carbon Emissions   总被引：7，自引：0，他引：7  
Russian boreal forests are subject to frequent wildfires. The resulting combustion of large amounts of biomass not only transforms forest vegetation, but it also creates significant carbon emissions that total, according to some authors, from 35–94 Mt C per year. These carbon emissions from forest fires should be considered an important part of the forest ecosystem carbon balance and a significant influence on atmospheric trace gases. In this paper we discuss a new method to assess forest fire damage. This method is based on using multi-spectral high-resolution satellite images, large-scale aerial photography, and declassified images obtained from the space-borne national security systems. A normalized difference vegetation index (NDVI) difference image was produced from pre- and post-fire satellite images from SPOT/HRVIR and RESURS-O/MSU-E images. A close relationship was found between values of the NDVI difference image and forest damage level. High-resolution satellite data and large-scale aerial-photos were used to calibrate the NDVI-derived forest damage map. The method was used for mapping of forest fire extent and damage and for estimating carbon emissions from burned forest areas.  相似文献   

8.
Forest inventories and remote sensing are the two principal data sources used to estimate carbon (C) stocks and fluxes for large forest regions. National governments have historically relied on forest inventories for assessments but developments in remote sensing technology provide additional opportunities for operational C monitoring. The estimate of total C stock in live forest biomass modeled from Landsat imagery for the St. Petersburg region was consistent with estimates derived from forest inventory data for the early 1990s (272 and 269 TgC, respectively). The estimates of mean C sink in live forest biomass also agreed well (0.36 and 0.34 Mg C ha–1 yr–1). Virtually all forest lands were accumulating C in live biomass, however when the net change in total ecosystem C stock was considered, 19% of the forest area were a net source of C. The average net C sink in total ecosystem biomass is quite weak (0.08 MgC ha–1 yr–1 and could be reversed by minor increases in harvest rates or a small decline in biomass growth rates.  相似文献   

9.
Forest inventories and remote sensing are the two principal data sources used to estimate carbon (C) stocks and fluxes for large forest regions. National governments have historically relied on forest inventories for assessments but developments in remote sensing technology provide additional opportunities for operational C monitoring. The estimate of total C stock in live forest biomass modeled from Landsat imagery for the St. Petersburg region was consistent with estimates derived from forest inventory data for the early 1990s (272 and 269 TgC, respectively). The estimates of mean C sink in live forest biomass also agreed well (0.36 and 0.34 Mg C ha–1 yr–1). Virtually all forest lands were accumulating C in live biomass, however when the net change in total ecosystem C stock was considered, 19% of the forest area were a net source of C. The average net C sink in total ecosystem biomass is quite weak (0.08 MgC ha–1 yr–1 and could be reversed by minor increases in harvest rates or a small decline in biomass growth rates.  相似文献   

10.
An integrated assessment of carbon balance in biomass removed during lumbering and transformed into products of forest, woodworking, and pulp and paper industry is conducted. Carbon sequestration was calculated with the IPCC technique. Depending on the economic state of the forest complex, from 1961 to 2005, its products can be both a source of emission of about 15 Mt CO2 per year and a pool that can uptake up to 54.1 Mt CO2 per year. In 2004, 28.3 Mt CO2 or 1.4% equivalent emission from other national economy sectors came to forest products from the atmosphere. Rational use of forest products and reduced non-productive losses of raw wood can lead to a significant contribution of the forest complex to decrease in greenhouse gas emissions into the atmosphere.  相似文献   

11.
In this study we estimated the amount of carbon (C) stored in the forest growing stock and in wood-based products, and the C-sequestration capacity of the forest sector in Finland. Comparison of different management and utilization options for forest resources over the period 1990-2039 indicates that C is stored more efficiently in standing timber than in wood-based products. This implies that an appropriate increase in the length of the rotation in forestry could be optimal for balancing the needs of forest resources for C sequestration and timber production. Increased use of wood, based on sustainable use of forest resources, to substitute for fossil fuels and materials, could decrease the overall C emissions. Release of sequestered C back to the atmosphere can be delayed by prolonging product lifespans, by increasing recycling, or by disposing of discarded products in landfills. To delay C release, and affect the C balance, however, these changes should be substantial.In 1990, the net C balance of the growing stemwood stock was 5.5 Tg C/a, which increased to 16.3 Tg C/a by 2039 if in the future the use of wood would be at the level of the late 1980s. Increased use of wood resulted in a balance of 6.6 Tg C/a or -0.2 Tg C/a, depending on the extent of the use of wood. The average C balance in wood products for the whole period was 3.9, 5.6 or 6.6 Tg C/a, respectively. Changes in production capacity, and consideration of timber and product import and export decreased the average balance from 6.6 Tg C/a to 0.9–1.3 Tg C/a. By comparison, emission from the use of fossil fuels in 1990 C was 14.5 Tg C/a.  相似文献   

12.
A process-based approach to modelling the effects of land use change and climate change on the carbon balance of terrestrial ecosystems was applied at global scale. Simulations were run both with and without land use change. In the absence of land use change between 1700 and 1990, carbon storage in terrestrial ecosystems was predicted to increase by 145 Pg C. When land use change was represented during this period, terrestrial ecosystems became a net source of 97 Pg C. Land use change was directly responsible for a flux of 222 Pg C, slightly higher but close to estimates from other studies. The model was then run between 1990 and 2100 with a climate simulated by a GCM. Simulations were run with three land use change scenarios: 1. no land use change; 2. land use change specified by the SRES B2 scenario, and; 3. land use change scaled with population change in the B2 scenario. In the first two simulations with no or limited land use change, the net terrestrial carbon sink was substantial (358 and 257 Pg C, respectively). However, with the population-based land-use change scenario, the losses of carbon through land use change were close to the carbon gains through enhanced net ecosystem productivity, resulting in a net sink near zero. Future changes in land use are highly uncertain, but will have a large impact on the future terrestrial carbon balance. This study attempts to provide some bounds on how land use change may affect the carbon sink over the nextcentury.  相似文献   

13.
中国森林乔木林碳储量及其固碳潜力预测   总被引：5，自引：0，他引：5  
加强对我国森林碳储量和固碳潜力的研究,是制定中国增汇减排政策的重要依据,对我国国际气候谈判和全面了解森林碳汇潜力具有重要作用。利用我国第七次和第八次森林资源清查中各优势树种的面积和蓄积量数据,采用IPCC材积源生物量法（volume-biomass method),估算了我国森林（乔木林）碳储量和碳密度及其分布,分析我国不同省份天然乔木林和人工乔木林碳储量龄组结构特征;建立分区域、分起源主要优势树种的单位面积蓄积-林龄Logistic生长方程,结合我国森林2020年和2030年面积蓄积增长目标,预测我国乔木林2010—2050年间碳汇潜力。结果表明：第八次清查期间中国乔木林总碳储量为6135.68 Tg,碳密度为37.28 Mg/hm 2;天然乔木林和人工乔木林的碳储量分别为5246.07 Tg和889.61 Tg,分别占总碳储量的85.50%和14.50%。到2050年,中国乔木林和新造林的总碳储量和平均碳密度将分别达到11125.76 Tg和52.52 Mg/hm 2,与2010年相比分别增加81%和41%。分析结果表明中国乔木林有很大的碳汇潜力,将在应对和减缓全球气候变化中发挥重要作用。  相似文献   

14.
Terrestrial carbon pools in southeast and south-central United States   总被引：1，自引：0，他引：1  
Analyses of regional carbon sources and sinks are essential to assess the economical feasibility of various carbon sequestration technologies for mitigating atmospheric CO2 accumulation and for preventing global warming. Such an inventory is a prerequisite for regional trading of CO2 emissions. As a U.S. Department of Energy Southeast Regional Carbon Sequestration Partner, we have estimated the state-level terrestrial carbon pools in the southeast and south-central US. This region includes: Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Texas, and Virginia. We have also projected the potential for terrestrial carbon sequestration in the region. Texas is the largest contributor (34%) to greenhouse gas emission in the region. The total terrestrial carbon storage (forest biomass and soils) in the southeast and south-central US is estimated to be 130 Tg C/year. An annual forest carbon sink (estimated as 76 Tg C/year) could compensate for 13% of the regional total annual greenhouse gas emission (505 Tg C, 1990 estimate). Through proper policies and the best land management practices, 54 Tg C/year could be sequestered in soils. Thus, terrestrial sinks can capture 23% of the regional total greenhouse emission and hence are one of the most cost-effective options for mitigating greenhouse emission in the region.  相似文献   

15.
全球CO2浓度增加造成的全球变暖已成为人类亟需解决的问题,陆地生态系统在过去几十年一直扮演着重要的碳汇角色,吸收了30％左右的人类活动排放CO2。本文调研分析了陆地生态系统固碳速率空间估算方法,包括样地调查、通量监测、模型模拟、遥感估算等,梳理了各种估算方法的研究现状与进展。样地调查、通量观测等方法可以提供点尺度的固碳速率直接测量信息,但存在观测样本有限、空间代表性不足等问题。模型模拟方法可以从机理的角度描述陆地碳、水、能量循环,模拟预测陆地生态系统固碳速率的状态和变化。然而,在模型建立过程中,抽象和简化会引入结构与假设的不确定性,以及模型驱动数据引入的不确定性等问题是碳循环模型模拟方法面临的重大挑战。卫星遥感具有全球覆盖、分辨率精细、时间序列观测等优点,结合机器学习方法,为地球大数据驱动的全球碳源汇估算提供了新的研究范式。但是,当前各种固碳速率的监测方法还没有满足高度时空异质性的陆地生态系统固碳量监测需求,未来需要整合地面观测、模型模拟和卫星遥感等多种技术手段,提供区域和全球尺度的陆地生态系统碳汇精确估算方法体系和科学数据产品。  相似文献   

16.
This study is a contribution to the ongoing debate about the selection of the approach for carbon accounting in wood products to be used, in the future, in the national greenhouse gas inventories under the UNFCCC (United Nations Framework Convention on Climate Change). Two accounting approaches are used in this analysis: the stock-change approach and the atmospheric-flow approach. They are applied to the Portuguese Eucalyptus globulus forest sector. To achieve this objective, the fluxes of wood removed from the forest are tracked through its life cycle, which includes products manufacture (mainly pulp and paper), use and final disposal (landfilling, incineration and composting). This study develops a framework to the estimation of carbon sequestration in the forest of E. globulus, a fast growing species, more specifically, in the calculation of the conversion factors such as bark and foliage percentages and densities, used to convert wood volumes into total biomass. A mass balance approach based on real data from mills is also proposed, in order to assess carbon emissions from wood processing. The results show that E. globulus forest sector was a carbon sink, but the magnitude of the carbon sequestration differs substantially depending on the accounting approach used. The contribution of the forest ecosystem was smaller than the aggregated contribution of wood products in use and in landfills (including industrial waste), which reinforces the role that wood products play in national carbon budgets.  相似文献   

17.
Previous research has identified the importance of the role of land cover in the global carbon cycle. In particular, forests have been identified as a significant carbon sink that can mitigate the rate of global climate change. Policy makers are faced with complex and difficult challenges in getting timely and useful information in monitoring global forest resources. Recent advances in the tools and methods of forest carbon accounting have produced new, innovative approaches to forest-based carbon inventories. But it is important as new tools are developed that scientists understand the needs of policy makers and that policy makers understand the capabilities and limitations of forest inventory methods. This paper explores four different policy applications that rely, or could benefit from, national carbon inventories. The goal is to help build a bridge between the communities of climate policy makers and scientists specialized in forest carbon inventories. To this end, we pursue three specific objectives: First we provide an overview for policy makers about approaches to forest carbon inventories, paying particular attention to the contributions of remote sensing technologies. Second, we outline the issues particularly relevant to forest inventory scientists who are interested in responding to public policy needs. We then discuss the tradeoffs between information cost, accuracy, precision, transparency and timeliness that need to be balanced in long-term monitoring of forest carbon. Finally, the article concludes with a series of observations and recommendations for the implementation of forest carbon inventories as increasingly central components of global climate change policy.  相似文献   

18.
为了应对全球气候变化带来的挑战,2020年9月中国提出努力争取在2060年前实现碳中和。对此,生态系统固碳被寄予厚望;然而,生态学理论认为,成熟生态系统的碳输入输出趋于平衡,没有碳的净积累,也就没有碳汇功能,而未成熟的生态系统虽有碳的净积累并具有碳汇功能,但自然界任何未成熟生态系统从它建立的时候开始都在不断地向成熟生态系统演替,即任一生态系统演替的最终结果必然是碳输入输出达到平衡状态。由于森林生态系统碳库是陆地生态系统中最大的碳库,所以人们对其在碳中和上的贡献充满期待。本文以森林生态系统为例,分别考虑森林生态系统碳库的生物量碳库和土壤有机碳库,并基于全球最新研究成果,论证了森林生态系统土壤碳库积累过程具有长久的固碳功能,且不违背成熟生态系统碳输入输出趋于平衡的生态学理论,它能为实现碳中和目标做出贡献。  相似文献   

19.
Development trends of Russian forests and their impact on the global carbon budget were assessed at the national level on the basis of long-term forest inventory data (1961–1998). Over this period, vegetation of Russian forest lands are estimated as a carbon sink, with an annual average level of carbon sequestration in vegetational organic matter of 210 ± 30 Tg C · yr–1 (soil carbon is not considered in this study), of which 153 Tg C · yr–1 were accumulated in live biomass and 57 Tg C · yr–1 in dead wood. The temporal variability of the sink is very large; for the five-year averages used in the analysis, the C sequestration varies from about 60 to above 300 Tg C· yr–1. It is shown that long-term forest inventory data could serve as an important information base for assessing crucial indicators of full carbon accounting of forests.  相似文献   

20.
省级土地利用变化和林业（LUCF）温室气体清单主要评估“森林和其他木质生物质生物量碳储量的变化”和“森林转化温室气体排放”两类主要温室气体的排放源或吸收汇。省级LUCF温室气体清单编制方法以政府间气候变化专门委员会（IPCC）有关国家温室气体清单指南为基础,结合中国LUCF活动的实际情况,特别是在考虑核心关键数据的可获得性与可靠性的基础上制订完成。同时还建立了适用于不同省的关键排放因子和参数数据库,旨在为科学合理地编制中国省级LUCF温室气体清单提供方法学依据。  相似文献   

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