Using China's ground observations,e.g.,forest inventory,grassland resource,agricultural statistics,climate,and satellite data,we estimate terrestrial vegetation carbon sinks for China's major biomes between 19...Using China's ground observations,e.g.,forest inventory,grassland resource,agricultural statistics,climate,and satellite data,we estimate terrestrial vegetation carbon sinks for China's major biomes between 1981 and 2000.The main results are in the following:(1)Forest area and forest biomass car-bon(C)stock increased from 116.5×10^(6) ha and 4.3 Pg C(1 Pg C=10^(15) g C)in the early 1980s to 142.8×10^(6) ha and 5.9 Pg C in the early 2000s,respectively.Forest biomass carbon density increased form 36.9 Mg C/ha(1 Mg C=10^(6) g C)to 41.0 Mg C/ha,with an annual carbon sequestration rate of 0.075 Pg C/a.Grassland,shrub,and crop biomass sequestrate carbon at annual rates of 0.007 Pg C/a,0.014―0.024 Pg C/a,and 0.0125―0.0143 Pg C/a,respectively.(2)The total terrestrial vegetation C sink in China is in a range of 0.096―0.106 Pg C/a between 1981 and 2000,accounting for 14.6%―16.1%of carbon dioxide(CO_(2))emitted by China's industry in the same period.In addition,soil carbon sink is estimated at 0.04―0.07 Pg C/a.Accordingly,carbon sequestration by China's terrestrial ecosystems(vegetation and soil)offsets 20.8%―26.8%of its industrial CO_(2) emission for the study period.(3)Considerable uncertainties exist in the present study,especially in the estimation of soil carbon sinks,and need further intensive investigation in the future.展开更多
Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF),...Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.展开更多
Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C b...Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China's forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China's forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1Tg=1012g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg Ca-1 , offsetting 7.8% of the contemporary fossil CO2 emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China's forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density.展开更多
PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National ...PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National Forest Park in Chongming Island （CM）, Dinghu Mountain Nature Reserve （DH）, Jianfengling Nature Reserve in Hainan Island （HN）. The mass concentrations of PM2.5, organic carbon （OC）, elemental carbon （EC）, water soluble organic carbon （WSOC） as well as concentrations of ten inorganic ions （F？, Cl？, NO3？, SO42？, C2O42？, NH4＋, Na＋, K＋, Ca2＋, Mg2＋） were determined. Aerosol chemical mass closures were achieved. The 24-hr average concentrations of PM2.5 were 38.8, 89.2, 30.4, 18 μg/m3 at CB, CM, DH and HN, respectively. Organic matter and EC accounted for 21%–33% and 1.3%–2.3% of PM2.5 mass, respectively. The sum of three dominant secondary ions （SO42-, NO3-, NH4＋） accounted for 44%, 50%, 45% and 16% of local PM2.5 mass at CB, CM, DH and HN, respectively. WSOC comprised 35%–65% of OC. The sources of PM2.5 include especially important regional anthropogenic pollutions at Chinese forest areas.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.90211016,40638039,40228001,and 40021101)the Key MOE Research Project(Grant No.306019)
文摘Using China's ground observations,e.g.,forest inventory,grassland resource,agricultural statistics,climate,and satellite data,we estimate terrestrial vegetation carbon sinks for China's major biomes between 1981 and 2000.The main results are in the following:(1)Forest area and forest biomass car-bon(C)stock increased from 116.5×10^(6) ha and 4.3 Pg C(1 Pg C=10^(15) g C)in the early 1980s to 142.8×10^(6) ha and 5.9 Pg C in the early 2000s,respectively.Forest biomass carbon density increased form 36.9 Mg C/ha(1 Mg C=10^(6) g C)to 41.0 Mg C/ha,with an annual carbon sequestration rate of 0.075 Pg C/a.Grassland,shrub,and crop biomass sequestrate carbon at annual rates of 0.007 Pg C/a,0.014―0.024 Pg C/a,and 0.0125―0.0143 Pg C/a,respectively.(2)The total terrestrial vegetation C sink in China is in a range of 0.096―0.106 Pg C/a between 1981 and 2000,accounting for 14.6%―16.1%of carbon dioxide(CO_(2))emitted by China's industry in the same period.In addition,soil carbon sink is estimated at 0.04―0.07 Pg C/a.Accordingly,carbon sequestration by China's terrestrial ecosystems(vegetation and soil)offsets 20.8%―26.8%of its industrial CO_(2) emission for the study period.(3)Considerable uncertainties exist in the present study,especially in the estimation of soil carbon sinks,and need further intensive investigation in the future.
基金the National Natural Science Foundation of China (Nos. 30471378, 90202010 and 30211130504),and the Program of 100 Distinguished Young Scientists of the Chinese Academy of Sciences.
文摘Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.
基金supported by the National Basic Research Program of China on Global Change (2010CB950600)the National Natural Science Foundation of China (31021001, 30721140306)'Strategic Priority Research Program-Climate Change: Carbon Budget and Related Issues' of the Chinese Academy of Sciences (XDA05050503)
文摘Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China's forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China's forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1Tg=1012g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg Ca-1 , offsetting 7.8% of the contemporary fossil CO2 emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China's forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density.
基金supported by the National Natrual Science Foundation of China (No. 20677036, 20877051)the Shanghai Leading Academic Disciplines (No. S30109)+1 种基金the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministrysupported by the Graduate Innovative Fund from Shanghai University
文摘PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National Forest Park in Chongming Island （CM）, Dinghu Mountain Nature Reserve （DH）, Jianfengling Nature Reserve in Hainan Island （HN）. The mass concentrations of PM2.5, organic carbon （OC）, elemental carbon （EC）, water soluble organic carbon （WSOC） as well as concentrations of ten inorganic ions （F？, Cl？, NO3？, SO42？, C2O42？, NH4＋, Na＋, K＋, Ca2＋, Mg2＋） were determined. Aerosol chemical mass closures were achieved. The 24-hr average concentrations of PM2.5 were 38.8, 89.2, 30.4, 18 μg/m3 at CB, CM, DH and HN, respectively. Organic matter and EC accounted for 21%–33% and 1.3%–2.3% of PM2.5 mass, respectively. The sum of three dominant secondary ions （SO42-, NO3-, NH4＋） accounted for 44%, 50%, 45% and 16% of local PM2.5 mass at CB, CM, DH and HN, respectively. WSOC comprised 35%–65% of OC. The sources of PM2.5 include especially important regional anthropogenic pollutions at Chinese forest areas.
