Vegetation Carbon Density Research Articles

Linking landscape patterns with ecological functions: A case study examining the interaction between landscape heterogeneity and carbon stock of urban forests in Xiamen, China

The relationship between landscape patterns and functions is the central research theme of landscape ecology and forest management. This study assesses the interactive relationship of landscape heterogeneity with the carbon stock of urban forests in the city of Xiamen, Fujian Province, China, using spatial and statistical analyses. The objectives of this study are to explore the most appropriate scale for studying urban landscape patterns in Xiamen, analyze the dynamics of forested landscape heterogeneity at different scales, and identify suitable landscape metrics that are closely related to and can be used to describe vegetation carbon density. This study is based on data from 31,933 plots measured during the years 1972, 1996, and 2006 and collected as part of the Chinese National Forest Resource Planning and Inventory Program. A total of 12 landscape metrics were used to quantify spatial patterns and were subsequently related to vegetation carbon density. The results show that the most appropriate scale for landscape pattern analysis is 80km2. With urbanization advancing between 1972 and 1996, landscape heterogeneity at both class and landscape levels showed a significant increase and then remained stable from 1996 to 2006. Shannon’s diversity index was the most sensitive landscape metric among all selected landscape heterogeneity metrics, and its ability to explain the variation of carbon density was better than that of forest types. This study clearly shows that information on spatial patterns of landscape heterogeneity is important for urban forest landscape planning to achieve forest carbon objective.

基于林业清查资料的桂西北植被碳空间分布及其变化特征

Based on the vegetation inventory data,we investigated the density,storage and spatial characteristics and dynamics of vegetation carbon in Northwest Guangxi,China from 2005 to 2010,using biomass expansion factors and spatial analysis,respectively.The results showed that the total storage of vegetation carbon increased from 4.19 × 104 t to 4.27 × 104 t,about 1.84% per year.Similarly,the density of vegetation carbon also increased from 29.04t/hm2 to 29.57 t/hm2.Vegetation carbon density was highest(40 t/hm2) in National Nature Reserve.From 2005 to 2010,vegetation carbon density in the previously non-vegetated land increased significantly through artificial seeding,direct seeding,aerial seeding or natural germination.Vegetation carbon density of revegetated land through Conversion of Cropland into Forestland Program was also increased by 3.00 t/hm2.Vegetation carbon density from all types of forest stand was increased.With regards to the spatial distribution of carbon storage and density,the density was higher in the west,north,but lower in the middle-east,south.The average carbon density was more than 40 t/hm2 in the west but lower than 25 t/hm2 in the east and middle.The carbon storage and density in the karst areas and non-karst areas increased.Furthermore,vegetation carbon density in seven counties had increased to higher grade.Our study indicated that the carbon storage and density of vegetation in the study area was increased significantly and ecosystem conditions was improved through the application of policies of karst rocky desertification control,such as ecological migration and Conversion of Cropland into Forestland Program.

Carbon allocation, sequestration and carbon dioxide mitigation under plantation forests of north western Himalaya, India

The organic carbon and soils of the world comprise bulk of the terrestrial carbon and serve as amajorsink and source of atmospheric carbon. Increasing atmospheric concentrations of green house gases may be mitigated by increasing carbon sequestration in vegetation and soil. The study attempted to estimate biomass production and carbon sequestration potential of different plantation ecosystems in north western Himalaya, India. Biomass, carbon density of biomass, soil, detritus, carbon sequestration and CO2 mitigation potential were studied underdifferent plantation forest ecosystems comprising of eight different tree species viz. Quercus leucotrichophora, Pinus roxburghii), Acacia catechu, Acacia mollissima, Albizia procera, Alnus nitida, Eucalyptus tereticornis and Ulmus villosa . Above (185.57 ą 48.99 tha-1) and below ground (42.47 ą 10.38 tha-1 ) biomass was maximum in Ulmus villosa . The vegetation carbon density was maxium in Albizia procera (118.37 ą 1.49 tha-1) and minimum (36.50 ą 9.87 tha-1) in Acacia catechu . Soil carbon density was maximum (219.86ą 10.34 tha-1) in Alnus nitida , and minimum (170.83ą 20.60 tha-1)in Pinus roxburghii . Detritus was higher in Pinus roxburghii (6.79 ą 2.0 tha-1). Carbon sequestration (7.91ą 3.4 tha-1) and CO2 mitigation potential (29.09 ą 12.78 tha-1) was maximum in Ulmus villosa . Pearson correlation matrix revealed significant positive relationship of ecosystem carbon with plantation biomass, soil carbon and CO2 mitigation potential. With the emerging threat of climate change, such assessment of forest and soil carbon inventory would allow to devise best land management and policy decisions forsustainable management of fragile hilly ecosystem.

Estimated carbon dioxide emissions from tropical deforestation improved by carbon-density maps

Deforestation contributes 6–17% of anthropogenic carbon dioxide emissions. However, much uncertainty in the calculation of deforestation emissions stems from the inadequacy of forest carbon-density and deforestation data. Now an analysis provides the most-detailed estimate so far of the carbon density of vegetation and the associated carbon dioxide emissions from deforestation for ecosystems across the tropics.

基于RS/GIS的重庆缙云山自然保护区植被及碳储量密度空间分布研究

PDF HTML阅读 XML下载 导出引用 引用提醒 基于RS/GIS的重庆缙云山自然保护区植被及碳储量密度空间分布研究 DOI: 10.5846/stxb201108021134 作者: 作者单位: 三峡库区生态环境教育部重点实验室 西南大学生命科学学院,三峡库区生态环境教育部重点实验室 西南大学生命科学学院,三峡库区生态环境教育部重点实验室 西南大学生命科学学院,三峡库区生态环境教育部重点实验室 西南大学生命科学学院,三峡库区生态环境教育部重点实验室 西南大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(31070474); 西南大学研究生科技创新基金项目(KB2010010) Spatial distribution of vegetation and carbon density in Jinyun Mountain Nature Reserve based on RS/GIS Author: Affiliation: Laboratory of Eco-environments of Three Gorges Reservoir Region(Ministry of Education); Shool of Life Science;Southwest University,Laboratory of Eco-environments of Three Gorges Reservoir Region(Ministry of Education); Shool of Life Science;Southwest University,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:对森林植被类型和碳储量密度空间分布的研究,可以为森林生态系统服务功能和价值的提高、充分发挥"增汇减排"的碳库经营和管理工作提供重要的基础数据。利用缙云山高分辨率影像(WorldView-2)解译植被专题图和1∶10 000地形图生成数字高程模型,结合野外样方调查、文献中植被生物量回归(经验)模型和碳含量数据资料,在ArcGIS支持下对缙云山自然保护区植被和碳储量密度空间分布进行研究。研究显示,缙云山植被以针叶林为主(30%),人为干扰程度较高的灌木林也占有相当大的比例(21%),地带性顶级植被——常绿阔叶林面积较小(6%);碳储量密度为针阔混交林(74.23 Mg/hm2) > 针叶林(62.97 Mg/hm2) > 常绿阔叶林(62.65 Mg/hm2) > 针竹混交林(59.84 Mg/hm2) > 慈竹林(48.72 Mg/hm2) > 毛竹林(47.88 Mg/hm2) > 灌木林(10.66 Mg/hm2),平均碳储量密度高于全国和同地区的平均值,达到了50.45 Mg/hm2;在空间分布上,针叶林在中高海拔(>500 m)和斜坡(>15°)以上优势明显,灌木林则相反,针阔混交林、常绿阔叶林的优势随着海拔升高或坡度增大而增加,植被的碳储量密度也随海拔的增高或坡度增大而增势明显。结果表明缙云山积累和存贮了较多的碳,"库"的功能强;而处于演替阶段初期的针叶林及灌木林明显占优,表明其在碳的积累上还有很大的提升空间,具有"汇"的潜能。此外,在较高海拔和较大坡度上的高碳储量密度,与人类的活动频度较小和对植被干扰较轻相关。因此可以推测,随着自然演替和保护区的封育改造、退耕还林及择伐补阔等森林管理措施的进行,将利于森林植被的保护、发育和更新,促使缙云山森林生态系统的碳储量密度进一步增大,碳"汇"潜能进一步增强,生态服务功能和价值得到进一步提高。 Abstract:Forest ecosystem, as a major body of terrestrial ecosystem, holding 85% of terrestrial biomass plays an irreplaceable role in the global carbon cycle and consequently in global climate change. Although China has the smallest forest area among mid-latitude nations, it contains a relatively large forest vegetation carbon pool and high forest carbon density as a result of intensive forestation programs and forest managements. Thus, natural reserves are the most effective areas for forest management, and they often complement some environmental goals including protection of carbon sink, and should not be ignored in regional carbon researches. In former studies, the capability, distribution and changing of carbon resource and sink are basic scientific issues in regional carbon sequestration researches, and these issues are closely related to vegetation distribution, composition, carbon density and other forest statuses. Jinyun Mountain is one of the national natural reserves in China. As the mountain holds well-protected subtropical evergreen broad-leaved forest (EBF) accompanied by coniferous forest (CF), mixed coniferous and evergreen broad-leaved forest (MCB), etc., it has been concerned by many researchers. Consequently, studying the spatial distribution of vegetation and carbon density of Jinyun Mountain Nature Reserve can provide important basic data for forest ecosystem operation, carbon pool management and even regional carbon sequestration researches. In this study, high-resolution remote sensing image and 1∶10 000 relief maps were used to generate Jinyun vegetation map and digital elevation model respectively, combining with non-destructive method to acquire forest biomass by field investigation and the data of carbon content and biomass regression models from the published papers. And then, the spatial characteristics of vegetation and carbon density in Jinyun Mountain Natural Reserve were analyzed by ArcGIS. The results showed that CF was the dominating forest stand, followed by SH (shrub). The vegetation area ranged as CF (30%) > SH (21%) > MCB (16%) > NS (neosinocalams stand, 11%) > EBF (6%) > MCN (mixed coniferous and neosinocalsms stand, 5%) > MBS (moso bamboo stand, 4%). The average vegetation carbon density in Jinyun Mountain was 50.45 Mg/hm2, which was higher than the average level in China, ranged as MCB (74.23 Mg/hm2) > CF (62.97 Mg/hm2) > EBF (62.65 Mg/hm2) > MCN (59.84 Mg/hm2) > NS (48.72 Mg/hm2) > MBS (47.88 Mg/hm2) > SH (10.66 Mg/hm2). Moreover, vegetation and carbon density had clear spatial variations with altitude, slope and aspect. CF dominated in altitude higher than 500 m and slope > 15°, but the shrub was the other way around. The carbon density of MCB and EBF increased with the increasing of altitude and slope. EBF had a large area in the northwest aspect, and MCB had a large distribution in the north, northwest, east and southeast aspects. NS and MCN were the dominating forest stand in the south relatively. CF, dominated with Pinus lanceolata, and SH were at primary stage of forest recovery succession in the Jinyun Mountain. The results indicate that the actual carbon sequestration of Jinyun Mountain is still much lower than the potential value of the zonal climax vegetation in this subtropical area. As we find the carbon storage and density are negatively correlated with human disturbance, forest reserve managements, such as enclosure of forest region, might contribute to conserve and sequester carbon in Jinyun Mountain. 参考文献 相似文献 引证文献

江西中南部红壤丘陵区主要造林树种碳固定估算

根据江西第6次森林清查小班数据,运用基于实地样方数据拟合的森林植被生物量与蓄积量的关系,并采用空间替代时间的方法,估算了1985-2003年江西中南部红壤丘陵区泰和和兴国县主要造林树种马尾松、湿地松、杉木林的生物量和碳储量,分析了时空动态特征。结果表明:(1) 2003年研究区主要造林树种林分面积31.04×10⁴ hm²,总生物量22.20 Tg,植被碳储量13.07T gC,平均碳密度42.36 tC/hm²。(2) 1985-2003年研究区主要造林树种碳密度呈逐年上升趋势,增加了8.58 tC/hm²;1985、1994、2003年3个树种植被碳储量分别为4.91、11.41和13.07TgC,年均固碳量0.45 TgC/a。(3) 海拔位于700-900 m之间的树种平均碳密度最大,坡度位于25-35°之间的树种平均碳密度最大。森林植被碳密度总体呈现随海拔高度的增加而增加,随坡度的增大而增大的分布。人工造林工程使江西红壤丘陵区森林植被碳储量增加显著,森林生态系统的固碳能力明显增强。;Using field survey data from the sixth inventory of forest in Jiangxi Province and calculating the relationship between forest biomass and carbon storage from this, we estimated total forest biomass and carbon storage for the three major plantation forest species, <em>Pinus massoniana</em>, <em>Cunninghamia lanceolata</em>, and <em>Pinus elliottii</em>, in the red soil hilly region of southern-central Jiangxi Province. We also analyzed the relationship between carbon density and age for these forest species, using logistic equations, and described the spatiotemporal dynamics of forest biomass and carbon storage between 1985 and 2003 in the study area.<br> In this study, we used three methods of biomass expansion factor, biomass organ distribution and parameter fitting, to estimate carbon density. Qianyanzhou Experimental Station was chosen to compare these three corresponding results. The result obtained from parameter fitting was found to be the best way of calculating forest biomass and carbon storage on a regional scale. Increasing sample size would increase reliability of results.<br> The following conclusions were obtained from this study. In 2003, total stand area of the three forest species was 31.04×10⁴ hm²; total biomass was 22.20 Tg; vegetation carbon storage was 13.07 Tg C; and average carbon density was 42.36 t C/hm². Carbon storage by different forest types in descending order was: <em>Pinus massoniana</em>, <em>Pinus elliottii </em>and <em>Cunninghamia lanceolata</em>. Carbon storage by age group in descending order was middle stand forests, young stand forests, near-mature stand forests, mature stand forests. Storage of carbon by plantation forests was 1.89 times higher than by natural forests. <em>Pinus massoniana</em> and <em>Cunninghamia lanceolata </em>forests were the main natural forest carbon sinks, while <em>Pinus elliottii </em>forests were the main plantation carbon sinks. Carbon density of the three species increased each year and increased 8.58 tC / hm² during the study period; this was 1.66 times higher than in 1985. Forest carbon storage was 4.91, 11.41, and 13.07 Tg C in 1985, 1994, and 2003, respectively. Average amount of carbon fixation was 0.45 Tg C/a per year. Stand area enlarged from 15.54 × 10⁴ hm²in 1985 to 30.30×10⁴ hm²in 1994. The carbon density of the three species was higher in the east and west of Taihe County and lower in the middle. It was higher in the east and north of Xingguo County than in the middle. Average carbon density was highest at 700 to 900 m altitude and 25 to 35° slope. Overall, carbon density of forest vegetation increased with increasing altitude and slope.<br> Afforestation projects contributed significantly to the increase in carbon storage in the red soil hilly region of Jiangxi Province. Understanding the growth patterns of the three species was important for calculation of biomass and carbon storage in these plantation ecosystems, and was crucial for forest management. Reasonable forest management may improve the carbon sequestration capacity of forest ecosystems. Further study should focus on the carbon reservoirs provided by other species and the soil in order to estimate the carbon fixation potential of the whole forest ecosystem.

Carbon Storage Estimation of Artificial Vegetation based on NDVI

Artificial vegetation is the important bio-component with absorbing dioxide carbon for supporting ecosystem health.Artificicial carbon sink forest play important function on reduction of carbon dioxide emission.Based on TM data of August,2009,the eco-landscape pattern information is obstained.Furthermore,using NDVI to estimate vegetation carbon density,which is a viable method.Through investigation the biomass of arbor layer and herbage layer,the carbon density of arbor layer and herbage layer are determined.The result as follows,the average carbon density is 37.04 mg/hm2 in the arbor layer,meanwhile,the average carbon density is 59.65 g/m2 in the 1 m×1 m sample site in the herbage layer.So,the total vegetation carbon density above the ground is about 37.64 mg/hm2.As a result,the carbon reserves is 250 915.5 mg in the whole vegetation layer.With the vegetation growth and biomass accumulation effects,the carbon sink function of the artificial vegetation will be further more bringing into played.

Carbon density and accumulation in woody species of tropical dry forest in India

We studied the carbon density and accumulation in trees at five sites in a tropical dry forest (TDF) to address the questions: how is the TDF structured in terms of tree and carbon density in different DBH (diameter at breast height) classes? What are the levels of carbon density and accumulation in the woody species of TDF? Is the vegetation carbon density evenly distributed across the forest? Does carbon stored in the soil reflect the pattern of aboveground vegetation carbon density? Which species in the forest have a high potential for carbon accumulation? The WSG among species ranged from 0.39 to 0.78 g cm −3. Our study indicated that most of the carbon resides in the old-growth (high DBH) trees; 88–97% carbon occurred in individuals ⩾19.1 cm DBH, and therefore extra care is required to protect such trees in the dry forest. Acacia catechu, Buchanania lanzan, Hardwickia binata, Shorea robusta and Terminalia tomentosa accounted for more than 10 t ha −1 carbon density, warranting extra efforts for their protection. Species also differed in their capacity to accumulate carbon indicating variable suitability for afforestation. Annually, the forest accumulated 5.3 t-C ha −1 yr −1 on the most productive, wettest Hathinala site to 0.05 t-C ha −1 yr −1 on the least productive, driest Kotwa site. This study indicated a marked patchy distribution of carbon density (151 t-C ha −1 on the Hathinala site to 15.6 t-C ha −1 on the Kotwa site); the maximum value was more than nine times the minimum value. These findings suggest that there is a substantial scope to increase the carbon density and accumulation in this forest through management strategies focused on the protection, from deforestation and fire, of the high carbon density sites and the old-growth trees, and increasing the stocking density of the forest by planting species with high potential for carbon accumulation.

Relationship between vegetation carbon storage and urbanization: A case study of Xiamen, China

Rapid growth of the Chinese urban population and the expansion of urban areas have led to changes in urban forest structure and composition, and consequently changes in vegetation carbon storage. The purpose of this study is to quantify the effects of urbanization on vegetation carbon storage in Xiamen, a city located in southern China. Data used for this study were collected from 39,723 sample plots managed according to the forest management planning inventory program. Data from these plots were collected in 4 non-consecutive years: 1972, 1988, 1996 and 2006. The study area was divided into three zones, which were defined according to their level of urbanization: the urban core, the suburban zone, and the exurban zone. Total vegetation carbon storage and the vegetation carbon density for each study period were calculated for each zone. Our results show that urban vegetation carbon storage has increased by 865,589.71 t during the period from 1972 to 2006 (34 years) in Xiamen, with a rapid increase between 1972 and 1996, then relatively little change between 1996 and 2006. The increase in vegetation carbon storage is mainly due to the large percentages of the suburban and exurban areas which exist in Xiamen city, and the implementation of reforestation programs in these two zones. The percentage of total regional carbon storage in the city center (urban core), suburbs and exurbs was 5%, 23% and 72%, respectively. This demonstrates that the exurbs store the majority of vegetation carbon, and thus play a critical role in the vegetation carbon storage of the study area. The intensification of urbanization in the future will likely expand the urban core and reduce the area of the suburbs and exurbs, and thus potentially decrease total vegetation carbon storage. This article concludes with a discussion of the implications of these results for vegetation carbon management and urban landscape planning.

Quantitative classification and carbon density of the forest vegetation in Lüliang Mountains of China

Forests play a major role in global carbon (C) cycle, and the carbon density (CD) could reflect its ecological function of C sequestration. Study on the CD of different forest types on a community scale is crucial to characterize in depth the capacity of forest C sequestration. In this study, based on the forest inventory data of 168 field plots in the study area (E 111°30′–113°50′, N 37°30′–39°40′), the forest vegetation was classified by using quantitative method (TWINSPAN); the living biomass of trees was estimated using the volume-derived method; the CD of different forest types was estimated from the biomass of their tree species; and the effects of biotic and abiotic factors on CD were studied using a multiple linear regression analysis. The results show that the forest vegetation in this region could be classified into 9 forest formations. The average CD of the 9 forest formations was 32.09 Mg ha−1 in 2000 and 33.86 Mg ha−1 in 2005. Form. Picea meyeri had the highest CD (56.48 Mg ha−1), and Form. Quercus liaotungensis + Acer mono had the lowest CD (16.14 Mg ha−1). Pre-mature forests and mature forests were very important stages in C sequestration among four age classes in these formations. Forest densities, average age of forest stand, and elevation had positive relationships with forest CD, while slope location had negative correlation with forest CD.

Carbon storage in the grasslands of China based on field measurements of above- and below-ground biomass

Above- and below-ground biomass values for 17 types of grassland communities in China as classified by the Chinese Grasslands Resources Survey were obtained from systematic replicated sampling at 78 sites and from published records from 146 sites. Most of the systematic samples were along a 5,000-km-long transect from Hailar, Inner Mongolia (49°15′N, 119°15′E), to Pulan, Tibet (30°15′N, 81°10′E). Above-ground biomass was separated into stem, leaf, flower and fruit, standing dead matter, and litter. Below-ground biomass was measured in 10-cm soil layers to a depth of 30 cm for herbs and to 50 cm for woody plants. Grassland type mean total biomass carbon densities ranged from 2.400 kg m -2 for swamp to 0.149 kg m -2 for alpine desert grasslands. Ratios of below- to above-ground carbon density varied widely from 0.99 for tropical tussock grassland to 52.28 for alpine meadow. Most below-ground biomass was in the 0-10 cm soil depth layer and there were large differences between grassland types in the proportions of living and dead matter and stem and leaf. Differences between grassland types in the amount and allocation of biomass showed patterns related to environments, especially aridity gradients. Comparisons of our estimates with other studies indicated that above-ground biomass, particularly forage-yield biomass, is a poor predictor of total vegetation carbon density. Our estimate for total carbon storage in the biomass of the grasslands of China was 3.32 Pg C, with 56.4% contained in the grasslands of the Tibet-Qinghai plateau and 17.9% in the northern temperate grasslands. The need for further standardized and systematic measurements of vegetation biomass to validate global carbon cycles is emphasised. © 2007 Springer Science+Business Media B.V.

Effects of soil freezing and thawing on vegetation carbon density in Siberia: A modeling analysis with the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ‐DGVM)

The current latitudinal gradient in biomass suggests a climate‐driven limitation of biomass in high latitudes. Understanding of the underlying processes, and quantification of their relative importance, is required to assess the potential carbon uptake of the biosphere in response to anticipated warming and related changes in tree growth and forest extent in these regions. We analyze the hydrological effects of thawing and freezing of soil on vegetation carbon density (VCD) in permafrost‐dominated regions of Siberia using a process‐based biogeochemistry‐biogeography model, the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ‐DGVM). The analysis is based on spatially explicit simulations of coupled daily thaw depth, site hydrology, vegetation distribution, and carbon fluxes influencing VCD subject to climate, soil texture, and atmospheric CO2 concentration. LPJ represents the observed high spring peak of runoff of large Arctic rivers, and simulates a realistic fire return interval of 100 to 200 years in Siberia. The simulated VCD changeover from taiga to tundra is comparable to inventory‐based information. Without the consideration of freeze‐thaw processes VCD would be overestimated by a factor of 2 in southern taiga to a factor of 5 in northern forest tundra, mainly because available soil water would be overestimated with major effects on fire occurrence and net primary productivity. This suggests that forest growth in high latitudes is not only limited by temperature, radiation, and nutrient availability but also by the availability of liquid soil water.

Carbon Storage of Forest Vegetation in China and its Relationship with Climatic Factors

Estimates of forest vegetation carbon storage in China varied due to different methods used in the assessments. In this paper, we estimated the forest vegetation carbon storage from the Fourth Forest Inventory Data (FFID) in China using a modified volume-derived method. Results showed that total carbon storage and mean carbon density of forest vegetation in China were 3.8 Pg C (about 1.1% of the global vegetation carbon stock) and 41.32 Mg/ha, respectively. In addition, based on linear multiple regression equation and factor analysis method, we analyzed contributions of biotic and abiotic factors (including mean forest age, mean annual temperature, annual precipitation, and altitude) to forest carbon storage. Our results indicated that forest vegetation carbon storage was more sensitive to changes of mean annual temperature than other factors, suggesting that global warming would seriously affect the forest carbon storage.

VEGETATION CARBON STORAGE OF MAJOR SHRUBLANDS IN CHINA

Background and Aims Shrublands is one of the major types of terrestrial ecosystems, which widely distributes from tropical to polar regions. Due to their largely distributional area in China, it is very important for us to exactly estimate their carbon storages and spatial distributions. Answers to the following questions were sought: (a) How much is the vegetation carbon storage of major shrublands in China? (b) How are their spatial distributions in China? Methods Based on published biomass data in shrublands and 1∶4 000 000 digital vegetation map of China, carbon storage of major shrublands in China was estimated using the method of mean biomass carbon density for different shrublands types. Key Results The carbon storage of six shrublands in China is 1.68±0.12 Pg C (1 Pg = 10 15 g) with an total area of 15 462.64×104 hm2. The average vegetation carbon density is 10.88±0.77 Mg C·hm -2 , varying from 5.92 to 17.00 Mg C·hm -2 for different shrubland types. The distribution of shrublands is spatially heterogeneous in the country. Shrublands in three provinces (Yunnan, Guizhou and Sichuan) in Southwest China occupies 23.5% of the total area and contributes to approximately one-third (32.6%) of the total carbon storage of six shrubland types in China due to favorable climeste and soil conditions. The area of six shrubland types in Inner Mongolia is the second largest among all the provinces. However, the vegetation carbon storage in Inner Mongolia shrublands is only 84.81 Tg C (1 Tg = 10 12 g), following that of Yunnan, Guizhou, Sichuan, Jiangxi, and Hunan. The probable reason is ascribed to its arid or semiarid climatic conditions. Although shrublands hold about 1.5 times the area of forests in China, the carbon storage of shrublands corresponds 27%-40% of forests because carbon density of shrublands accounts for only one-fifth of forests. Similarly, the proportion of vegetation carbon storage of shrublands to that of grasslands in China varies from 36% to 55% due to the different areas of grasslands used in previous studies. Conclusions This study draw the following conclusions: (a) As important ecosystem types in China, shrublands hold large vegetation carbon storage, which is main component of China's vegetation carbon storage. (b) Because of different climatic and soil conditions, their distributions are spatially heterogeneous in China and The average vegetation carbon density varies greatly for different shrubland types.

Vegetation and soil carbon storage in China

This study estimated the current vegetation and soil carbon storage in China using a biogeochemical model driven with climate, soil and vegetation data at 0.5° latitude-longitude grid spatial resolution. The results indicate that the total carbon storage in China’s vegetation and soils was 13.33 Gt C and 82.65 Gt C respectively, about 3% and 4% of the global total. The nationally mean vegetation and soil carbon densities were 1.47 kg C/m 2 and 9.17 kg C/m 2 , respectively, differing greatly in various regions affected by climate, vegetation, and soil types. They were generally higher in the warm and wet Southeast China and Southwest China than in the arid Northwest China; whereas vegetation carbon density was the highest in the warm Southeast China and Southwest China, soil carbon density was the highest in the cold Northeast China and southeastern fringe of the Qinghai-Tibetan Plateau. These spatial patterns are clearly correlated with variations in the climate that regulates plant growth and soil organic matter decomposition, and show that vegetation and soil carbon densities are controlled by different climatic factors.

In search of the missing carbon sink: a model of terrestrial biospheric response to land-use change and atmospheric CO&lt;sub&gt;2&lt;/sub&gt;

Estimates of the net exchange of carbon between the terrestrial biosphere and the atmosphere may be too large because the models of carbon release from changes in land use do not allow for enhanced carbon assimilation by the terrestrial biosphere in response to increasing atmospheric CO 2 . We address this deficiency with a model of terrestrial biosphere that includes both ecosystem response to land-use perturbation and vegetation response to atmospheric CO 2 . Model inputs specify the areas affected by land-use change since 1700. The carbon dynamics of the affected areas are described by an area distribution function for vegetation carbon density and a compartment model of carbon in vegetation, litter, and soil. Vegetation growth is modeled as the difference between net primary production (NPP) and mortality. NPP, the net flux of carbon from atmosphere to vegetation, is a logistic function of vegetation carbon density. The response of NPP to atmospheric CO 2 is modeled with three response functions: a logarithmic, a rectangular-hyperbolic, and a response function derived from a biochemical model of C 3 photosynthesis. The response functions are parameterized by ecosystem type with data from CO 2 exposure experiments. Elevated CO 2 affects the NPP of both undisturbed and recovering ecosystems. We use the model to test the hypothesis that the CO 2 enhancement of terrestrial NPP explains the historical missing carbon sink of the global carbon cycle budget. Our estimates of the biosphere's CO 2 enhanced carbon flux are much smaller than the reconstructed missing carbon sink. We conclude that our model results do not support the hypothesis. DOI: 10.1034/j.1600-0889.47.issue4.9.x