Estimating the carbon fluxes of forests with an individual-based forest model

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.

The impacts of modeling global CO2 concentrations with GEOS-Chem using different ocean carbon fluxes

The rise in atmospheric carbon dioxide(C02)concentrations caused by human activities is leading to global climate change,which poses a threat to human development and survival.This study analyzed the distribution of the ocean carbon flux with interannual changes and compared it with the climatological ocean carbon flux to deepen our understanding of carbon sources and sinks.To simulate global CO2 concentrations for the years2008-2010,the ocean carbon flux with interannual changes and the climatological ocean carbon flux were used to drive the GEOS-Chem model,an atmospheric chemical transport model.The simulated values were compared with the CO2 concentrations at nine observation stations to explore the influence of interannual changes in the ocean carbon fluxes on the simulated CO2 concentrations.The authors found that the difference between the two simulation results was greater in the Southern Hemisphere all year,and the difference in autumn was the largest.Compared with the observations,the simulated CO2 concentration of the ocean carbon flux with interannual changes is closer to the observations,indicating that this simulation is more accurate.

Carbon Fluxes and Sinks:the Consumption of Atmospheric and Soil CO_2 by Carbonate Rock Dissolution

Carbonate rock outcrops cover 9%-16% of the continental area and are the principal source of the dissolved inorganic carbon （DIC） transferred by rivers to the oceans, a consequence their dissolution. Current estimations suggest that the flux falls between 0.1-0.6 PgC/a. Taking the intermediate value （0.3 PgC/a）, it is equal to 18% of current estimates of the terrestrial vegetation net carbon sink and 38% of the soil carbon sink. In China, the carbon flux from carbonate rock dissolution is estimated to be 0.016 PgC/a, which accounts for 21%, 87.5%-150% and 2.3 times of the forest, shrub and grassland net carbon sinks respectively, as well as 23%-40% of the soil carbon sink flux. Carbonate dissolution is sensitive to environmental and climatic changes, the rate being closely correlated with precipitation, temperature, also with soil and vegetation cover. HCO3 in the water is affected by hydrophyte photosynthesis, resulting in part of the HCO~ being converted into DOC and POC, which may enhance the potential of carbon sequestration by carbonate rock dissolution. The possible turnover time of this carbon is roughly equal to that of the sea water cycle （2000a）. The uptake of atmospheric/soil CO2 by carbonate rock dissolution thus plays an important role in the global carbon cycle, being one of the most important sinks. A major research need is to better evaluate the net effect of this sink in comparison to an oceanic source from carbonate mineral precipitation.

Air-sea carbon fluxes and their controlling factors in the Prydz Bay in the Antarctic

The Prydz Bay in the Antarctic is an important area in the Southern Ocean due to its unique geographic feature. It plays an important role in the carbon cycle in the Southern Ocean. To investigate the distributions of carbon dioxide in the atmosphere and surface seawater and its air-sea exchange rates in this region, the Chinese National Antarctic Research Expedition （CHINARE） had set up several sections in the Prydz Bay. Here we present the results from the CHINARE-XVI cruises were presented onboard R/V Xue/ong from November 1999 to April 2000 and the main driving forces were discussed controlling the distributions of partial pressure of carbon dioxide. According to the partial pressure of carbon dioxide distributions, the Prydz Bay can be divided into the inside and outside regions. The partial pressure of carbon dioxide was low in the inside region but higher in the outside region during the measurement period. This distribution had a good negative correlation with the concentrations of ehlorophyll-a in general, suggesting that the partial pressure of carbon dioxide was substantially affected by biological production. The results also indicate that the biological produetion is most likely the main driving force in the marginal ice zone in the Southern Ocean in summer. However, in the Antarctic divergence sector of the Prydz Bay （about 64°S）, the hydrological processes become the controlling factor as the sea surface partial pressure of carbon dioxide is much higher than the atmospheric one due to the upwelling of the high DIC CDW, and this made the outside of Prydz Bay a source of carbon dioxide. On the basis of the calculations, the CO2 flux in January （austral summer） was -3.23 mmol/（m^2 · d） in the inner part of Prydz Bay, i.e. , a sink of atmospheric CO2, and was 0.62 mmol/（m^2 · d） in the outside part of the bay, a weak source of atmospheric CO2. The average air-sea flux of CO2 in the Prydz Bay was 2.50 mmol/（m^2 · d）.

Carbon fluxes in soil:long-term sequestration in deeper soil horizons

Terrestrial ecosystems represent the second largest carbon reservoir, and the C balance in terrestrial ecosystems can be directly impacted by human activities such as agricultural management practices and land-use changes. This paper focuses on the C-sequestration in soil. Although many studies showed that the concentration of SOC is much higher in the shallow soils (0-30 cm), the deeper horizons represent a much greater mass of soil and represent a huge C-storage pool. The process of preferential retention of more strongly adsorbing components, along with competitive displacement of weakly binding components are the key processes that enhance the movement of organic carbon to deeper soil horizons. DOC represents the most dynamic part of organic carbon in soils, and thus can be used as a timely indicator of the short-term change of C-sequestration. Long-term experiments have demonstrated that higher SOC levels in shallow soils would lead to increased fluxes of DOC to deeper horizons, but more data on a wider range of soils and treatment strategies are needed to fully evaluate the linkages between changes in SOC in shallow soil, vertical fluxes of DOC to deeper soil horizons, and enhanced C-inventories in deeper, slow-turnover SOC pools.

Carbon dioxide partial pressure and carbon fluxes of air-water interface in Taihu Lake, China

To obtain carbon dioxide （CO2） flux between water-air interface of Taihu lake, monthly water samplers at 14 sites and the local meteorological data of the lake were collected and analyzed in 1998. Carbon dioxide partial pressures （pCO2） at air-water interface in the lake were calculated using alkalinity, pH, ionic strength, active coefficient, and water temperature. The carbon fluxes at different sublakes and areas were estimated by concentration gradient between water and air in consideration of Schmidt numbers of 600 and daily mean windspeed at 10 m above water surface. The results indicated that the mean values of pCO2 in Wuli Lake,Meiliang Bay, hydrophyte area, west littoral zone, riverine mouths, and the open lake areas were 1 807.8±1 071.4（mean±standard deviation）μatm （latm=1.013 25×10^5pa）, 416.3±217.0μatm, 576.5±758.8μatm, 304.2±9.43.5μatm, 1 933.6±1 144.7 μatm, and 448.5±202.6μatm, respectively. Maximum and minimum pCO2 values were found in the hypertrophic （4 053.7μatm） and the eutrophic （3.2 μatm） areas. The riverine mouth areas have the maximum fluxes （82.0±62.8 mmol/m^2a）. But there was no significant difference between eutrophic and mesotrophic areas in pCO2 and the flux of CO2. The hydrophyte area, however, has the minimum （--0.58±12.9mmol/m^2a）. In respect to CO2 equilibrium, input of the rivers will obviously influence inorganic carbon distribution in the riverine estuary. For example, the annual mean CO2 flux in Zhihugang River estuary was 19 times of that in Meiliang Bay, although the former is only a part of the latter. The sites in the body of the lake show a clear seasonal cycle with pCO2 higher than atmospheric equilibrium in winter, and much lower than atmospheric in summer due to CO2 consumption by photosynthesis. The CO2 amount of the net annual evasion that enters the atmosphere is 28.42×10^4 t/a, of which those from the west littoral zone and the open lake account for 53.8% and 36.7%, respectively.

Changes in Global Vegetation Distribution and Carbon Fluxes in Response to Global Warming:Simulated Results from IAP-DGVM in CAS-ESM2

Terrestrial ecosystems are an important part of Earth systems,and they are undergoing remarkable changes in response to global warming.This study investigates the response of the terrestrial vegetation distribution and carbon fluxes to global warming by using the new dynamic global vegetation model in the second version of the Chinese Academy of Sciences(CAS)Earth System Model(CAS-ESM2).We conducted two sets of simulations,a present-day simulation and a future simulation,which were forced by the present-day climate during 1981-2000 and the future climate during 2081-2100,respectively,as derived from RCP8.5 outputs in CMIP5.CO_(2)concentration is kept constant in all simulations to isolate CO_(2)-fertilization effects.The results show an overall increase in vegetation coverage in response to global warming,which is the net result of the greening in the mid-high latitudes and the browning in the tropics.The results also show an enhancement in carbon fluxes in response to global warming,including gross primary productivity,net primary productivity,and autotrophic respiration.We found that the changes in vegetation coverage were significantly correlated with changes in surface air temperature,reflecting the dominant role of temperature,while the changes in carbon fluxes were caused by the combined effects of leaf area index,temperature,and precipitation.This study applies the CAS-ESM2 to investigate the response of terrestrial ecosystems to climate warming.Even though the interpretation of the results is limited by isolating CO_(2)-fertilization effects,this application is still beneficial for adding to our understanding of vegetation processes and to further improve upon model parameterizations.

Characteristics of Lake Breezes and Their Impacts on Energy and Carbon Fluxes in Mountainous Areas

In mountainous lake areas, lake–land and mountain–valley breezes interact with each other, leading to an "extended lake breeze". These extended lake breezes can regulate and control energy and carbon cycles at different scales. Based on meteorological and turbulent fluxes data from an eddy covariance observation site at Erhai Lake in the Dali Basin,southwest China, characteristics of daytime and nighttime extended lake breezes and their impacts on energy and carbon dioxide exchange in 2015 are investigated. Lake breezes dominate during the daytime while, due to different prevailing circulations at night, there are two types of nighttime breezes. The mountain breeze from the Cangshan Mountain range leads to N1 type nighttime breeze events. When a cyclonic circulation forms and maintains in the southern part of Erhai Lake at night, its northern branch contributes to the formation of N2 type nighttime breeze events. The prevailing wind directions for daytime, N1, and N2 breeze events are southeast, west, and southeast, respectively. Daytime breeze events are more intense than N1 events and weaker than N2 events. During daytime breeze events, the lake breeze decreases the sensible heat flux(Hs) and carbon dioxide flux(F_(CO_2)) and increases the latent heat flux(LE). During N1 breeze events, the mountain breeze decreases Hs and LE and increases F_(CO_2). For N2 breeze events, the southeast wind from the lake surface increases Hs and LE and decreases suppress carbon dioxide exchange.

A study on the simulation of carbon and water fluxes of Dangxiong alpine meadow and its response to climate change

The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of the Tibetan Plateau,is a typical example.To understand the carbon and water fluxes,water use efficiency(WUE),and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area,two parameter estimation methods,the Model-independent Parameter Estimation(PEST)and the Dynamic Dimensions Search(DDS),were used to optimize the Biome-BGC model.Then,the gross primary productivity(GPP)and evapotranspiration(ET)were simulated.The results show that the DDS parameter calibration method has a better performance.The annual GPP and ET show an increasing trend,while the WUE shows a decreasing trend.Meanwhile,ET and GPP reach their peaks in July and August,respectively,and WUE shows a“dual-peak”pattern,reaching peaks in May and November.Furthermore,according to the simulation results for the next nearly 100 years,the ensemble average GPP and ET exhibit a significant increasing trend,and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario.WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario.This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.

Carbon distribution and fluxes of 16 rivers discharging into the Bohai Sea in summer

Riverine carbon input is closely related to the inshore aquatic environment, the marine carbon pool and climate change. Samples were synchronously obtained from 16 rivers discharging into the Bohai Sea （China） in 1-5 July 2005. The dissolved organic carbon （DOC） concentrations of the 16 rivers were mainly controlled by anthropogenic activities. The particulate organic carbon （POC） of the Haihe, Luanhe, Ziyaxinhe, Chaobaixinhe, Xiaoqinghe, Xiaolinghe, Duliujianhe, Jiyunhe, and Majiahe Rivers mainly originated from pollutants discharged by human, while that of the Huanghe River （Yellow River）, Daliaohe, Shuangtaizihe, Tuhaihe, Dalinghe, Daqinghe, and Liuguhe Rivers were generated mainly by soil erosion. Higher dissolved inorganic carbon （DIC） concentrations in the 16 rivers were detected, which were influenced by the large amounts of carbonate and industrial pollution. The estimated DOC, POC and DIC fluxes from the 16 rivers discharging into the Bohai Sea in summer, 2005 were 0.91×10^5, 1.23×10^5 and 6.31×10^5t, respectively.

An inversion model based on GEOS-Chem for estimating global and China's terrestrial carbon fluxes in 2019

The 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories added the method of assimilating atmospheric CO_(2) concentrations to invert carbon sources and sinks;however,many global carbon inversion models are not publicly available.In addition,our regional assimilation inversion system,CCMVS-R(China Carbon Monitoring,Verification and Supporting for Regional),needs a global carbon inversion model with higher assimilation efficiency to provide boundary conditions.Here,an inversion model based on the global atmospheric chemistry model GEOS-Chem and a more accurate and easier-to-implement ensemble square root Kalman filter(EnSRF)algorithm is constructed and used to infer global and China's carbon fluxes in 2019.Atmospheric CO_(2) concentrations from ObsPack sites and five additional CO_(2) observational sites from China's Greenhouse Gas Observation Network(CGHGNET)were used for data assimilation to improve the estimate.The inverted annual global terrestrial and oceanic carbon uptake is 2.12 and 2.53 Pg C per year,respectively,accounting for 21.1%and 25.1%of global fossil fuel CO_(2) emissions.The remaining 5.41 Pg C per year in the atmosphere is consistent with the global atmospheric CO_(2) growth rates of 5.44 Pg C per year reported by the National Oceanic and Atmospheric Administration(NOAA),showing that the inversion model can provide a reasonable estimate of global-scale natural carbon sinks.The inverted terrestrial carbon sink of China is 0.37 Pg C per year,accounting for approximately 13%of China's fossil CO_(2) emissions.

Warming effects on permafrost ecosystem carbon fluxes controlled by plant nutrients

With the support by the National Natural Science Foundation of China,a recent study by the research group led by Prof.Yang Yuanhe(杨元合)from the Institute of Botany,Chinese Academy of Sciences shows that plant nutrients control the response of permafrost ecosystem carbon fluxes to warming。

Divergence of carbon dioxide fluxes in different trophic areas of Taihu Lake,China

Carbon dioxide partial pressures(pCO 2) and CO 2 fluxes on air water interface in different trophic level areas of Taihu Lake were calculated and corrected using alkalinity, pH, ionic strength, active coefficient, water temperature and wind speed on the basis of the data sets of monthly sampling in 1998 The mean values of pCO 2 in the hypertrophic, eutrophic, and mesotrophic areas are 1807 8±1025 8(mean±standard deviation) μatm, 416 3±207 8 μatm, and 448 5±194 0 μatm,respectively. A maximum and minimum pCO\-2 values were found in the hypertrophic(4053 7 μatm) and the eutrophic(3 2 μatm) areas. There was about one magnitude order of difference in mean CO\-2 fluxes between the hypertrophic area(27 3±17 4 mmol/(m\+2·d)) and the eutrophic(1 99±4 50 mmol/(m\+2·d)) and mesotrophic (2 22±4 31 mmol/(m\+2·d)) areas. But there was no significant difference between eutrophic and mesotrophic areas in pCO 2 and the flux of CO 2 In respect to CO 2 equilibrium, input of the rivers will obviously influence inorganic carbon distribution in the riverine estuary. An exponential relationship between the pCO 2 values and chlorophyll a concentrations was obtained( r =0 8356, n =60) in eutrophic bay. Results suggested that lake ecosystems, also may be considered as unique aggregation, which can contain and be patient of different components that have their relative independence so long as its size enough to large. A productive lake, though it has positive fluxes of CO 2 to atmosphere during the most of time, is a huge and permanent sink of carbon in terrestrial ecosystems through receiving a great quantity of carbon materials via rivers, precipitation, and biological production.

Lagged climatic effects on carbon fluxes over three grassland ecosystems in China

Aims The plasticity of ecosystem responses could buffer and post-pone the effects of climates on ecosystem carbon fluxes,but this lagged effect is often ignored.In this study,we used carbon flux data collected from three typical grassland ecosystems in China,including a temperate semiarid steppe in Inner mongolia(Neimeng site,Nm),an alpine shrub-meadow in Qinghai(Haibei site,Hb)and an alpine meadow steppe in Tibet(Dangxiong site,DX),to examine the time lagged effects of environmental factors on CO_(2) exchange.Methods Eddy covariance data were collected from three typical Chinese grasslands.In linking carbon fluxes with climatic factors,we used their averages or cumulative values within each 12-month period and we called them‘yearly’statistics in this study.To investigate the lagged effects of the climatic factors on the car-bon fluxes,the climatic‘yearly’statistics were kept still and the‘yearly’statistics of the carbon fluxes were shifted backward 1 month at a time.Important Findingssoil moisture and precipitation was the main factor driving the annual variations of carbon fluxes at the alpine Hb and DX,respectively,while the Nm site was under a synthetic impact of each climatic factor.The time lagged effect analysis showed that temperature had several months,even half a year lag effects on Co2 exchange at the three studied sites,while moisture’s effects were mostly exhibited as an immediate manner,except at Nm.In general,the lagged climatic effects were relatively weak for the alpine ecosystem.our results implied that it might be months or even 1 year before the variations of ecosystem carbon fluxes are adjusted to the current climate,so such lag effects could be resistant to more frequent climate extremes and should be a critical component to be considered in evaluating ecosystem stability.an improved knowledge on the lag effects could advance our understanding on the driving mechanisms of climate change effects on ecosystem carbon fluxes.

Integration of nitrogen dynamics into the land surface model AVIM.Part 2:baseline data and variation of carbon and nitrogen fluxes in China

The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.

Variation of fluxes of water vapor, sensible heat and carbon dioxide above winter wheat and maize canopies

Surface energy fluxes were measured using Bowen-Ratio Energy Balance technique (BREB) and eddy correlation system at Luancheng of Hebei Province, on the North China Plain from 1999 to 2001. Average diurnal variation of surface energy fluxes and CO2 flux for maize showed the inverse “U” type. The average peak fluxes did not appear at noon, but after noon. The average peak CO2 flux was about 1.65 mg m-2 s-1. Crop water use efficiency (WUE) increased quickly in the morning, stabilized after 10:00 and decreased quickly after 15:00 with no evident peak value. The ratio of latent heat flux (λE) to net solar radiation (Rn) was always higher than 70% during winter wheat and maize seasons. The seasonal average ratio of sensible heat flux (H) divided byR n stayed at about 15% above the field surface; the seasonal average ratio of conductive heat flux (G) divided by Rn varied between 5% and 13%, and the averageG/R> n from the wheat canopy was evidently higher than that from the maize canopy. The evaporative fraction (EF) is correlated to the Bowen ratio in a reverse function.EF for winter wheat increased quickly during that revival stage, after the stage, it gradually stabilized to 1.0, and fluctuated around 1.0. EF for maize also fluctuated around 1.0 before the later grain filling stage, and decreased after that stage.

Burial fluxes and source apportionment of carbon in culture areas of Sanggou Bay over the past 200 years

In this study, we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay, and preliminarily analyzed the reasons for the greater proportion of inorganic carbon burial fluxes （BFTIc）. The average content of total carbon （TC） in the Sanggou Bay was 2.14%. Total organic carbon （TOC） accounted for a small proportion in TC, more than 65% of which derived from terrigenous organic carbon （Ct）, and while the proportion of marine-derived organic carbon （Ca） increased significantly since the beginning of large-scale aquaculture. Total inorganic carbon （TIC） accounted for 60%-75% of TC, an average of which was 60%, with a maximum up to 90% during flourishing periods （1880-1948） of small natural shellfish derived from seashells inorganic carbon （SheU-IC）. The TC burial fluxes ranged from 31 g/（m2.a） to 895 g/（m2.a） with an average of 227 g/（m2.a）, which was dominated by TIC （about 70%）. Shell-IC was the main source of TIC and even TC. As the main food of natural shellfish, biogenic silica （BSi） negatively correlated with BFTIc through affecting shellfish breeding. BFTIc of Sta. S1, influenced greatly by the Yellow Sea Coastal Current, had a certain response to Pacific Decadal Oscillation （PDO） in some specific periods.

Application of least squares vector machines in modelling water vapor and carbon dioxide fluxes over a cropland

Least squares support vector machines (LS-SVMs), a nonlinear kemel based machine was introduced to investigate the prospects of application of this approach in modelling water vapor and carbon dioxide fluxes above a summer maize field using the dataset obtained in the North China Plain with eddy covariance technique. The performances of the LS-SVMs were compared to the corresponding models obtained with radial basis function (RBF) neural networks. The results indicated the trained LS-SVMs with a radial basis function kernel had satisfactory performance in modelling surface fluxes; its excellent approximation and generalization property shed new light on the study on complex processes in ecosystem.

Particulate organic carbon export fluxes on Chukchi Shelf,western Arctic Ocean,derived from ^(210)Po/^(210)Pb disequilibrium

Fluxes of particulate organic carbon （POC） were derived from ^210Po/^210Pb disequilibrium during the 4th Chinese National Arctic Research Expedition （CHINARE-4） from July 1 to September 28, 2010. Average residence times of particulate ^210Po in the euphotic zone were -16.00 a to 1.54 a, which are higher than those of dissolved ^210^Po （-6.89 a to -0.70 a）. Great excesses of dissolved ^210Po were observed at all stations, with an average 210^Po/^210^Pb ratio of 1.91±0.20, resulting from 210^Pb atmospheric deposition after sea ice melt. POC fluxes from the euphoric zone were estimated by two methods （E and B） in the irreversible scavenging model. Estimated POC fluxes were 945-126 mmol C/（m^2·a）and 1 848-109 mmol C/（m^2·a） by methods E and B, respectively, both decreasing from low to high latitude. The results are comparable to previous works for the same region, indicating efficient biological pumping in the Chukchi Sea. The results can improve understanding of the carbon cycle in the western Arctic Ocean.

Carbon storage and flux for alpine tundra ecosystems in Changbai Mountains,Northeast China

This paper examined the carbon storage and flux of vegetation-litter-soil in alpine tundra ecosystems in Changbai Mountains. Approximately 17251 t·a-1 of carbon was yearly stored in the vegetation and 15043.1 t·a^-1of carbon flew into soil by litters. The vegetation-litter-soil ecosystem stored 452624 t·a^-1 of carbon, which was the important CO2 sink. The net carbon storage was currently 3146 t·a^-1 in vegetation-litter-soil ecosystem.