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Due to a series of human activities like deforestation and land degradation, the concentration of greenhouse gases has risen significantly. Forest vegetation is an important part of forest ecosystems with high carbon sequestration potential. Estimates of the carbon sequestration rate of forest vegetation in various provinces and districts are helpful to the regional and global Carbon cycle. How to build an effective carbon sequestration potential model and reveal the spatiotemporal evolution trend and driving factors of carbon sequestration potential is an urgent challenge to be solved in carbon cycle simulation and prediction research. This study characterized the carbon sequestration status of forest vegetation using the modified CASA (Carnegie-Ames Stanford Approach) model and estimated the carbon sequestration potential from 2010 to 2060 using the FCS (Forest Carbon Sequestration) model combined with forest age and biomass under the four future Shared Socioeconomic Pathways (SSP) scenarios: SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, then proposes natural, social, and economic perspectives. This study found that the average NPP of the forest vegetation in Chongqing from 2000 to 2020 was 797.95 g C/m2, and the carbon storage by 2060 was 269.94 Tg C. The carbon sequestration rate varied between <0.01 Tg C/a and 0.20 Tg C/a in various districts and counties. Over time, forest growth gradually slowed, and carbon sequestration rates also decreased. Under the four future climate scenarios, the SSP5-8.5 pathway had the highest carbon sequestration rate. Natural factors had the greatest influence on changes in carbon sequestration rate. This result provides data support and scientific reference for the planning and control of forests and the enhancement of carbon sequestration capacity in Chongqing. [ABSTRACT FROM AUTHOR]

The destruction of vegetation structure and quantity leads to the weakening of the carbon sequestration capacity of the ecosystem. Building an ecological spatial network is a potent method for studying vegetation spatial distribution structures. The relationship between the spatial distribution structure of vegetation networks and carbon sequestration, as approached from the perspective of complex network theory, is understudied. This study uses the minimum resistance model (MCR) and morphological spatial pattern analysis (MSPA) to study the eco-space network and ecological node spatial structure and topological characteristics of vegetation in the ecologically sensitive area of the middle reaches of the Yellow River (ESAMRYR). Based on the Carnegie-Ames-Stanford approach (CASA) model, the vegetation Net Primary Productivity (NPP) of the study area is calculated, and the ecological carbon sequestration function of the ecological node is estimated, and the relationship between the ecological node and the topological indicators is analyzed. The study shows that the forest land carbon storage in the regions situated toward the south and east of the Yellow River ecologically sensitive area is the highest, accounting for twice the proportion of the area, and is very important in terms of increasing carbon storage. Most of the ecological sources in the study area have a higher topological importance than functional importance, and the sources with low coordination are mainly distributed in the southwest and northeast. We construct a topology and function coupling optimization model (TFCO) to explore the coordination between vegetation structure and carbon sequestration function, to determine the network optimization direction, and to propose optimization solutions. Analysis of network robustness and carbon sequestration capacity shows that the sturdiness and carbon sequestration of the enhanced network are significantly improved. This study provides strategies and methods for protecting ecological sensitive areas, optimizing vegetation spatial distribution, and enhancing carbon sequestration capacity. [ABSTRACT FROM AUTHOR]

(1) Background--The key and difficult point for all Chinese people to achieve common prosperity lies in some remote mountainous areas and forest areas, because these areas are highly overlapping areas of " old areas, ethnic minorities areas, border areas and poor areas" and they are the most unbalanced and inadequate areas of China's development. However, these areas are rich in forest resources. Forests are "reservoirs" "grain depots" "money banks" and "carbon pools". The realization quality of forests as "four repositories" is closely related to the realization degree of common prosperity. Giving full play to the role of forests as "four repositories" can not only promote the modernization of remote mountainous areas and forest areas, shorten the gap between urban and rural areas, but also an important cornerstone for promoting common prosperity. (2) Methods--This paper firstly analyzed the theoretical logic and historical logic of forests as "four repositories" promoting common prosperity by using historical analysis and case analysis, then discussed the practical logic of forests as "four repositories" promoting common prosperity by using case analysis, and finally put forward the realistic paths of forests as "four repositories" promoting common prosperity. (3) Results Forest is a "money bank", which contains its natural attributes, reflecting that forest re sources can be transformed into economic benefits, and it is consistent with the " two mountains" concept of "clear waters and green mountains are as valuable as mountains of gold and silver". Forest is a "reservoir", which contains its spiritual attributes, reflects the balance of forest and water and the symbiotic relationship of forest and water. Forest is a "carbon pool", which contains its social attributes, it is conducive to the moral awakening of social ecological protection, and improving the distribution system based on the principles of fairness and justice. Forest is a "grain depot", which contains its historical attributes, it demonstrates the bottom line thinking of maintaining food security, holding well and holding firmly China's rice bowls, and is of great significance to enhancing the people's sense of gain, happiness and security on the grain issue. (4) Conclusions and Discussions--This paper puts forward the following paths to give full play to the role of forests as " four repositories" to promote common prosperity: First, strive to form a value realization mechanism of forest ecological products with the government as the lead and the market as the main body. We can learn from the advanced experiences such as Costa Rica's horizontal payment for forest ecological services, Finland's biodiversity protection and ecological compensation system based on the voluntary participation of forest farmers and the signed agreements through negotiations, and Zhejiang's " 10,000 yuan per acre mountain" model to enrich the people, so as to give full play to the role of forests as "money banks" to ensure the rich wealth of people in remote mountainous areas and forest areas. Second, give full play to the role of forests as "reservoirs", realize the spatio-temporal regulation of water resources, and promote the realization of forest functions such as purifying water quality, regulating climate and beautifying the environment. Third, vigorously seek food from forests, which will help ease the pressure on arable lands, ensure grain and oil security, and effectively promote the efficiency of forestry and increase the income of forest farmers. Fourth, give full play to the role of forests as "carbon pools" and enhance the capacity of forest carbon sequestration and sinks. It is conducive to giving full play to the role of " carbon sinks" forestry in climate changes in the context of the " double carbon" era, and better achieve the goal of improving the forest governance system and promoting the common prosperity of remote mountainous areas and forest areas. [ABSTRACT FROM AUTHOR]

Forest stock volume (FSV) is a major indicator of forest ecosystem health and it also plays an important part in understanding the worldwide carbon cycle. A precise comprehension of the distribution patterns and variations of FSV is crucial in the assessment of the sequestration potential of forest carbon and optimization of the management programs of the forest carbon sink. In this study, a novel vegetation index based on Sentinel-2 data for modeling FSV with the random forest (RF) algorithm in Helan Mountains, China has been developed. Among all the other variables and with a correlation coefficient of r = 0.778, the novel vegetation index (NDVIRE) developed based on the red-edge bands of the Sentinel-2 data was the most significant. Meanwhile, the model that combined bands and vegetation indices (bands + VIs-based model, BVBM) performed best in the training phase (R2 = 0.93, RMSE = 10.82 m3ha−1) and testing phase (R2 = 0.60, RMSE = 27.05 m3ha−1). Using the best training model, the FSV of the Helan Mountains was first mapped and an accuracy of 80.46% was obtained. The novel vegetation index developed based on the red-edge bands of the Sentinel-2 data and RF algorithm is thus the most effective method to assess the FSV. In addition, this method can provide a new method to estimate the FSV in other areas, especially in the management of forest carbon sequestration. [ABSTRACT FROM AUTHOR]

Nature-based Solutions (NbS) can undoubtedly play a significant role in carbon neutrality strategy. Forests are a major part of the carbon budget in terrestrial ecosystems. The possible response of the carbon balance of southwestern forests to different climate change scenarios was investigated through a series of simulations using the forest ecosystem carbon budget model for China (FORCCHN), which clearly represents the influence of climate factors on forest carbon sequestration. Driven by downscaled global climate model (GCM) data, the FORCCHN evaluates the carbon sink potential of southwestern forest ecosystems under different shared socioeconomic pathways (SSPs). The results indicate that, first, gross primary productivity (GPP), ecosystem respiration (ER) and net primary productivity (NPP) of forest ecosystems are expected to increase from 2020 to 2060. Forest ecosystems will maintain a carbon sink, but net ecosystem productivity (NEP) will peak and begin to decline in the 2030s. Second, not only is the NEP in the SSP1-2.6 scenario higher than in the other climate change scenarios for 2025–2035 and 2043–2058, but the coefficient of variation of the NEP is also narrower than in the other scenarios. Third, in terms of spatial distribution, the carbon sequestration potential of northwest and central Yunnan is significantly higher than that of other regions, with a slight upward trend in NEP in the future. Finally, GPP and ER are significantly positively correlated with temperature and insignificantly correlated with precipitation, and the increasing temperature will have a negative and unstable impact on forest carbon sinks. This study provides a scientific reference for implementing forest management strategies and achieving sustainable development. [ABSTRACT FROM AUTHOR]

Subtropical forests act as a carbon sink and play an important role in mitigating global warming. However, the understanding of the effects of stand characteristics and climatic factors on forest carbon sequestration capacity remains limited. Based on multiple regression analyses using structural equation modeling and plot-level data of coniferous and broadleaf forests from the national forest resource inventories, our study quantified vegetation carbon accumulation rate (VCAR) and the underlying influence pattern in Zhejiang Province, Southeastern China. The mean VCAR of coniferous and broadleaf forests was 2.30 Mg C ha−1 yr−1 and 4.53 Mg C ha−1 yr−1 during 2004–2009, and 1.56 Mg C ha−1 yr−1 and 1.98 Mg C ha−1 yr−1 during 2009–2014, respectively. Stand characteristics (i.e., change in tree density and mean diameter at breast height) and climatic factors (i.e., mean annual precipitation (MAP), temperature, sunshine hours, and monthly precipitation fluctuation) were the major driving factors on the change patterns of VCAR. All factors, except precipitation fluctuation, had positive effects on VCAR. The positive effects of MAP decreased with the increase in MAP, but the negative effects of precipitation fluctuation increased with the increase in precipitation fluctuation. Precipitation increased with increasing elevation, while the VCAR was lower at lower elevations. Additionally, we found that broadleaf forests could be able to cope better with the negative effects of precipitation fluctuation. Overall, this study provides new insights into the sensitivity and potential of vegetation carbon accumulation for structural development and climate change response in Zhejiang Province to better promote sustainable forestry development. [ABSTRACT FROM AUTHOR]

Forest ecosystems can be regarded as huge carbon sinks. In order to effectively assess carbon balance in such ecosystems, rapid and accurate estimation of the aboveground biomass of a forest is critically needed. However, the current methods for biomass estimation and mapping are of limited spatial resolution and mostly depend on large numbers of measurements. In order to obtain better biomass estimation outcomes with higher spatial resolution, a rapid method is introduced for region-scale biomass estimation in alpine and canyon areas using space-borne light detection and ranging (LiDAR) data and optical remote-sensing images. Specifically, we explored alpine and canyon areas in Shangri-La City in China using space-borne LiDAR data from ICESAT-2 and optical remote-sensing images from Landsat8 OLI, Sentinel-2, and Microwave remote sensing Sentinel-1. An extrapolation model of the forest canopy heights in these areas was constructed with a 30-m resolution of continuous canopy height outputs. For continuously estimating the diameter at breast height (DBH) in Shangri-La City, a tree height-DBH growth model was constructed based on the LiDAR and remote-sensing measurements. Finally, based on the average DBH of the explored forests, a model was constructed for estimating and mapping the aboveground biomass and carbon storage in Shangri-La with a spatial resolution of 30 m. The results show that the forest canopy height in Shangri-La City is mainly in the range of 2.82–30.96 m, and that the estimation accuracy is verified by the LiDAR-based canopy height model (CHM) with a coefficient of determination of R2 = 0.7143. The inversion results were still largely affected by geospatial location factors (longitude, latitude), terrain factors (slope, elevation), and vegetation indices (NBR, NDGI, NDVI). Based on the relationship between the tree height and the DBH, the DBH of trees in Shangri-La City was estimated to be mainly in the range of 20 cm to 30 cm, and this estimate was verified by actual measurements with R2 greater than 0.7 all. Finally, the established model estimated the aboveground forest biomass and carbon storage of the study area of Shangri-La City in 2020 to be 1.28 × 108 t and 6.41 × 107 t, respectively. These estimates correspond to total accuracies of 92.28%, respectively. [ABSTRACT FROM AUTHOR]

Forest carbon sinks (FCS) play an important role in mitigating global climate change, but there is a lack of more accurate, comprehensive, and efficient forest carbon stock estimates and projections for larger regions. By combining 1980–2020 land use data from the Northeast China Forestry (NCF) and climate change data under the Shared Socioeconomic Pathway (SSP), the land use and cover change (LUCC) of NCF in 2030 and 2050 and the FCS of NCF were estimated based on the measured data of forest carbon density. In general, the forest area of NCF has not yet recovered to the level of 1980. The temporal change in the FCS experienced a U-shaped trend of sharp decline to slow increase, with the inflection point occurring in 2010. If strict ecological conservation measures are implemented, the FCS of the NCF is expected to recover to the 1980 levels by 2050. We believe that the ecological priority (EP) scenario is the most likely and suitable direction for future development of the NCF. We also advocate for more scientific and stringent management measures for NCF natural forests to unlock the huge potential for forest carbon sequestration, which is important for China to meet its carbon neutrality commitments. [ABSTRACT FROM AUTHOR]

• Propose a novel method for post-fire forest recovery extraction. • Modify LandTrendr algorithm for identifying finer post-fire recovery patterns. • Quantify post-fire forest recovery over large areas and long time series. • Reveal latitudinal and altitudinal gradients in P. yunnanensis forest recovery. Forest fires profoundly affect forest growth, and then alter forest ecosystem services and global carbon cycles. Quantitatively characterizing the trajectories of post-fire forest recovery or regrowth is crucial for understanding the effects of increasing wildfires from local to global scales. However, obtaining synoptic and large-scale patterns of post-fire recovery trajectories from remotely sensed data remains challenging. In this study, we propose a modified LandTrendr (LT) recovery detection method (mLT-Recovery) that integrates an optimal segmented LandTrendr algorithm (os-LT) with a recovery trajectory classification method (ReTClass). This novel approach was applied to map and classify the post-fire recovery trajectories of forests predominantly composed of Pinus yunnanensis (P. yunnanensis) , which is a typical fire-adapted tree species in southwest China. The os-LT derives optimal segmented trajectories for each pixel by limiting the maximum number of segments to 3, allowing adjustable trajectory length from the disturbance year to the latest year, and using RMSE instead of p-value from F-statistics as the criterion for selecting an optimal trajectory. The resulting trajectories are classified by the ReTClass based on trajectory morphology, number of segments, and two derivative metrics (i.e., Years to Recovery and Recovery Ratio). Compared to the LT, the os-LT increased the proportion of trajectories with three segments by 59.81 % and lowered the median RMSE of trajectories by 30.63 %. Generally, fire-disturbed P. yunnanensis forests exhibit a dominant recovery trajectory characterized by rapid initial recovery followed by stabilization. The average recovery duration varies substantially across different geographical zones: 8.88 years in plateau temperate humid/sub-humid zone, 6.61 years in mid-subtropical humid zone, and 5.71 years in southern subtropical humid zone, respectively. The outperformance of the mLT-Recovery proposed herein highlights a promising application prospect for accurately characterizing post-fire forest recovery trajectories and estimating carbon sequestration in forest ecosystems. [ABSTRACT FROM AUTHOR]

• A new forest carbon sink potential index (FCSPI) coupled forest growth model and climate-productivity model was constructed. • Wall-to-wall mapping FCSPI across subtropical forest based on the site quality index for carbon sink (SIC). • Forest carbon sequestration potential ability may gradually decrease over the next 3 decades in subtropical zone. Due to the important role of forests in carbon neutrality, it is a big task in accurately calculating and predicting forest carbon storage and carbon sink capacity in recent years. However, considering the factors on the capacity of forest carbon sequestration, ecologists and foresters consider different models to evaluate the forest carbon sink ability at different scales, with foresters focusing more on forest growth models, while ecologists adding more climate and environmental factors, which may result in inconsistent results in carbon storage. Therefore, constructing an integrated model by combining the forestry and ecology models is essential for accurately quantifying and characterizing the forest carbon sink potential at the regional scale. Here, we proposed a new forest carbon sink potential index (FCSPI), which is defined as fractional deficiency of the current forest carbon to its maximum level, based on forest permanent plots, climate, and edaphic data to evaluate the forest sink potential ability from stand level to zonal scale across the northern subtropical zone in Hubei province, China, which coupled the stand growth model and climate-productivity model. The results at stand level showed that the R2 and RMSE of FCSPI were 0.78 and 0.072 respectively, which indicated that the FCSPI is an intuitive, highly practical, straightforward, easy, and rapid to implement methodology for forest carbon sequestration assessment. Moreover, FCSPI can conveniently extended from stand scale to zonal scale based on the site quality index for carbon sink (SIC) and stand age variables, which were derived from the opened climate, edaphic, and topographic data. The results of wall-to-wall FCSPI across the subtropical forest in Hubei province reveal the current and future carbon potential sequestration, which can help managers to focus on forest management for climate-smart actions and planning in forest ecosystem services framework. [ABSTRACT FROM AUTHOR]

The area of forest established through afforestation/reforestation has been increasing on a global scale, which is particularly important as these planted forests attenuate climate change by sequestering carbon. However, the determinants of soil organic carbon (SOC) sequestration and their contribution to the ecosystem carbon sink of planted forests remain uncertain. By using globally distributed data extracted from 154 peer‐reviewed publications and a total of 355 sampling points, we investigated above‐ground biomass carbon (ABC) sequestration and SOC sequestration across three different climatic zones (tropical, warm temperate, and cold temperate) through correlation analysis, regression models, and structural equation modeling (SEM). We found that the proportion of SOC sequestration in the ecosystem C sequestration averaged 14.1% globally, being the highest (27.0%) in the warm temperate and the lowest (10.7%) in the tropical climatic zones. The proportion was mainly affected by latitude. The sink rate of ABC (RABC) in tropical climates (2.48 Mg C ha−1 year−1) and the sink rate of SOC (RSOC) in warm temperate climates (0.96 Mg C ha−1 year−1) were higher than other climatic zones. The main determinants of RSOC were the number of frost‐free days, latitude, mean annual precipitation (MAP), and SOC density (SOCD) at the initial observation; however, these variables depended on the climatic zone. According to the SEM, frost‐free period, mean annual temperature (MAT) and MAP are the dominant driving factors affecting RSOC in Chinese plantations. MAT has a positive effect on RSOC, and global warming may increase RSOC of temperate plantations in China. Our findings highlight the determinants of SOC sequestration and quantitatively reveal the substantial global contribution of SOC sequestration to ecosystem carbon sink provided by planted forests. Our results help managers identify and control key factors to increase carbon sequestration in forest ecosystems. [ABSTRACT FROM AUTHOR]

Carbon sink is an effective measure to balance the contradiction between economic development and mitigating climate change in China. This paper reveals that environmental performance of forest carbon sinks reflects in economic value by reducing the emissions abatement cost. The carbon trading system is used to demonstrate the environmental and economic value of forests. The forest carbon sequestrations are estimated and predicted in different regions of China. Furthermore, a market model has been established to assess how the emission reduction costs can be reduced among all regions by the year 2030 to achieve the goal of carbon emissions intensity in China. The results show that carbon sequestration trades can reduce the emissions reduction costs and it can represent the value of forest carbon sinks. In particular, when economic growth is maintained in moderate and low level in China, the national carbon trading market with carbon sequestration will decrease the carbon emissions reduction costs more effectively. Besides, carbon sink can bring economic benefits to under-developed regions where there are rich forest resources. Image 1 • Carbon sinks are coordination between the environment and the economy. • Carbon sinks can be valued by emissions trading market. • Forest carbon sinks help to achieve carbon emissions reduction targets. • Forest carbon sinks promote economic development in some backward areas. [ABSTRACT FROM AUTHOR]

It is critical to accurately estimate carbon (C) turnover time as it dominates the uncertainty in ecosystem C sinks and their response to future climate change. In the absence of direct observations of ecosystem C losses, C turnover times are commonly estimated under the steady state assumption (SSA), which has been applied across a large range of temporal and spatial scales including many at which the validity of the assumption is likely to be violated. However, the errors associated with improperly applying SSA to estimate C turnover time and its covariance with climate as well as ecosystem C sequestrations have yet to be fully quantified. Here, we developed a novel model‐data fusion framework and systematically analyzed the SSA‐induced biases using time‐series data collected from 10 permanent forest plots in the eastern China monsoon region. The results showed that (a) the SSA significantly underestimated mean turnover times (MTTs) by 29%, thereby leading to a 4.83‐fold underestimation of the net ecosystem productivity (NEP) in these forest ecosystems, a major C sink globally; (b) the SSA‐induced bias in MTT and NEP correlates negatively with forest age, which provides a significant caveat for applying the SSA to young‐aged ecosystems; and (c) the sensitivity of MTT to temperature and precipitation was 22% and 42% lower, respectively, under the SSA. Thus, under the expected climate change, spatiotemporal changes in MTT are likely to be underestimated, thereby resulting in large errors in the variability of predicted global NEP. With the development of observation technology and the accumulation of spatiotemporal data, we suggest estimating MTTs at the disequilibrium state via long‐term data assimilation, thereby effectively reducing the uncertainty in ecosystem C sequestration estimations and providing a better understanding of regional or global C cycle dynamics and C‐climate feedback. Underestimated ecosystem carbon turnover time and sequestration under the steady state assumption (SSA) written summary: Considerable biases may arise when improperly invoking the SSA to estimate carbon turnover time at realistic dynamic disequilibrium state. This issue has not yet been carefully examined. Our finding provides a better understanding of the SSA‐induced uncertainty and the global carbon cycle dynamics and carbon‐climate feedback for future research. The SSA significantly underestimates the carbon turnover time by 29% and its sensitivity to temperature and precipitation by 22% and 42%, respectively, thereby leading to a 4.83‐fold underestimation of NEP in China's monsoonal forests, a principal C sink globally. These biases are negatively associated with forest age. [ABSTRACT FROM AUTHOR]

• We predicted China's forest carbon sinks with and without carbon trading. • Forest carbon sinks will help China achieve carbon neutrality. • Trading forest carbon sinks can boost China's sequestration. • The effect of the existing carbon trading price ($6.84/ton) will not be obvious. • China's unified carbon emission trading market should include forests. To achieve carbon peaking and neutrality goals, China is establishing a national unified carbon emission trading market, especially including forest carbon sequestration market. This study assesses the potential of China's forest carbon sinks and mitigation potential. We use the Global Forest Products Model to simulate the dynamic changes in China's forest resources from 2018 to 2060, under different carbon sequestration prices scenarios. The projection results indicate that China's forest carbon sinks will be 1.26 Pg (peta-grams) in 2021–2030 and 6.78 Pg in 2021–2060, giving an offset ratio of 4.9–7.0 % and 13.2–18.2 % of China's projected carbon emission in the same period, respectively. Therefore, China's forest carbon sinks will play an important role in carbon peaking and neutrality goals. Meanwhile, forest carbon trading has the potential to increase China's forest carbon sequestration, although the impact may not be immediately apparent. The additional increase in forest carbon sinks from carbon sequestration trading scenarios will not exceed 1.6 % of China's total carbon emissions between 2021 and 2030. At the current carbon trading price in China ($6.84/t), the increase in forest carbon sinks resulting from forest carbon trading will give an offset ratio of approximately 1 % of total carbon emissions from 2021 to 2060. When the carbon price rises, this offset ratio is 2.3 % to 3.1 % ($25/t), 4.1 % to 5.6 % ($54/t). China should therefore hasten the integration of forest carbon sinks into the national carbon emission unified market and boost the carbon trading price by policy design and market adjustment, or government directly compensate for the forest carbon sequestration function. For forest carbon sinks to play their role in reducing the carbon neutral cost of society, China should raise the amount of forest carbon sink CCERs (Chinese Certified Emission Reductions) used to offset carbon emission allowances in key emission units. [ABSTRACT FROM AUTHOR]

This paper reports change in forest carbon stocks and their relationship to investment in forestry fixed assets in silviculture in China employing the forest stock volume conversion method for carbon stocks and annual sinks. The paper establishes carbon stock estimates, and then analyses recent carbon stock trends of main coniferous species based on the latest inventory of China’s forest resources. The inventory data cover the seven dominant coniferous species from 1989 to 2008. The paper shows that investment in forestry fixed assets in silviculture and forest carbon stocks of some species have a significant effect with a lag of 3–7 years; and there is discussion of various problems regarding forest carbon stocks and sinks. [ABSTRACT FROM PUBLISHER]

Biomass carbon accumulation in forest ecosystems is a widespread phenomenon at both regional and global scales. However, as coupled carbon-climate models predicted, a positive feedback could be triggered if accelerated soil carbon decomposition offsets enhanced vegetation growth under a warming climate. It is thus crucial to reveal whether and how soil carbon stock in forest ecosystems has changed over recent decades. However, large-scale changes in soil carbon stock across forest ecosystems have not yet been carefully examined at both regional and global scales, which have been widely perceived as a big bottleneck in untangling carbon-climate feedback. Using newly developed database and sophisticated data mining approach, here we evaluated temporal changes in topsoil carbon stock across major forest ecosystem in China and analysed potential drivers in soil carbon dynamics over broad geographical scale. Our results indicated that topsoil carbon stock increased significantly within all of five major forest types during the period of 1980s-2000s, with an overall rate of 20.0 g C m−2 yr−1 (95% confidence interval, 14.1-25.5). The magnitude of soil carbon accumulation across coniferous forests and coniferous/broadleaved mixed forests exhibited meaningful increases with both mean annual temperature and precipitation. Moreover, soil carbon dynamics across these forest ecosystems were positively associated with clay content, with a larger amount of SOC accumulation occurring in fine-textured soils. In contrast, changes in soil carbon stock across broadleaved forests were insensitive to either climatic or edaphic variables. Overall, these results suggest that soil carbon accumulation does not counteract vegetation carbon sequestration across China's forest ecosystems. The combination of soil carbon accumulation and vegetation carbon sequestration triggers a negative feedback to climate warming, rather than a positive feedback predicted by coupled carbon-climate models. [ABSTRACT FROM AUTHOR]

Accurate estimates of forest carbon storage and changes in storage capacity are critical for scientific assessment of the effects of forest management on the role of forests as carbon sinks. Up to now, several studies reported forest biomass carbon (FBC) in Liaoning Province based on data from China's Continuous Forest Inventory, however, their accuracy were still not known. This study compared estimates of FBC in Liaoning Province derived from different methods. We found substantial variation in estimates of FBC storage for young and middle-age forests. For provincial forests with high proportions in these age classes, the continuous biomass expansion factor method (CBM) by forest type with age class is more accurate and therefore more appropriate for estimating forest biomass. Based on the above approach designed for this study, forests in Liaoning Province were found to be a carbon sink, with carbon stocks increasing from 63.0 TgC in 1980 to 120.9 TgC in 2010, reflecting an annual increase of 1.9 TgC. The average carbon density of forest biomass in the province has increased from 26.2 Mg ha−1 in 1980 to 31.0 Mg ha−1 in 2010. While the largest FBC occurred in middle-age forests, the average carbon density decreased in this age class during these three decades. The increase in forest carbon density resulted primarily from the increased area and carbon storage of mature forests. The relatively long age interval in each age class for slow-growing forest types increased the uncertainty of FBC estimates by CBM-forest type with age class, and further studies should devote more attention to the time span of age classes in establishing biomass expansion factors for use in CBM calculations. [ABSTRACT FROM AUTHOR]

In response to climate change, carbon emission reduction has become an important goal worldwide. Forests are the largest carbon pool in terrestrial ecosystems with a high carbon density and a fast carbon accumulation rate, and play a key role in the global carbon cycle. In this paper, the dynamic change and influence factors of forest carbon sequestration efficiency was analysis using the Data Envelopment Analysis Malmquist method in province level of China. The results showed that Heilongjiang, Yunnan, Tibet, Sichuan, and Inner Mongolia had the highest carbon sequestration, while northern China, eastern China, and southwestern China had the highest carbon sequestration efficiency. Furthermore, the factors of gross domestic product (GDP) per capita, urbanization, and the length of the highway network had significant positive impacts on the carbon sequestration efficiencies, while the total imports and exports had a significant negative impact. Ecological afforestation, temperature, GDP per capita, urbanization, population, and total imports and exports had spillover effects. It is recommended that the northeastern, central-southern, and southwestern regions with high carbon sequestration efficiencies should be used as the main areas to enhance carbon sinks in the future, and the areas with low efficiencies should respect the laws of nature more. Provinces should take into account the characteristics of the science and technology needs of forest areas and should provide forestry technology extension services. The results of this study are of great significance to improving the efficiency of financial investments, forest quality, and carbon sinks. • Forest transition has shifted from increased forest land cover to increased forest ecosystem services; •Factors affecting the level of forest carbon sequestration productive efficiency are Natural conditions--bio-physical; urbanization rate; economic and demographic conditions; degree of openness •Northeast, Central South, and Southwest of China with high carbon sequestration efficiency can be used as the main areas; •This result would be conducive to carry out the ecological construction of suitable forests. [ABSTRACT FROM AUTHOR]

Over the past two decades, the burning of fossil fuels in China has been excessive, causing carbon emissions to increase. Surface temperatures and the occurrence of natural disasters have also increased. Considering the important role of forests in reducing emissions, China conducted a series of studies on carbon storage by forest vegetation that involved well-developed estimation methods. However, there are still uncertainties in predicting future changes in forest vegetation acting as a carbon sink. This study used data collected from 7801 national forest inventory (NFI) forest plots in 2003, 2008 and 2013 as well as related forest ecosystem biomass data. The dynamic growth, biomass and carbon storage of arbor, economic and shrubbery forests were studied. This study made a breakthrough in predicting forest biomass and carbon storage based on growth-related changes in forest vegetation in China, improved the accuracy of predicting arbor forest carbon storage and filled a gap in research on the carbon storage/sink properties of economic, shrubbery and bamboo forests. In the results of this study, from 2003 to 2050, the carbon storage, density and carbon sink of forest vegetation in China increased rapidly. Mature forests in China played a major role in the increase in carbon storage, and the quality of young, half-mature and mature forests steadily improved. China's forest carbon storage was mainly concentrated in the southwestern and northeastern regions, between which the southwestern region had the highest carbon density. In addition, carbon storage and density increased faster in the southwestern region than in the northeastern region. The carbon storage and density of forest vegetation were greater in Tibet than in other areas. The carbon storage of forest vegetation in Tibet increased faster than that in other areas, and the carbon density of forest vegetation in Xinjiang increased faster than that in other areas. In addition, the carbon storage and carbon density of forest vegetation in Ningxia increased slower than those in other areas. From 2020 to 2050, China's forest vegetation will absorb 22.14% of CO 2 emissions from fossil fuel combustion, which will play an important role in slowing increases in greenhouse gases in the next 30 years. • Breakthrough in predicting forest carbon storage from vegetation growth changes. • Filling the carbon sink research gap of economic, shrubbery and bamboo forests. • China's mature forests will play a major role in the growth of carbon storage. • China's forest carbon storage is concentrated in southwest and northeast regions. • China's forest vegetation will absorb 22.14% of CO 2 emissions from 2020 to 2050. [ABSTRACT FROM AUTHOR]