Search

As a key parameter for C pool and flux assessments, vegetation carbon (C) content can be used in ecological models to predict climate-induced changes in the C sequestration capacity of vegetation. However, the differences in methods for upscaling C content from the organ to the community scale and their impact on regional C stock estimates have been ignored. Based on a comprehensive community structure survey of 72 typical natural ecosystems in China and 27,905 measured samples of plant organs (leaves, twigs, trunks, and roots), we first quantified the differences among scaling-up methods for vegetation C content. These methods included the community or dominant species-weighted mean, geometric mean, arithmetic mean, and traditional empirical coefficients (45 % and 50 %), and their impact on C storage estimation at the regional scale. Comparing the accuracy, variability, and response patterns of the different scaling-up methods, the dominant C species biomass-weighted mean (C DWM ) method had the highest similarity to the community-weighted C mean (C CWM ) method. Concerning vegetation C storage estimation in China's natural terrestrial ecosystems, the relative errors of the other methods ranged from -2.6 % to 8.22 % compared with that of the C CWM method (18.39 Pg C). The empirical coefficients had the highest uncertainty, with a 45 % empirical coefficient underestimating the vegetation C stock by 2.60 %, and a 50 % empirical coefficient overestimating it by 8.22 %. The C DWM method proposed here has high reliability for C storage estimation (overestimated by only 0.44 %), making it a preferable sampling and scaling-up method for regional C content and stock assessment. Additionally, our study provided the C content of plant organs for China's provinces and typical vegetation types based on the C CWM , which could be used for regional C stock assessment and C cycle models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The rapid increase in carbon and other greenhouse gases is likely to change the regional and global temperature, and planning of these gases is needed. The present study focused on National Highway-16 of the Srikakulam district, which was upgraded from 4 to 6 lane standards to facilitate traffic. This study intended to compute the carbon sequestration and storage capacity of above and belowground biomass. This helps in the comparison and impact of the road project on flora and its carbon pool, from where future tree stock changes can be prepared. A total of 1930 plots were constructed of criss-crosses of equal size (2 × 100 m). All woody trees with dbh ≥ 30 cm were considered and their diameters were measured. A total of 29 tree species belonging to 13 families were identified; the quantity of macrobiotic carbon sequestered as a whole, i.e., above and below ground, was 768,890.29 tC and 199,911.48 tC , respectively. The mean sequestration rate of carbon as biomass above ground was 1.19 tC/tree, and that below ground was 0.31 tC/tree . The estimated average C-Stock per tree was 1.5 tC ; however, the mean C-Stock per quadrate was 250.2 tC ., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The intensification and expansion of changes in land use and land cover (LULC) can reduce the availability and quality of natural habitats and ecosystem services (ES). These changes have generated environmental damage in different parts of the world, especially in biomes more susceptible to modifications, such as the Pampa biome in the extreme south of Brazil. The Pampa biome has been neglected by environmental protection laws, despite its broad ecosystem and social importance. In this study, we used InVEST models to map and quantify five ES provided (i.e., water supply, carbon stock, groundwater stock, sediment retention and habitat quality) by 14 watersheds distributed in the Brazilian Pampa biome as well as determine ES hotspots by summing the areas with high provision of ES. We identified low availability of water supply and groundwater stock in practically the entire study area. High sediment retention and carbon stock were reported in areas with the presence of native vegetation. In addition, despite the large degraded areas, we observed high habitat quality associated with native vegetation in all studied watersheds. The hotspots varied spatially in the study area according to the proposed scenarios, the supply and the overlap of ES. Scenario 1 (>50% of ES) presented a larger area of high provision of ES. In contrast, scenario 2 (>75% of ES) presented smaller patches of areas with high provision of ES distributed across different watershed. We observed that large territorial extensions with high and medium provision of ES are vulnerable to the negative effects of LULC. Our study presented scenarios that indicate areas of high provision of ES, contributing to a more practical application, being a simplified and useful tool that can assist conservation and sustainable policies., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The organic carbon (OC) cycle at the land-ocean interface is an important component of the global carbon budget, yet the processes that control the transfer, transformation, and burial of OC in these regions remain poorly understood. In this work, we examined sedimentary OC (SOC) in short core sediments, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and chromophoric dissolved organic matter (CDOM), as well as other solutes in sediment porewaters of the Changjiang Estuary and adjacent East China Sea (ECS) shelf. The main goal of this work is to investigate the variation of the sources and composition of different forms of carbon in estuarine sediments associated with different sedimentary regimes, to further understand the role of sediment porewater in carbon sequestration at the land-ocean interface. Concentrations of Fe 2+ and Mn 2+ in porewaters of the muddy sediments are much higher than those in the sandy sediments, and SO 4 2- decreases with depth in the deep sediment layer, indicating the degradation of SOC in mobile muds is mainly driven by suboxic and/or anoxic diagenetic processes (e.g., iron-manganese reduction). The accumulation of DIC in the muddy sediment is higher compared to the sandy sediment, indicating relatively complete SOC remineralization. The DOC in porewaters of the muddy areas is mainly composed of highly degraded and low molecular weight humic-like substances (C1), whereas in the sandy area, porewater DOC is mainly composed of less degraded and high molecular weight protein-like substances (C2 and C3). The average DOC stock (28.5 t/km 2 ) in the upper 30 cm sediment porewaters is significantly higher than that of DIC (12.5 t/km 2 ) in sandy area, but less in muddy areas (17.0 t/km 2 of DIC). The total DOC stock in sediment porewaters of the sandy area accounted for ∼61 % of DOC stock in water column of the ECS, indicating that the porewater is an important DOC pool in the ECS. However, this DOC pool is rather transient due to its high reactivity and mobility, especially in sandy area. Nevertheless, compared with other marine environments, the carbon stock of DOC (average of 43.8 t/km 2 of DIC). The total DOC stock in sediment porewaters of the sandy area accounted for ∼61 % of DOC stock in water column of the ECS, indicating that the porewater is an important DOC pool in the ECS. However, this DOC pool is rather transient due to its high reactivity and mobility, especially in sandy area. Nevertheless, compared with other marine environments, the carbon stock of DOC (average of 43.8 t/km 2 ) in porewaters of stable sedimentary environments is much higher than that of DIC (average of 21.7 t/km 2 ). This work further supports the notion that sedimentary regime plays an important role in OC cycling at the land-ocean interface and highlights the significance of sediment porewaters as a vast carbon pool in marine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Estimation of plant community composition, aboveground biomass and carbon stock is crucial for understanding forest ecology, strengthening environmental management, and developing effective tools and policies for forest restoration. This study was conducted in nine different forest reserves in Sri Lanka from 2012 to 2018 to examine the impact of community-based forest restoration (CBFR) on stand structural attributes, aboveground biomass, and carbon stock compared to state-managed forests. In total, 180 plots (90 plots in community-managed restoration blocks (CMRBs) and 90 plots assigned to state-managed restoration blocks (SMRBs)) were sampled at the study site. To conduct an inventory of standing trees, circular plots with a radius of 12.6 m (equivalent to an area of 500 square meters) were established. The Shannon diversity index, Allometric equations and Difference in Differences (DID) estimation were used to assess the data. Our study provides evidence of the positive impact of the CBFR program on enriching trees diversity. Considering stand structural attributes of both blocks showed higher trees density in the smaller diameter at breast height (DBH) category, indicating growth in both CMRBs and SMRBs. The results showed that tree biomass and carbon density were disproportionally distributed across the nine different forest reserves. On average, tree biomass and carbon density were higher in SMRBs (79.97 Mg ha -1 , 37.58 Mg C ha -1 ) compared to CMRBs (33.51 Mg ha -1 , 15.74 Mg C ha -1 ). However, CMRBs in Madigala reserve represent the highest biomass (56.53 and 59.92 Mg ha -1 ) and carbon density (26.57 and 28.16 Mg C ha -1 ). The results of biomass and carbon estimates were higher in all SMRBs in the nine different forest reserves compared to CMRBs. The findings suggest that future forest restoration programs in Sri Lanka should enhance participatory approaches to optimize tree species diversity, density and carbon storage, particularly in community-controlled forests. Our findings could assist developing tropical nations in understanding how CBFR impacts forest restoration objectives and improves the provision of ecological services within forests., Competing Interests: The authors declare that they have no competing interests., (© 2024 Ahmad et al.)

Using satellite RS data predicting mangrove vegetation carbon stock (MVC) is the popular and efficient approach at a large scale to protect mangroves and promote carbon trading. Satellite data have performed poorly in predicting MVC due to saturation issues. UAV-LiDAR data overcomes these limitations by providing detailed structural vegetation information. However, how to cross-scale integration of UAV-LiDAR and satellite RS data and the selection of features and machine learning methods hampered the practitioner in making a lightweight but efficient model to predict the MVC. Our study integrated UAV-LiDAR, Sentinel-1, and Sentinel-2 to extract spectral, structural, and textural features at the regional scale. We estimated the influences of different combinations between three vegetation features and machine learning methods (Support Vector Machine (SVM), Random Forest (RF), Gradient Boosting Regression Tree (GBDT), and Extreme Gradient Regression Tree (XGBOOST)) on the results of MVC prediction, and constructed a framework for estimating mangrove vegetation aboveground (ACG) and belowground (BCG) carbon storage in Zhanjiang, the largest mangrove area of China. Our research shows: 1) Compared to using satellite remote sensing (RS), integrating UAV and satellite RS data and fusing multiple vegetation features significantly improved the accuracy of mangrove vegetation carbon stock (MVC) predictions. 2) Structural features, particularly canopy height retrieved from UAV and satellite RS, are essential indicators for predicting MVC. Combined with spectral and structural features, regional MVC was precisely predicted. 3)Although the influence of different machine learning methods on MVC prediction was not significant, XGBOOST demonstrated relatively high precision. We recommend that mangrove practitioners integrate UAV and satellite RS data to predict MVC at a regional scale. Importantly, governments should prioritize the application of UAV-LiDAR in forestry monitoring and establish a long-term mangrove monitoring database to aid in estimating blue carbon resources and promoting blue carbon trading., Competing Interests: Declaration of competing interest There is no conflict of interests between the authors., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Long-term excessive use of fertilizers and intensive cultivation not only decreases soil organic carbon (SOC) and productivity, but also increases greenhouse gas emissions, which is detrimental to sustainable agricultural development. The purpose of this paper is to identify organic amendments suitable for winter wheat growth in the North China Plain by studying the effects of organic amendments on the economic benefits, carbon emissions, and carbon sequestration for winter wheat fields and to provide a theoretical basis for the wide application of organic amendments in agricultural fields. The two nitrogen rates were N0 (0 kg ha -1 ) and N240 (240 kg ha -1 ), and the four organic amendments were straw, manure, mushroom residue (M R), and biochar. The results showed that, compared to N0, N240 significantly increased the yield by 244.1-318.4% and the organic carbon storage by 16.7-30.5%, respectively, but increased the carbon emissions by 29.3-45.5%. In addition, soil carbon stocks increased with all three types of organic amendments compared to the straw amendment, with the biochar treatment being the largest, increasing carbon storage by 13.3-33.6%. In terms of yield and economic benefits, compared to the straw amendment, the manure and biochar amendments increased winter wheat yields by 0.0-1.5% and 4.0-13.3%, respectively, and M R slightly decreased wheat yield; only the economic benefit of the M R amendment was greater than that of the straw amendment, with an increase in economic benefit of 1.3% and 8.2% in the 2021-2022 and 2022-2023 seasons, respectively. Furthermore, according to the net ecosystem productivity (NEP), N0 was the source of CO 2 , while N240 was a sink of CO 2 . The TOPSIS results showed that N240 with a mushroom residue amendment could be recommended for increasing soil carbon stocks and economic benefits for winter wheat in the NCP and similar regions. Low-cost M R can increase farmer motivation and improve soil organic carbon, making a big step forward in the spread of organic materials on farmland.

Background: Implementing large-scale carbon sink afforestation may contribute to carbon neutrality targets and increase the economic benefits of forests in rural areas. However, how to manage planted forests in China to maximize the joint benefits of timber production and carbon sequestration is still unclear. Therefore, the present study quantified the effects of different rotation lengths, thinning treatments, site quality (SCI), stand density (SDI), and management costs on the joint benefits of carbon sequestration and timber production based on a stand-level model system developed for larch plantations in northeast China., Results: The performances of the different scenarios on carbon stocks were satisfactory, where the variations in the outcomes of final carbon stocks could be explained by up to 90%. The joint benefits increased significantly with the increases of SDIs and SCIs, regardless of which rotation length and thinning treatments were evaluated. Early thinning treatments decreased the joint benefits significantly by approximately 131.53% and 32.16% of middle- and higher-SDIs, however longer rotations (60 years) could enlarge it by approximately 71.39% and 80.27% in scenarios with and without thinning when compared with a shorter rotation length (40 years). Discount rates and timber prices were the two most important variables affecting joint benefits, while the effects of carbon prices were not as significant as expected in the current trading market in China., Conclusions: The management plans that promote longer rotations, higher stand densities, and no thinning treatments can maximize the joint benefits of carbon sequestration afforestation and timber production from larch plantations located in northeast China., (© 2024. The Author(s).)

It is important to study the impact of land use change on terrestrial ecosystem carbon stocks in urban agglomerations for the optimization of land use structure and sustainable development in urban agglomerations. Based on the patch-generating land use simulation (PLUS) model and integrated valuation of ecosystem services and trade-offs (InVEST) model, a simulation was developed that predicted the land use change and carbon stock of the Guanzhong Plain urban agglomeration in 2040 under different scenarios and further analyzed the impact of land use change on carbon stock. The results showed that:① The land use types of the Guanzhong Plain urban agglomeration were mainly cultivated land, forest land, and grassland, which accounted for more than 90 % of the total study area. ② From 2000 to 2020, the carbon stock in the Guanzhong Plain showed a continuous downward trend, with cropland, woodland, and grassland being the main sources of carbon stock in the Guanzhong Plain, and the overall carbon stock declined by 15.12×10 6 t, with the spatial distribution presenting the distribution characteristics of "high in the north and south and low in the middle." ③ By 2040, the carbon stock would decrease the most under the urban development scenario, with a total reduction of 27.08×10 6 t, and the least under the ecological development scenario, with a total reduction of 4.14×10 6 t. The research results can provide data support for the high-quality development and rational land use planning of the Guanzhong Plain urban agglomeration.

Natural forests are crucial for climate change mitigation and adaptation, but deforestation and degradation challenges highly reduce their value. This study evaluates the potential of natural forest carbon stock and the influence of management interventions on enhancing forest carbon storage capacity. Based on forest area cover, a study was conducted in nine purposely selected forest patches across various forest ecosystems. Data on diameter, height, and environmental variables from various forest management approaches were collected and analyzed with R Ver. 4.1. The findings revealed a substantial difference ( p .029) in carbon stock between environmental variables and management interventions. The findings revealed a strong connection between environmental variables and the overall pool of carbon stock within forest patches ( p .029). Carbon stocks were highest in the Moist-montane forest ecosystem (778.25 ton/ha), moderate slope (1019.5 ton/ha), lower elevation (614.50 ton/ha), southwest-facing (800.1 ton/ha) and area exclosures (993.2 ton/ha). Accordingly, natural forests, particularly unmanaged parts, are sensitive to anthropogenic stresses, decreasing their ability to efficiently store carbon. As a result, the study highlighted the importance of sustainable forest management, particularly area exclosures and participatory forest management, in increasing forest carbon storage potential., Competing Interests: There is no conflict of interest or copyright issue., (© 2024 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Forests, the ancient wooden giants, are both symbols of natural beauty and reservoirs of carbon stocks. The current climate crisis has created an urgent need for an in-depth study of forest ecosystems and carbon stocks. Based on forest inventory data from field surveys and four bioclimatic zones [Zone 1 (Z1, humid forest), Zone 2 (Z2, semi-humid forest), Zone 3 (Z3, semi-humid to semi-arid forest-grassland), and Zone 4 (Z4, semi-arid typical grassland)], two methods [Method 1 (M1) and Method 2 (M2)] were used to estimate carbon stocks in forest ecosystems in Shaanxi Province, China, and explored the spatial patterns of carbon pools and potential influences. The total forest ecosystem carbon pool amounted to 520.80 Tg C, of which 53.60% was stored aboveground, 17.16% belowground, and 29.24% in soil (depth of 0-10 cm). Spatially, there were marked north-south gradients in both biomass (Z2 > Z3 > Z1 > Z4) and soil organic carbon densities (Z1 > Z2 > Z3 > Z4). The differences between aboveground and belowground biomass carbon density across broadleaf, needle-leaf, and broadleaf and needle-leaf mixed forest were not pronounced, while soil organic carbon density had the order of broadleaf (18.38 Mg C/ha) > needle-leaf (11.29 Mg C/ha) > broadleaf and needle-leaf mixed forest (10.33 Mg C/ha). Under an ideal scenario that excludes external factors, mainly forest growth, the sequestration potential of forest biomass by 2032 was estimated by M1 as 85.43 Tg, and by M2 to be substantially higher at 176.21 Tg. As of 2062, M1 estimated 155.97 Tg of sequestration potential for forest biomass. The spatial patterns of forest biomass and soil carbon density were closely related to climatic factors, and these relationships allowed the spatial division into two distinct climatic regions. Moreover, biomass carbon density was significantly correlated with the normalized difference vegetation index, soil silt, and elevation. This study provides key information for promoting the strategic shift from light-green to deep-green forest systems in Shannxi Province and updates the estimation methods of forest ecosystems' carbon pools based on field surveys., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Roots play a fundamental role in forest ecosystems, but obtaining samples from deep layers remains a challenging process due to the methodological and financial efforts required. In our quest to understand the dynamics of Eucalyptus roots, we raise three fundamental questions. First, we inquire about the average extent of the roots of two contrasting Eucalyptus genotypes. Next, we explore the factors that directly influence the growth and depth of these roots, addressing elements such as soil type, climate, and water availability. Lastly, we investigate how the variation in Eucalyptus species may impact root growth patterns, biomass, and carbon stock. In this study, we observed that the maximum root depth increased by an average of 20% when genotypes were grown on sites with higher water availability (wet site). E. urophylla stands had a higher biomass and carbon stock (5.7 Mg C ha -1 ) of fine roots when cultivated on dry sites (annual rainfall~727 mm) than the wet sites (annual rainfall~1590 mm). In E. grandis × E. camaldulensis stands, no significant differences were observed in the stock of fine root biomass (3.2 Mg C ha -1 ) between the studied environments. Our results demonstrated that genotypes with greater drought tolerance ( E. grandis × E. camaldulensis ) tend to maintain higher stocks of fine root biomass (3.2-6.3 Mg ha -1 ) compared to those classified as plastic ( E. urophylla ), regardless of the edaphoclimatic conditions of the cultivation site. Finally, our research helps understand how Eucalyptus trees adapt to their environment, aiding sustainable forest management and climate change mitigation. We also provide a practical tool to estimate underground biomass, assisting forest managers and policymakers in ensuring long-term forest sustainability.

The rapid and accurate estimation of aboveground forest phytomass remains a challenging research task. In general, methods for estimating phytomass fall mainly into the category of field measurements performed by ground-based methods, but approaches based on remote sensing and ecological modelling have been increasingly applied. The aim is to develop the scientific and methodological framework for the remote sensing estimation of qualitative and quantitative characteristics of forest stands, using the combination of surveys and machine learning models to determine phytomass of forest stands and calculate the carbon balance. Even-aged stands of different tree species growing in the forest steppe zone of the East European Plain were chosen as test objects. We have applied the modernized methodological approaches to compare and integrate forest and tree stand characteristics obtained by ground-based and UAV-based comprehensive surveys; additionally, we developed computer vision models and methods for determining the same characteristics by remote sensing methods. The key advantage of the proposed methodology for remote monitoring and carbon balance control over existing analogues is the minimization of the amount of groundwork and, consequently, the reduction inlabor costs without loss of information quality. Reliable data on phytomass volumes will allow for operational control of the forest carbon storage, which is essential for decision-making processes. This is important for the environmental monitoring of forests and green spaces of various economic categories. The proposed methodology is necessary for the monitoring and control of ecological-climatic and anthropogenic-technogenic transformations in various landscapes. The development is useful for organizing the management of ecosystems, environmental protection, and managing the recreational and economic resources of landscapes with natural forests and forest plantations.

Background: Carbon (C) sink and stock are among the most important ecosystem services provided by forests in climate change mitigation policies. In this context, old-growth forests constitute an essential reference point for the development of close-to-nature silviculture, including C management techniques. Despite their small extent in Europe, temperate old-growth forests are assumed to be among the most prominent in terms of biomass and C stored. However, monitoring and reporting of C stocks is still poorly understood. To better understand the C stock amount and distribution in temperate old-growth forests, we estimated the C stock of two old-growth stands in the Dinaric Alps applying different assessment methods, including direct and indirect approaches (e.g., field measurements and allometric equations vs. IPCC standard methods). This paper presents the quantification and the distribution of C across the five main forest C pools (i.e., aboveground, belowground, deadwood, litter and soil) in the study areas and the differences between the applied methods., Results: We report a very prominent C stock in both study areas (507 Mg C ha - 1 ), concentrated in a few large trees (36% of C in 5% of trees). Moreover, we found significant differences in C stock estimation between direct and indirect methods. Indeed, the latter tended to underestimate or overestimate depending on the pool considered., Conclusions: Comparison of our results with previous studies and data collected in European forests highlights the prominence of temperate forests, among which the Dinaric Alps old-growth forests are the largest. These findings provide an important benchmark for the development of future approaches to the management of the European temperate forests. However, further and deeper research on C stock and fluxes in old-growth stands is of prime importance to understand the potential and limits of the climate mitigation role of forests., (© 2024. The Author(s).)

This study aimed to analyze mangrove extent (ME), carbon stock, blue carbon potential, and CO 2 emission from 1996 to 2020 in Southeast Asia region. The data was obtained through the Global Mangrove Alliance (GMA) on the platform www.globalmangrovewatch.org v.3. Furthermore, ME was analyzed descriptively and the triggers for mangrove land changes in each country were investigated through a relevant literature review. The spatial analysis was conducted for blue carbon potential, while CO 2 emission was derived by multiplying net change by emission factor (EF) of mangrove ecosystem. The results showed that the total ME in Southeast Asia was 5.07 million hectares (Mha) in 1996, decreasing to 4.82 Mha by 2020 due to various land uses, primarily shrimp farming. The total carbon stock potential was 2367.68 MtC, while a blue carbon potential was 8682.32 MtCO 2 -e, consisting of 1304.33 MtCO 2 -e and 7377.99 MtCO 2 -e from above-ground and soil carbon. Indonesia contributed 5939.57 MtCO 2 -e to blue carbon potential, while Singapore and Timor-Leste had the lowest contributions of 1.05 MtCO 2 -e and 1.37 MtCO 2 -e, respectively. Carbon stock potential (AGC and SOC) in Southeast Asia was influenced by ME conditions. The relationship between ME and AGC was found to be exponential (AGC = 0.0307e 0.8938x ; R 2  = 0.9331; r ME-AGC  = 0.9964, P < 0.01). Similarly, ME and SOC, or AGC and SOC showed a relationship where SOC = 0.2e 0.8829x (R 2  = 0.937, r ME-S O C  = 0.9965 and r AGC-S O C  = 0.9989, P < 0.01). The average CO 2 -e emission in Southeast Asia reached 17.0760 MtCO 2 -e yr -1 and the largest were attributed to Indonesia at 16.3817 MtCO 2 -e yr -1 . Meanwhile, Brunei and Timor Leste did not show CO 2 -e emission as mangrove in these countries absorbed more CO 2 from the atmosphere at -0.034 MtCO 2 -e yr -1 and -0.0002 MtCO 2 -e yr -1 , respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The blue carbon ecosystem, including the salt marsh ecosystem, possesses a significant carbon sequestration potential. Therefore, accurately quantifying the carbon storage within such ecosystems is crucial for the adequate accounting of carbon sequestration. The present work chose a Spartina alterniflora ecosystem in the Xiaogan Island (China) as the study area (approximately 11 ha), and employed the Bayesian maximum entropy (BME) approach to assimilate both hard organic carbon (OC) data and soft OC data measured from 2 cm and 10 cm stratified samples. A 3-dimensional model was developed for space-time OC estimation purposes based on the sediment chronology results. The 10-fold BME cross validation results demonstrated a high estimation accuracy, with the R 2 , RMSE and MAE values equal to 0.8564, 0.1026 % and 0.0748 %, respectively. A noteworthy outcome was the BME-generated carbon storage density maps with 1 m spatial resolution. These maps revealed that the carbon storage density at the top 30 cm sediment depth in the stable zone (with elder stand age of S. alterniflora) was higher than that in the rapid expansion zone, i.e., 71.79 t/ha vs. 69.82 t/ha, respectively. Additionally, the study found that the averaged carbon burial rate and the total carbon storage at the top 30 cm sediment depth across the study area were 266 g C/m 2 /yr and 781.50 t, respectively. Lastly, the proposed BME-based framework of carbon storage estimation was found to be versatile and applicable to other blue carbon ecosystems. This approach can foster the development of a standardized carbon sink metrological methodology for diverse blue carbon ecosystems., Competing Interests: Declaration of competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite the progress made in understanding relevant carbon dynamics under grazing exclusion, previous studies have underestimated the role of soil bulk density (BD), and its implications for potential accumulation of soil organic carbon (SOC), especially at regional scale over long term. In this study, we first constructed a database covering a vast majority of the grasslands in northwestern China based on 131 published literatures. A synthesis was then conducted by analyzing the experimental data to comprehensively investigate the mechanisms of vegetation recovery, carbon-nitrogen coupling, and the importance of changed soil BD in evaluating SOC sequestration potential. The results showed that although the recovery of vegetation height and cover were both critical for improving vegetation biomass, vegetation height required a longer recovery period. While the SOC accumulation was found to be greater in surface layers than deeper ones, it exhibited a reduced capacity for carbon sequestration and an increased risk of SOC loss. Grazing exclusion significantly reduced soil BD across different soil profiles, with the rate of change influenced by soil depth, time, geographical and climatic conditions. The potential for SOC accumulation in the top 30 cm of soil based on data of 2003-2022 was 0.78 Mg ha -1 yr -1 without considering BD effects, which was significantly underestimated compared to that of 1.16 Mg ha -1 yr -1 when BD changes were considered properly. This suggests that the efficiency of grazing exclusion in carbon sequestration and climate mitigation may have been previously underreported. Furthermore, mean annual precipitation represented the most relevant environmental factor that positively correlated to SOC accumulation, and a wetter climate may offer greater potential for carbon accumulation. Overall, this study implies grazing exclusion may play an even more critical role in carbon sequestration and climate change mitigation over long-term than previously recognized, which provides essential scientific evidence for implementing stepwise ecological restoration in grasslands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This study examines soil properties in 30- and 60-year-old agricultural biocorridors and provides a comparative overview with neighbouring farmland. Both mixed and undisturbed soil samples were collected from six farmland/biocorridor study areas to assess a wide spectrum of physical, hydrophysical, chemical and biological soil properties. Biocorridor soils were characterised by higher water retention capacities, porosity, aeration and soil carbon stock, the latter increasing with depth. On the other hand, biocorridor bulk density under forest vegetation cover was lower, indicating progressive soil restoration. Slightly lower soil reactions in biocorridor soils disproved the hypothesis that nutrient-rich soils under biocorridors would form substrates with a high base cation content, leading to soil acidification. Biological activity, expressed through respiration coefficients, was generally low due to unfavourable physical conditions (clayey or silty-clay substrates), with the lowest levels in biocorridors. Nevertheless, biocorridor soil microbiota displayed more effective utilisation of organic matter as a carbon and nitrogen source, with lighter-textured soils tending to show more effective organic matter utilisation after excluding the influence of land use. Our results confirm biocorridors as an important landscape component, contributing to both soil stability and local revitalisation of soil environments and further emphasising their potential as climate-change mitigation tools in their role as carbon sinks., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Tropical and subtropical forests play a crucial role in global carbon (C) pools, and their responses to warming can significantly impact C-climate feedback and predictions of future global warming. Despite earth system models projecting reductions in land C storage with warming, the magnitude of this response varies greatly between models, particularly in tropical and subtropical regions. Here, we conducted a field ecosystem-level warming experiment in a subtropical forest in southern China, by translocating mesocosms (ecosystem composed of soils and plants) across 600 m elevation gradients with temperature gradients of 2.1°C (moderate warming), to explore the response of ecosystem C dynamics of the subtropical forest to continuous 6-year warming. Compared with the control, the ecosystem C stock decreased by 3.8% under the first year of 2.1°C warming; but increased by 13.4% by the sixth year of 2.1°C warming. The increased ecosystem C stock by the sixth year of warming was mainly attributed to a combination of sustained increased plant C stock due to the maintenance of a high plant growth rate and unchanged soil C stock. The unchanged soil C stock was driven by compensating and offsetting thermal adaptation of soil microorganisms (unresponsive soil respiration and enzyme activity, and more stable microbial community), increased plant C input, and inhibitory C loss (decreased C leaching and inhibited temperature sensitivity of soil respiration) from soil drying. These results suggest that the humid subtropical forest C pool would not necessarily diminish consistently under future long-term warming. We highlight that differential and asynchronous responses of plant and soil C processes over relatively long-term periods should be considered when predicting the effects of climate warming on ecosystem C dynamics of subtropical forests., (© 2023 John Wiley & Sons Ltd.)

Mangroves are highly efficient in sequestering carbon from the atmosphere and can accumulate carbon in sediments for millennials. However, The fate of mangrove carbon has not been well constrained due to the lack of data on different pools of sediment carbon sinks and sources. This study examined the variation of carbon stocks and fluxes at the water-sediment-air interface in both estuarine mangroves (natural: Mai Po, restored: Gei Wai) and oceanic mangroves (Ting Kok). There are divergent patterns in biogeochemical variables at the sediment-water-air interface, likely due to significant variation within sites. Total sediment carbon stocks (TCs) ranked in the order of restored estuarine mangroves (392.5 ± 8.8 Mg ha -1 ), natural estuarine mangroves affected by aquaculture (315.2 ± 21.4 Mg ha -1 ) and oceanic mangroves (229.1 ± 32.3 Mg ha -1 ). Sediment organic carbon stocks (SOC) and inorganic carbon stocks (SIC) accounted for 84.1-90.2 % and 9.8-15.9 % of TC, respectively. The highest sediment-air CO 2 and CH 4 fluxes occurred in restored and natural estuarine mangroves affected by aquaculture, respectively. The isotope of CO 2 fluxes (δ 13 C-CO 2 ) indicates higher contributions from the degradation of mangrove-derived organic carbon in restored (-25.94 ‰ ± 3.37 ‰) and natural estuarine mangroves affected by aquaculture (-25.54 ‰ ± 0.96 ‰) than in oceanic mangroves (-21.55 ‰ ± 1.36 ‰). The isotope of CH 4 fluxes (δ 13 C-CH 4 ) indicates CH 4 production dominated by acetate fermentation in restored estuarine mangroves but dominated by the reduction of CO 2 for other sites. Future studies should better constrain the fate of mangrove carbon by considering local drivers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The effect of the time-scale of water conditions on vegetation productivity has been widely studied by the academic community. However, the relationship between the time-scale of water conditions and the vegetation growth rhythm and the effect of this relationship on vegetation biomass estimation have rarely been discussed. Here, we analyzed the occurrence times of major phenological events on alpine grasslands using the widely distributed "site-dominant species" dataset and set a series of time-scales for accumulated precipitation and standardized precipitation evapotranspiration index based on phenological information. Then, we combined large-scale aboveground/belowground biomass datasets to evaluate the role of the optimal time-scale for water conditions in aboveground/belowground biomass estimation. The results showed that (1) the optimal time-scale for water conditions with the greatest effects on aboveground biomass was on the month before the end of flowering or the onset of fruit maturity. The optimal time-scale for water condition effects on belowground biomass was earlier and longer than that for the aboveground biomass. The optimal time-scales for accumulated precipitation and standardized precipitation evapotranspiration index effects on belowground biomass were at five months before the end of flowering or the beginning of fruit ripening and the three months before the first flowering, respectively. (2) The aboveground and belowground biomass were underestimated by 11 % and 9 %, respectively, when the water conditions at the optimal time-scales were ignored. (3) The interannual variability in aboveground/belowground biomass was more effectively captured by considering the optimal time-scales of water conditions, especially in water-restricted areas. Overall, this study indicated that terrestrial carbon cycle models should incorporate information on the lag-effects of the water conditions in previous periods. In the future, increasing the number of belowground biomass observations and conducting monthly belowground biomass monitoring sooner will be key to revealing the mechanisms of the belowground biomass response to climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Arid forest lands account for 6 % of the world's forest area, but their carbon density and carbon storage capacity have rarely been assessed. Forest inventories provide estimates of forest stock and biomass carbon density, improve our understanding of the carbon cycle, and help us develop sustainable forest management policies in the face of climate change. Here, we carried out three forest inventories at five-year intervals from 2006 to 2016 in 104 permanent sample plots covering the Qinghai spruce (Picea crassifolia) distribution in the north slope of Qilian Mountains, northeastern Tibetan Plateau. Results shows that mean biomasses for Qinghai spruce were 133.80, 144.89, and 157.01 Mg ha -1 while biomass carbon densities were 65.52, 70.92, and 76.88 Mg C ha -1 , in 2006, 2011, and 2016, respectively. This shows an increase in the Qinghai spruce carbon density of 17.34 % from 2006 to 2016. Both the precipitation and temperature play crucial roles on the increase of aboveground carbon density. The average carbon densities were different among forests with different ages and were higher for older forests. Our results show that the carbon sequestration rate for Qinghai spruce in the Qilian Mountains is significantly higher than the average rates of national forest parks in China, suggesting that this spruce forest has the potential to sequester a significant amount of carbon despite the general harsh growing conditions of cold and arid ecoregions. Our findings provide important insights that are helpful for the assessment of forest carbon for cold and arid lands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Smallholder farmers in the Wondo Genet were forced to switch from long-standing, diverse traditional home gardens to monoculture khat production due to increasing population pressure-induced farmland constraints. The composition of woody species and the biomass carbon stock are thought to drop as homegardens transition from polyculture to monoculture; however there is little quantitative evidence to support this claim. This study was started to assess the effects on woody species, enset, and biomass carbon of converting traditional homegardens to a fast spreading perennial monocropping of khat (Catha edulis Forskal). In 10 m × 10 m (100m2) plots from 43 farms with neighboring land use patterns for each homegarden and khat, woody species and enset were inventoried, the total number of tree, shrub, and enset species counted, as well as the height and diameter of each species measured. To determine the biomass carbon stock of each land use type, both general and species-specific allometric equations are used. Simpson's diversity index, Shannon-Wiener, and Shannon equitability were used to evaluate the diversity of enset and woody species. There were 27 different types of woody species identified, with trees making up 67 % of the total and shrubs accounting for 33 %. Shannon, Simpson, and the richness of woody species all decreased by 46 %, 51 %, and 38 %, respectively, in comparison to residential gardens. For homegardens and khat, respectively, the mean Evenness values were 0.876 and 0.539. In homegardens, Coffea arabica was the most valuable woody species, followed by Cordia africana Lam, Persea americana, Eucalyptus camaldulensis, and Grevillea Robusta. In contrast, Catha edulis was the most valuable woody species in the Khat land use type, followed by Coffea arabica, Croton macrostachyus Del, and Cordia africana. In comparison to homegardens, the above-ground, below-ground, and total biomass carbon reported in khat land use types were reduced by 18 %, 63 %, and 42 %, respectively. Grevillea and Eucalyptus species made up 51 % of the total biomass carbon stock in the homegardens, which suggests that khat and quickly expanding fast-growing plants have displaced native woody species.Understanding the long-term effects of agro-biodiversity loss requires greater research on the implications of the decline in woody species diversity and biomass carbon stock on soil fertility and sustainable farming. This is due to the numerous functions that woody species and enset play., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)

Backgorund: Forest plays an important role in the global carbon cycle by sequestering carbon dioxide and thereby mitigating climate change. In this study, an attempt was made to investigate the effects of land use/land cover (LULC) change (1989-2017) on carbon stock and its economic values in tropical moist Afromontane forests of the Majang Forest Biosphere Reserve (MFBR), south-west Ethiopia. Systematic sampling was conducted to collect biomass and soil data from 140 plots in MFBR. The soil data were collected from grassland and farmland. InVEST modelling was employed to investigate the spatial and temporal distribution of carbon stocks. Global Voluntary Market Price (GVMP) and Tropical Economics of Ecosystems and Biodiversity (TEEB) analysis was performed to estimate economic values (EV) of carbon stock dynamics. Correlation and regression analyses were also employed to identify the relationship between environmental and anthropogenic impacts on carbon stocks., Results: The results indicated that the above-ground carbon and soil organic carbon stocks were higher than the other remaining carbon pools in MFBR. The mean carbon stock (32.59 M tonne) in 2017 was lower than in 1989 (34.76 Mt) of MFBR. Similarly, the EV of carbon stock in 2017 was lower than in 1989. Elevation, slope, and harvesting index are important environmental and disturbance factors resulting in major differences in carbon stock among study sites in MFBR., Conclusions: Therefore, the gradual reduction of carbon stocks in connection with LULC change calls for urgent attention to implement successful conservation and sustainable use of forest resources in biosphere reserves., (© 2023. The Author(s).)

Seagrass ecosystems are important organic carbon (C org ) sinks with great potential to contribute to climate change mitigation strategies. However, the high spatial and temporal variability is a barrier to the accurate assessment of national C org stocks. This study provides a national assessment of C org within seagrass meadows, including spatial and temporal variations. The highest C org stocks were within mangrove-associated (44.3 ± 8.27 Mg ha -1 ), while near-surface sediments were highest in reef-associated meadows (10.20 ± 3.69 Mg ha -1 ). Regionally, the highest stocks were in the Upper Andaman coast in monospecific meadows (51.7 ± 7.14 Mg ha -1 ). C org stocks in near-surface sediments were significantly different across historical trends (p < 0.001), with the highest stocks in stable meadows (9.28 ± 3.39 Mg ha -1 ). The national C org stock within seagrass meadows sediment was 40.45 ± 11.59 Mg C ha -1 . The results of this study highlighted the complexity of blue carbon in seagrass meadows and the associated impacts on national C org assessments, carbon accounting, and conservation strategies., Competing Interests: Declaration of competing interest Anchana Prathep, Milica Stankovic and Janmanee Panyawai report financial support from Center of Excellence on Biodiversity grant (2563-BCD-PG2-163003) for the project “Seagrass and it's blue carbon under the climate change world Anchana Prathep, Milica Stankovic and Janmanee Panyawai report the support from Program Management Unit for Human Resources & Institutional Development, Research and Innovation (PMU-B) on a project (B13F660071) “Capacity building on Nature based Solution for Carbon Net Zero”. Nattacha Khanthasimachalerm has nothing to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Urban trees and forests play a vital role in maintaining the balance of urban ecosystems and mitigating global warming. However, due to the lack of data and information on the potential of urban forests, their importance remains largely unknown. This study aims to describe citizens' perceptions of trees and assess the forest community's density, diversity, and carbon stock in the residential area of Bobo-Dioulasso, the second-largest city in Burkina Faso. To carry out the study, tree inventories, and interviews were conducted on 240 selected dwellinghouses using a two-stage stratified sampling approach. The sample was allocated proportionally to three strata based on their population size: the center town (20 %), pericenter (20 %), and periphery (60 %). Trees were found in 86 % ± 0.5 % of dwellings, with an average of four trees per dwellinghouse (4 ± 1). About 63 % of households reported planting trees in their homes, including along roadsides. The main motivations for planting trees were for fruits, shading, and ornamental purposes. However, factors such as discomfort, property ownership, and management costs discouraged some residents from planting more trees. A total of 934 trees belonging to 69 species and 30 botanic families were counted in the study sample. The most abundant species families were Anacardiaceae, Moraceae, and Moringaceae. Mangifera indica (41 %), Ficus polita (12 %), and Moringa oleifera (8 %) had the highest relative densities of all species found in dwellings. Using existing allometric equations, the study estimated that the residential area trees stored about 210,000 tons of carbon dioxide equivalent. Based on these findings, it is recommended that city governments implement an action plan to promote urban forestry to strengthen and protect urban forest cover., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Over the last two decades, bamboo has received increasing attention owing to its socio-economic and environmental importance. Environmentally, bamboo plays an important role in carbon sequestration, thus enhancing climate change mitigation. In Cameroon, knowledge about the importance of Bambusa vulgaris Schrad. ex J.C.Wendl. to climate change mitigation is deficient, despite the fact that it is the most abundant bamboo species in Cameroon's Bimodal rainforest agroecological zone (Agroecological zone 5 - AEZ5). This study was initiated to develop allometric equations and estimate carbon stocks of B. vulgaris in Cameroon's AEZ5. The destructive, clump-based method was used for bamboo biomass data collection on 40 clumps and 86 culms. Regression analyses were performed to obtain allometric models for B. vulgaris biomass prediction which were used for B. vulgaris carbon stocks estimation in AEZ5. The best allometric model for culms was obtained when all predictive variables including age, diameter and height were considered into the model. For clump, the best model was obtained when the number of culms per clump, girth and average diameter were considered in the model. Model quality adjustment was better for clump aboveground biomass (AGB) compared to those of culm AGB. The model of B. vulgaris of the evergreen rainfall forest was validated with a bias of 45.5 %. Bamboo aboveground biomass proportions were 77 %, 15 % and 8 %, respectively for culms, branches and leaves. The mean density and carbon stocks of B. vulgaris were estimated at 2,0679 culms.ha -1 , 257 clumps.ha -1 , and 61.65 tC ha -1 . B. vulgaris has a veritable carbon sequestration capacity which policymakers should consider in climate change mitigation strategies like those linked to payments for ecosystem services, voluntary carbon stocks market, Bonn Challenge, AFR100 initiative, and the Paris agreement ratified by the government of Cameroon., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Rene Kaam reports financial support, administrative support, and equipment, drugs, or supplies were provided by International Network for Bamboo and Rattan. Rene Kaam reports a relationship with International Network for Bamboo and Rattan that includes: employment., (© 2023 The Authors.)

Even though, the blue carbon ecosystems are gaining keen research interest around the globe, the carbon stock of South-West coast of India was poorly reported, and this study is a pioneer attempt and will be an important document for filling the gaps in uncertainties in global carbon stock assessment and also will increase knowledge on biomass variability among mangrove species and mangrove habitats. The study also highlighted the vital role of biomass carbon pool for long-term soil carbon burial. We estimated the above and below-ground biomass carbon stock of 13 mangrove species using two common allometric equations and species-specific equations and reported a very high mean total living biomass carbon stock of Kochi mangroves at 237.19 ± 113.82 Mg C ha -1 , 295.78 ± 143.14 Mg C ha -1 , and 272.42 ± 132.78 Mg C ha -1 according to Chave's, Komiyama equation and species-specific equation respectively corresponding to carbon dioxide equivalent (CO 2 e) of approximately 4,37,774.51 Mg CO 2 e. The biomass stock was significantly differed between the stations (p = 0.000) and also within species (p = 0.020). Among the mangrove species, Avicennia officinalis contributed highest and Bruguiera sexangula contributed least. Variation was observed for biomass stock of mangroves with large trunk diameter while comparing different allometric equations and therefore projected the need for the development of site- and species-specific equations for solving the uncertainty in global mangrove carbon stock. The study observed that dominant mangrove vegetation type, salinity and also the geomorphology of mangrove habitat had strong influence on variability in biomass stock within a small regional area. The study also suggests that understanding the structure and biomass carbon storage of each regional mangrove habitats can be wisely used in mangrove restoration and conservation programmes and in turn for nature-based solutions for climate change mitigation efforts., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Subsurface drainage (SSD) has been proved to be an effective technology to reclaim waterlogged saline soils. Three SSD projects were implemented in Haryana, India in 2009, 2012 and 2016 to study the long term effect of SSD (10, 7 and 3 years) operation on restoring productivity and carbon sequestration potential of degraded waterlogged saline soils under prevalent rice-wheat cropping system. These studies indicated that successful operation of SSD improved soil quality parameters such as bulk density, BD (from 1.58 to 1.52 Mg m -3 ), saturated hydraulic conductivity, SHC (from 3.19 to 5.07 cm day -1 ); electrical conductivity, EC e (from 9.72 to 2.18 dS m -1 ), soil organic carbon, OC (from 0.22 to 0.34 %), dehydrogenase activity, DHA (from 15.44 to 31.65 μg g -1 24 h -1 ), and alkaline phosphatase, ALPA (from 16.66 to 40.11 μg P-NP g -1  h -1 ) in upper soil surface (0-30 cm). The improved soil quality resulted in increased rice-wheat system yield (rice equivalent yield) by 328 %, 465 % and 665 % at Kahni, Siwana Mal and Jagsi sites, respectively. Studies also revealed that carbon sequestration potential of degraded land increased with the implementation of SSD projects. The principal component analysis (PCA) showed that % OC, EC e , ALPA, available N and K content were the most contributing factor for soil quality index (SQI). The overall result of the studies showed that SSD technology holds great potential to improve soil quality, increase crop productivity, farmers' income and ensure land degradation neutrality and food security in waterlogged saline areas of western Indo Gangetic Plain of India. Hence, it can be concluded that large scale adoption of SSD may fulfill the promise "No poverty, Zero hunger, and Life on land" sustainable development goals of United Nation in degraded waterlogged saline areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The "Production-Living-Ecological Space" (PLES) is a paramount indicator in the filed of territory space development and optimization in China, under the new era. Exploring the driving factors of the PLES'land expansion is of great significance for improving space utilization, mitigating severe climate changes, and promoting green, healthy and sustainable development. In the background of the "Carbon Emissions Peak and Carbon Neutrality" strategy, analyzing and predicting the carbon stock of PLES is effective to boosting the achievement of 'Dual-Carbon' vision. Based on the above research questions， this study constructs the PLES based on statistics about land use (Year 1990, 2000, 2010 and 2020) in three northeastern provinces, and reveals the spatial correlation of PLES' carbon stock in the research area through ArcGIS spatial analysis and InVEST model. Then, the PLUS model was used to clarify the contribution of each driver to the conversion of space land, and to predict the distribution of the PLES pattern and the carbon stock's spatial correlation in 2030 and 2060 under the Natural-Development Scene and Ecological-Protection-Development Scene. Results show that: (1) The PLES in the three northeastern provinces of China is primarily green ecological space (55.71%) and agricultural production space (38.10%), while industrial production space (3.60%) and urban living space (2.76%) expand significantly, and green ecological space (-0.17%) and blue ecological space (-0.89%) are on a recession trend. Besides, 2000-2010 is the most intense period of all kinds of space land transformation in the study area. (2) Population density, proximity to roads at all levels, annual average temperature and elevation are the prime drivers of PLES' profile within the scope of the study region, but the contribution rate is significant difference. (3) The urban living space decreases and the green and blue ecological space increases significantly in the predicted years under the scene of Natural-Development and Ecological-Protection development; the pattern of PLES is relatively stable in the predicted years under both scenarios. (4) The spatial correlation of carbon stock is closely related to the distribution of PLES, with the high-value significant regions primarily in the distribution region of green ecological space, otherwise, the low-value significant regions mostly concentrated in the region with complex spatial land use types and large spatial development intensity; the overall structure within the scope of the study region shows a layout of high value areas surrounding low value areas. It can show that insisting on the ecological civilization construction is an effective way to achieve sustainable development and practice the "double carbon" strategy; in the future spatial land use control, ecological protection measures should still be adopted to ensure the sustainable development and positive operation of the study area., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Urban expansion, especially the construction of megacities, increases carbon emissions and adversely affects the carbon storage of terrestrial ecosystems. However, scientific land-use management policies can increase carbon storage. This study takes two megacities at different stages of development, Beijing and Tianjin, as examples to explore the impact of different ecological conservation scenarios on both urban land use and carbon storage to provide recommendations for the construction planning of large cities with low-carbon development as the goal. Furthermore, we coupled the patch-generating land use simulation (PLUS) model with the integrated valuation of ecosystem services and tradeoffs (InVEST) model to simulate land use and carbon storage under a natural development scenario, a planned ecological protection scenario (PEPS), and a policy-based ecological restoration scenario (PERS). From 2000 to 2020, both cities had different degrees of construction land expansion and carbon loss, and Tianjin's dynamic degree of construction land was 0.94% higher than Beijing's, with a carbon loss 183,536.19 Mg higher than Beijing's; this trend of reducing carbon reserves will continue under the natural development scenario (NDS). Under the PEPS and PERS, the carbon stock of both cities increases, and the impact on Tianjin is greater, with an increase of 4.51% and 8.04%, respectively. Under PERS, the carbon stock increases the most, but the dynamic degree of construction land use is negative for both cities. Beijing's carbon stock is 0.40% lower than Tianjin's, which deviates slightly from the trend of urban economic development. Megacities in the rapid development stage can refer to Tianjin, strictly following the ecological protection land planning scope and vigorously implementing ecological restoration policies to effectively increase regional carbon stock. Megacities in the mature stage of development can refer to Beijing, and flexibly implement ecological restoration policies to increase regional carbon stock without affecting the city's economic development., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The annual average increase in carbon dioxide (CO 2 ) concentration is touching new heights every year. Global climate change and warming are twin outcomes of record-breaking CO 2 levels. The trees outside forests (TOF) are the most promising and suitable components in the ecosystem for combating global warming via carbon (C) sequestration. Urban university campuses are the hotspot regions of TOF. We have attempted to quantify the C stock, C sequestration potential, and C credit value of dominant tree species at Maharshi Dayanand University (MDU), Rohtak. Different volumetric and biomass equations were used for biomass computation. We assessed a total of 29,442 trees (top 10) for measuring phytosociological parameters like total tree count, age, height (H), and diameter at breast height (DBH) to quantify the amount of C stored. The total C stock, C sequestration rate, and monetary value were 78.67 (Mg C ha -1 ), 19.05 (Mg CO 2 ha -1 year -1 ), and 23,101.59 $ year -1 , respectively. Eucalyptus globulus is the most dominant tree species on the campus and topped almost all the quantitative characteristics like total tree count (~40 %), age (25 years), density (D) (55.35 trees ha -1 ), and total C stock (16.06 ± 9.90 Mg C ha -1 ). Tree basal area (BA), D, diversity, and H positively affected the total C stocks. When the C market becomes operational, these C credits can be traded while generating additional income for the university. The results from this study can also help calculate the total C footprint of the campus., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The soil carbon (C) dynamics is strongly influenced by climate and land-use patterns in the Himalayas. Therefore, soils under five prominent land use [e.g., maize (Zea mays), horticulture, natural forest, grassland, and wasteland] were sampled down up to 30 cm depth under two climatic conditions viz., temperate and subtropical to assess the impacts of climate and landuse on soil C dynamics. Results demonstrated that irrespective of land use, temperate soil contains 30.66% higher C than subtropical soils. Temperate soils under natural forests had the higher total organic carbon (TOC, 21.90 g kg -1 ), Walkley-Black carbon (WBC, 16.42 g kg -1 ), contents, and stocks (TOC, 66.92 Mg ha -1 and WBC, 50.24 Mg ha -1 ), and total soil organic matter (TSOM, 3.78%) concentration as compared to other land uses like maize, horticulture, grassland, and wasteland. Under both climatic conditions, maize land use had the lowest TOC 9.63, 6.55 g kg -1 and WBC 7.22, 4.91 g kg -1 at 0-15 and 15-30 cm soil depth, respectively. Horticulture land use had 62.58 and 62.61% higher TOC and WBC over maize-based land use under subtropical and temperate climatic conditions at 0-30 cm soil depth, respectively. However, soils of maize land use under temperate conditions had ∼2 times more TOC than in subtropical conditions. The study inferred that the C-losses is more in the subtropical soil than in temperate soils. Hence, the subtropical region needs more rigorous adoption of C conservation farming practices than the temperate climatic setting. Although, the adoption of C storing and conserving practices is crucial under both climatic settings to arrest land degradation. Horticultural land uses along with conservation effective soil management practices may be encouraged to restore more soil C and to improve the livelihood security of the hill populace in the North Western Himalayas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The aboveground carbon sequestration rate (ACSR) of forests serves as an indicator of their carbon sequestration capacity over time, providing insights into the potential carbon sequestration capacity of forest ecosystems. To explore the long-term Spatiotemporal variation of ACSR in the transitional ecotone of the eastern Tibetan Plateau under climate change scenarios, we utilized a forest landscape model that was parameterized with forest inventory data from the eastern Tibetan Plateau to simulate this ecological function changes. The study found that climate warming had significant effect on forests ACSR in different types of forests. ACSR was significantly reduced (p<0.05) in cold temperate coniferous and temperate coniferous forests, whereas it was significantly increased in deciduous broad-leaved forests. However, the impact of climate warming on evergreen broad-leaved forests was found to be negligible. At the species level, climate warming has mostly suppressed the ACSR of coniferous trees, except for Chinese hemlock. The main dominant species, spruce and fir, have been particularly affected. Conversely, the ACSR of most broad-leaved trees has increased due to climate warming. In addition, at the landscape scale, the ACSR within this region is expected to experience a steady decline after 2031s-2036s. Despite the effects of climate warming, this trend is projected to persist. In conclusion, the forests ACSR in this region will be significantly affected by future climate warming. Our research indicates that climate warming will have a noticeable suppressive effect on conifers. It is imperative that this factor be taken into account when devising forest management plans for the future in this region., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lin, Cong, Xiao, Kou, Li, Yu, Qi, Gou, Bai and Ren.)

The foremost role of forest vegetation in storing biomass and carbon (C) stock constitutes one of the main nature-based solutions to mitigate climate change. In this study, we aimed to quantify biomass and C stock partitioning in multiple vegetation strata (tree, shrub, herb, and ground floor layers) of major forest types in Jammu and Kashmir, Western Himalaya, India. We used a stratified random cluster sampling strategy to collect field data in 96 forest stands of 12 forest types (altitudinal range: 350 to 3450 m) in the study region. We evaluated the degree to which the carbon stock of the entire ecosystem was dependent on the multiple vegetation strata using the Pearson method. Across all the forest types, the average total ecosystem-level biomass was estimated to be 181.95 Mgha -1 (range: 60.64-528.98). Forest strata-wise, the maximum biomass of 172.92 Mgha -1 (range: 50.64-514.97) was found in the tree vegetation, followed by 5.58 Mgha -1 (range: 2.59-8.93) in understory vegetation (shrubs and herbaceous), and 3.44 Mgha -1 (range: 0.97 and 9.14) in the forest floor. The total ecosystem-level biomass showed a peak at mid-elevation coniferous forest types, whereas the lowest was observed in low-elevation broad leaved forest types. At the ecosystem-level, on average, the understory contributed 3% and the forest floor 2% to the total C stock across the forest types. The shrub layer contributed up to 80% of total understory C, with the herbaceous layer accounting for the remaining 20%. The ordination analysis clearly shows that anthropogenic and environmental variables significantly (p ≤ 0.002) influence the forest types' C stock in the region. Our findings have significant implications for conserving natural forest ecosystems and restoring degraded forest  landscapes in this Himalayan region, which in turn can lead to better carbon sequestration and climate mitigation outcomes., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Road construction will have a large impact on the ecosystem in the road area, and carbon stock, as an important indicator to measure the scale and quantity of primary productivity of the ecosystem, will also change, but the specific pattern is not clear. It is important to study the impact of road construction on carbon stock for regional ecosystem protection and sustainable economic and social development. Based on the InVEST model, this paper quantifies the spatial and temporal changes of carbon stocks in Jinhua, Zhejiang Province, from 2002 to 2017, using remote sensing image classification data land cover types as model driving data, geodetector, trend analysis, and buffer zone analysis methods, explores the driving effect of road construction on carbon stocks, and analyzes the spatial and temporal impacts of road construction on carbon stocks within the buffer zone. Results indicate that the total carbon stock in the Jinhua area showed a decreasing trend during the 16 years, decreasing by about 8.58 × 10 6 t. The spatial changes in the areas with higher carbon stocks were not significant. The explanatory power of road network density on carbon stock reaches 37%, and the anisotropic effect of road construction on carbon stock is strong and had a significant driving effect on carbon storage reduction. The new highway construction will accelerate the rate of carbon stock decline in the buffer zone, and the spatial situation is generally "the farther away from the highway, the higher the carbon stock.", (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: In Ethiopia, highland bamboo has been cultivated in various niches: farmlands, riverbanks, woodlot boundaries, and homesteads, and agroforestry systems. However, the biomass and carbon storage of potential of bamboo forests across niches is not well characterized in Ethiopia. Therefore, this study was conducted to estimate the biomass and carbon storage potential of highland bamboo plantations in northwestern Ethiopia. To this end, a total of 60 circular plots measuring 100 m 2 with a radius of 5.64 m were randomly established on the homestead, woodlot, and riverbank plantation niches to conduct the inventory. The biomass storage of bamboo was calculated based on previously published allometric equations. Biomass and carbon stock variations among age-classes and niches of bamboo forests were analyzed using analysis of variance (ANOVA) and subsequent pairwise means comparisons of carbon stocks among niches were performed via post hoc Tukey test at p < 0.05., Results: Results showed that the mean aboveground biomass (AGB) ranged from 150.18 - 191.42 Mg ha -1 in the entire niches. The highest amount of AGB was stored in the homestead niche (191.42 Mg ha -1 ) followed by the woodlot (180.11 Mg ha -1 ) and riverbank niche (150.17 Mg ha -1 ), respectively. The highest carbon stock (111.56 Mg C ha -1 ) was found in the homestead niche while the smallest amount was recorded in the riverbank niche (87.52 Mg ha -1 ). The homestead bamboo plantation has the highest biomass storage due to the application of manure and natural fertilizer, regular harvesting and management of culms, and protection from illegal harvesting and grazing., Conclusion: This study highlights the importance of bamboo plantations in climate change mitigation. Hence, bamboo plantation should be promoted; and natural resource management and forestry departments of the government, Universities, research centers, the International Bamboo and Rattan Organization (INBAR), and other partners should work with local communities to expand bamboo plantation on their homesteads and degraded lands., (© 2023. The Author(s).)

Terrestrial ecosystems such as forest landscapes provide critical ecosystem services such as carbon sequestration, fundamental to people, society and the global climate change discourse. Just like moist forest, dry Afromontane forests too present a high carbon sequestration potential. However, Uganda has since not undertaken carbon stock inventories for these conservation areas, especially with dry Afromontane forests like Agoro-agu central forest reserve (CFR). So, their potential to capture and store carbon is yet to be understood in Uganda. This study was carried out to estimate carbon stock of Agoro-agu CFR, for its potential in climate change mitigation. A stratified sampling design was used, where 65 sample plots were established. Nested, fixed area circular sample plots with sub-plots of varying radii for tree height, diameter measurements and soil sampling, were used. The mean total carbon stock of Agoro-agu CFR was estimated at 606.7 Mg C ha -1 , for which 409, 72, 124 and 0.24 Mg C ha -1 was stored as above ground carbon, below ground carbon, soil organic carbon and carbon in litter herbs and grass respectively. The study illustrates the carbon sequestration potential of the forest reserve for any results-based payment projects for climate change mitigation. This is mainly due to the interventions through collaborative forest management arrangements and the pro-poor reducing emissions from Deforestation and forest Degradation (REDD+) pilot project in the landscape. This however, calls for more multi-stakeholders' collaboration from direct resource users to national level to enhance forest conservation and reduce forest degradation for sustainable resource benefits and other ecosystem services., Competing Interests: The authors declare no conflict of interest., (© 2023 Published by Elsevier Ltd.)

Mangroves in tropical and subtropical regions worldwide are recognized as important sinks for microplastics (MPs). However, recent studies have focused on surface sediments, and in China, the vertical distribution and characteristics of MPs in mangrove sediments remain poorly understood. In this study, sediment cores of 100 cm depth were collected from six representative mangroves in China to investigate MPs via chronological analysis. Futian had the highest abundance of MPs (0-3123 n/kg), followed by Dongfang, Yunxiao, Zhanjiang, Dongzhaigang and Fangchenggang. The earliest MPs occurring in mangroves were dated back to 1955, and their abundance increased exponentially from bottom to surface sediments. MPs were mainly white in color, fiber-shaped, 1000-5000 μm in size, and of polypropylene/polyethylene polymer types. Furthermore, the MPs in the urban mangrove also showed a higher diversity in color. The results showed that the MP stocks in the urbanized Futian mangrove reached 1828 mg/m 3 , an order of magnitude higher than in other areas (251 ± 180 mg/m 3 ), contributing to 0.0057 % of the carbon storage of the sediment. The abundance of MPs in mangrove sediments is expected to increase by 2.38-9.54 times by 2030, and therefore deserve further attention., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Woodlot plantation takes our attention nowadays because of having high wood value, biomass and carbon stock. It also has considerable potential for regulating climate change by sinking CO 2 . This study investigated the market value of Swietenia macrophylla  woodlots concerning the current carbon trade mechanism, local timber and oxygen value. The carbon-di-oxide equivalence (CO 2e ) and release oxygen (O 2 Release ) ranged from 125.5 to 1004.5 Mg/ha (mean 436.3 Mg/ha) and 91.25-730.26 Mg/ha (mean 317.2 Mg/ha), respectively. Form carbon trade, the Swietenia macrophylla woodlots owner will earn 4,285-34,470 BDT/ha (mean 14,900 BDT/ha). It also seemed that the present market value of release oxygen (O 2 Release ) ranged from 3.2 to 25.5 million BDT/ha (average 11.1 million BDT/ha). However, the study area's average DBH, height, density, and basal area were 18.9 cm, 12.6 m, 1233 stem/ha, and 36.6 m 2 /ha, respectively. The above-ground biomass, below-ground biomass, and total biomass ranged from 45.9 to 389.7 Mg/ha (mean 166.5 Mg/ha), 22.5-157.7 Mg/ha (mean 71.2 Mg/ha), and 68.4-547.4 Mg/ha (mean 237.7 Mg/ha) correspondingly. Besides, the produced wood volume ranged from 64.95-1225.19 m 3 /ha (average 481.48 m 3 /ha). While the price of wood ranged from 0.8 to 15.14 million BDT/ha (mean 5.95 million BDT/ha). However, the above-ground, below-ground, and total carbon ranged 22.97-194.85 Mg/ha (mean 87.27 Mg/ha, 11.23-78.85 Mg/ha (35.61 Mg/ha), and 34.2-273.7 Mg/ha (118.89 Mg/ha) independently. Moreover, our three developed basal area-based allometric models are fit for calculating the carbon stock of Swietenia macrophylla woodlots. This study explores the potentiality of woodlots in Bangladesh. Policymakers should encourage the farmers to create more woodlots that actively participate in climate change mitigation., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Tropical grasses are the primary source of forage for livestock and a valuable resource for improving soil health and environmental sustainability in semi-arid regions. A study was carried out in a semi-arid region of central India to determine the short-term (6-year) impact of nine range grasses on soil physio-chemical and biological properties, carbon stock, and forage security. The experiment was carried out in a randomized block design with three replications. Results show that the majority of the grass roots were distributed in the upper soil layer (0-10 cm, 63.5-76.5 %), and then in the middle (10-20 cm, 21.3-25 %) and lower (20-30 cm, 2.2-11.5 %) layers. Perennial tussock grass (Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult) had a higher root volume (2219 mm 3 ), followed by Guinea grass [Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs] (1860 mm 3 ). A lower soil bulk density (BD, 1.11-1.23 g cm -3 ), higher gravimetric water content (GMW, 14.0-17.8 %), and soil organic carbon (0.38-0.73 %) were recorded for grass-cultivated plots compared to the barren land (1.38 g cm -3 , 13.0 %, and 0.28 %, respectively). The perennial tussock grass and Guinea grass resulted in the highest soil microbial biomass carbon (SMBC, 70.1 mg kg -1 soil) and enzyme activities (dehydrogenase, 17.09 μg TPF g -1 day -1 and fluorescein diacetate activity 4.94 μg fluorescein g -1 h -1 ). The considerable improvement in soil properties with minimal inputs resulted in a higher sustainable yield index and carbon sustainability index in plots planted with Guinea grass (0.9 and 89.29) and perennial tussock grass (0.89 and 71.61). Therefore, the cultivation of either Guinea grass or perennial tussock grass as an intercrop or sole crop in the semi-arid environment can be an ecologically sound strategy to improve soil health, C sequestration, and fodder supply., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest in conducting research and submitting this manuscript., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We investigated the sediment carbon (C) stocks, sequestration and sources in tidal flats and their adjacent mangroves in two coastal wetlands in Hong Kong (the Mai Po Nature Reserve (MPNR) and Ting Kok (TK)), part of a megacity of ∼20 million. At both locations, the C stock of tidal flats was lower than that of mangroves. In MPNR, tidal flats indicated a higher C burial rate (75.2 g C m -2  yr -1 ) compared to mangroves (64.3 g C m -2  yr -1 ). The C of tidal flats mainly originated from mangroves and riverine sources, while those in deeper sediments (below 60 cm) in the mangroves originated from the tidal flats. In TK, the C of tidal flats was dominated by oceanic sources. Our study indicates that tidal flats are also important in coastal C sequestration. On highly urbanized coasts, tidal flats and their connected mangroves can play a critical role for C mitigation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Biochar (BC) soil amendments could partially counteract soil carbon (C) stock decrease in broad-leaved forests in Italy; however, its effects on the growth of representative tree species- Fagus&nbsp;sylvatica L. and Quercus&nbsp;cerris L.-has not yet been addressed. We examine whether seed germination and growth of these species are affected by addition of BC obtained from deciduous broadleaf trees. Seeds were left to germinate in greenhouse conditions under three different BC amendments: 0% (control), 10% and 20% ( v / v ). Seedlings were then subjected to controlled conditions under the same BC percentage. Biochar effects on seed germination were assessed measuring germination time and percentage, while effects on photosynthesis were assessed using leaf chlorophyll content (mg/m 2 ) and photosynthetic efficiency (F V /F M ). Plant growth was estimated by recording leaf number, longest leaf length and plant height. Biochar treatments had no negative effects on germination and early growth stage of the two species. Positive effects were found on the chlorophyll content of both species (ca. +8%) regardless of the treatment and on the leaf number (+30%), leaf length (+14%) and plant height (+48%) of Q. cerris (only with 10% BC). Biochar applications seem, therefore, a suitable method for increasing broad-leaved forest C stock in Italy.

Peatlands at high latitudes have accumulated >400 Pg carbon (C) because saturated soil and cold temperatures suppress C decomposition. This substantial amount of C in Arctic and Boreal peatlands is potentially subject to increased decomposition if the water table (WT) decreases due to climate change, including permafrost thaw-related drying. Here, we optimize a version of the Organizing Carbon and Hydrology In Dynamic Ecosystems model (ORCHIDEE-PCH4) using site-specific observations to investigate changes in CO 2 and CH 4 fluxes as well as C stock responses to an experimentally manipulated decrease of WT at six northern peatlands. The unmanipulated control peatlands, with the WT <20 cm on average (seasonal max up to 45 cm) below the surface, currently act as C sinks in most years (58 ± 34 g C m -2  year -1 ; including 6 ± 7 g C-CH 4 m -2  year -1 emission). We found, however, that lowering the WT by 10 cm reduced the CO 2 sink by 13 ± 15 g C m -2  year -1 and decreased CH 4 emission by 4 ± 4 g CH 4 m -2  year -1 , thus accumulating less C over 100 years (0.2 ± 0.2 kg C m -2 ). Yet, the reduced emission of CH 4 , which has a larger greenhouse warming potential, resulted in a net decrease in greenhouse gas balance by 310 ± 360 g CO 2-eq  m -2  year -1 . Peatlands with the initial WT close to the soil surface were more vulnerable to C loss: Non-permafrost peatlands lost >2 kg C m -2 over 100 years when WT is lowered by 50 cm, while permafrost peatlands temporally switched from C sinks to sources. These results highlight that reductions in C storage capacity in response to drying of northern peatlands are offset in part by reduced CH 4 emissions, thus slightly reducing the positive carbon climate feedbacks of peatlands under a warmer and drier future climate scenario., (© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Based on datasets from plot survey and bibliographic of Larix olgensis plantations in Maoer Mountain, the CO 2 FIX model was used to quantitatively simulate the effects of different rotations (30, 40, 50, 60 years), site indices (12, 16, 20 m), and initial densities (2500, 3333, 4444 trees·hm -2 ) on the stand level carbon flows among different carbon pools ( i.e. , biomass carbon pool, soil carbon pool, and product carbon pool). The results showed that the CO 2 FIX model had high reliability for simulating the processes of L. olgensis plantation, with the average relative errors of stand biomass and volume between analog and measured values being 6.4% and 3.7%. Under the baseline conditions of initial density of 3333 trees·hm -2 , site index of 16 m and rotation of 40 years, the carbon stock of total and sub-pool of L. olgensis plantation changed periodically with rotation. The total stand carbon stock and volume for L. olgensis plantation increased with the extension of rotation, the improvement of site index, and the increase of initial density. The stand carbon stock and volume would be increased by 12.2% and 31.2%, 36.7% and 67.8%, respectively, when the reference rotation was correspondingly extended by 10 and 20 years. However, if the reference rotation was shortened by 10 years, stand carbon stock and volume would be correspondingly decreased by 20.9% and 40.4%, respectively. When the initial density was set as 3333 and 4444 trees·hm -2 , stand carbon stock and volume were increased by 27.8% and 50.9%, 27.4% and 49.1%, respectively. When the site index was under the range of 12 to 20 m, stand carbon stock and volume could be increased by 36.0% and 40.3%, 39.3% and 44.2%, respectively, with each increase of 4 m in site index. During one rotation, 271.57 t C per hectare could be fixed into L. olgensis plantation. At the end round of the rotation, 27.47 and 56.75 t C were transferred to soil and wood product carbon pools. Therefore, when the site condition was good, the management model with a higher initial density (4444 trees·hm -2 ) and longer rotation (60 years) would be more beneficial to maximizing the carbon sink and timber benefits of L. olgensis plantation.

In the last decades, the increasing necessity to reduce atmospheric carbon dioxide (CO 2 ) concentrations has intensified interest in quantifying the capacity of coastal ecosystems to sequester carbon, referred to commonly as 'Blue Carbon' (BC). Among coastal habitats, seagrass meadows are considered as natural carbon sinks due to their capacity to store large amounts of carbon in their sediments over long periods of time. However, the spatial heterogeneity of carbon stocks in seagrass sediments needs to be better understood to improve the accuracy of BC assessments, particularly where there is high environmental variability. In the Mediterranean, Posidonia oceanica (L.) Delile constitutes extensive meadows considered as long-term carbon sinks due to the development of an exceptional structure known as 'matte', reaching several meters in height, which can be preserved over millennia. In order to specify the role of P. oceanica meadows in climate change mitigation, an estimate of carbon stocks has been conducted along the eastern coast of Corsica (NW Mediterranean). The approach is mainly based on the biogeochemical analysis of 39 sediment cores. Organic carbon (C org ; 327 ± 150 t ha -1 , mean ± SE) and inorganic carbon stocks (C inorg ; 245 ± 45 t ha -1 ) show a high variability related to water depth, matrix (sandy vs rocky substrate) or the depositional environment (coastal vs estuary). The isotopic signature (δ 13 C) revealed a substantial contribution of allochthonous inputs of organic matter (macroalgae and sestonic sources) mainly in estuarine environment and shallow areas. The carbon stocks in the first 250 cm of matte (average thickness) were estimated at 5.6-14.0 million t C org (study site) and 14.6-36.9 million t C org (Corsica), corresponding to 11.6-29.2 and 30.4-76.8 years of CO 2 emissions from the population of Corsica., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In the context of carbon peak, neutrality, and circular agricultural economy, the use of renewable resources from agricultural processing for plant cultivation still needs to be explored to clarify material flow and its ecological effects. Paddy-upland rotation is an effective agricultural strategy to improve soil quality. This study evaluated the effects of biogas slurry application against those of chemical fertilisers in these two typical Chinese cropping soils. The application of biogas slurry increased total carbon content in paddy soil by 73.4%, and that in upland soil by 65.8%. Conversely, application of chemical fertiliser reduced total carbon in both soil types. There were significant positive correlations between total carbon and Zn, Cu, and Pb in rice husks grown in paddy soil (R 2  = 0.95, 0.996, 0.95; p < 0.05). The content of amylose in biogas slurry treatment of paddy soil increased by 35.9%, while that in upland soil decreased by 19.2%. After biogas slurry was applied, the contents of fulvic acid- and humic acid-like substances in paddy soil average increased by 40.9% and 45.6%, while the contents of protein-like components were enhanced by 46.8% in upland soil. This result was consistent with predictions of microbial community function. Microorganisms in paddy soil generally preferred carbon fixation, while those in upland soil preferred hydrocarbon degradation and chemoheterotrophy. Understanding the changes in soil carbon stock and microbial function after biogas slurry application will contribute to sustainable agricultural development and food security., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Destructively sampling old Pedunculate oak ( Quercus robur ) trees on the active floodplain of the Middle Elbe to create an allometric equation to estimate carbon stocks (CS) and carbon sequestration rates (CSR) would defeat the purpose of protecting increasingly vulnerable and threatened primeval floodplain forests. To nondestructively estimate CS and CSR, we have adapted a two-parameter allometric equation which uses tree height (H) and diameter at breast height (DBH) (Dik 1984, Zianis et al. 2005) into a 1-parameter equation that requires only DBH to quantify stocks and annual changes in carbon stock (carbon sequestration rates) for individual Q. robur trees. The equations have also been adapted to estimate below- and above-ground carbon stocks of individual trees. The new method has:•Adapted a 2-parameter Quercus robur allometric equation which estimates tree volume to a 1-parameter equation which estimates above and below-ground carbon stock•Removed the requirement of tree height to reconstruct the carbon stock of trees at an annual timestep•An almost perfect linear relationship (Pearson R 2 = 0.998) between carbon sequestration rate and basal area increment (BAI)., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

There is a growing awareness surrounding the importance of maintaining and increasing soil organic carbon (SOC, henceforth) stocks in vineyard systems. Increasing SOC positively influences numerous soil properties and has the added advantage of removing atmospheric CO 2 , thereby helping to mitigate the effects of climate change. Cover crops have long been used to influence soil properties in vineyard mid-rows, including increasing SOC content. Few studies, however, have quantified cover crop influence on SOC stocks and composition in the under-vine area, owing to a general reluctance to adopt under-vine cover crop management. This research aims to quantify SOC stocks and dissolved organic carbon (DOC) in soils from four treatments of under-vine management practice including two cover crop combinations, a straw mulch and herbicide-managed control across two vineyard sites established in 2014. We sampled soils under-vine to depths of 0-30 cm (stratified; 0-10 cm and 10-30 cm) and quantified both SOC concentrations and bulk density to ascertain SOC stocks. Further to this, we quantified water extractable organic carbon (WEOC) as a measure of the labile carbon stock, and measured heterotrophic respiration in a laboratory incubation as an indication of SOC turnover. We found that cover crop-managed soil under-vine sequesters up to 23% more soil organic carbon (SOC) as the traditional, herbicide practice over a five-year period of growth. Microbial activity increased by more than double in cover crop soils, owing to an increase in DOC and that there is evidence for more resistant C in cover crop soils. These results suggest that cover crop management under-vine is a viable solution to increase SOC stocks within vineyard systems. Taken together, the results of this study indicate that a shift from bare earth to cover crops in the under-vine region has the potential to sequester carbon in vineyard soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Blue carbon ecosystems are a vital part of nature-based climate solutions due to their capacity to store and sequester carbon, but often exclude macroalgal beds even though they can form highly productive coastal ecosystems. Recent estimates of macroalgal contributions to global carbon sequestration are derived primarily from temperate kelp forests, while tropical macroalgal carbon stock in living biomass is still unclear. Here, using Singapore as a case study, we integrate field surveys and remote sensing data to estimate living macroalgal carbon stock. Results show that macroalgae in Singapore account for up to 650 Mg C biomass stock, which is greater than the aboveground carbon found in seagrass meadows but lower than that in mangrove forests. Ulva and Sargassum dominate macroalgal assemblages and biomass along the coast, with both genera exhibiting distinct spatio-temporal variation. The annual range of macroalgal biomass carbon is estimated to be 450 Mg C yr -1 , or 0.77 Mg C ha -1 yr -1 . Noting the uncertainties of the fate of macroalgal biomass carbon, we estimate the potential sequestration rate and find that it is comparable to mature terrestrial ecosystems such as tropical grasslands and temperate forests. This study demonstrates that macroalgal seasonality allows for a consistent amount of biomass carbon to either be exported and eventually sequestered, or harvested for utilization on an annual basis. These findings on macroalgal growth patterns and their considerable contributions to tropical coastal carbon pool add to the growing support for macroalgae to be formally included in blue carbon assessments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)