Variation In Carbon Stocks Research Articles

Identifying bacterial fixation pathway of mediating soil carbon stock changes along tropical forest restoration

The mechanism mediating carbon accumulation changes along ropical forest restoration remains unclear. Here, we identified how functional bacteria, litter input, and abiotic variables control soil organic carbon stock changes along an age-chronosequence of tropical forest restoration. Over 51-yr recovery, significant increases in total organic carbon stocks (∼1.7 fold) were strongly associated with increases in copy number of carbon fixation bacterial genes (cbbL) (∼2.6 fold). The direct pathways of cbbL abundance, microbial and mineral-associated organic carbon explained 76 % of carbon stock variation. In contrast, litter carbon, soil water, and bulk density indirectly regulated carbon stocks through affecting cbbL abundance (68 %) and microbial carbon level (29 %). Furthermore, cbbL abundance had a higher contribution (71 %) to carbon fraction transformation than microbial carbon level (19 %). We suggest that tropical forest restoration controls carbon stocks primarily via direct bacterial fixation pathway mediated by litter carbon and physical soil variables. Our results are helpful to further understand the mechanism of tropical forest restoration regulating carbon transformation and accumulation.

Variations in carbon stocks across traditional and improved agroforestry in reference to agroforestry and households’ characteristics in southeastern Ethiopia

Variations in carbon stocks across traditional and improved agroforestry in reference to agroforestry and households’ characteristics in southeastern Ethiopia

Carbon stock in calophyllum inophyllum provenances from eight islands in Indonesia: associate soil physicochemical properties and litter fiber content

Calophyllum inophyllum is a superior choice for sustainable biodiesel production. This tree is highly productive, adaptable to various land types, and has a significant potential for carbon sequestration. This study aimed to determine carbon storage variation in biomass, litter, and soil among C. inophyllum provenances from eight islands in Indonesia; identify the best allometric model for estimating total plant biomass carbon stock; and assess the impact of soil physicochemical properties and litter fiber content on total carbon stock. Plant, litter and soil samples were purposively selected from a total of 32 sample points of 8 provenances. Analysis of variance was carried out to determine variations among provenances on carbon storage in plant biomass and its components (stems, branches, twigs, leaves, stumps, and roots), in litter, as well as in soil organic carbon. The best allometric equation was selected to estimate the total plant biomass carbon based on the value of coefficient determination (R2) and RMSE (Root Mean Square Error). Redundancy Analysis (RDA) was carried out to determine the effect of the soil physicochemical properties and litter fiber content on total biomass carbon and total soil organic carbon followed by a partial analysis (Variation Partitioning Analysis). The results of this study showed that variations on carbon storage in plant biomass and its components, in litter, as well as in soil organic carbon were not significantly different among the provenances. The tBC averaged 13.46 tons ha−1, the litter carbon 4.75 tons ha−1, and tSOC 75.91 ton ha−1 with most biomass carbon stored in trunks (31.02%) and most of carbon stock was stored as tSOC (81%). Quadratic (tBC = 0,4172DBH2 - 1,3433DBH + 2,3498) was the best allometric model for estimating carbon storage on plant biomass with diameter at breast height (DBH) as a predictor variable. Most of the variation in total carbon stock was influenced by soil chemical properties (76%) followed by soil physical properties (11%) and litter fiber content (5%). This study implies that the development of C. inophyllum in Indonesia for carbon storage may utilize seeds or planting materials from any origin, disregarding provenances. Applying organic and/or mineral nutrients (N, P, and K) will increase carbon stock in C. inophyllum plantations. This study underscores the significance of assessing C. inophyllum carbon stocks to enhance its role in establishing climate change policies and promoting sustainable resource management.

Seafloor sediment characterization improves estimates of organic carbon standing stocks: an example from the Eastern Shore Islands, Nova Scotia, Canada

Abstract. Continental shelf sediments contain some of the largest stocks of organic carbon (OC) on Earth and play a vital role in influencing the global carbon cycle. Quantifying how much OC is stored in shelf sediments and determining its residence time is key to assessing how the ocean carbon cycle will be altered by climate change and possibly human activities. Spatial variations in terrestrial carbon stocks are well studied and mapped at high resolutions, but our knowledge of the distribution of marine OC in different seafloor settings is still very limited, particularly in dynamic and spatially variable shelf environments. This lack of knowledge reduces our ability to understand and predict how much and for how long the ocean sequesters CO2. In this study, we use high-resolution multibeam echosounder (MBES) data from the Eastern Shore Islands offshore Nova Scotia (Canada), combined with OC measurements from discrete samples, to assess the distribution of OC content in seafloor sediments. We derive four different spatial estimates of organic carbon stock: (i) OC density estimates scaled to the entire study region assuming a homogenous seafloor, (ii) interpolation of OC density estimates using empirical Bayesian kriging, (iii) OC density estimates scaled to areas of soft substrate estimated using a high-resolution classified substrate map, and (iv) empirical Bayesian regression kriging of OC density within areas of estimated soft sediment only. These four distinct spatial models yielded dramatically different estimates of standing stock of OC in our study area of 223 km2: 80 901, 58 406, 16 437 and 6475 t of OC, respectively. Our study demonstrates that high-resolution mapping is critically important for improved estimates of OC stocks on continental shelves and for the identification of carbon hotspots that need to be considered in seabed management and climate mitigation strategies.

Stand structure and Brazilian pine as key determinants of carbon stock in a subtropical Atlantic forest.

Understanding the drivers of variations in carbon stocks is essential for developing the effective management strategies that contribute to mitigating climate change. Although a positive relationship between biodiversity and the aboveground carbon (AGC) has been widely reported for various Brazilian forest types, representing a win-win scenario for climate change mitigation, this association has not been commonly found in Brazilian subtropical forests. Therefore, in the present study, we aimed to evaluate the effects of Araucaria angustifolia, stand structure and species diversity in shaping AGC stocks in Brazilian subtropical mixed forest. We hypothesized that the effects on the AGC of stand structure and diversity would be mediated by A. angustifolia. We also evaluated the expectation of higher carbon stocks in protected forest as a result of their positive correlation with biodiversity conservation. We found that stand structure, followed by A. angustifolia, played the most important role in shaping the AGC stock. Our hypothesis was partially confirmed, the indirect effects of A. angustifolia on stand structure being found to have shaped the AGC. Similarly, our expectation was partially supported, with the higher AGC in the protected area being related not to diversity, but rather to the presence of larger trees, denser stands, and a greater abundance of A. angustifolia. Although the win-win strategy between diversity conservation and carbon storage is not a peculiarity of Araucaria forests, we highlight the potential of these forests as a nature-based climate solution, maintaining high levels of carbon storage in harmony with the provision of keystone socio-economic resources.

Impacts of Land‐Use Change on Past and Future Carbon Stocks in the Tianshan North Slope Economic Belt

ABSTRACTTo study the connection between land use and regional ecological carbon stocks, predicting the future evolution of land use and understanding the trends of changes in carbon stocks are essential to environmental protection and sustainable development. However, the changes in carbon stocks within ecosystems driven by land‐use and land‐cover change (LUCC) are characterized by large uncertainties. This study took the Tianshan North Slope Economic Belt in Xinjiang Autonomous Region, China, as an example to investigate the spatiotemporal changes of carbon stocks and their relationship with LUCC, and used 11 variables in a Geo Detector model to analyze the drivers of spatial differentiation in carbon stocks. We trained six variables to predict the changes in carbon stocks under a natural development scenario (NDS) and ecological protection scenario (EPS) in 2030. The following results were obtained: (1) the land use was dominated by unused land in the 20‐year study period (2000–2020). Grassland showed a continuous decrease; unused land decreased and then increased, while others continued to increase. The most drastic change was for cropland, which was 7785 km2 (an increase of 39.76%), while grassland was reduced by 9402 km2 (a decrease of 9.05%). (2) Carbon stocks showed an increasing and then a decreasing trend, with an overall increase of 2.05 × 106 t. The spatial distribution was more centralized in the southwest, showing a continuous distribution with slice‐like bands, while the higher values took an irregular form in the northeastern portion of the region. (3) Carbon stocks under NDS reached 1427.50 × 105 t, an increase of 6.26 × 106 t compared with 2020; while under EPS, they reached 1427.79 × 105 t, an increase of 6.29 × 106 t, mainly due to grassland and unused land conversion. Therefore, the protection and restoration of grassland should continue to be strengthened in the future. (4) NDVI and soil erosion had strong explanatory power for the spatial variability of carbon stocks. There was two‐factor and nonlinear enhancement interaction in different factors, indicating that natural and human factors enhance the explanation of the spatial variation, the results of which can be applied to the ecosystems of the region.

Variation of shade tree composition and carbon stock of smallholder coffee agroforestry systems along an elevation gradient in Khun Mae Kuang Forest area, northern Thailand

The coffee (Coffea arabica L.) agroforestry systems (CASs) of smallholder farmers can enhance species diversity and carbon stock by managing the shade tree component. This study investigated the variation in shade tree composition and carbon stock of CASs along an elevation gradient in Khun Mae Kuang Forest, Ching Mai Province. Data were collected from 80 plots (20 m × 20 m each) that were divided into groups of 20 plots at four elevation ranges: lower (LE), middle-lower (MLE), middle-upper (MUE), and upper (UE). Differences in species composition and carbon stock were examined to determine the effect of elevation on both characteristics. The results show that the shade tree compositions within MLE and MUE were significantly different, dividing the shade tree composition of CASs according to location (lower vs. upper zone). Species richness and stem density were highest in the lower zone (LE and MLE) forest trees and in the upper zone (MUE and UE) horticultural trees. The total carbon stock at each elevation range was high (186.32–264.12 Mg C ha–1), and increased with elevation. The aboveground biomass carbon of forest trees contributed the most to the CAS carbon stock, suggesting that the CAS system plays a significant role in carbon storage by promoting the conservation of natural trees in highland agricultural. These findings will help to improve CAS management in mountainous areas, as well as biodiversity conservation and efforts to mitigate climate change.

Exploring the role of canopy cover and environmental factors in shaping carbon storage in Desa’a forest, Ethiopia

BackgroundDry Afromontane forests play a vital role in mitigating climate change by sequestering and storing carbon, as well as reducing greenhouse gas emissions. Despite previous research highlighting the importance of carbon stocks in these ecosystems, the influence of canopy cover and environmental factors on carbon storage in dry Afromontane forests has been barely assessed. This study addresses this knowledge gap by investigating the effects of environmental factors and vegetation cover on carbon stocks in Desa’a forest, a unique and threatened Afromontane dry forest ecosystem in northern Ethiopia. Data on woody vegetation, dead litter, grass biomass, and soil samples were collected from 57 plots. A one-way analysis of variance (ANOVA) was performed at a 95% confidence level (α = 0.05) to examine the influence of canopy cover and environmental factors on the carbon stocks of various pools.ResultsAmong the 35 woody species identified, Juniperus procera was the most dominant, while Carissa edulis Vahl and Eucalyptus globulus were the least dominant. The average total carbon stock was 92.89 Mg ha−1, with contributions from aboveground carbon, below-ground carbon, litter carbon, grass carbon, and soil organic carbon. Among the carbon pools, soil organic carbon had the highest carbon stock, accounting for 76.8% of the total, followed by above-ground biomass carbon at 17.7%. Significant variations in carbon stocks were found across altitude class and canopy level but not slope and aspect factors.ConclusionsIn summary, altitude and canopy level were found to significantly influence carbon stocks in Desa’a forest, providing valuable insights for conservation and climate change mitigation efforts in dry Afromontane forests. Forest intervention planning and management strategies should consider the influence of different environmental variables and tree canopy levels.

Spatio-temporal Dynamics of Land Use/Cover Change and Associated Carbon Stocks in Kanyabaha Wetland in Rukiga District, Uganda

Wetlands play an important ecological function of sequestering atmospheric carbon dioxide and thereby moderating adverse impacts of climate change. It is therefore important to understand the dynamics of carbon stocks in wetland vegetation and soils. This study investigated the spatio-temporal dynamics of aboveground, belowground, and total carbon stocks in Kanyabaha Wetland, located in Rukiga District, Uganda, spanning from 1990 to 2021. Through field sampling and laboratory analysis, aboveground carbon stocks were assessed by harvesting vegetation biomass and converting it to carbon stock using established conversion factors. Soil samples collected at different depths (0-20cm, 20-50cm, 50-100cm) were analyzed for soil organic carbon content to determine belowground carbon stocks. The study reveals variable spatio-temporal patterns of carbon stocks across land use types, with papyrus-dominated areas exhibiting the highest aboveground carbon stocks (49.66 tC/ha), followed by small-scale farmlands (33.73 tC/ha) and tree plantations (23.01 tC/ha). Conversely, built-up areas exhibit the lowest carbon stocks (1.29 tC/ha). Temporal analysis reveals fluctuating patterns in carbon stocks, with increases observed in built-up areas and small-scale farmlands, and decreases in grasslands and tree plantations that could be due to changes in hydrological cycle. Belowground carbon stocks follow similar trends, with papyrus areas maintaining the highest stocks (39.96 tC/ha), particularly at deeper soil depths that exhibit the highest carbon accumulation due to its extensive network of papyrus rhizome. Changes in land use, especially reclamation of the wetlands for farming and settlements affected carbon capture and storage in the wetland ecosystem. These findings highlight the importance of targeted conservation of natural wetlands and sustainable land management strategies in the Kanyabaha Wetland catchment for enhanced carbon sequestration. Further, in depth studies in the variability of carbon stocks due to various eco-climatic factors and anthropogenic activities are necessary to support sustainable wetland land management practices in Uganda.

Hydrology, vegetation, and soil properties as key drivers of soil organic carbon in coastal wetlands: A high-resolution study

Coastal wetlands are important blue carbon ecosystems that play a significant role in the global carbon cycle. However, there is insufficient understanding of the variations in soil organic carbon (SOC) stocks and the mechanisms driving these ecosystems. Here we analyze a comprehensive multi-source dataset of SOC in topsoil (0–20 cm) and subsoil (20–100 cm) across 31 coastal wetlands in China to identify the factors influencing their distribution. Structural equation models (SEMs) reveal that hydrology has the greatest overall effect on SOC in both soil layers, followed by vegetation, soil properties, and climate. Notably, the mechanisms driving SOC density differ between the two layers. In topsoil, vegetation type and productivity directly impact carbon density as primary sources of carbon input, while hydrology, primarily through seawater salinity, exerts the largest indirect influence. Conversely, in subsoil, hydrology has the strongest direct effect on SOC, with seawater salinity also influencing SOC indirectly through soil and vegetation mediation. Soil properties, particularly pH, negatively affect carbon accumulation, while climate influences SOC indirectly via its effects on vegetation and soil, with a diminishing impact at greater depths. Using Random Forest, we generate high-resolution maps (90 m × 90 m) of topsoil and subsoil carbon density (R2 of 0.53 and 0.62, respectively), providing the most detailed spatial distribution of SOC in Chinese coastal wetlands to date. Based on these maps, we estimate that SOC storage to a depth of 1 m in Chinese coastal wetlands totals 74.58 ± 3.85 Tg C, with subsoil carbon storage being 2.5 times greater than that in topsoil. These findings provide important insights into mechanism on driving spatial pattern of blue carbon and effective ways to assess carbon status on a national scale, thus contributing to the advancement of global blue carbon monitoring and management.

Partitioning the sources of sediment organic carbon in South African seagrass meadows

In the sediments of seagrass meadows, allochthonous carbon sources can account for 50–90% of sediment organic carbon (SOC), in which non-seagrass carbon is derived from external organic matter advected into the meadow’s sediments or trapped by the seagrass canopy. Identifying the SOC origin is essential to accurately estimate the climate change mitigation potential of seagrass ecosystems, yet the ratio of allochthonous to autochthonous SOC in South African seagrass populations has not been investigated. In this study, we measured the SOC and carbon isotope ratio (δ13C) in Zostera capensis seagrass meadows in the Berg River and Breede River estuaries and applied Bayesian mixing models to disentangle the SOC contributory sources. Sediment organic carbon differed not only between estuaries, but also showed variability within each estuary, with autochthonous carbon accounting for between ∼35% (SD 0.23) and ∼42.3% (SD 0.18) of total meadow SOC. Other sources of SOC included macroalgae, salt marsh and seagrass species. Our work highlights the importance of accounting for allochthonous carbon in disentangling the drivers of high variability of carbon stocks in estuarine environments and contributes to improving the accuracy of South African seagrass carbon stock estimates.

Changes in carbon stocks according to stand development stages in oriental beech forests in the Marmara Region of Türkiye.

This study was conducted to determine the changes in carbon stocks of oriental beech (Fagus orientalis) according to stand development stage in the Marmara Region of Türkiye. For this purpose, sample plots were taken from a total of 32 areas encompassing four stand development stages (young, middle age, mature and overmature stand). The diameter at breast height and height of all trees in the sample plots were measured, and only three dominant trees's ages per plot were determined. Aboveground carbon stock was calculated using equations developed for beech forests, while the coefficients in the Agriculture, Forestry and Other Land Use guide were used to determine belowground carbon stocks. A soil pit was dug in each plot and soil samples were taken at different depths (0-10, 10-30, 30-60, 60-100cm). In addition, litters were sampled from four different 25 × 25cm sections in each plot, and then the physical and chemical properties of the soil and litters were analysed. The variations in carbon stocks in above- and below-ground tree mass, litter and soil, and in ecosystem carbon stocks according to development stage were examined by analysis of variance and Duncan test, and the relationships between the carbon stocks were investigated by correlation analysis. Aboveground (AG) and belowground (BG) tree, soil and ecosystem carbon stocks showed significant differences between the four stand development stages (P < 0.05), but not the litter carbon stocks (P > 0.05). AG and BG tree and ecosystem carbon stocks increased with progressive stand development stages, while the soil carbon stock was the highest at the young stage. These findings will contribute to the preparation of forest management plans and the national greenhouse gas inventory.

An Integrating Framework for Biomass and Carbon Stock Spatialization and Dynamics Assessment Using Unmanned Aerial Vehicle LiDAR (LiDAR UAV) Data, Landsat Imagery, and Forest Survey Data in the Mediterranean Cork Oak Forest of Maamora

Spatialization of biomass and carbon stocks is essential for a good understanding of the forest stand and its characteristics, especially in degraded Mediterranean cork oak forests. Furthermore, the analysis of biomass and carbon stock changes and dynamics is essential for understanding the carbon cycle, in particular carbon emissions and stocks, in order to make projections, especially in the context of climate change. In this research, we use a multidimensional framework integrating forest survey data, LiDAR UAV data, and extracted vegetation indices from Landsat imagery (NDVI, ARVI, CIG, etc.) to model and spatialize cork oak biomass and carbon stocks on a large scale. For this purpose, we explore the use of univariate and multivariate regression modeling and examine several types of regression, namely, multiple linear regression, stepwise linear regression, random forest regression, simple linear regression, logarithmic regression, and quadratic and cubic regression. The results show that for multivariate regression, stepwise regression gives good results, with R2 equal to 80% and 65% and RMSE equal to 2.59 and 1.52 Mg/ha for biomass and carbon stock, respectively. Random forest regression, chosen as the ML algorithm, gives acceptable results, explaining 80% and 60% of the variation in biomass and carbon stock, respectively, and an RMSE of 2.74 and 1.72 Mg/ha for biomass and carbon stock, respectively. For the univariate regression, the simple linear regression is chosen because it gives satisfactory results, close to those of the quadratic and cubic regressions, but with a simpler equation. The vegetation index chosen is ARVI, which shows good performance indices, close to those of the NDVI and CIG. The assessment of biomass and carbon stock changes in the study area over 35 years (1985–2020) showed a slight increase of less than 10 Mg/ha and a decrease in biomass and carbon stock over a large area.

Predictive mapping of organic carbon stocks in surficial sediments of the Canadian continental margin

Abstract. Quantification and mapping of surficial seabed sediment organic carbon have wide-scale relevance for marine ecology, geology and environmental resource management, with carbon densities and accumulation rates being a major indicator of geological history, ecological function and ecosystem service provisioning, including the potential to contribute to nature-based climate change mitigation. While global analyses can appear to provide a definitive understanding of the spatial distribution of sediment carbon, regional maps may be constructed at finer resolutions and can utilise targeted data syntheses and refined spatial data products and therefore have the potential to improve these estimates. Here, we report a national systematic review of data on organic carbon content in seabed sediments across Canada and combine this with a synthesis and unification of the best available data on sediment composition, seafloor morphology, hydrology, chemistry and geographic settings within a machine learning mapping framework. Predictive quantitative maps of mud content, dry bulk density, organic carbon content and organic carbon density were produced along with cell-specific estimates of their uncertainty at 200 m resolution across 4 489 235 km2 of the Canadian continental margin (92.6 % of the seafloor area above 2500 m) (https://doi.org/10.5683/SP3/ICHVVA, Epstein et al., 2024). Fine-scale variation in carbon stocks was identified across the Canadian continental margin, particularly in the Pacific Ocean and Atlantic Ocean regions. Overall, we estimate the standing stock of organic carbon in the top 30 cm of surficial seabed sediments across the Canadian shelf and slope to be 10.9 Gt (7.0–16.0 Gt). Increased empirical sediment data collection and higher precision in spatial environmental data layers could significantly reduce uncertainty and increase accuracy in these products over time.

Assessing and Forecasting Carbon Stock Variations in Response to Land Use and Land Cover Changes in Central Aceh, Indonesia

Assessing and Forecasting Carbon Stock Variations in Response to Land Use and Land Cover Changes in Central Aceh, Indonesia

Carbon Sequestration Dynamics in Peri-Urban Forests: Comparing Secondary Succession and Mature Stands under Varied Forest Management Practices

This study examines the impact of silvicultural and land-use management practices on carbon sequestration in peri-urban forest ecosystems, with a particular focus on human-induced carbon dynamics. The study area’s complex profile spans from a compact native forest to varying degrees of fragmentation. This included areas undergoing secondary succession forest without silvicultural interventions (No-SI) alongside sites subjected to high-intensity (High-SI) and low-intensity silvicultural interventions (Low-SI). The research assessed carbon stocks and sequestration in different carbon pools (living biomass, dead organic matter and soil) using field data, allometric equations and laboratory analysis. Findings reveal a significant correlation between the intensity of anthropogenic interventions and variations in carbon stocks. The CASMOFOR model facilitated the reconstruction of carbon stock and carbon-stock change dynamics over four decades (1980–2022), showing disparities in carbon storage capabilities linked to the structural characteristics of the sites. The Low-SI site had the highest carbon stock in all carbon pools (378 tonnes C ha−1), which is more than double compared to High-SI (161 tonnes C ha−1) or No-SI sites (134 tonnes C ha−1). However, the secondary succession forest (No-SI) demonstrated the highest annual carbon stock change (4.4 tonnes C ha−1 year−1), two times higher than the Low-SI mature stand (2.2 tonnes C ha−1 year−1), emphasising the resilience of forest ecosystems to recover and sustain carbon sequestration capacities after harvesting if forest land use remains unchanged. The study underscores the significant importance of anthropogenic interventions on carbon dynamics, especially for living tree biomass, which has consequences in enhancing carbon sequestration and contributing to emission reduction targets.

Effect of soil and water conservation practices and slope gradient on organic carbon stocks micronutrients: A case study on Kulkullessa sub-watershed, Eastern Ethiopia

Soil degradation in sub-Saharan Africa is a serious problem that causes declines in agricultural productivity linked to hunger and poverty. The study was conducted in the Kulkullessa sub-watershed of Goro Gutu District in Eastern Ethiopia to assess the effects of climate-smart soil and water conservation (SWC) practices and slope gradient on selected physicochemical properties of the soil and the soil’s organic carbon stocks. The farmland conserved by stone bund (SB), bench terrace (BT), and gras strip (GS) five years after construction with two slope gradients (15-20%) and (21-30%) was selected. Twenty-four composite soil samples were collected from a depth of 20 cm and tested in the Haramaya University soil laboratory. The study found that climate-smart SWC practices were very effective on the soil physicochemical properties and soil organic carbon stock (SOCS) of the study area. Similarly, the slope gradient brought considerable variation in soil physicochemical properties and soil organic carbon stock. On farmland that a bench terrace had preserved, the bulk density (BD) value was lower. The recorded value for total porosity on the farmland conserved by BT was also positively higher and significant (p ≤ 0.05). Likewise, the higher mean values for micronutrients and SOCS were recorded on farmlands conserved by SB, BT, and GS in contrast to the values recorded on non-conserved farmland (NCF) in the study area. Based on the study findings, climate-smart soil water and conservation practices have outstanding potential for improving soil physicochemical properties essential for agricultural crop production, climate change adaptation, and strengthening smallholder farmers’ resilience.

Seed‐dispersal mode and habitat connectivity underpin variation in carbon stocking between Brazilian biomes

Abstract In tropical forests, about 60%–80% of woody plant species depend on animal–plant interactions for dispersal. The dependence on animal species for dispersal makes this interaction very fragile in the face of anthropogenic changes in land use. Disrupting seed‐dispersal processes, principally zoochoric dispersal, could significantly alter the long‐term carbon storage potential of tropical forests. An important question is how landscape structure changes tree carbon stocks in different types of tropical vegetation and how variation is mediated by the dispersal mode of animal (zoochoric) or abiotic (non‐zoochoric) seeds. We focused on tree plots at 126 sites in Brazil spanning four types of forest and savanna vegetation, and calculated carbon stored in zoochoric, non‐zoochoric, and large frugivore‐dispersed species. Our results showed that carbon stocks in zoochoric species and non‐zoochoric species differ significantly among vegetation types, with rainforests having higher stocks in zoochoric species and deciduous seasonally dry tropical forests having higher values in non‐zoochoric species. A greater area of native vegetation promotes higher proportions of carbon stocks dispersed by large frugivore species, whereas a higher mean shape index reduces this proportion. Synthesis. This study highlights that seed‐dispersal type underpins the variation in carbon stocks between vegetation types and that the maintenance of habitat of large dispersers and connectivity are key for retaining carbon stocks in zoochoric species, particularly in rainforest and cerrado sensu stricto.

Fungal community composition predicts forest carbon storage at a continental scale.

Forest soils harbor hyper-diverse microbial communities which fundamentally regulate carbon and nutrient cycling across the globe. Directly testing hypotheses on how microbiome diversity is linked to forest carbon storage has been difficult, due to a lack of paired data on microbiome diversity and in situ observations of forest carbon accumulation and storage. Here, we investigated the relationship between soil microbiomes and forest carbon across 238 forest inventory plots spanning 15 European countries. We show that the composition and diversity of fungal, but not bacterial, species is tightly coupled to both forest biotic conditions and a seven-fold variation in tree growth rates and biomass carbon stocks when controlling for the effects of dominant tree type, climate, and other environmental factors. This linkage is particularly strong for symbiotic endophytic and ectomycorrhizal fungi known to directly facilitate tree growth. Since tree growth rates in this system are closely and positively correlated with belowground soil carbon stocks, we conclude that fungal composition is a strong predictor of overall forest carbon storage across the European continent.

Variation of biomass carbon stock within agroforestry systems in the Senegalese groundnut basin

Agroforestry plays a pivotal role in mitigating greenhouse gas (GHG) emissions and addressing the challenges posed by climate change. While carbon sequestration efforts have primarily centred on forests, it is imperative to acknowledge the contribution that non-forest ecosystems, such as agroforestry, can offer. This study investigated the influence of agroforestry systems on the variation of biomass carbon stocks in the Sahelo-Sudanian and Sudanian regions of the Senegalese Groundnut basin. Three primary agroforestry systems were studied: silvopastoral, agrisilvicultural, and agrosilvopastoral. Forty-six (46) 100 m × 100 m plots were sampled, within which 1 × 1 m2 subplots were used to sample understory biomass across three agroforestry systems in the two climatic zones. Analysis of variance was performed to assess the influence of agroforestry systems and climatic zones on biomass carbon stocks. The findings showed that in the Sahelo-Sudanian region, the agrisilvicultural system exhibited the highest AGC + BGC stocks, averaging 43.42 ± 21.61 tCha−1. In contrast, the silvopastoral system showed significantly higher AGC + BGC stocks, which amounted to 36.33 ± 12.27 tCha−1 in the Sudanian region. On the other hand, understory carbon stocks were significantly higher (p < 0.01) in the agrisilvicultural and agrosilvopastoral systems than in the silvopastoral system in both climatic zones. Agroforestry systems had a significant effect on AGC + BGC stocks within climatic zones. Nevertheless, the effect was less pronounced when comparing across climatic regions. These results underscore the importance of specific land management practices interacting with local climatic conditions to influence AGC + BGC stocks. Therefore, policy makers should carefully consider the interaction of these factors when implementing carbon management practices and planning mitigation strategies in West Africa.