Estimation of Aboveground and Belowground Carbon Stocks in Homegardens of Low Country Wet Zone, Sri Lanka

Tropical montane forests (TMFs) play an important role as a carbon reservoir at a global scale. However, there is a lack of a comprehensive understanding on the variation in carbon storage across TMF compartments [namely aboveground biomass (AGB), belowground biomass (BGB), and soil organic matter] along altitudinal and environmental gradients and their potential trade-offs. This study aims to: 1) understand how carbon stocks vary along altitudinal gradients in Andean TMFs, and; 2) determine the influence of climate, particularly precipitation seasonality, on the distribution of carbon stocks across different forest compartments. The study was conducted in sixty 0.1 ha plots along two altitudinal gradients at the Podocarpus National Park (Ecuador) and Río Abiseo National Park (Peru). At each plot, we calculated the amount of carbon in AGB (i.e. aboveground carbon stock, AGC), BGB (i.e. belowground carbon stock, BGC), and soil organic matter (i.e. soil organic carbon stock, SOC). The mean total carbon stock was 244.76 ± 80.38 Mg ha–1 and 211.51 ± 46.95 Mg ha–1 in the Ecuadorian and Peruvian plots, respectively. Although AGC, BGC, and SOC showed different partitioning patterns along the altitudinal gradient both in Ecuador and Peru, total carbon stock did not change with altitude in either site. The combination of annual mean temperature and precipitation seasonality explained differences in the observed patterns of carbon stocks across forest compartments between the two sites. This study suggests that the greater precipitation seasonality of colder, higher altitudes may promote faster turnover rates of organic matter and nutrients and, consequently, less accumulation of SOC but greater AGC and BGC, compared to those sites with lesser precipitation seasonality. Our results demonstrate the capacity of TMFs to store substantial amounts of carbon and suggest the existence of a trade-off in carbon stocks among forest compartments, which could be partly driven by differences in precipitation seasonality, especially under the colder temperatures of high altitudes.

Woody species diversity and the carbon stock potentials of different land use types in agroecosystem of Jimma Ganati District, Western Ethiopia

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.

Mangrove forests provide a variety of ecosystem services, and among them, the ability to sequester large quantities of below-ground carbon reservoirs is considered the most critical service for mitigating climate change. Therefore, most mangrove studies are highly concerned with estimating ecosystem carbon stocks, while only a few studies have focused on the factors driving these carbon stocks. Thus, we examined the role of stand structure, species diversity, and functional traits on above-ground, below-ground, and total carbon stocks using data from 28 sample plots from the low salinity zone of the Sundarbans mangrove forest of Bangladesh. We also aimed to understand the distribution patterns of carbon stocks among different components of the ecosystem, such as above-ground, below-ground soil, and roots. The study results revealed that tree height, diameter at breast height (DBH), and basal area were highly correlated with both above-ground (AGC) and below-ground carbon (BGC, incuding soil carbon at 0–50 cm depth) stocks. Multiple regression models indicated that tree height and basal area were two significant positive predictors for AGC, BGC and total carbon stocks (TCS) (p < 0.05). Species richness and community-weighted mean wood density were significant positive predictors for BGC and TCS. In contrast, Simpson diversity and community-weighted mean specific leaf area negatively influenced BGC. Furthermore, we observed that the above-ground tree carbon (AGTC = 80.4 ± 32.0 Mg ha−1) was significantly higher than below-ground soil carbon to 50 cm depth (BGSC-50 cm = 41.0 ± 5.4 Mg ha−1), followed by below-ground root carbon (BGRC = 37.1 ± 10.1 Mg ha−1), pneumatophore (Pneu_C = 28.8 ± 18.8 Mg ha-1), and downed wood (DW = 0.03 ± 0.02 Mg ha−1) (p < 0.05). In terms of specific species contribution, Heritiera fomes contributed the most to AGTC and BGRC, followed by other species such as Avicennia officinalis > Excoecaria agallocha > Sonneratia apetala > Xylocarpus mekongensis > Bruguiera sexangula. Our findings indicate that maintaining dominant trees (H. fomes) and a diverse stand can be an effective way to enhance carbon stocks in a mangrove ecosystem.

BackgroundAlthough great efforts have been made to quantify mangrove carbon stocks, accurate estimations of below-ground carbon stocks remain unreliable. In this study, we examined the distribution patterns of mangrove carbon stocks in China and other countries using our own field survey data and datasets from published literature. Based on these data, we investigated the possible relationships between above-ground carbon stock (AGC) and below-ground carbon stock (BGC) for mangrove forests, aiming to provide a scientific basis for estimation of total mangrove carbon stocks.ResultsThe average above-ground carbon stock in each region was sizeable (ranging from 12.0 to 150.2 Mg/ha), but average below-ground carbon stock was dominant (ranging from 46.6 to 388.6 Mg/ha), accounting for 69–91% of total carbon stock at the sites studied in China. Significant positive relationships were found between above-ground and below-ground mangrove carbon stocks, with the best fitting equation as BGC = 1.58 * AGC + 81.06 (Mg/ha, R2 = 0.62, p < 0.01, n = 122) for China. Such linear relationships vary for mangrove forests of different types and locations, from different geographical regions in China to other countries worldwide.ConclusionThe positive relationship we found between above- and below-ground carbon stocks of mangrove forests in China and worldwide can facilitate more accurate assessments of mangrove blue carbon stocks at regional or global scales using modern techniques including remote sensing.

Structural development and carbon dynamics of Moso bamboo forests in Zhejiang Province, China

The unprecedented increase in atmospheric CO2 concentration has attracted global research attention on the potential role of tree plantations in climate change mitigation. There is an urgent need to estimate the above-ground biomass (AGB) and carbon stock in forest plantations. This is particularly essential for Sierra Leone, where above-ground biomass (AGB) and carbon stock data are presently lacking. This study estimated the above-ground biomass accumulation and carbon stock of Tectona grandis Linn.f. and Gmelina arborea Roxb. in the spacing and plantation trials at Njala University, Southern Sierra Leone. The assessment was based on a total inventory of trees having a diameter at breast height (DBH) ≥ 5 cm and tree height. Above-ground biomass (AGB) was estimated using the allometric equation by Chave et al. (2005), and above-ground carbon (AGC) stock was calculated by multiplying the biomass with a conversion factor of 0.5. The result showed that the mean above-ground carbon stock for Gmelina arborea was higher in the plantation trial (25.2 t ha-1) than in the spacing trial (7.5 t ha-1). For Tectona grandis, the mean above-ground carbon stock was similarly higher in the plantation trial (6.6 t ha-1) than in the spacing trial (1.5 t ha-1). The results further suggest that the variation in the means of above-ground carbon stock is not dependent on the tree species type and experimental site because there were no significant differences (P&gt;0.05) between the tree species and experimental sites.

Above- and belowground carbon stocks are decoupled in secondary tropical forests and are positively related to forest age and soil nutrients respectively

Accurately measuring forest carbon (C) stocks is crucial for evaluating Community Forests' contribution to mitigating climate change and for bolstering Nepal's carbon-based payment systems. In order to determine the importance of Rani Community Forest in Makawanpur District for mitigating climate change, this August 2024 study evaluated the forest's capacity to store carbon. In accordance with the MoFSC Guideline for Forest Carbon Measurement (2010), 31 concentric circular plots were sampled. Aboveground and belowground biomass carbon stocks were estimated following national guideline-recommended allometric equations, and Soil organic carbon (0–30 cm) was analyzed using the Walkley–Black method (1934). Results showed that total vegetation biomass was 292.21 t ha⁻¹, corresponding to total vegetation carbon stock 137.33 t ha⁻¹ where trees/poles contributed 91.98% of vegetation carbon. As a result, the total SOC stock was 79.73 tha⁻¹, with an average soil bulk density of 1.23 g cm⁻³ and a SOC content of 2.17%. The maximum SOC was found in the 0–10 cm layer, and a one-way ANOVA showed significant variations in SOC throughout depths (p &lt;0.004). A significant positive correlation (r = 0.62, p &lt; 0.001) between SOC and aboveground vegetation carbon indicated strong vegetation–soil linkages. The total carbon stock of 217.05 t ha⁻¹ corresponds to 796.57 t ha⁻¹ Carbon-dioxide (CO2,) demonstrating substantial carbon sequestration potential. These findings emphasize the critical role of Community Forests in Nepal's climate mitigation strategies and their potential contribution in REDD⁺ and carbon financing mechanisms.

The purpose of this study was to examine the carbon stock potential of church forests and their contribution to climate change mitigation. A stratified systematic sampling approach was utilised, and data were gathered from 60 sample plots using sampling quadrats of 15 × 15 m for large trees, 10 × 10 m for shrubs and 5 × 5 m for grassland areas. The diameter at breast height of trees was measured at 1.3 m. The findings of this study revealed that in the semi‐arid agroecological zone, church forests had a total mean aboveground, belowground and total carbon stock of 76.6 t ha −1 (280.3 CO 2 ), 19.2 t ha −1 (70.4 CO 2 ) and 95.8 t ha −1 (350.8 CO 2 ), respectively. In the sub‐humid agroecological zone, church forests had a total mean aboveground, belowground and total carbon density of 12.4 t ha −1 (45.14 CO 2 ), 3.1 t ha −1 (11.37 CO 2 ) and 15.5 t ha −1 (56.51 CO 2 ). In the temperate highland agroecological zone, church forests had a total mean aboveground, belowground and total carbon stock of 11.2 t ha −1 (40.73 CO 2 ), 2.8 t ha −1 (10.27 CO 2 ) and 14.02 t ha −1 (51.01 CO 2 ). The mean aboveground, belowground and total carbon stock for the three agroecological zones were 33.4, 8.3 and 41.8 t ha −1 , respectively. A one‐way analysis of variance (ANOVA; F = 3.54, DF = 2, p &lt; .033) indicated a significant difference in carbon stock between agroecological zones. These findings underscore the important role of local carbon sequestration in mitigating greenhouse gas emissions, supporting regional forest management and land‐use planning. They also demonstrate that indigenous conservation practices offer measurable environmental benefits, and that sacred natural sites can serve spiritual, ecological and climate‐related functions simultaneously.

Mangroves are vital coastal ecosystems that provide numerous ecological benefits, including carbon sequestration, which plays a crucial role in mitigating climate change. The Baros Mangrove Conservation Area in Bantul Regency is an essential site for studying these valuable ecosystems, given its diverse mangrove species and varying age structures. This study aims to determine the distribution of mangrove species and estimate the above-ground carbon (AGC) and below-ground carbon (BGC) stock values in the Baros Mangrove Conservation Area, Bantul Regency. Data were collected using purposive sampling from four sample plots selected based on species differences, planting age, and site accessibility. Species identification was conducted through high-resolution aerial imagery and field validation. The results indicate that the dominant mangrove species are Avicennia sp. and Rhizophora sp., with the highest AGC found in Plot 2 at 198.14 tons/ha and the highest BGC also in Plot 2 at 121.36 tons/ha. Plot 2, which features the most mature vegetation, shows the highest carbon storage capacity, while Plot 4, dominated by younger mangroves, has the lowest AGC and BGC at 46.05 tons/ha and 40.70 tons/ha, respectively. With a total AGC and BGC carbon stock of 411.32 tons/ha for AGC and 601.28 tons/ha. This study underscores the importance of mangrove conservation and management, particularly in plots with mature vegetation, to maintain significant carbon reserves for climate change mitigation.

Forests are important carbon pools as they provide pathway to mitigate climate change. Quantification of forest carbon has gained momentum after Paris Agreement in 2015. This information is a prerequisite for REDD+ implementation and carbon trading. Temperate and subtropical mountain systems of Khyber Pakhtunkhwa province host about one third of Pakistan's 4.51 million ha forests. Present study estimated forest carbon stocks in theKhyber Pakhtunkhwa provinceof Pakistan. The data was collected from 449 sites in different forests across the province using a stratified cluster sampling technique. Total carbon stock in the forests of the province was estimated at 144.71 million tons with anaverage of 127.66 ± 9.32t/ha. Aboveground carbon stock was 68.15 million tons accounting for 48% of the total forest carbon stock of the province. Further, belowground biomass and litter accounted for 10% and 1% respectively. The mean aboveground carbon stock was 59.98 ± 4.26t/ha. The highest aboveground carbon stock was found in dry temperate forests (99.41t/ha) followed by moist temperate (85.04t/ha). Overall, temperate forests have aboveground carbon stock of 90.52t/ha. Temperate and subtropical forests of Pakistan with high carbon densities have ample potential for reducing forest sector emissions. Therefore, forests of Khyber Pakhtunkhwa province having substantial carbon stocks must be conserved for climate change mitigation. Present study provides a framework for carbon stockassessments in other temperate and subtropical regions of the world.

Improved forest management may offer climate mitigation needed to hold warming to below 2°C. However, uncertainties persist about the effects of harvesting intensity on forest carbon sequestration, especially when considering interactions with regional climate and climate change. Here, we investigated the combined effects of harvesting intensity, climatic aridity, and climate change on carbon stocks in Douglas-fir [Pseudotsuga menziesii Mirb. (Franco)] stands. We used the Carbon Budget Model of the Canadian Forest Sector to simulate the harvest and regrowth of seven Douglas-fir stand types covering a 900 km-long climate gradient across British Columbia, Canada. In particular, we simulated stand growth under three regimes (+17%, −17% and historical growth increment) and used three temperature regimes [historical, representative concentration pathways (RCP) 2.6 and RCP 8.5]. Increasing harvesting intensity led to significant losses in total ecosystem carbon stocks 50 years post-harvest. Specifically, forests that underwent clearcutting were projected to stock about 36% less carbon by 2,069 than forests that were left untouched. Belowground carbon stocks 50 years into the future were less sensitive to harvesting intensity than aboveground carbon stocks and carbon losses were greater in arid interior Douglas-fir forests than in humid, more productive forests. In addition, growth multipliers and decay due to the RCP’s had little effect on total ecosystem carbon, but aboveground carbon declined by 7% (95% confidence interval [−10.98, −1.81]) in the high emissions (RCP8.5) scenario. We call attention to the implementation of low intensity harvesting systems to preserve aboveground forest carbon stocks until we have a more complete understanding of the impacts of climate change on British Columbia’s forests.

The date palm (Phoenix dactylifera) is a fruit tree that grows from 392 to 1500 m above sea level. In addition to their socioeconomic, traditional, and religious value, it is a tree that tolerates high temperatures, drought, and salinity better than many other fruit crop plant species and plays an important role in the balancing and sequestration of atmospheric carbon. Date palm has been cultivated by agro pastoralists in Northeastern Ethiopia since ancient times, but no research has been done on the carbon stock of date palm farms (DPF) in the region. Therefore, the focus of the current study was to examine the carbon storage capacity in the biomass and soil of a DPF in the Aysaita and Afambo Districts of Northeastern Ethiopia. The ages of recorded date palm on the plot were classified into three age classes using information collected from the farm owners: 1st age class (for plantations less than 10 years), 2nd age class (for plantations between 10 and 20 years), and 3rd age class (for plantations older than 20 years). In the DPF, 45 main plots (20 m × 20 m) were established for tree species inventory. In the main plots, three 1 m × 1 m subplots were set up to collect soil samples. A total of 360 soil samples were collected; 180 for soil organic carbon fraction analysis and 180 for bulk density determination. The total carbon stock was calculated by adding the carbon stocks in biomass and soil (0–60 cm depth). Date palm trees accounted for 98.79% of total biomass carbon stocks in the date palm farm. The average aboveground biomass carbon stock of date palm trees older than 20 years was 1.55 and 1.36 times higher than the first and second age classes, respectively. Date palm trees between the ages of 5 and 20 years contributed 69.45% of total biomass carbon stocks (Mg C ha−1). Soil organic carbon made for 32.9% of total carbon stocks. Our research found that the date palm farm of this study would contribute to emission reduction and carbon sink enhancement, as well as improving local livelihoods in the study area.

Abstract. Bao TQ, Ha NT, Nguyet BTM, Hoan VM, Viet LH, Hung DV. 2021. Aboveground biomass and carbon stock of Rhizophora apiculata forest in Ca Mau, Vietnam. Biodiversitas 23: 403-414. Despite the small proportion of mangrove forests globally, they contribute significantly in carbon storage. Yet, biomass and carbon stock in mangrove forests might vary depending on various factors including the dominant species that occurred. This study was conducted to determine the biomass and carbon stock of a mangrove forest dominated by Rhizophora apiculata Blume in Ca Mau, Vietnam. Data were collected from 56 representative sample plots (50m x 50m), and 46 sample trees with different age classes and diameter sizes were cut down to measure the fresh biomass. The dry biomass and carbon content were analyzed in the laboratory. The average aboveground biomass and carbon stock of the individual tree and the R. apiculata forest at different diameter sizes had a significant difference and were mostly found in the stem (74.5%-79.5%). The conversion factor from fresh biomass to dry biomass was 0.56; the conversion factor from dry biomass to carbon was 0.46. The total biomass of the individual trees had a close relationship with two variables diameter at breast height (DBH) and height (Hvn) in the form of the logarithmic function: ln(Wtk) = -1,86412 - 1,95419*ln(Hvn) + 2,26798*ln(DBH*Hvn). The total biomass and carbon stock of the entire forest stand increased in accordance with the diameter size and age classes. The R. apiculata stand had a density of 1,040-15,800 trees/ha and a timber volume of 27.2 to 365.6 m3/ha. The average biomass of the R. apiculata stand was 191.1 tons/ha with a range from 49.6 to 357.4 tons/ha. The carbon stock in forest biomass ranged from 23.8 to 188.7 tons C/ha, with an average of 117.4 tons C/ha. The forest’s CO2 absorption ranged from 60.0 to 691.7 tons CO2/ha, with an average of 415.9 tons/ha. The carbon stocks of trees of age class I to age class VI were 41.6 tons C/ha, 79.4 tons C/ha, 101.4 tons C/ha, 132.9 tons C/ha, 154.0 tons C/ha, and 167.4 tons C/ha, respectively.