Total Carbon Stock Research Articles

Exploring the limits to sustainable pellet production for international markets: The impact of increasing pellet production in the US Southeast on feedstock use, production cost and carbon sequestration in forest areas

AbstractWith rising demand for wood pellets from the US Southeast (US SE), the environmental limits to additional biomass demand are increasingly questioned. This study analyses the impact of increased pellet production in the US SE until 2030 on feedstock allocation, carbon flux in forest areas and costs of pre‐treatment and transport of feedstock and pellets. This by linking locations of forest biomass supply and demand through supply‐side logistics, allocating feedstock based on lowest costs of pre‐treatment, transport of feedstock and pellets, for the entire wood products sector. The impact is analysed for different scenarios with varied pellet production levels, additional inclusion of logging residues and optimization either on costs or on maintaining total carbon stock in sourcing areas of new pellet mills. In a scenario of 20 Mt pellet production, the roundwood share increases from 0% in 2020 to 37% pulplogs and 11% sawlogs in 2030. Costs increase with 57% towards 2030 compared to 2020, largely because of higher costs for pulplogs and sawlogs. In a scenario without pellet production, forest carbon removal in the US SE is 3 Mt CO2/year lower than in 2020. In the Reference scenario, additional carbon removal of 6, 21 and 38 Mt CO2/year is observed for 10, 20 and 30 Mt pellet production, respectively. In all cases, the forests of the US SE remain a net sink until 2030. The impact of a selection criteria for new pellet mill locations based on keeping local growth/drain ratios above 1 in sourcing areas is small since this mostly results in displacement of impacts and does not affect the total feedstock availability. Additional mobilization of logging residues is a key strategy to reduce carbon impacts, resulting in a smaller additional flux of 2, 11 and 29 Mt CO2/year for 10–30 Mt pellet production.

What Influence Does Conventional Tillage Have on the Ability of Soils to Sequester Carbon, Stabilise It and Become Saturated in the Medium Term? A Case Study in a Traditional Rainfed Olive Grove

Soils have the capacity to store three times more carbon (C) than the atmosphere. This fact has focused scientific and governmental attention because it is one way to mitigate climate change. However, there comes a time when the capacity of soils to store C reaches a limit, considering soil organic carbon (SOC) saturation. In the Mediterranean area, agricultural soils are traditionally exposed to conventional tillage (CT), causing soil properties and quality degradation. Therefore, this study aimed to determine whether CT modifies the carbon storage capacity (carbon saturation), linked to soil mineral fractions <20 µm in olive grove soil in a Mediterranean area over 15 years. The results showed losses of SOC and soil organic carbon stock (SOC-S) over the period studied. Moreover, CT significantly affected aggregate grain size, reducing the percentage of small macro-aggregates (2000–250 µm) by 51.1%, 32.9%, 46.6%, and 50.6% for the Ap, Bw, BC, and C horizons, respectively, and promoting an increase in fine fractions (large micro-aggregates (250–53 µm), silt + clay fraction (53–20 µm) and fine silt + clay (<20 µm)). After 15 years, SOC fractionation showed a decrease in SOC concentration within the large macro-aggregate fraction (>2000 µm) of 38.6% in the Bw horizon; however, in the small macro-aggregates (2000–250 µm), an increase in SOC concentration over time, of 33.5%, was observed in the Ap and Bw horizons. This increasing trend continued in the fine soil fractions. Concerning SOC bound to the fine mineral fraction (<20 µm), evolution over time with CT led to an increase in soil sequestration capacity in the first horizons of 44.7% (Ap horizon) and 42.9% (Bw horizon), and a decrease in depth (BC horizon) of 31.3%. Finally, the total saturated soil organic carbon stock (T-SOC-Ssat), after 15 years, experienced an increase of 30.5 Mg ha−1, and these results conditioned the soil organic carbon stock deficit (SOC-Sdef), causing a potential increase in the capacity of soils to sequester carbon, of 15.2 Mg ha−1 in 15 years. With these results, we can affirm that the effect of CT in the medium term has conditioned the degradation of these soils and the low SOC concentrations, and has therefore made it possible for these soils, with the application of sustainable management practices, to have a high carbon storage capacity and become carbon sinks.

Recovery of Carbon and Vegetation Diversity 23 Years after Fire in a Tropical Dryland Forest of Indonesia

Understanding the recovery rate of forest carbon stocks and biodiversity after disturbance, including fire, is vital for developing effective climate-change-mitigation policies and actions. In this study, live and dead carbon stocks aboveground, belowground, and in the soil to a 30 cm depth, as well as tree and shrub species diversity, were measured in a tropical lowland dry forest, 23 years after a fire in 1998, for comparison with adjacent unburned reference forests. The results showed that 23 years since the fire was insufficient, in this case, to recover live forest carbon and plant species diversity, to the level of the reference forests. The total carbon stock, in the recovering 23-year-old forest, was 199 Mg C ha−1 or about 90% of the unburned forest (220 Mg C ha−1), mainly due to the contribution of coarse woody debris and an increase in the 5–10 cm soil horizon’s organic carbon, in the burned forest. The carbon held in the live biomass of the recovering forest (79 Mg C ha−1) was just over half the 146 Mg C ha−1 of the reference forest. Based on a biomass mean annual increment of 6.24 ± 1.59 Mg ha−1 yr−1, about 46 ± 17 years would be required for the aboveground live biomass to recover to equivalence with the reference forest. In total, 176 plant species were recorded in the 23-year post-fire forest, compared with 216 in the unburned reference forest. The pioneer species Macaranga gigantea dominated in the 23-year post-fire forest, which was yet to regain the similar stand structural and compositional elements as those found in the adjacent unburned reference forest.

Vermont Global Warming Solutions Act: The Costs of Inaction from Land Conversions

The Vermont (VT) Global Warming Solutions Act (GWSA, 2020) sets greenhouse gas (GHG) emissions reduction targets at 26% below 2005 by 2025, 40% below 1990 by 2030 and 80% below 1990 by 2050 for energy-related emissions only. Vermont’s omission of GHG emissions from land conversions could result in significant costs of inaction (COI), which could hinder the state’s mitigation and adaptation plans and result in climate crisis-related risks (e.g., credit downgrade). Science-based spatio-temporal data of GHG emissions from soils because of land conversions can be integrated into the conceptual framework of “action” versus “inaction” to prevent GHG emissions. The application of soil information data and remote sensing analysis can identify the GHG emissions from land conversions, which can be expressed as “realized” social costs of “inaction”. This study demonstrates the rapid assessment of the value of regulating ecosystems services (ES) from soil organic carbon (SOC), soil inorganic carbon (SIC), and total soil carbon (TSC) stocks, based on the concept of the avoided social cost of carbon dioxide (CO2) emissions for VT by soil order and county using remote sensing and information from the State Soil Geographic (STATSGO) and Soil Survey Geographic Database (SSURGO) databases. Classified land cover data for 2001 and 2016 were downloaded from the Multi-Resolution Land Characteristics Consortium (MRLC) website. These results provide accurate and quantitative spatio-temporal information about likely GHG emissions, which can be linked to VT’s climate action plan. A failure to considerably reduce emissions from land conversions would increase climate change costs and potential legal consequences for VT and beyond its borders.

Crop Production and Carbon Sequestration Potential of Grewia oppositifolia-Based Traditional Agroforestry Systems in Indian Himalayan Region

Bhimal (Grewia oppositifolia) is the most important agroforestry tree species used for fodder, fuel and fiber in the Himalayan region. In the present study, G. oppositifolia-based traditional agroforestry systems were selected for the estimation of carbon stock and the production potential of barnyard millet (Echinochloa frumentacea) and finger millet (Eleusine coracana), with two elevational ranges, i.e., 1000–1400 and 1400–1800 m amsl, in Garhwal Himalaya, India. The results of the investigation showed a decline in the growth and yield attributes of both the millet crops under the G. oppositifolia-based agroforestry system at both elevations as compared to their respective control sites (sole crops). Among the elevations, the total number of tillers per plant (2.70 and 2.48), the number of active tillers per plant (2.18 and 2.25), panicle length (17.63 cm and 6.95 cm), 1000-seed weight (5.49 g and 4.33 g), grain yield (10.77 q ha−1 and 11.35 q ha−1), straw yield (37.43 q ha−1 and 30.15 q ha−1), biological yield (48.21 q ha−1 and 41.51 q ha−1) and the harvest index (22.53% and 27.78%) were recorded as higher in the lower elevation in both E. frumentacea and E. coracana, respectively, while plant population per m2 (18.64 and 25.26, respectively) was recorded as higher in the upper elevation. Plant height for E. frumentacea (180.40 cm) was also observed to be higher in the upper elevation, while for E. coracana (98.04 cm), it was recorded as higher in the lower elevation. Tree carbon stock was reported negatively with an increase in altitude. The maximum amount of sequestered carbon in the tree biomass for G. oppositifolia was 23.29 Mg ha−1 at the lower elevation and 18.09 Mg ha−1 at the upper elevation. Total carbon stock in the tree biomass was reported to be the highest (15.15 Mg ha−1) in the 10–20 cm diameter class, followed by 20–30 cm (6.99 Mg ha−1), >30 cm (2.75 Mg ha−1) and the lowest (2.32 Mg ha−1) in the <10 cm diameter class. The results show that the yield of E. frumentacea and E. coracana was not reduced so severely under the G. oppositifolia system; however, keeping in mind the other benefits of this multipurpose tree, i.e., carbon sequestration and socioecological relevance, farmers can get benefit from adopting these crops under G. oppositifolia-based agroforestry systems.

Spatial patterns and driving factors of carbon stocks in mangrove forests on Hainan Island, China

AbstractAimMangrove forests are important coastal wetlands for the blue carbon budget and play a significant role in mitigating global climate change. However, spatial patterns of carbon stocks in mangrove forests on an island scale have not been quantified owing to methodological limitations and lack of understanding of controlling factors. We took the entire Hainan Island as a case study and aimed to carry out a comprehensive investigation of the spatial patterns and driving factors of carbon stocks in mangrove forests.LocationSouthern China.Time period2017–2020.Major taxa studiedMangrove forest.MethodsThe upscaling method combined with field surveys and Sentinel‐2 imagery analysis were used to compare different models for optimization of mangrove ecosystem carbon stock estimations. We also used structural equation modelling (SEM) to evaluate the factors driving the distributional patterns of mangrove carbon stocks on an island scale.ResultsThe current total mangrove carbon stock of the entire Hainan Island was estimated to be 703,181 Mg C (with a mean density of 192 Mg C/ha), with the above‐ and below‐ground carbon stocks averaging at 44.7 and 147.3 Mg C/ha, respectively. The mangrove carbon storage in the north‐eastern region of the island was the highest and in the west region the lowest. Sediment nitrogen content and plant species diversity had the most positive driving effects on the distribution of total carbon stock for Hainan Island mangroves.Main conclusionsThe combination of field surveys and Sentinel‐2 imagery analysis can be applied to regional‐scale estimations of carbon stocks for mangrove forests. Spatial pattens of mangrove carbon stocks vary among locations on Hainan Island, and soil nutrient (especially nitrogen) availability is the dominant factor regulating carbon stock variations along the land‐to‐sea gradient. Our findings have significant implications for better understanding the distribution of mangrove carbon stocks and quantification of the global blue carbon budget.

Impact of mangrove planting on forest biomass carbon and other structural attributes in the Rufiji Delta, Tanzania

Mangrove forests provide important ecosystem services to the human society and nature including mitigation of climate change. The quality and quantity of ecosystem services offered by mangrove forests are however at risk when mangroves are degraded. The restoration of mangrove areas is considered as a natural solution to recover lost ecosystem services such as securing of carbon stocks. This study was set to assess the extent to which mangrove planting activities compensate for the loss of biomass carbon stocks and other structural attributes in Rufiji Delta-Tanzania through analysis of biomass carbon loss and gain as a result of conversion of mangroves forest into rice farms and planting of mangroves respectively. Circular sampling plots were established in good, degraded and restored mangrove areas where total tree heights and Diameter at Breast Height (DBH) of all standing trees were measured and recorded by species and used to compute biomass carbon stock. The mangrove species composition changed from 7 in 1989 to 2 species in degraded plots in 2016. The species dominance changed from Avicennia marina in 1989 to Rhizophora mucronata in 2016 in good mangrove plots and from A. marina and Sonneratia alba to an invasive Baringtonia racemosa in degraded plots. Bruguiera gymnorrhiza was the only mangrove species used for restoration through planting in the delta and the overall survival rate was 37%. The above-ground carbon (AGC) and below-ground carbon (BGC) for the good natural mangrove plots ranged from 28.18 to 299.43 and 16.00–164.51 Mg C ha−1 respectively compared to 0–150.88 and 0–967.01 Mg C ha−1 in the degraded plots. The total biomass carbon stock in the good natural mangrove plots ranged from 44.14 to 463.94 Mg C ha−1 while for the degraded plots the range was 0–247.89 Mg C ha−1. The carbon stocks in 5, 10 and 15 year old planted mangroves were 13.65, 20.13 and 57.53 Mg C ha−1 respectively. The biomass loss of 172.91 Mg C ha−1 was estimated in a period of 25 years (1989–2016), equivalent to an annual loss rate of 6.9 Mg C ha−1year−1, demonstrating that degradation has a significant contribution to loss of carbon stocks. Nevertheless, an average of 3.8 Mg C ha−1year−1 was stocked by 15 years old planted mangroves, demonstrating that there is potential for the planted mangroves to compensate for the lost carbon if the anthropogenic drivers such as rice farming is controlled. These findings call for urgent collective actions among stakeholders to consider and improve the integrated management of the delta.

Effects of whole-tree and stem-only clearcutting on forest floor and soil carbon and nutrients in a balsam fir (Abies balsamea (L.) Mill.) and red spruce (Picea rubens Sarg.) dominated ecosystem

Intensive harvesting of forest biomass for bioenergy has the potential to degrade forest soils and productivity if ecosystem carbon and other nutrients are depleted faster than replenished naturally or by management inputs. Climate change mitigation potential associated with bioenergy may be threatened if forest management operations reduce soil carbon stocks. Research reported here was initiated in 1979 to determine the effects of whole-tree harvesting on long-term site productivity and ecosystem carbon and nutrient pools and fluxes in a northeastern North American temperate balsam fir-red spruce forest. A sequence of harvesting and silvicultural treatments were applied from 1981 to 1993 using a paired-watershed experimental design. Treatments included whole-tree clearcutting, stem-only harvesting, simulated by return of chipped or lopped delimbing residue, conifer release by applying herbicide, and pre-commercial thinning and fertilizer application. Quantitative samples of the forest floor were excavated in 2016. Quantitative soil pits were sampled in 2017 to a depth of 50 cm below the forest floor, where possible; the basal till subsoil was sampled to a depth of 100 cm with an auger. Forest floor samples were analyzed for total carbon, nitrogen, phosphorus, potassium, calcium, magnesium and aluminum. Organic and mineral soil layer samples from the quantitative pits were analyzed for pH, short and long-lived soil carbon via 13C cross polarization magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR), total carbon and nitrogen and extractable phosphorus, potassium, calcium, magnesium and aluminum. Forest floor carbon and nitrogen on whole-tree harvested plots 35 years after harvest were about 50% of the amount on the unharvested watershed. Stem-only harvesting partially mitigated the reduction, and gross losses were apparently offset by increases in the mineral soil solum to depth 50 cm, suggesting that downward translocation of soil organic matter was a significant ecosystem process during the 35 years since harvest. Accumulated forest floor and mineral soil stock of total carbon and nitrogen and extractable nutrients to depth 100 cm did not differ significantly between the harvested and unharvested watershed. A corresponding similarity in mineral soil pools of extractable phosphorus and non-acid cations in the two watersheds suggests that inputs from atmospheric deposition, primary and secondary mineral weathering, organic matter mineralization and litterfall balanced exports including leaching and plant uptake. Ecosystem stocks of extractable phosphorus, base cations, and total organic carbon and nitrogen were maintained 35 years after whole-tree harvesting of a primary spruce-fir forest.

Micronutrient Content, Soil Carbon and Nitrogen Stocks in Forested and Deforested Sites

Summary The research examines micronutrient contents, soil carbon and nitrogen stocks of forested and deforested sites at Bobiri forest reserve in the Ashanti region, Ghana. Each site had 12 soil profiles excavated, six of which were from natural forest areas and six were from deforested areas. The samples were taken at 0-15 cm, 15-50 cm and 50-80 cm depths and repeated thrice. The contents of DTPA-extractable micronutrients in the forested sites were higher than in the deforested sites at all soil depths. There were significant differences between the forested and deforested sites. The soils at 0-15 cm depth in the forested sites showed improved micronutrient contents, which largely declined with the soil depth. At the same time, there was no consistent pattern of distribution in the deforested soil. According to the findings, all three depths and sites tested had enough extractable Fe, Mn and Cu, however only 15-50 cm depth of forested and deforested sites had sufficient Zn. All the soil depths except 50–80 cm showed significant differences in soil organic carbon and nitrogen stocks in the forested sites compared to the deforested sites. The forested sites had the largest amount of total soil organic carbon stocks (365 Mg ha−1), whereas the deforested sites had the lowest amount (181 Mg ha−1). It was found that micronutrient content and distribution in the soils at the research sites were influenced by organic matter, clay and soil pH.

Analysis of carbon emissions from land cover change during 2000 to 2020 in Shandong Province, China

Land cover change affects the carbon emissions of ecosystems in some way. The qualitative and quantitative understanding of carbon emissions from human activities (e.g., land cover change, industrial production, etc.) is highly significant for realizing the objective of carbon neutrality. Therefore, this paper used GlobeLand30 land cover maps, annual average normalised difference vegetation index (NDVI) data, annual average net ecosystem productivity (NEP) data and statistical yearbook data from 2000 to 2020 to explore the relationship between land cover change and carbon emissions. Specifically, it included land cover change, carbon storage changes influenced by land cover change, spatial and temporal analysis of carbon sources and sinks, land use intensity change and anthropogenic carbon emissions. The results of the study show that the main land cover changes in Shandong province during 2000–2020 was cultivated land conversion to artificial surfaces. Among them, the area of cultivated land converted to artificial surfaces from 2000 to 2010 was 4930.62 km2, and the proportion of cultivated land converted to artificial surfaces from 2010 to 2020 was as high as 78.35%. The total carbon stock of vegetation affected by land cover change decreased by 463.96 × 104 t and 193.50 × 104 t in 2000–2010 and 2010–2020 respectively. The spatial and temporal distribution of carbon sources and sinks differed more markedly from 2000 to 2020, and land use intensity changes in Shandong Province showed an upward trend. Of the total energy production, industry has the largest energy consumption, followed closely by total energy consumption in transportation, storage and postal services.

Soil organic carbon of grassland and bush forest on dryland in Aceh Besar District, Indonesia

Abstract. Abdullah UH, Sufardi S, Syafruddin S, Arabia T. 2022. Soil organic carbon of grassland and bush forest on dryland in Aceh Besar District, Indonesia. Biodiversitas 23: 2594-2600. Soil organic carbon (SOC) is one of the important components that can improve soil conditions and maintain agriculture sustainability. This study was conducted to determine the potential of soil organic carbon in grassland and bush forest in Aceh Besar District. We used purposive random sampling by taking soil samples at various depths with five samples for each land type. The parameters of soil bulk density, % carbon soil, the potential of carbon and carbon stock were analyzed. Soil organic carbon (SOC) analysis followed the Walkley and Black method using analytical guidelines from the Indonesian Soil Research Institute. The results showed that land type and soil depth affected bulk density, % carbon soil, the potential of carbon and carbon stock. Land type affected soil organic carbon in which grasslands had a higher soil carbon than bush forests. In total, total soil carbon stock in the bush forest of Aceh Besar District was higher than that in grassland due to the much larger extent of bush forest in the district. Land use management efforts to improve soil SOC need to be carried out and in collaboration with various parties. Thus, it is necessary to maintain the availability of soil carbon stock for sustainable land management, including agriculture.

Estimating regional timber supply and forest carbon sequestration under shared socioeconomic pathways: A case study of Maine, USA

This study provides a regional model framework to evaluate timber supply and carbon impacts of environmental and socioeconomic change in Maine, USA. We construct alternative future narratives that vary economic growth, forest management, and environmental policies and then conduct econometric analysis to project forest area and timber supply over the next 80 years under five shared socioeconomic pathways (SSPs). Forest area changes from 2020–2100 ranged from a 11% decline in SSP3 (regional rivalry) to 0.2% for SSP1 (sustainability). Maine’s forest carbon stocks and timber supply can still mutually increase before 2070 for all pathways, largely due to improvements in forest management, growth, and yield. Overall timber supply is projected to increase by 0.21–0.51% per annum, with supply expanding faster for pathways with higher timber price growth. Total forest carbon stocks (ecosystem and products) are projected to increase 0.40–0.64%/yr for similar reasons. Sensitivity analysis indicated the key drivers most likely to affect Maine’s forest sector are timber prices, population change, personal income, land value, and conservation land area. This study offers valuable insight on possible methods about region-specific socio-economic assessments.

Blue Carbon Ecosystems in Brazil: Overview and an Urgent Call for Conservation and Restoration

In this article, we discuss knowledge and gaps regarding blue carbon ecosystems (BCEs) in Brazil, considering the urgency to apply protection actions and policies to safeguard their biodiversity and associated ecosystem services. We also indicate areas of further research to improve carbon stocks and sequestration rate estimates. We call attention to the shortage of studies on Brazilian BCEs relative to the growing knowledge on the Blue Carbon Framework accumulated worldwide over the last decade. Considering the extensive Brazilian Economic Exclusive Zone (known as “Blue Amazon”), knowledge concerning blue carbon stocks is vital at regional and global scales for mitigating global increases in atmospheric carbon dioxide (CO2). The Blue Amazon has at least 1,100,000 ha of vegetated and non-vegetated coastal ecosystems (mangroves, salt marshes, seagrass meadows, and hypersaline tidal flats) that collectively contain vast amounts of stored carbon, making Brazil an ideal place to test mechanisms for evaluating, conserving, and restoring BCEs. Other poorly understood potential sinks and sources of carbon are macroalgal and rhodolith beds, mudflats, continental shelf sediments, and marine animal forests in shallow, mesophotic, and deep waters. The carbon fluxes between diverse environmental compartments, such as soil–air, soil–water, groundwater–water–surface water, air–water, and land–ocean, in BCEs across the Blue Amazon must be studied. We emphasize the importance of assessing the total carbon stock and the recent dismantling of environmental laws that pose great risks to these important BCEs. The conservation and recovery of these areas would enhance the carbon sequestration capacity of the entire country. Furthermore, we highlight priorities to improve knowledge concerning BCEs and their biogeochemical cycles in the Blue Amazon and to provide information to assist in the reduction of atmospheric levels of CO2 for the United Nations Decade of Ocean Science (2021–2030).

Effects of Environmental Factors on Carbon Stocks of Dry Evergreen Afromontane Forests of the Choke Mountain Ecosystem, Northwestern Ethiopia

The purpose of this research was to quantify and compare carbon stocks in two selected dry evergreen montane forests of the Choke Mountain ecosystem that are under different management regimes. The study also attempted to assess the carbon stock along environmental gradients. The average carbon stock throughout the whole plots investigated in Anshirava forest (protected) was 180.18 t·ha−1 (53%) in AGB, 111.43 t·ha−1 (33%) in soil, 36.43 t·ha−1 (11%) in BGB, 6.09 t·ha−1 (2%) in USB, 2.69 t·ha−1 (1%) in litter, and 1.36 t·ha−1 (less than 1%) in DW. In Ziba forest (high human intervention), the average carbon stock was 106.71 t·ha−1 (44%) in AGB, 100.07 t·ha−1 (42%) in soil, 21.34 t·ha−1 (9%) in BGB, 5.41 t·ha−1 (2%) in USB, 4.82 t·ha−1 (2%) in litter, and 2.00 t·ha−1 (1%) in DW. The AGB had the greatest carbon share in both forests, followed by soil. In Anshirava and Ziba forests, the mean total carbon stocks (TCS) were 338.18 t·ha−1 and 240.36 t·ha−1, with CO2 equivalents of 1241.14 t·ha−1 and 882.12 t·ha−1, respectively. The study indicated a significant variation between the two forests. Anshirava forest has larger total carbon stocks than Ziba forest. For lower, medium, and higher altitudes, the total carbon stock variation along an altitudinal gradient was 289.67 t·ha−1, 347.93 t·ha−1, and 414.89 t·ha−1 in Anshirava forest and 270.99 t·ha−1, 204.24 t·ha−1, and 224.82 t·ha−1 in Ziba forest, respectively. As a result, a greater amount of carbon was stored at higher altitudes in Anshirava and at lower altitudes in Ziba, with no significant difference in both forests. The total carbon stock variation along slope gradient was 392.60 t·ha−1, 344.59 t·ha−1, and 295.49 t·ha−1 in Anshirava forest and 258.74 t·ha−1, 222.46 t·ha−1, and 171.46 t·ha−1 in Ziba forest for flat, intermediate, and steep slopes, respectively. This resulted in higher carbon being stored in flat slopes in both forests. Also, only at the Ziba site, a significant difference was found along the slope gradient. In each forest, eight distinct aspect facings were observed, with the western (W) aspect containing the highest value of total carbon stock in both forests. Lower values, on the other hand, were recorded in the south (S) and flat (F) aspects of Anshirava and Ziba forests, respectively. The slope aspects of both forests varied significantly. As a result, the research reveals that environmental factors have a significant impact on carbon stock value of Choke Mountain forest ecosystem, but the impact is not consistent among carbon pools.

Effect of Land Use on Plant Nutrient Availability and Soil Carbon Stock of Mokonisa Machi Watershade, Dugda Dawa Woreda, West Guji Zone, Southern Ethiopia

Background: Various land use practices have a different influence on soil degradation on both physical and chemical property of soil as well as on soil carbon sequestration capacity. A small number of studies have studied the effects of land use on plant nutrient availability and soil carbon sequestration in Ethiopia. Therefore, current study was to explore the effects of land use on vegetation nutrient accessibility and soil carbon restoration. Methods: Further definitely the study pointed out the difference between various land use category on soil texture, soil pH, available phosphorus and exchangeable potassium and the implication the farming practices on soil carbon sequestration. Soil sample were collected from the upper 0-40 cm depth of forest land, cultivated land and grazing land. The soil texture was primarily clay and heavy clay textural class. Result: Along soil depth, bulk density (BD) increasing ranges from (1.12 to 1.27 g/cm in all sampling sites. Slight increase in pH was recorded with increase in soil depth in all land use system. The average total soil organic carbon stock forest, grazing and farm land was ranged between 95.2, 88.45 and 65.5 t/ha, respectively for surface soil and 93.3, 73.75, 62.5 respectively for sub surface soil. Soil organic carbon concentration and bulk density improvement are the most important management interventions to increase soil organic carbon storage capacity.

Vegetation and Soil Carbon Pool in Chirpine (Pinus roxburghii Sarg.) Forest of Mahabharat Hill, Nepal

This study analyzed the vegetation and soil carbon stock in natural forest in Mahabharat hill of Bagmati Province, Pinus roxburghii Nepal. Systematic random sampling method was applied for forest inventory and forest biomass was estimated by using standard allometric models. Soil samples were taken from soil profile up to 60 cm depth at the interval of 20 cm. Total carbon stock in forest was Pinus roxburghii found 193.54 t ha and 226.54 t ha for Aphnai CF and Okhe CF, respectively. Among the carbon pools carbon stock was found in the order of -1 -1 above ground carbon stock > soil organic carbon stock > below ground carbon stock for both CF. The forest carbon stock showed a positive relationship with biomass, tree diameter, and height but no relationship with tree density. The study concluded that forest vegetation and soil can play vital role on carbon sequestration and subsequently mitigating the problem of global warming.

Mineral inputs, paleoecological change, and Holocene carbon accumulation at a boreal peatland in the Hudson Bay Lowlands, Canada

The Hudson Bay Lowlands (HBL) is a vast contiguous peatland extending over >370,000 km2 in Canada's boreal-subarctic, and is the traditional land of the Omushkego Cree. It is currently undergoing climatic warming alongside other anthropogenic stressors, and contains a large below-ground carbon pool. Understanding how climate variability and multiple stressors impact peat accumulation in this region is critical to discerning how northern peatlands will respond to future climate and land-use changes. Pollen- and macrofossil-based paleoecological reconstructions, and analyses of aluminum (Al) and titanium (Ti) fluxes in a Holocene-aged peat core (VM375) taken from a bog in the Attawapiskat watershed were conducted to link ecosystem changes with hydroclimate and long-term carbon storage. Peat initiation is dated to 5780 cal yr B.P., coincident with land emergence driven by glacial isostatic adjustment. From 4500 to 4200 cal yr B.P., apparent rate of carbon accumulation increased, and was linked to more rapid rates of peat accretion and increases in minerotrophic indicators in the pollen record. This increase in peat accretion and shift in vegetation composition co-occur with higher rates of mineral influx as shown by Ti and Al concentrations, which may have supplied nutrients. A fen to bog transition takes place ~3300 cal yr B.P., with increases in Sphagnum spores and macrofossils, and a decline in the apparent rate of carbon accumulation relative to the earlier half of the record, where paleoecological proxies indicate treed wetland and fen stages. Since peat inception, the total carbon stock of the 260-cm peat column is 110 kg C m−2. This multi-proxy record shows an association between changing peat types and variability in apparent rates of carbon accumulation, and supports the hypothesis that mineral nutrients either supplied by surface hydrology or by eolian deposition played a role in Holocene peat carbon accumulation in eastern North American boreal peatlands.

Allometric equations may underestimate the contribution of fine roots to mangrove carbon sequestration

The biomass and production of fine roots (diameter < 2 mm) are often omitted or derived simply from allometric equations when calculating mangrove carbon sinks. The purpose of this study was to assess the significance of fine roots by measuring the biomass and production of the fine roots in two mangrove species (Kandelia obovata and Avicennia marina) with distinct root structures. The aboveground portion of K. obovata and A. marina contributed 44% and 32% of the total carbon stock, respectively. The nonfine roots accounted for 17% of the total carbon stock of both mangrove species. The fine roots and dead fine roots of K. obovata contributed 5% of the total carbon stock, whereas the contribution of fine roots and dead fine roots of A. marina, which possessed pneumatophores, was higher (12%). Comparison of the field measurements with the estimates of belowground net production derived from frequently used allometric equations showed that equation-derived estimates were notably underestimated, particularly for A. marina. The aboveground net production of K. obovata and A. marina averaged 17.04 and 7.46 Mg C ha−1 yr−1, respectively, but 84% and 92% of the litterfall was lost after a year. Subtracting only 4% of the fine root production of K. obovata and 17% of the fine root production of A. marina to account for further decomposition in the soils within a year, an additional 13.67 Mg C ha−1 yr−1 for K. obovata and 11.05 Mg C ha−1 yr−1 for A. marina were calculated to be buried in the soils, which can increase the carbon sequestration capacity estimated from aboveground litterfall only by 5 and 19 times, respectively, for each mangrove species. This suggests that the contribution of fine roots should be accounted for when estimating mangrove carbon sinks.

Growth performance, biomass accumulation, and energy production in age series of clonal teak plantation

Clonal teak plantation has been extensively developed in Java and providing a purposeful contribution to improve the productivity of the state forests. It also plays a crucial role in climate change mitigation and serves as a primary source of renewable energy. However, information about its stand dynamics has been rarely documented. This study investigated the growth, biomass, carbon stock, and energy storage along an age series of clonal teak plantation. The study site was located in the Kendal Forest Management Unit. Data were collected from 14 different compartments as the priority sites of clonal teak establishment. Every compartment had similar site quality but different in age stand. Results demonstrated that the incremental rate of diameter and height was higher during the initial period between 1 and 3 years. The mean volume increased along with age and reached its maximum value at 14 years (164.54 m3 ha−1). Biomass distribution in each tree component varied from 8.75 to 66.72%. More than 80% biomass production was accumulated above ground. Total carbon stock improved from 2.68 Mg ha−1 at 1 year to 54.01 Mg ha−1 at 14 years. Our study noted that the total energy storage in clonal teak plantation increased progressively from 22.71 × 106 MJ ha−1 at 1 year to 377.74 × 106 MJ ha−1 at 14 years. Overall, this study concluded the growth, biomass, carbon, and energy in clonal teak increased progressively with age. Further investigations are still required to understand the stand dynamics of clonal teak at different sites.

Coastal Ecosystem Services Modeling in Latin America to Guide Conservation and Restoration Strategies: The Case of Mangroves in Guatemala and El Salvador

We modeled the coastal protection and blue carbon ecosystem services provided by the mangroves of the Paz River Basin (El Salvador and Guatemala) using InVEST Coastal Vulnerability and Coastal Blue Carbon Models, with the goal of supporting the Regional Coastal Biodiversity Project of the International Union for the Conservation of Nature, in determining potential priority mangrove areas for conservation and restoration. To quantify the relative coastal protection that mangroves provide, we combined maps of different aspects of vulnerability, including ecological, physical, and social data. We also estimated carbon stocks, net sequestration, and the economic value of carbon sequestration as a service in 2050 and 2100. We then developed a combined index of coastal protection and carbon sequestration services to highlight potential priority conservation and restoration areas for mangroves. We found that in Guatemala the coastal protection service was provided in greater quantity in the province of Moyuta, while in El Salvador this service was the highest in the provinces of San Francisco Menéndez, Jujutla and Acajutla, which also had the greatest total carbon stock. In the Paz River Basin, we estimate there are approximately 1,741 hectares of mangroves that provide the highest coastal protection and carbon sequestration services. Furthermore, we identified 318.9 hectares across both countries where mangroves could potentially be restored.