High Carbon Storage Research Articles

Territorially ecological restoration zoning and optimization strategy in Guyuan City of Ningxia, China: Based on the balance of ecosystem service supply and demand

Scientifically identifying the territorially ecological restoration zoning is a vital prerequisite for implementing ecological restoration projects and enhancing environmental quality. Based on remote sensing data, we syste-matically assessed supply and demand for ecosystem service and their relationship in Guyuan City, China by using the InVEST model, coordination degree model, and spatial autocorrelation analysis. We carried out territorially ecological restoration zoning by coupling the ecosystem service supply and demand. Furthermore, the corresponding optimization strategies were put forward according to the regional characteristics of natural resources and socio-economic development. The results showed that the areas with high water yield, carbon storage, soil conservation and habitat quality were mainly located in the southern part of Guyuan City. The areas with high population density, economic development level and high ecological demand were mainly located in the central urban area and the location towns of the county government. The spatial mismatch of supply and demand for ecosystem services in Guyuan City was dominant, as indicated by the fact that the areas with high ecological supply having low ecological demand and low ecological supply having high ecological demand. The average coordination index was 0.5, indicating that the relationship between ecological supply and ecological demand was basically coordinated. Based on the diffe-rences between supply and demand of ecosystem services and regional natural geographical pattern, the administrative township units in Guyuan could be classified into six ecological restoration zonings: key ecological restoration area, potential ecological restoration area, ecological economic reconstruction area, characteristic agricultural development area, ecological core protection area, and ecological industry construction area. Different management strategies were proposed to provide scientific support for ecological restoration.

부산 육상 지역 탄소보유량 및 경제적 가치 평가

Studies on estimating and assessing carbon storage related to natural-based solutions that reduce carbon by utilizing ecosystems, one of the carbon neutral strategies to cope with climate change, are being conducted. In this study, assessment of carbon storage and economic value of terrestrial area area in Busan were conducted using the Carbon model of InVEST, an ecosystem service-based assessment model. As a result of the study, it was found that the current terrestrial area increased from the past time due to the development of coastal stations and urban areas, but the amount of carbon storage decreased. Dong-Busan and Gijang-gun, which have the largest area, had the highest carbon storage per unit area. In the case of Gijang-gun, the rate of reduction in carbon storage was the largest among administrative districts. In order to realize carbon neutrality in Busan, it is necessary to minimize the impact on the carbon storage capacity of important ecosystems by comparing the current status of carbon storage and the amount of carbon changes caused by development.

Assessment of coordinative relationship between comprehensive ecosystem service and urbanization: A case study of Yangtze River Delta urban Agglomerations, China

Understanding the coordinative relationship between urbanization and ecosystem services (ESs) has a great significance in sustainable development in urban agglomeration. In this paper, InVEST model was firstly used to assess the spatio-temporal evaluation of four types of ESs (water yield, carbon storage, soil retention and nitrogen export) in the Yangtze River Delta Urban Agglomerations (YRDUA) of China from 2000 to 2020. Then comprehensive evaluation index system of urbanization was established from the multi-dimensions of economy, population and land to analyze the urbanization level during the study period. Finally, a comprehensive ecosystem service (CES) index was developed to explore the coordinative relationship between ESs and urbanization by using coupling coordinating degree model (CCDM). The results revealed that: 1) Urbanization has led to greatly land use/ land cover change, which caused the degradation of carbon storage and water purification, and the improvement of water yield and soil retention. The higher water yield and nitrogen export mainly clustered around urban areas, while higher carbon storage and soil retention were distributed in forest-rich cities in the Zhejiang and the southern of Anhui. There were positive correlations between different ESs. And the CES of cities in the YRDUA had deteriorated during the study period. 2) The urbanization levels of almost all cities showed an overall upward trend, with Shanghai the highest urbanization, followed by Nanjing and Hangzhou, and rapid urban expansion mainly occurred in developed urban areas. 3) The coordinative relationship between CES and urbanization in the YRDUA was always in mild incoordination, showing an obvious spatial distribution pattern of “higher in the south, but lower in the north”. The coordinative relationship between CES and urbanization in most cities in the north of YRDUA has not achieved coordination development, with the state of moderate or mild incoordination, while the cities in the south has attained coordination development, with the state of primary or even superior coordination. Therefore, our study suggested that differentiated urban space management and control policies should be made for the YRDUA to improve the overall coordinative relationship between CES and urbanization.

An Investigation on Shenzhen Urban Green Space Changes and Their Effect on Local Eco-Environment in Recent Decades

Rapid urbanization and population growth impact enormous pressures on urban natural, economic and social environments. The quantitative analysis of urban green space (UGS) landscape dynamics and their impact on the urban eco-environment is of great significance for urban planning and eco-environment protection. Taking Shenzhen as an example, the UGS landscape changes and their impact on urban heat islands (UHI), surface wetness, air pollution and carbon storage were comprehensively investigated with Landsat and MODIS images. Results showed a large number of lands transferring from UGS to non-UGS from 1978 to 2018, especially for cropland. Built-up regions have adverse influences on eco-environment factors, and then they suffer high SUHI and AOD and low humidity and carbon storage. The growth of built-up areas not only enlarges the area of SUHI, but also enhances the intensity of heat islands. On the contrary, UGS patches have beneficial influences on all eco-environment factors and then enjoy a better eco-environment, including low SUHII, high surface wetness, high carbon storage and low AOD. It is expected that this study could provide scientific support for UGS plans and for conserving and sustainable urban development for developing cities.

Assessment of polymer based carbonation in weak/strong alkaline media for energy production and carbon storage: An approach to address carbon emissions

Polymer methods are typically used to control mobility and the areal sweep of injected carbon dioxide in oil recovery and sequestration applications. Carbon dioxide utilization can be further improved through the increment in absorption potential of these methods. Therefore, in this study, the role of both weak (sodium carbonate) and strong (sodium hydroxide) alkalis is investigated on absorption, retention, oil recovery, and carbon storage potential of oilfield hydrolyzed polyacrylamide at elevated pressure (3 MPa) and temperature (70 °C). The inclusion of alkali (1 wt%) increased the carbon dioxide absorption capacity of polymer solution with maximum absorption by sodium hydroxide treatment. However, the retention capacity of the polymer solution was different in presence of alkalis and strong alkali suggested minimum retention. Similar behavior was observed during a rheological investigation where sodium hydroxide suggested a sharp drop (∼85%) in viscosity values of polymer solution while sodium carbonate was offered only ∼40% drop. Moreover, moduli (elastic and viscous) results showed that sodium carbonate treated polymer solution exhibited viscoelastic nature while a dominating liquid-like nature was evident in the case of sodium hydroxide. The tapered water-alternating gas injection was also explored for sodium carbonate treated polymer solution where carbon dioxide injection before chemical slug was found desirable for higher oil recovery (69%) than the one associated with chemical slug injection before carbon dioxide (65%). In addition, higher carbon storage (44% of injected carbon) was also obtained when carbon dioxide injection was performed before the chemical slug.

Global patterns of particulate organic carbon export from land to the ocean

AbstractGlobal rivers and streams are important carbon transport pathways from land to the ocean. However, few studies have quantified terrigenous carbon dynamics in river ecosystems and its variations due to climate change and anthropogenic perturbations. Therefore, our study analysed fluvial particulate organic carbon (POC) and developed a processed‐based model (TRIPLEX‐HYDRA) to simulate the production, transport and removal (i.e., deposition, degradation and dam retention) processes of fluvial POC along the land–ocean aquatic continuum (LOAC). Based on our results, approximately 0.29 Pg of POC is exported from land to the ocean through rivers each year. More specifically, we found that rivers at low latitudes (30°S–30°N, 0.18 Pg yr−1) and high northern latitudes (60°N–90°N, 0.05 Pg yr−1) had higher POC fluxes compared to rivers in other regions. This high POC flux is related to strong erosion rates and high soil organic carbon storage. Additionally, our model simulation revealed that total POC flux from global river has not significantly changed from 1983 to 2015 but displays markedly decreased or increased trend at regional scale. These regional variations in POC export are affected by climate warming and dam construction. Moreover, approximately 0.46 Pg of POC is deposited or trapped by dams along the LOAC system, which plays a vital role in the global river carbon budget. Although some limitations and uncertainties remain, this study establishes a theoretical and methodological basis for quantifying riverine POC dynamics in the LOAC system.

Multi-predictor mapping of soil organic carbon in the alpine tundra: a case study for the central Ecuadorian p\xe1ramo

BackgroundSoil organic carbon (SOC) affects essential biological, biochemical, and physical soil functions such as nutrient cycling, water retention, water distribution, and soil structure stability. The Andean páramo known as such a high carbon and water storage capacity ecosystem is a complex, heterogeneous and remote ecosystem complicating field studies to collect SOC data. Here, we propose a multi-predictor remote quantification of SOC using Random Forest Regression to map SOC stock in the herbaceous páramo of the Chimborazo province, Ecuador.ResultsSpectral indices derived from the Landsat-8 (L8) sensors, OLI and TIRS, topographic, geological, soil taxonomy and climate variables were used in combination with 500 in situ SOC sampling data for training and calibrating a suitable predictive SOC model. The final predictive model selected uses nine predictors with a RMSE of 1.72% and a R2 of 0.82 for SOC expressed in weight %, a RMSE of 25.8 Mg/ha and a R2 of 0.77 for the model in units of Mg/ha. Satellite-derived indices such as VARIG, SLP, NDVI, NDWI, SAVI, EVI2, WDRVI, NDSI, NDMI, NBR and NBR2 were not found to be strong SOC predictors. Relevant predictors instead were in order of importance: geological unit, soil taxonomy, precipitation, elevation, orientation, slope length and steepness (LS Factor), Bare Soil Index (BI), average annual temperature and TOA Brightness Temperature.ConclusionsVariables such as the BI index derived from satellite images and the LS factor from the DEM increase the SOC mapping accuracy. The mapping results show that over 57% of the study area contains high concentrations of SOC, between 150 and 205 Mg/ha, positioning the herbaceous páramo as an ecosystem of global importance. The results obtained with this study can be used to extent the SOC mapping in the whole herbaceous ecosystem of Ecuador offering an efficient and accurate methodology without the need for intensive in situ sampling.

Organic carbon stock and composition in 3.5-m core mangrove soils (Trat, Thailand)

Mangroves are increasingly recognized as an important component of regional and global carbon cycles especially for their high carbon storage capacity. Global estimation of mangrove soil organic carbon (SOC) storage requires detailed regional studies, but estimates of SOC data in deep soils are currently missing in many countries. Furthermore, little is explored on the molecular composition of mangrove SOC. Here, we assessed the SOC stock in a Trat mangrove forest (Thailand) by collecting deep soils (3.5 m) and analyzed the SOC composition for better understanding its potential sources and influencing factors. The Trat mangrove forest had four times higher SOC stock than has been considered for Thai mangrove forests, with the per-area SOC stock of nearly 1000 Mg C ha–1 which rivals that of Indo-Pacific mangrove forests. The SOC composition analyzed by C/N ratios and spectroscopic techniques differed by tree species and depth. Compositional data principal component analysis revealed that a biological factor (root abundance) had stronger influences than the soil texture (sand versus clay) on the abundance and composition of mangrove SOC. Although surface soil (~1 m) C density was largely controlled by the recent vegetation, deep soil C density reflected other historical processes. This study contributed to a refined estimate of Thailand mangrove SOC stock and revealed that factors influencing SOC abundance and composition differ by tree species and depth.

Processes Influencing Autocompaction Modulate Coastal Wetland Surface Elevation Adjustment With Sea-Level Rise

The fate of coastal wetlands and their ecosystem services is dependent upon maintaining substrate elevations within a tidal frame that is influenced by sea-level rise. Development and application of morphodynamic models has been limited as few empirical studies have measured the contribution of key processes to surface elevation change, including mineral and organic matter addition, autocompaction of accumulating sediments and deep subsidence. Accordingly, many models presume that substrates are in equilibrium with relative sea-level rise (RSLR) and the composition of substrates are relatively homogenous. A 20-year record of surface elevation change and vertical accretion from a large tidal embayment in Australia coupled with analyses of inundation frequency and the character of sediments that have accumulated above mean sea level was analyzed to investigate processes influencing surface elevation adjustment. This study confirms the varying contribution of addition, decomposition and compression of organic material, and mineral sediment consolidation. Autocompaction of substrates was proportional to the overburden of accumulating sediments. These processes operate concurrently and are influenced by sediment supply and deposition. Vertical accretion was linearly related to accommodation space. Surface elevation change was related to vertical accretion and substrate organic matter, indicated by carbon storage above mean sea level. Surface elevation change also conformed to models that initially increase and then decrease as accommodation space diminishes. Rates of surface elevation change were largely found to be in equilibrium with sea-level rise measured at the nearest tide gauge, which was estimated at 3.5 mm y–1 over the period of measurements. As creation of new accommodation space with sea-level rise is contrary to the longer-term history of relative sea-level stability in Australia since the mid-Holocene, striking stratigraphic variation arises with deeper sediments dominated by mineral sands and surficial sediments increasingly fine grained and having higher carbon storage. As the sediment character of substrates was found to influence rates of surface elevation gain, we caution against the unqualified use of models derived from the northern hemisphere where substrates have continuously adjusted to sea-level rise and sediment character is likely to be more homogenous.

Peat Carbon Vulnerability to Projected Climate Warming in the Hudson Bay Lowlands, Canada: A Decision Support Tool for Land Use Planning in Peatland Dominated Landscapes

Peatlands help regulate climate by sequestering (net removal) carbon from the atmosphere and storing it in plants and soils. However, as mean annual air temperature (MAAT) increases, peat carbon stocks may decrease. We conducted an in-depth synthesis of current knowledge about ecosystem controls on peatland carbon storage and fluxes to constrain the most influential parameters in probabilistic modelling of peat carbon sinks, such as Bayesian belief networks. Evaluated parameters included climate, carbon flux and mass, land cover, landscape position (defined here as elevation), fire records, and current and future climate scenarios for a 74,300 km2landscape in the Hudson Bay Lowlands, Canada. The Bayesian belief network was constructed with four tiers: 1) exposure, expressed as MAAT, and the state variables of elevation and land cover; 2) sensitivity, expressed as ecosystem conditions relevant to peat carbon mass and its quality for decomposition, peat wetness, and fire; 3) carbon dioxide and methane fluxes and peat combustion; and 4) vulnerability of peat carbon sink strength under warmer MAAT. Simulations were conducted using current (−3.0 to 0.0°C), moderately warmer (0.1–4.0°C), and severely warmer (4.1–9.0°C) climate scenarios. Results from the severely warmer climate scenario projected an overall drying of peat, with approximately 20% reduction in the strong sink categories of net ecosystem exchange and peat carbon sink strength for the severely and, to a lesser degree, the moderately warmer climate scenarios relative to current MAAT. In the warmest temperature simulation, probability of methane emission decreased slightly and the probability of the strong peat carbon sink strength was 27% lower due to peat combustion. Our Bayesian belief network can assist land planners in decision-making for peatland-dominated landscapes, such as identifying high carbon storage areas and those projected to be at greatest risk of carbon loss due to climate change. Such areas may be designated, for example, as protected or reduced management intensity. The Bayesian belief network presented here is built on an in-depth knowledge synthesis to construct conditional probability tables, so is expected to apply to other peatland-dense jurisdictions by changing only elevation, peatland types, and MAAT.

Tropical cyclones cumulatively control regional carbon fluxes in Everglades mangrove wetlands (Florida, USA)

Mangroves are the most blue-carbon rich coastal wetlands contributing to the reduction of atmospheric CO2 through photosynthesis (sequestration) and high soil organic carbon (C) storage. Globally, mangroves are increasingly impacted by human and natural disturbances under climate warming, including pervasive pulsing tropical cyclones. However, there is limited information assessing cyclone’s functional role in regulating wetlands carbon cycling from annual to decadal scales. Here we show how cyclones with a wide range of integrated kinetic energy (IKE) impact C fluxes in the Everglades, a neotropical region with high cyclone landing frequency. Using long-term mangrove Net Primary Productivity (Litterfall, NPPL) data (2001–2018), we estimated cyclone-induced litterfall particulate organic C (litter-POC) export from mangroves to estuarine waters. Our analysis revealed that this lateral litter-POC flux (71–205 g C m−2 year−1)—currently unaccounted in global C budgets—is similar to C burial rates (69–157 g C m−2 year−1) and dissolved inorganic carbon (DIC, 61–229 g C m−2 year−1) export. We proposed a statistical model (PULITER) between IKE-based pulse index and NPPL to determine cyclone’s impact on mangrove role as C sink or source. Including the cyclone’s functional role in regulating mangrove C fluxes is critical to developing local and regional climate change mitigation plans.

Impact of Shrimp Ponds on Mangrove Blue Carbon Stocks in Ecuador

Mangrove forests play an important role in mitigating climate change but are threatened by aquaculture expansion. The inclusion of mangroves in climate change mitigation strategies requires measuring of carbon stocks and the emissions caused by land use change over time. This study provides a synthesis of carbon stocks in mangrove and shrimp ponds in the Gulf of Guayaquil. In this study area, we identified 134,064 ha of mangrove forest and 153,950 ha of shrimp farms. Two mangrove strata were identified according to their height and basal area: medium-statured mangrove (lower height and basal area) and tall mangrove (greater height and basal area). These strata showed statistical differences in aboveground carbon stocks. In both strata, the most abundant mangrove species was Rhizophora mangle. For both strata, trees had a maximum height (>30 m), and their density was greater than 827 ha−1. Total ecosystem level carbon stocks (measured to 1 m soil depth) were 320.9 Mg C ha−1 in medium-statured mangroves and 419.4 Mg C ha−1 in tall mangroves. The differences are attributable to higher basal area, soil organic carbon concentrations and salinity, tidal range, origin of allochthonous material, and herbivory patterns. Mangrove soils represented >80% of the total ecosystem carbon. Ecosystem carbon stocks were lower (81.9 Mg C ha−1) in the shrimp farms, 50% less than in undisturbed mangroves. Our results highlight mangroves as tropical ecosystems with extremely high carbon storage; therefore, they play an important role in mitigating climate change. This research provides a better understanding of how carbon stocks in this gulf are found and can be used for design strategies to protect global natural carbon sinks.

Potential carbon storage of Indonesian mangroves

Even though it only covers 0.1% of the surface of the continent, mangrove forests recorded as carbon-rich forests on earth. Forest loss and degradation together, especially in the tropics contributes about 12% of the total annual anthropogenic CO2 emissions. Mangrove forests ecosystem have high carbon storage potential. The study results show that the ratio of carbon to area in mangrove ecosystems is almost 13 times greater than that of tropical rainforest ecosystems in Indonesia. This study has used published data recorded in Google Scholar and Science Direct. Indonesia’s mangroves, with a total area of 3.1 million ha, store a total carbon of 5.2 Gt. The average stand biomass or aboveground biomass is around 407.15 tons ha−1, storing carbon as much as 191.36 tons ha−1 which is equivalent to the potential for CO2 absorption (CO2e) by mangrove stands of 702.29 tons ha−1. Papua has the largest mangrove forest in Indonesia that has the potential for CO2e. Assessment of carbon storage in soil needs to be done in estimating the total carbon stored in mangrove ecosystems, given the large potential for stored carbon that plays a role in climate change mitigation.

Impact of Atmospheric Optical Properties on Net Ecosystem Productivity of Peatland in Poland

Peatlands play an important role in the global carbon cycle due to the high carbon storage in the substrate. Ecosystem production depends, for example, on the solar energy amount that reaches the vegetation, however the diffuse component of this flux can substantially increase ecosystem net productivity. This phenomenon is observed in different ecosystems, but the study of the atmosphere optical properties on peatland production is lacking. In this paper, the presented methodology allowed us to disentangle the diffuse radiation impact on the net ecosystem production (NEP) of Rzecin peatland, Poland. It allowed us to assess the impact of the atmospheric scattering process determined by the aerosol presence in the air mass. An application of atmospheric radiation transfer (ART) and ecosystem production (EP) models showed that the increase of aerosol optical thickness from 0.09 to 0.17 caused NEP to rise by 3.4–5.7%. An increase of the diffusion index (DI) by 0.1 resulted in an NEP increase of 6.1–42.3%, while a DI decrease of 0.1 determined an NEP reduction of −49.0 to −10.5%. These results show that low peatland vegetation responds to changes in light scattering. This phenomenon should be taken into account when calculating the global CO2 uptake estimation of such ecosystems.

Soil Fungal Community Structure in Boreal Pine Forests: From Southern to Subarctic Areas of Finland.

The boreal forest environment plays an important role in the global C cycle due to its high carbon storage capacity. However, relatively little is known about the forest fungal community at a regional scale in boreal forests. In the present study, we have re-analyzed the data from our previous studies and highlighted the core fungal community composition and potential functional groups in three forests dominated by Scots pine (Pinus sylvestris L.) in Finland, and identified the fungal generalists that appear across geographic locations despite differences in local conditions. The three forests represent subarctic, northern and southern boreal forest, and are all in an un-managed state without human interference or management. The subarctic and northern areas are subject to reindeer grazing. The results showed that the three locations formed distinct fungal community structures (P < 0.05). Compared to the two northern locations, the southern boreal forest harbored a greater abundance of Zygomycota, Lactarius, Mortierella Umbelopsis, and Tylospora, in which aspect there were no differences between the two northern forests. Cortinarius, Piloderma, and Suillus were the core fungal genera in the boreal Scots pine forest. Functionally, the southern boreal forest harbored a greater abundance of saprotroph, endophytes and fungal parasite-lichen, whereas a greater abundance of ectomycorrhizal fungi was observed in the northern boreal forests. Moreover, the pathotroph and wood saprotrophs were commonly present in these three regions. The three locations formed two distinct fungal community functional structures, by which the southern forest was clearly separated from the two northern forests, suggesting a distance–decay relationship via geographic location. This study provides useful information for better understanding the common fungal communities and functions in boreal forests in different geographical locations.

Urban sacred grove forests are potential carbon stores: A case study from Sikkim Himalaya

Urban forests function as lungs in the cities and help in providing a healthy environment to people by reducing warming and improving air & water quality. Information on the carbon storage and capture capacity of the urban forests especially sacred forests in India is limited. We estimated and examined the different carbon pools and sequestration potentials of two urban sacred forests i.e. Deorali Chorten monastery sacred forest (DMS) and Enchey monastery sacred forest (EMS) and tested its performance against a rural natural forest (STF). Carbon in trees was estimated allometrically from five plots of 31.6 × 31.6 m2 in each of the study sites using the Forest Survey of India's volume equations, wood density, and tree height. Thirty soil samples collected from three soil depths (0–15, 15–30, and 30–45 cm) from each of the study sites were colorimetrically estimated for soil carbon. Litter biomass collected from ten quadrats of 1 × 1m2 from each of the study sites was used for the estimation of litter carbon. Ecosystem carbon sequestration was calculated from the carbon stock values of each of the study sites by dividing by the corresponding age of sites. Tree carbon density varies significantly (p<0.001) across sites, and aboveground biomass exhibited a positive significant relationship with tree density (p<0.05), and basal area (p<0.01). Pattern of carbon stock and sequestration is EMS (156.04 Mg C ha−1; 2.5 Mg C ha−1y−1) ; DMS (155.39 Mg C ha−1; 3.42 Mg C ha−1y−1) ; STF (76.58 Mg C ha−1; 5.27 Mg C ha−1y−1).Topsoil has the highest carbon stock with a peak value in EMS (118.70 Mg C ha−1) followed by STF (107.84 Mg C ha−1), and DMS (97.64 Mg C ha−1). The Present study revealed that old forests have higher carbon storage but reduced sequestration potential. Urban forests allocate more carbon in vegetation than in soil, and warming and a shift in precipitation pattern due to climate change may decrease soil carbon and fertility. Hence, proper management of urban forests by replacing old trees with new ones can effectively mitigate the ill effects of global warming in the cities by regulating the climate through CO2 sequestration.

Spatial-temporal variations of carbon storage and carbon sequestration rate in China's national forest parks.

Forests play an important role in regulating climate change and maintaining carbon balance. To explore the carbon storage and carbon sequestration rate of national forest parks is of great significance for carbon sequestration capacity assessment and sustainable forest management. A process-based ecosystem model (CEVSA2 model) was used to simulate the spatial distribution of carbon density, carbon storage and carbon sequestration rate of 881 national forest parks in China during 1982-2017. The results showed that the average carbon density of national forest parks was 255.18 t C·hm-2, being higher than the average carbon density of forest ecosystem in China. In 2017, the total carbon storage of national forest parks increased to 3.56 Pg C, accounting for 11.0%-12.2% of the total carbon storage in national forest ecosystems. During 1982-2017, the average carbon sequestration rate of national forest parks reached 0.45 t C·hm-2·a-1, and the carbon sequestration rate of all national forest parks was above 0.30 t C·hm-2·a-1. National forest parks in the northeast and southwest of China had the highest total carbon storage. The national forest parks in northeast of China had the highest soil organic carbon sequestration rate, while those in eastern China and central southern China had the highest biomass carbon sequestration rate. The area of national forest parks accounted for 5.8% of the total forest area of China, playing an important role in forest carbon sink management of China. Accurate assessment of the growth status, carbon sequestration potential and carbon absorption characteristics of national forest parks could provide reference for the comprehensive assessment of ecosystem service of forest parks in China.

Assessment of Carbon Density in Natural Mountain Forest Ecosystems at Northwest China.

The natural mountain forests in northwest China are recognized as a substantial carbon pool and play an important role in local fragile ecosystems. This study used inventory data and detailed field measurements covering different forest age groups (young, middle-aged, near-mature, mature, old-growth forest), structure of forest (tree, herb, litter and soil layer) and trees (leaves, branches, trunks and root) to estimate biomass, carbon content ratio, carbon density and carbon storage in Altai forest ecosystems. The results showed that the average biomass of the Altai Mountains forest ecosystems was 126.67 t·hm−2, and the descending order of the value was tree layer (120.84 t·hm−2) > herb layer (4.22 t·hm−2) > litter layer (1.61 t·hm−2). Among the tree parts, trunks, roots, leaves and branches accounted for 50%, 22%, 16% and 12% of the total tree biomass, respectively. The average carbon content ratio was 0.49 (range: 0.41–0.52). The average carbon density of forest ecosystems was 205.72 t·hm−2, and the carbon storage of the forest ecosystems was 131.35 Tg (standard deviation: 31.01) inside study area. Soil had the highest carbon storage (65.98%), followed by tree (32.81%), herb (0.78%) and litter (0.43%) layers. Forest age has significant effect on biomass, carbon content ratio, carbon density and carbon storage. The carbon density of forest ecosystems in study area was spatially distributed higher in the south and lower in north, which is influenced by climate, topography, soil types and dominant tree species.

The soil Microbial Carbon Pump as a new concept for terrestrial carbon sequestration

Soil is a huge terrestrial carbon pool, which has higher carbon storage than the sum of atmospheric and terrestrial vegetation carbon. Small fluctuations in soil carbon pool can affect regional carbon flux and global climate change. As soil organic carbon plays key roles in soil carbon storage and sequestration, studying its composition, sources and stability mechanism is a key to deeply understand the functions of terrestrial ecosystem and how it will respond to climate changes. The recently-proposed concept of soil Microbial Carbon Pump (MCP) emphasizes the importance of soil microbial anabolism and its contributions to soil carbon formation and stabilization, which can be applied for elucidating the source, formation and sequestration of soil organic carbon. This article elaborates MCP-mediated soil carbon sequestration mechanism and its influencing factors, as well as representative scientific questions we may explore with the soil MCP conceptual framework.

Land use change in the Ecuadorian páramo: The impact of expanding agriculture on soil carbon storage

ABSTRACT The Andean páramo is notable for high soil carbon storage and its contribution to ecosystem services. However, the páramo’s ability to maintain high soil carbon levels is threatened by land use change from tussock grassland and shrublands to agricultural uses. A chronosequence study was conducted in the páramo around Quito, Ecuador, to determine the rate of soil carbon loss from traditional fallow agriculture. In parallel, a land use and land cover classification of Landsat images was used to measure the change in agricultural areas between 1991 and 2017. There was a significant negative relationship between the time since initial cultivation of a field and soil C: Older agricultural sites had significantly less C compared to natural ecosystems due to an average loss of 0.045 percent soil C per year. Undisturbed sites had significantly more soil C than cultivated sites but not pastures or fallow fields, indicating that cultivation is the most detrimental stage of the fallow agricultural cycle for soil C storage. There was an 838 percent increase in cultivated land between 1991 and 2017 but a 10 percent decrease in pastures, indicating a trend away from traditional regenerative agriculture toward land use types that lead to substantial losses in soil carbon.