Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon...Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.展开更多
Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests und...Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.展开更多
Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately e...Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately estimate the soil organic carbon stocks(SOCS)in the coastal wetlands of Tianjin and Hebei,China.To reduce data redundancy,simplify model complexity,and improve model inter-pretability,Pearson correlation analysis(PsCA),Boruta,and recursive feature elimination(RFE)were employed to optimize features.Combined with the optimized features,the soil organic carbon density(SOCD)prediction model was constructed by using multivariate adaptive regression splines(MARS),extreme gradient boosting(XGBoost),and random forest(RF)algorithms and applied to predict the spatial distribution of SOCD and estimate the SOCS of different wetland types in 2020.The results show that:1)different feature combinations have a significant influence on the model performance.Better prediction performance was attained by building a model using RFE-based feature combinations.RF has the best prediction accuracy(R^(2)=0.587,RMSE=0.798 kg/m^(2),MAE=0.660 kg/m^(2)).2)Optical features are more important than radar and geo-climatic features in the MARS,XGBoost,and RF algorithms.3)The size of SOCS is related to SOCD and the area of each wetland type,aquaculture pond has the highest SOCS,followed by marsh,salt pan,mud-flat,and sand shore.展开更多
Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We co...Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.展开更多
Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protectiv...Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protective measures.However,the aboveground carbon(AGC)stock potential of China's natural forests remains considerably uncertain in spatial and temporal dynamics.In this study,we provide a spatially detailed estimation of the maximum AGC stock potential for China's natural forests by integrating high-resolution multi-source remote sensing and field survey data.The analysis reveals that China's natural forests could sequester up to 9.880.10 Pg C by 2030,potentially increasing to 10.460.11 Pg C by 2060.Despite this,the AGC sequestration rate would decline from 0.190.001 to 0.080.001 Pg C·yr^(-1)over the period.Spatially,the future AGC accumulation rates exhibit marked heterogeneity.The warm temperate deciduous broadleaf forest region with predominantly young natural forests,is expected to exhibit the most significant increase of 26.36%by 2060,while the Qinghai-Tibet Plateau Alpine region comprising mainly mature natural forests would exhibit only a 0.74%increase.To sustain the high carbon sequestration capacity of China's natural forests,it is essential to prioritize protecting mature forests alongside preserving and restoring young natural forest areas.展开更多
Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwes...Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.展开更多
In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with veget...In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil （0-100 cm）, plant biomass and the ecosystem （plant and soil） following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation （natural restoration） or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0-100 cm. Moreover, there was a time lag of about 15-30 years between biomass production and soil carbon sequestration in 0-100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.展开更多
This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuma...This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.展开更多
Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of poll...Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.展开更多
Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land...Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land use changes in the Kumrat valley KPK, Pakistan, were determined： a net decrease of 11.56 and 7.46 % occurred in forest and rangeland, while 100 % increase occurred in agriculture land（AL）. Biomass in different land uses,forest land（FL）, AL, and range land（RL） was determined by field inventory. From the biomass data, the amount of carbon was calculated, considering 50 % of the biomass as carbon. Soil carbon was also determined to a depth of 0–15and 16–30 cm. The average carbon stocks（C stocks） in all land uses ranged from 28.62 ± 13.8 t ha-1in AL to486.6 ± 32.4 t ha-1in pure Cedrus deodara forest. The results of the study confirmed that forest soil and vegetation stored the maximum amount of carbon followed by RL. Conversion of FL and RL to AL not only leads to total loss of about 56 %（from FL conversion） and 37 %（RL conversion） of soil carbon in the last decades but also the loss of a valuable carbon sink. In order to meet the emissions reduction obligations of the Kyoto Protocol, Conservation of forest and RL in the mountainous regions of the Hindu Kush will help Pakistan to meet its emissions reduction goals under the Kyoto Protocol.展开更多
Variation of soil carbon stock in the cropping systems is an important indicator of their sustainability.The present study was conducted in 2015 and 2018 in seven organic cotton production areas distributed over the S...Variation of soil carbon stock in the cropping systems is an important indicator of their sustainability.The present study was conducted in 2015 and 2018 in seven organic cotton production areas distributed over the Southern and Northern Sudan agro-ecological zones in Burkina Faso.Soil samples were collected in 2015 as baseline and in 2018,after three years of cropping seasons,to determine the variations in carbon stocks in plots under organic farming systems.Surveys were also conducted to understand the fertilization practices implemented by producers during the same period.The results revealed that the recommended fertilization packages were not respected due to low production capacity and under using of organic manure.After three years of cropping in 2018,the deficit of organic restitution has led to a high decline of the soil carbon stocks.This decline was more severe in the 0-10 cm depth in some soils where the decrease in carbon stocks ranged from-4.6 t/ha to-5.5 t/ha.The correlation between soil types and their carbon stocks in the 0-10 cm soil layer was found to be significant(p<0.05)in the Northern Sudan agro-ecological zone with adjusted R2=74%and 54%in 2015 and 2018,respectively,and adjusted R2=56%(2015)and 44%(2018)in the Southern Sudan agro-ecological zone.After three years of organic cotton-based farming,a decrease in the correlation between soil types and their carbon content was observed in the majority of cases.These results show that the process of carbon storage in soil is more influenced by agricultural practices and agro-ecological conditions than by the soil type.展开更多
Although it has been recognized that soils play a critical role in carbon storage and that coastal temperate forests have considerable potential to sequester soil organic carbon (SOC), studies related to SOC stocks an...Although it has been recognized that soils play a critical role in carbon storage and that coastal temperate forests have considerable potential to sequester soil organic carbon (SOC), studies related to SOC stocks and stability are scarce in these ecosystems. Forest disturbances may leave legacies on SOC properties and may further compromise SOC storage capacity of these ecosystems. In the Pacific Spirit Regional Park of southwestern British Columbia, we compared SOC stocks and stability among three second-growth forests that have been affected by disturbances of different magnitudes. We collected data on soil chemical and physical properties to estimate SOC content and assess SOC stability. We found that SOC stocks in the forest characterized by low magnitude disturbance were greater than those of the forest characterized by high magnitude disturbance (8.2 ± 1.3 kg·Cm<sup>-2</sup> versus 5.3 ± 0.1 kg·Cm<sup>-2</sup> to 30 cm depth). SOC was less stable in the highly disturbed forest and subsequent vegetation changes might have further reduced SOC stability. Our results provide insight into the role of disturbance history in the current SOC storage capacity of coastal temperate rainforests of British Columbia.展开更多
Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. Thi...Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. This study estimates soil carbon stock in a dense forest in central Amazonia from sets of soil samples collected in three topographic positions (plateau, slope and valley bottom). Soil organic matter (SOM) was fractionated by density and particle size, thus obtaining the free light fraction (FLF), intra-aggregated light fraction (IALF), sand fraction (F-sand), clay fraction (F-clay) and silt fraction (F-silt). Soil organic carbon (SOC) stocks on the plateaus (Oxisol), slopes (Ultisol) and valley bottoms (Spodosol) were 98.4 ± 7.8 Mg·ha-1, 72.6 ± 5.4 Mg·ha-1 and 81.4 ± 8.9 Mg·ha-1, respectively. Distribution of carbon in soil fractions was: 112.6 ± 15 Mg·ha-1 (FLF), 2.5 ± 0 Mg·ha-1 (ILAF), 40.5 ± 1.5 Mg·ha-1 (F-silt), 68.5 ± 4.2 Mg·ha-1 (F-clay) and 28.3 ± 1.4 Mg·ha-1 (F-sand), totaling 252.4 ± 22.1 Mg·ha-1 of carbon. Carbon is largely in labile form and near the soil surface, making it liable to release from deforestation or from climate change. Spodosols are more susceptible to soil carbon losses, demonstrating the need to preserve forested areas close to Amazonian rivers and streams.展开更多
Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear...Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha<sup>−</sup><sup>1</sup>. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha<sup>−</sup><sup>1</sup>) than upper layers (55.42 ± 25.37 MgC ha<sup>−</sup><sup>1</sup>). The study highlights that low deforestation rate have led to less CO<sub>2</sub> (705.3 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup> - 922.62 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup>) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha<sup>−</sup><sup>1</sup>) than primary (20.33 ± 12.7 MgC ha<sup>−</sup><sup>1</sup>), savanna and cropland (21.71 ± 15.10 MgC ha<sup>−</sup><sup>1</sup>). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.展开更多
The soils that lay below humid ecosystems are characterized as being significant holders of carbon. Because of the great susceptibility of this type of environment to anthropic changes, expressive quantities of carbon...The soils that lay below humid ecosystems are characterized as being significant holders of carbon. Because of the great susceptibility of this type of environment to anthropic changes, expressive quantities of carbon stored in the soil can be released into the atmosphere. In the Cerrado biome (Brazil), only a few types of vegetation have had carbon storage levels in their soil estimated. The main purpose of this study was to obtain basic quantitative parameters for carbon storage and to identify the general aspects of soil in regions where there exists Humid Grasslands (Campo Limpo úmido), a kind of humid area phytophysiognomy found in the Cerrado. We selected 6 regions of the Federal District with this kind of vegetation formation, characterized by low anthropic impact and located either in the interior or in the proximity of specially protected areas. In each one of the sampled regions, we marked a transect with 4 equidistant points and collected material at 7 different levels of depth: 0 - 5, 5 - 10, 10 - 20, 20 - 30, 30 - 40, 40 - 50 and 50 - 60 cm. We obtained 168 samples, with 84 related to Humid Grassland areas in gleysols and 84 samples related to areas in plinthosols—types of soil dominant in this environment. We determined the texture, bulk density and concentration of nitrogen and carbon at each depth. The average concentration of carbon for Humid Grassland areas was 55.19 g.kg-1, with an average of 61.65 g.kg-1 for Gleysols and 48.73 g.kg-1 for Plinthosols. The soil samples displayed distinct textural differences between gleysols and plinthosols. There were no significant differences in soil density (0.75 kg.dm-3 for Gleysols and 0.72 kg.dm-3 for Plinthosols). The average concentration of nitrogen was 20.66 g.kg-1, with 23.98 g.kg-1 for Gleysols and 17.34 g.kg-1 for Plinthosols. The average carbon storage for Humid Grassland areas, down to 60 cm deep, was 244.17 mg C ha-1 and the total estimated stock for these areas in the Federal District was 206.71 Gg.C. In general, the samples obtained in gleysols showed a carbon content and nitrogen level superior to those in plinthosols, although a greater sampling effort is needed to confirm the differences observed. The density values of stored carbon in the soil beneath Humid Grassland areas proved to be superior to those values observed for other types of vegetation typical for the Cerrado environment.展开更多
The urban population and urbanized land in China have both increased markedly since the 1980 s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In p...The urban population and urbanized land in China have both increased markedly since the 1980 s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In particular, the effect of rapid urbanization on the storage of soil carbon has not been studied extensively. In this study, we compared the soil carbon stocks of different land use types in Beijing Municipality. We collected 490 top-soil samples(top 20 cm) from urban and suburban sites within the Sixth Ring Road of Beijing, which cover approximately 2400 km2, and the densities of soil organic carbon(SOC), soil inorganic carbon(SIC), and total carbon(TC) were analyzed to determine the spatial distribution of urban and suburban soil carbon characteristics across seven land use types. The results revealed significant differences in soil carbon densities among land use types. Additionally, urban soil had significantly higher SOC and SIC densities than suburban soil did, and suburban shelterbelts and productive plantations had lower SIC densities than the other land use types. The comparison of coefficients of variance(CVs) showed that carbon content of urban topsoil had a lower variability than that of suburban topsoil. Further findings revealed that soil carbon storage increased with built-up age. Urban soil built up for more than 20 years had higher densities of SOC, SIC and TC than both urban soil with less than 10 years and suburban soil. Correlation analyses indicated the existence of a significantly negative correlation between the SOC, SIC, and TC densities of urban soil and the distance to the urban core, and the distance variable alone explained 23.3% of the variation of SIC density and 13.8% of the variation of TC density. These results indicate that SOC and SIC accumulate in the urban topsoil under green space as a result of the conversion of agricultural land to urban land due to the urbanization in Beijing.展开更多
Understanding the effects of land cover changes on ecosystem carbon stocks is essential for ecosystem management and envi- ronmental protection, particularly in the transboundary region that has undergone marked chang...Understanding the effects of land cover changes on ecosystem carbon stocks is essential for ecosystem management and envi- ronmental protection, particularly in the transboundary region that has undergone marked changes. This study aimed to examine the impacts of land cover changes on ecosystem carbon stocks in the transboundary Tureen River Basin （TTRB）. We extracted the spatial information from Landsat Thematic Imager （TM） and Operational Land Imager （OLI） images for the years 1990 and 2015 and obtained convincing estimates of terrestrial biomass and soil carbon stocks with the INVEST model. The results showed that forestland, cropland and built-up land increased by 57.5, 429.7 and 128.9 km2, respectively, while grassland, wetland and barren land declined by 24.9, 548.0 and 43.0 km2, respectively in the TTRB from 1990 to 2015. The total carbon stocks encompassing aboveground, belowground, soil and litter layer carbon storage pools have declined from 831.48 Tg C in 1990 to 831.42 Tg C in 2015 due to land cover changes. In detail, the carbon stocks de- creased by 3.13 Tg C and 0.44 Tg C in Democratic People＇s Republic of Korea （North Korea） and Russia, respectively, while increased by 3.51 Tg C in China. Furthermore, economic development, and national policy accounted for most land cover changes in the TTRB. Our results imply that effective wetland and forestland protection policies among China, North Korea, and Russia are much needed for protecting the natural resources, promoting local ecosystem services and regional sustainable development in the transnational area.展开更多
A study was conducted to assess carbon stocks in various forms and land-use types and reliably estimate the impact of land use on C stocks in the Nam Yao sub-watershed （19°05′10″N, 100°37′02″E）, Thaila...A study was conducted to assess carbon stocks in various forms and land-use types and reliably estimate the impact of land use on C stocks in the Nam Yao sub-watershed （19°05′10″N, 100°37′02″E）, Thailand. The carbon stocks of aboveground, soil organic and fine root within primary forest, reforestation and agricultural land were estimated through field data collection. Results re- vealed that the amount of total carbon stock of forests （357.62 ± 28.51 Mg·ha^-1, simplified expression of Mg （carbon）·ha^-1） was significantly greater （P〈 0.05） than the reforestation （195.25 ± 14.38 Mg·ha^-1） and the agricultural land （103.10 ± 18.24 Mg·ha^-1）. Soil organic carbon in the forests （196.24 ± 22.81 Mg·ha^-1） was also significantly greater （P〈 0.05） than the reforestation （146.83 ± 7.22 Mg·ha^-1） and the agricultural land （95.09± 14.18 Mg·ha^-1）. The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 40-cm layer and decreased with soil depth. The aboveground carbon：soil organic carbon： fine root carbon ratios （ABGC： SOC： FRC）, was 5：8：1, 2：8：1, and 3：50：1 for the forest, reforestation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land. However, the C can be effectively recaptured through reforestation where high levels of C are stored in biomass as carbon sinks, facilitating carbon dioxide mitigation.展开更多
The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the...The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broadleaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine （Pinus roxburghii） forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory car- ried out from 2005 to 2010. In total 261 plots （each of lha.） were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above- and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature （-100 years old） pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2.ha-1 represented mean volume of 243 and 197 m3·ha-1, respectively. The average biomass （t.ha-1） was 237 in Ghoragali site and 186 tha-1 in Lehterar site, which is equal to 128 and 100 t·ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t.ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% in the top soils. In mixed broadleaved evergreen forests a mean basal area （m2.ha-1）was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3.ha-1. The average upper and under storey biomass （t·ha-1） was 50.93 in Kherimurat site and 40.43 t.ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t ·ha-1 including soil C stocks. This study provides a protocol monitoring biomass and carbon stocks and valuable baseline data for in Pakistan＇s managed and unmanaged sub-tropical forests.展开更多
We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province,China.According to the definitions of the forest inventory,Henan forests w...We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province,China.According to the definitions of the forest inventory,Henan forests were categorized into five groups: forest stands,economic forests,bamboo forests,open forests,and shrub forests.We estimated biomass carbon in forest stands for each inventory period by using the continuous biomass expansion factor method.We used the mean biomass density method to estimate carbon stocks in economic,bamboo,open and shrub forests.Over the 60-year period,total forest vegetation carbon storage increased from34.6 Tg(1 Tg = 1×10;g) in 1949 to 80.4 Tg in 2008,a net vegetation carbon increase of 45.8 Tg.By stand type,increases were 39.8 Tg in forest stands,5.5 Tg in economic forests,0.6 Tg in bamboo forests,and-0.1 Tg in open forests combine shrub forests.Carbon storageincreased at an average annual rate of 0.8 Tg carbon over the study period.Carbon was mainly stored in young and middle-aged forests,which together accounted for 70–88%of the total forest carbon storage in different inventory periods.Broad-leaved forest was the main contributor to forest carbon sequestration.From 1998 to 2008,during implementation of national afforestation and reforestation programs,the carbon storage of planted forest increased sharply from 3.9 to 37.9 Tg.Our results show that with the growth of young planted forest,Henan Province forests realized large gains in carbon sequestration over a 60-year period that was characterized in part by a nation-wide tree planting program.展开更多
文摘Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.
文摘Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.
基金Under the auspices of National Natural Science Foundation of China(No.42101393,41901375,52274166)Hebei Natural Science Foundation(No.D2022209005,D2023209008)Central Guided Local Science and Technology Development Fund Project of Hebei Province(No.236Z3305G,246Z4201G)Key Research and Development Program of Science and Technology Plan of Tangshan,China(No.22150221J)。
文摘Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately estimate the soil organic carbon stocks(SOCS)in the coastal wetlands of Tianjin and Hebei,China.To reduce data redundancy,simplify model complexity,and improve model inter-pretability,Pearson correlation analysis(PsCA),Boruta,and recursive feature elimination(RFE)were employed to optimize features.Combined with the optimized features,the soil organic carbon density(SOCD)prediction model was constructed by using multivariate adaptive regression splines(MARS),extreme gradient boosting(XGBoost),and random forest(RF)algorithms and applied to predict the spatial distribution of SOCD and estimate the SOCS of different wetland types in 2020.The results show that:1)different feature combinations have a significant influence on the model performance.Better prediction performance was attained by building a model using RFE-based feature combinations.RF has the best prediction accuracy(R^(2)=0.587,RMSE=0.798 kg/m^(2),MAE=0.660 kg/m^(2)).2)Optical features are more important than radar and geo-climatic features in the MARS,XGBoost,and RF algorithms.3)The size of SOCS is related to SOCD and the area of each wetland type,aquaculture pond has the highest SOCS,followed by marsh,salt pan,mud-flat,and sand shore.
基金supported by the Key Science and Technology Project of Anhui Province,China(2023n06020056)the National Natural Science Foundation of China(32071628)the Colleges and Universities Science Foundation of Anhui Province,China(2024AH020002)。
文摘Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF1300203)the National Natural Science Foundation of China(Grant No.42371329s).
文摘Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protective measures.However,the aboveground carbon(AGC)stock potential of China's natural forests remains considerably uncertain in spatial and temporal dynamics.In this study,we provide a spatially detailed estimation of the maximum AGC stock potential for China's natural forests by integrating high-resolution multi-source remote sensing and field survey data.The analysis reveals that China's natural forests could sequester up to 9.880.10 Pg C by 2030,potentially increasing to 10.460.11 Pg C by 2060.Despite this,the AGC sequestration rate would decline from 0.190.001 to 0.080.001 Pg C·yr^(-1)over the period.Spatially,the future AGC accumulation rates exhibit marked heterogeneity.The warm temperate deciduous broadleaf forest region with predominantly young natural forests,is expected to exhibit the most significant increase of 26.36%by 2060,while the Qinghai-Tibet Plateau Alpine region comprising mainly mature natural forests would exhibit only a 0.74%increase.To sustain the high carbon sequestration capacity of China's natural forests,it is essential to prioritize protecting mature forests alongside preserving and restoring young natural forest areas.
基金financed by Debre Markose University Burie Campus.
文摘Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.
基金funded by the National Natural Science Foundation of China(4130161041501094+3 种基金41330858)the Key Research Program of the Chinese Academy of Sciences(KZZD-EW-04)the Natural Science Basic Research Plan in Shaanxi Province of China(2014JQ5170)the open foundation of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(A318009902-1510)
文摘In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil （0-100 cm）, plant biomass and the ecosystem （plant and soil） following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation （natural restoration） or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0-100 cm. Moreover, there was a time lag of about 15-30 years between biomass production and soil carbon sequestration in 0-100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.
文摘This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.
基金the Major Program of the National Fund of Philosophy and Social Science of China(Nos.21&ZD109).
文摘Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.
文摘Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land use changes in the Kumrat valley KPK, Pakistan, were determined： a net decrease of 11.56 and 7.46 % occurred in forest and rangeland, while 100 % increase occurred in agriculture land（AL）. Biomass in different land uses,forest land（FL）, AL, and range land（RL） was determined by field inventory. From the biomass data, the amount of carbon was calculated, considering 50 % of the biomass as carbon. Soil carbon was also determined to a depth of 0–15and 16–30 cm. The average carbon stocks（C stocks） in all land uses ranged from 28.62 ± 13.8 t ha-1in AL to486.6 ± 32.4 t ha-1in pure Cedrus deodara forest. The results of the study confirmed that forest soil and vegetation stored the maximum amount of carbon followed by RL. Conversion of FL and RL to AL not only leads to total loss of about 56 %（from FL conversion） and 37 %（RL conversion） of soil carbon in the last decades but also the loss of a valuable carbon sink. In order to meet the emissions reduction obligations of the Kyoto Protocol, Conservation of forest and RL in the mountainous regions of the Hindu Kush will help Pakistan to meet its emissions reduction goals under the Kyoto Protocol.
文摘Variation of soil carbon stock in the cropping systems is an important indicator of their sustainability.The present study was conducted in 2015 and 2018 in seven organic cotton production areas distributed over the Southern and Northern Sudan agro-ecological zones in Burkina Faso.Soil samples were collected in 2015 as baseline and in 2018,after three years of cropping seasons,to determine the variations in carbon stocks in plots under organic farming systems.Surveys were also conducted to understand the fertilization practices implemented by producers during the same period.The results revealed that the recommended fertilization packages were not respected due to low production capacity and under using of organic manure.After three years of cropping in 2018,the deficit of organic restitution has led to a high decline of the soil carbon stocks.This decline was more severe in the 0-10 cm depth in some soils where the decrease in carbon stocks ranged from-4.6 t/ha to-5.5 t/ha.The correlation between soil types and their carbon stocks in the 0-10 cm soil layer was found to be significant(p<0.05)in the Northern Sudan agro-ecological zone with adjusted R2=74%and 54%in 2015 and 2018,respectively,and adjusted R2=56%(2015)and 44%(2018)in the Southern Sudan agro-ecological zone.After three years of organic cotton-based farming,a decrease in the correlation between soil types and their carbon content was observed in the majority of cases.These results show that the process of carbon storage in soil is more influenced by agricultural practices and agro-ecological conditions than by the soil type.
文摘Although it has been recognized that soils play a critical role in carbon storage and that coastal temperate forests have considerable potential to sequester soil organic carbon (SOC), studies related to SOC stocks and stability are scarce in these ecosystems. Forest disturbances may leave legacies on SOC properties and may further compromise SOC storage capacity of these ecosystems. In the Pacific Spirit Regional Park of southwestern British Columbia, we compared SOC stocks and stability among three second-growth forests that have been affected by disturbances of different magnitudes. We collected data on soil chemical and physical properties to estimate SOC content and assess SOC stability. We found that SOC stocks in the forest characterized by low magnitude disturbance were greater than those of the forest characterized by high magnitude disturbance (8.2 ± 1.3 kg·Cm<sup>-2</sup> versus 5.3 ± 0.1 kg·Cm<sup>-2</sup> to 30 cm depth). SOC was less stable in the highly disturbed forest and subsequent vegetation changes might have further reduced SOC stability. Our results provide insight into the role of disturbance history in the current SOC storage capacity of coastal temperate rainforests of British Columbia.
基金the Large-Scale Atmosphere-Biosphere Experiment in Amazonia(LBA),Instituto Nacional de Pesquisas da Amazonia(INPA),Empresa Brasileira de Pesquisa Agropecuaria(EMBRAPA),Conselho Nacional do Desenvolvimento Cientifico e Tecnologico(CNPq:Proc.610042/2009-2,573810/2008-7,610042/2009-2)Fundacao de Amparo a Pesquisa do Estado do Amazonas(FAPEAM Proc.708565)for financial and logistical support.
文摘Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. This study estimates soil carbon stock in a dense forest in central Amazonia from sets of soil samples collected in three topographic positions (plateau, slope and valley bottom). Soil organic matter (SOM) was fractionated by density and particle size, thus obtaining the free light fraction (FLF), intra-aggregated light fraction (IALF), sand fraction (F-sand), clay fraction (F-clay) and silt fraction (F-silt). Soil organic carbon (SOC) stocks on the plateaus (Oxisol), slopes (Ultisol) and valley bottoms (Spodosol) were 98.4 ± 7.8 Mg·ha-1, 72.6 ± 5.4 Mg·ha-1 and 81.4 ± 8.9 Mg·ha-1, respectively. Distribution of carbon in soil fractions was: 112.6 ± 15 Mg·ha-1 (FLF), 2.5 ± 0 Mg·ha-1 (ILAF), 40.5 ± 1.5 Mg·ha-1 (F-silt), 68.5 ± 4.2 Mg·ha-1 (F-clay) and 28.3 ± 1.4 Mg·ha-1 (F-sand), totaling 252.4 ± 22.1 Mg·ha-1 of carbon. Carbon is largely in labile form and near the soil surface, making it liable to release from deforestation or from climate change. Spodosols are more susceptible to soil carbon losses, demonstrating the need to preserve forested areas close to Amazonian rivers and streams.
文摘Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha<sup>−</sup><sup>1</sup>. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha<sup>−</sup><sup>1</sup>) than upper layers (55.42 ± 25.37 MgC ha<sup>−</sup><sup>1</sup>). The study highlights that low deforestation rate have led to less CO<sub>2</sub> (705.3 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup> - 922.62 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup>) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha<sup>−</sup><sup>1</sup>) than primary (20.33 ± 12.7 MgC ha<sup>−</sup><sup>1</sup>), savanna and cropland (21.71 ± 15.10 MgC ha<sup>−</sup><sup>1</sup>). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.
文摘The soils that lay below humid ecosystems are characterized as being significant holders of carbon. Because of the great susceptibility of this type of environment to anthropic changes, expressive quantities of carbon stored in the soil can be released into the atmosphere. In the Cerrado biome (Brazil), only a few types of vegetation have had carbon storage levels in their soil estimated. The main purpose of this study was to obtain basic quantitative parameters for carbon storage and to identify the general aspects of soil in regions where there exists Humid Grasslands (Campo Limpo úmido), a kind of humid area phytophysiognomy found in the Cerrado. We selected 6 regions of the Federal District with this kind of vegetation formation, characterized by low anthropic impact and located either in the interior or in the proximity of specially protected areas. In each one of the sampled regions, we marked a transect with 4 equidistant points and collected material at 7 different levels of depth: 0 - 5, 5 - 10, 10 - 20, 20 - 30, 30 - 40, 40 - 50 and 50 - 60 cm. We obtained 168 samples, with 84 related to Humid Grassland areas in gleysols and 84 samples related to areas in plinthosols—types of soil dominant in this environment. We determined the texture, bulk density and concentration of nitrogen and carbon at each depth. The average concentration of carbon for Humid Grassland areas was 55.19 g.kg-1, with an average of 61.65 g.kg-1 for Gleysols and 48.73 g.kg-1 for Plinthosols. The soil samples displayed distinct textural differences between gleysols and plinthosols. There were no significant differences in soil density (0.75 kg.dm-3 for Gleysols and 0.72 kg.dm-3 for Plinthosols). The average concentration of nitrogen was 20.66 g.kg-1, with 23.98 g.kg-1 for Gleysols and 17.34 g.kg-1 for Plinthosols. The average carbon storage for Humid Grassland areas, down to 60 cm deep, was 244.17 mg C ha-1 and the total estimated stock for these areas in the Federal District was 206.71 Gg.C. In general, the samples obtained in gleysols showed a carbon content and nitrogen level superior to those in plinthosols, although a greater sampling effort is needed to confirm the differences observed. The density values of stored carbon in the soil beneath Humid Grassland areas proved to be superior to those values observed for other types of vegetation typical for the Cerrado environment.
基金Under the auspices of National Key Technology Research and Development Program(No.2007BAC28B01)Innovation Project of State Key Laboratory of Urban and Regional Ecology of China
文摘The urban population and urbanized land in China have both increased markedly since the 1980 s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In particular, the effect of rapid urbanization on the storage of soil carbon has not been studied extensively. In this study, we compared the soil carbon stocks of different land use types in Beijing Municipality. We collected 490 top-soil samples(top 20 cm) from urban and suburban sites within the Sixth Ring Road of Beijing, which cover approximately 2400 km2, and the densities of soil organic carbon(SOC), soil inorganic carbon(SIC), and total carbon(TC) were analyzed to determine the spatial distribution of urban and suburban soil carbon characteristics across seven land use types. The results revealed significant differences in soil carbon densities among land use types. Additionally, urban soil had significantly higher SOC and SIC densities than suburban soil did, and suburban shelterbelts and productive plantations had lower SIC densities than the other land use types. The comparison of coefficients of variance(CVs) showed that carbon content of urban topsoil had a lower variability than that of suburban topsoil. Further findings revealed that soil carbon storage increased with built-up age. Urban soil built up for more than 20 years had higher densities of SOC, SIC and TC than both urban soil with less than 10 years and suburban soil. Correlation analyses indicated the existence of a significantly negative correlation between the SOC, SIC, and TC densities of urban soil and the distance to the urban core, and the distance variable alone explained 23.3% of the variation of SIC density and 13.8% of the variation of TC density. These results indicate that SOC and SIC accumulate in the urban topsoil under green space as a result of the conversion of agricultural land to urban land due to the urbanization in Beijing.
基金Under the auspices of the National Key Research and Development Project(No.2016YFA0602301)National Natural Science Foundation of China(No.41730643,41671219,41771109,31500400)
文摘Understanding the effects of land cover changes on ecosystem carbon stocks is essential for ecosystem management and envi- ronmental protection, particularly in the transboundary region that has undergone marked changes. This study aimed to examine the impacts of land cover changes on ecosystem carbon stocks in the transboundary Tureen River Basin （TTRB）. We extracted the spatial information from Landsat Thematic Imager （TM） and Operational Land Imager （OLI） images for the years 1990 and 2015 and obtained convincing estimates of terrestrial biomass and soil carbon stocks with the INVEST model. The results showed that forestland, cropland and built-up land increased by 57.5, 429.7 and 128.9 km2, respectively, while grassland, wetland and barren land declined by 24.9, 548.0 and 43.0 km2, respectively in the TTRB from 1990 to 2015. The total carbon stocks encompassing aboveground, belowground, soil and litter layer carbon storage pools have declined from 831.48 Tg C in 1990 to 831.42 Tg C in 2015 due to land cover changes. In detail, the carbon stocks de- creased by 3.13 Tg C and 0.44 Tg C in Democratic People＇s Republic of Korea （North Korea） and Russia, respectively, while increased by 3.51 Tg C in China. Furthermore, economic development, and national policy accounted for most land cover changes in the TTRB. Our results imply that effective wetland and forestland protection policies among China, North Korea, and Russia are much needed for protecting the natural resources, promoting local ecosystem services and regional sustainable development in the transnational area.
文摘A study was conducted to assess carbon stocks in various forms and land-use types and reliably estimate the impact of land use on C stocks in the Nam Yao sub-watershed （19°05′10″N, 100°37′02″E）, Thailand. The carbon stocks of aboveground, soil organic and fine root within primary forest, reforestation and agricultural land were estimated through field data collection. Results re- vealed that the amount of total carbon stock of forests （357.62 ± 28.51 Mg·ha^-1, simplified expression of Mg （carbon）·ha^-1） was significantly greater （P〈 0.05） than the reforestation （195.25 ± 14.38 Mg·ha^-1） and the agricultural land （103.10 ± 18.24 Mg·ha^-1）. Soil organic carbon in the forests （196.24 ± 22.81 Mg·ha^-1） was also significantly greater （P〈 0.05） than the reforestation （146.83 ± 7.22 Mg·ha^-1） and the agricultural land （95.09± 14.18 Mg·ha^-1）. The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 40-cm layer and decreased with soil depth. The aboveground carbon：soil organic carbon： fine root carbon ratios （ABGC： SOC： FRC）, was 5：8：1, 2：8：1, and 3：50：1 for the forest, reforestation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land. However, the C can be effectively recaptured through reforestation where high levels of C are stored in biomass as carbon sinks, facilitating carbon dioxide mitigation.
文摘The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broadleaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine （Pinus roxburghii） forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory car- ried out from 2005 to 2010. In total 261 plots （each of lha.） were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above- and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature （-100 years old） pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2.ha-1 represented mean volume of 243 and 197 m3·ha-1, respectively. The average biomass （t.ha-1） was 237 in Ghoragali site and 186 tha-1 in Lehterar site, which is equal to 128 and 100 t·ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t.ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% in the top soils. In mixed broadleaved evergreen forests a mean basal area （m2.ha-1）was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3.ha-1. The average upper and under storey biomass （t·ha-1） was 50.93 in Kherimurat site and 40.43 t.ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t ·ha-1 including soil C stocks. This study provides a protocol monitoring biomass and carbon stocks and valuable baseline data for in Pakistan＇s managed and unmanaged sub-tropical forests.
基金funded by the National Key Research and Development Program of China(2016YFC0501605)the National Sci-Tech Basic Program of China(2014FY210100)+1 种基金the National Natural Science foundation of China(31200332)the University Youth Teacher Training Program by Education Department of Henan Province(2016GGJS-062)
文摘We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province,China.According to the definitions of the forest inventory,Henan forests were categorized into five groups: forest stands,economic forests,bamboo forests,open forests,and shrub forests.We estimated biomass carbon in forest stands for each inventory period by using the continuous biomass expansion factor method.We used the mean biomass density method to estimate carbon stocks in economic,bamboo,open and shrub forests.Over the 60-year period,total forest vegetation carbon storage increased from34.6 Tg(1 Tg = 1×10;g) in 1949 to 80.4 Tg in 2008,a net vegetation carbon increase of 45.8 Tg.By stand type,increases were 39.8 Tg in forest stands,5.5 Tg in economic forests,0.6 Tg in bamboo forests,and-0.1 Tg in open forests combine shrub forests.Carbon storageincreased at an average annual rate of 0.8 Tg carbon over the study period.Carbon was mainly stored in young and middle-aged forests,which together accounted for 70–88%of the total forest carbon storage in different inventory periods.Broad-leaved forest was the main contributor to forest carbon sequestration.From 1998 to 2008,during implementation of national afforestation and reforestation programs,the carbon storage of planted forest increased sharply from 3.9 to 37.9 Tg.Our results show that with the growth of young planted forest,Henan Province forests realized large gains in carbon sequestration over a 60-year period that was characterized in part by a nation-wide tree planting program.
