High Carbon Stocks Research Articles

Carbon sequestration potential under tea based cropping system

Aim: To study the carbon sequestration process in tea based plantation system and to identify more potential carbon sequestration system amongst the tea based cropping system by studying carbon storage in different components of the plantation system. Methodology: The experiment was carried out in the Experimental Garden for Plantation Crops of Assam Agricultural University, Jorhat, Assam. Treatments were made in an on going, long term shade experiment on mature tea bushes, adapted to three levels of shades viz. tea as monoculture; Tea based cropping system with Areca palm and Tea with Albizzia odoratissima. Results: Among different tea plantations, tea-albizzia recorded superior performance, followed by tea-areca palm plantation in respect to biomass accumulation and carbon sequestration. Similarly, higher carbon stock was found in tea-albizzia plantations along with other physiological and edaphic parameters related to carbon sequestration attributed to an increase in carbon stock. Interpretation: Tea-albizzia plantation system has maximum potential for carbon offsetting from the atmosphere as well as carbon storage both above and below ground in the plantation ecosystem which might be helpful for future carbon management and economy as a whole.

Palm oil cultivation on peatlands and its impact on increasing Indonesia’s greenhouse gas emissions

Peatlands store very high carbon stocks. Damage to peatland ecosystem will have an impact on increasing greenhouse gas (GHG) emissions and increasing the risk of climate change. Peatlands governance is important to prioritize the principle of conservation over cultivation. The aim of this study is to analyze and elaborate the conflict of interests between the Roundtable on Sustainable Palm Oil (RSPO) and Indonesia Sustainable Palm Oil (ISPO). The methods are normative-legal research to diagnose the difference in the application of law between RSPO and ISPO. The findings show that RSPO as one of the world sustainable palm oil management standards has banned palm oil planting on peatlands based on its 2018 Principles and Criteria for the Production of Sustainable Palm Oil (P&C). Unfortunately, the palm management instrument in Indonesia which is ISPO still provides space for palm oil cultivation on peatlands. Relation of this study with climate change issues is that ISPO ideas are counterproductive to Indonesia’s commitment in reducing GHG emissions by 29% in 2030. Indonesia needs to evaluate peatland governance policies to prioritize conservation rather than cultivation.

Characteristics and composition of vegetation carbon storage in natural grassland in Ning-xia, China.

We measured the total vegetation carbon stock in the widely distributed natural grassland of meadow steppe (MS), warm steppe (WS), steppe desert (SD) and desert steppe (DS)] in Ningxia, using survey and sampling method. The results showed that the average carbon rate of vege-tation, shrubs and root were 0.40, and that of litter was 0.39. The total vegetation carbon density of meadow steppe, warm steppe, steppe desert and desert steppe (including aboveground vegetation, litter and roots) was 470.26, 192.23, 117.17 and 83.36 g·m-2, while that of aboveground vegetation was 87.35, 68.50, 59.32 and 40.05 g·m-2, and that of roots was 344.29, 108.83, 50.65 and 30.29 g·m-2, litter carbon storage was 38.62,14.91, 7.19 and 13.03 g·m-2, respectively. The order of those grassland types ranked as MS＞WS＞SD＞DS. Root carbon storage contributed the most to carbon storage in meadow steppe and warm steppe, and aboveground vegetation carbon storage contributed the most to steppe desert and desert steppe. Root carbon storage showed a decreasing trend with the increases of soil depth within 40 cm soil layer. For the spatial distribution of total carbon stock, the southern part of meadow steppe and temperate steppe had obviously higher carbon stock than the middle and north part of desert steppe and steppe desert.

Carbon balance in an interplanting Pinus massoniana stand in subtropical eroded red soil region, China.

We measured the annual net biomass growth, carbon content of each component and soil heterotrophic respiration in four low-efficiency interplanting patterns, i.e., Pinus massoniana stands interplanting Myrica rubra, Sapindus mukurossi, Camellia oleifera and Gardenia jasminoides in Changting County, Fujian Province, with the aim to analyze the effects of interplanting patterns on carbon storage pattern and carbon balance of low-efficiency P. massoniana stand. The ranges of carbon content in different organs of M. rubra, S. mukurossi, C. oleifera, G. jasminoides and P. massoniana were 41.1%-50.1%, 42.2%-50.6%, 45.1%-48.9%, 44.7%-49.6% and 46.1%-51.9%, respectively. Carbon content of the same organ significantly differed among tree species. The pattern of P. massoniana interplanting M. rubra and S. mukurossi had the highest carbon stock and annual net carbon increase reserves, with values of 67.62-68.42 t·hm-2 and 9.21-9.45 t·hm-2·a-1, respectively. Followed by the lower pattern of C. oleifera, G. jasminoides, with values of 31.96-36.24 t·hm-2 and 4.09-4.16 t·hm-2·a-1, respectively. The P. massoniana pure forest was the lowest, with values of 17.01 t·hm-2 and 2.00 t·hm-2·a-1, respectively. Annual flux of soil heterotrophic respiration was following the order of P. massoniana interplanting M. rubra pattern (7.41 t·hm-2·a-1) > P. massoniana interplanting C. oleifera pattern (5.89 t·hm-2·a-1)> P. massoniana interplanting S. mukurossi pattern (5.86 t·hm-2·a-1) > P. massoniana interplanting G. jasminoides pattern (4.95 t·hm-2·a-1) > P. massoniana pure forest (2.45 t·hm-2·a-1). Annual net ecosystem carbon balance of P. massoniana interplanting M. rubra and S. mukurossi patterns were 2.04 and 3.27 t C·hm-2·a-1, showing a "carbon sink" pattern. The net carbon balance in the patterns of P. massoniana interplanting C. oleifera and G. jasminoides along with P. massoniana pure forest were -1.80, -0.80 and -0.45 t C·hm-2·a-1, which expressed a "carbon source" pattern. In the short-term, interplanting with M. rubra or S. mukurossi could improve the carbon income of the low-efficiency P. massoniana stand ecosystem.

Soil Water Characteristics of Gleysols in the Bamenda (Cameroon) Wetlands and Implications for Agricultural Management Strategies

Water budgeting in agriculture requires local soil moisture information as crops depend mainly on moisture available at root level. The present paper aims to evaluate the soil moisture characteristics of Gleysols in the Bamenda (Cameroon) wetlands and to evaluate the link between soil moisture content and selected soil characteristics affecting crop production. The work was conducted in the field and laboratory, and data were analyzed by simple descriptive statistics. The main results showed that the soils had a silty clayey to clayey texture, high bulk density, high soil organic carbon content, and high soil organic carbon stocks. The big difference between moisture contents at wilting point and at field capacity testified to very high plant-available water content. Also, the soils displayed very high contents of readily available water and water storage contents. The soil moisture characteristics give sigmoid curves and enabled noting that the Gleysols attain their full water saturation at a range of 57.68 to 91.70% of dry soil. Clay and SOC contents show a significant positive correlation with most of the soil moisture characteristics, indicating that these soil properties are important for soil water retention. Particle density, coarse fragments, and sand contents correlated negatively with the soil moisture characteristics, suggesting that they decrease soil water-holding capacity. The principal component analysis (PCA) enabled reducing 17 variables described to only three principal components (PCs) explaining 73.73% of the total variance; the first PC alone expressed 45.12% of the total variance, associating clay, SOC, and six soil moisture characteristics, thus portraying a deep correlation between these eight variables. Construction of contoured ditches, deep tillage, and raised ridges management techniques during the rainy season while channeling water from nearby water bodies into the farmland, opportunity cropping, and usage of water cans and other irrigation strategies are used during the dry season to combat water constraints.

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.

Organic carbon dynamics in interrows of Vitis vinifera with different years of soil use and management

This study aimed to evaluate the effects of soil use and management on organic carbon stocks in the interrows of Vitis vinifera with different years of cultivation. A vineyard located in Rio Grande do Sul state, with 4, 9 and 16 years of management, was evaluated. Soil samples from different layers, 0.0-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40, 0.40-0.50 and 0.50-0.60 m, were collected on wheel tracks, between wheel tracks and under the planting rows. As a reference, samples were collected in native grassland of the region. Organic matter content, bulk density and soil porosity were evaluated. Carbon stock was determined according to the correction of the sampled thickness. The results were subjected to analysis of variance and means were compared by Tukey test at 0.05 probability level. Soil management caused alterations in its structure and organic matter content, observed mainly in the first 30 cm, regardless of the area studied. Highest values of bulk density were observed on the tractor wheel tracks, followed by under the planting row and between wheel tracks. Alteration in soil cover for vineyard planting led to a reduction in the carbon stock, compared to the native grassland. The area under management for 4 years showed higher carbon stocks between the wheel tracks, whereas the areas under 9 and 16 years of management showed highest values in the wheel tracks.

Above ground biomass carbon assessment using field, satellite data and model based integrated approach to predict the carbon sequestration potential of major land use sector of Arunachal Himalaya, India

The land-use sector needs special importance owing to its ability to store and emit carbon back to the atmosphere. Land-use changes and their correlations could elucidate conditions that put forests at risk of conversion to other land uses. The impact of rapid forest cover change tends to reduce the percentage of forest cover, thereby reducing the potential for carbon storage in woody biomass. The study was conducted in the state of Arunachal Pradesh to estimate the above-ground biomass, carbon pool and sequestration potential of major land-use sectors. The above-ground biomass of selected land-uses viz. dense forest, moderately dense forest, open forest, plantations, Jhum >5 years, Jhum <5 years and current jhum are 332.28 t ha−1, 246.63 t ha−1, 145.36 t ha−1, 179.31 t ha−1, 149.63 t ha−1, 55.40 t ha−1, 16.84 t ha−1 respectively. The developed model is derived from Soil Adjusted Vegetation Index (SAVI) and Atmospherically Resistant Vegetation Index (ARVI) for prediction of above-ground biomass (AGB) (R 2 = 0.85, p < 0.05). The resultant R 2 value of 85% predicts that 79% of accuracy could be assumed by the model. The RMSE of the model was 53.21 t ha−1, having no multicollinearity problem keeping tolerance (0.49) and VIF (2.80). The spatial AGB density map was predicted using a step-wise linear regression model which used AGB, SAVI and ARVI of the corresponding sample plot location. The implication of the land-use change revealed that about 84% carbon will be lost from dense forest once it is converted to Jhum (Jhum is the alternate name of Shifting cultivation in India) followed by Jhum <5 years (65%). It is pertinent to mention here that, the present analysis will help the policymakers in visualizing a proper developmental goal to regulate land-use changes for achieving the higher carbon stock and maintaining balance in the global climate scenario.

Monitoring Area and Health Changes of Mangrove Forest Using Multitemporal Landsat Imagery in Taman Hutan Raya Ngurah Rai, Bali Province

The mangrove forest is a very productive ecosystem, both economically and ecologically. Mangrove forests can protect settlements, buildings, and agriculture on the coast from strong winds or seawater intrusion, support the livelihoods of coastal communities and store high carbon stocks. Regardless of its role, the Taman Hutan Raya Ngurah Rai Mangrove Forest continues to be threatened by human activities. This study aims to monitor changes in the area, health, and water quality of mangrove forests. The data used are Landsat 7 ETM + imagery and Landsat 8 OLI in 2010-2020. We used NDVI vegetation indices to analyze mangrove health and Total Suspended Solid (TSS) to investigate the water quality of the mangrove forest. Temporal water quality parameters are obtained by using the TSS algorithm on Landsat imagery. The results showed variations in mangrove forest area changes, NDVI values, and water quality. In 2010 - 2015 Mangrove Forest Area increase by 117.72 ha but decrease in 2015-2020 by 96.21 ha. Mangrove health was also improved in 2010-2015 but the decline in 2015-2020. Meanwhile, mangrove forest water quality seen from the TSS distribution tends to grow from 2010 to 2020.

Characteristics and Carbon Sequestration Potential of Lateritic Forest Soils under Different Management Systems in West Bengal, India

Lateritic soils of West Bengal supporting Sal (Shorea robusta Gaertn. f.) under different management systems viz., by Forest Protection Committee (FPC), Forest Department and without any management were studied to characterize the soils and their carbon sequestration potential. Soils were medium to high in bulk density, low in pH, low to medium in organic carbon, low in clay content and cation exchange capacity. The study reveals that the soils managed FPC contain higher carbon stock in comparison to that of plantation stand (managed by Forest Department) and degraded forest soils (all are in a contiguous area). The FPC management improves the soil health with comparatively high organic matter content which in turn lowers the bulk density, making the soil porous with higher moisture and nutrient holding capacity which ultimately enhances the carbon sequestration of soil. These results will be useful to the planners, forest managers and administrators.

Estimation of carbon stocks from tree stands vegetation in Universitas Indonesia’s urban forest, Depok

Urban forest has a function as CO2 emissions absorbers derived from human activities around the city. Universitas Indonesia (UI) Urban’s Forest is one of the Urban Forest which has potential carbon stocks. A study has been conducted to analyze the potential of carbon stocks and tree stands that have the highest carbon stock in UI Urban’s Forest. Tree stands are woody vegetation with a diameter ≥ 20 cm. The research was conducted in October-November 2017 in UI Urban’s Forest area covering three locations, west Wallace, east Wallace, and natural vegetation. Method of collecting data of vegetation was done by nondestructive sampling by measuring Breast Height Diameter (DBH). Data processing uses allometric equations with the specific wood density of each tree species. Results showed that the potential of carbon stocks in UI Urban’s Forest is 468.02 ton/ha with west Wallace, east Wallace, and natural vegetation are 138.62 ton/ha, 162.75 ton/ha, and 182.64 ton/ha. Overall, potential carbon stocks in UI Urban’s Forest is 11752.48 ton/ha. Species of trees with the highest potential of carbon stocks is Delonix regia.

Analysis of Carbon Stock Distribution of Mangrove Forests in The Coastal City of Benoa, Bali with Combination Vegetation Index, and Statistics Approach

Mangrove forests have an essential role in reducing the impact of global warming in the urban and surrounding areas; one of them is through carbon sequestration. Carbon sequestration is needed to reduce greenhouse gases in the atmosphere. The capacity of carbon sequestration or carbon stocks of mangrove forests can be seen from its biomass value. This study aims to produce a regression model between the vegetation index and the carbon stock of mangrove forests so that carbon stocks can be seen easily from satellite imagery and analyze their distribution in the Coastal City of Benoa, Bali. The distribution of carbon stocks was analyzed using a combination of vegetation index approach and statistical regression analysis. The vegetation index used is ARVI and EVI obtained from processing Sentinel 2-A satellite imagery in 2020. Mangrove forest biomass values are derived from allometric equations. After getting the amount of biomass, a regression model was built with a vegetation index. The model with the highest level of accuracy is used to process the image of the whole mangrove forest. This study's results indicate that the regression model formed by the ARVI has the highest level of accuracy compared to the EVI, with the best regression model for predicting carbon stock values is the exponential regression model with an ARVI vegetation index variable. High carbon stock values are distributed in almost all regions of Benoa Bay.

Exploring relationships between abundance of non-timber forest product species and tropical forest plant diversity

Despite the importance of non-timber forest products (NTFPs) for local livelihoods in tropical countries and the increasing attention for biodiversity-ecosystem services relationships, it remained unclear how the ecosystem service of NTFP provisioning is related to plant diversity. Although it is generally assumed that plant diversity is positively related to ecosystem services, this had not been assessed for NTFP provisioning. We applied bivariate and multiple regression models to explore the relationships between the abundance of 58 commercially relevant NTFP species and woody plant diversity across 287 plots of tropical forests in Northern Suriname. We found that NTFP abundance showed both positive and negative relationships to plant diversity indicators. In contrast to expectations, NTFP abundance was negatively related to woody species richness. In addition, across the plots disproportionately few (2–6) NTFP species determined >50% of NTFP abundance. The occurrence and the identity of these ‘NTFP oligarchs’ was associated to specific floristic compositions. Overall, more than half, i.e. 55.9%, of the observed variation in NTFP abundance could be explained by a combination of taxonomic and structural plant diversity indicators. Our case study findings are relevant for conservation policies in general. In most countries NTFPs are not on the agenda of governments and current tropical conservation policies often focus on forests with high species richness and/or carbon stocks. Our findings indicate that current policies may not cover valuable forests in terms of high NTFP abundance. To support sustainable NTFP provisioning, additional conservation efforts would need to include those vegetation types with high NTFP abundance.

Characteristics of mangrove ecosystems in Weda Bay: Environment, Vegetation, and Aboveground Carbon Stocks

Weda Bay is one of the largest mangrove habitat in North Maluku and one of mega-biodiversity spots in Indonesia. However, data and information of mangrove vegetation and its ecosystem services particularly carbon stocks were limited. Mangroves were mapped using GIS-remote sensing and vegetation were sampled using transects in five sites of mangroves across Weda Bay. Tansects were extended from seaward to landward to cover all vegetation variation and hydrodynamic conditions. Environmental data (water and substrate): temperature, pH, Dissolved Oxygen (DO), particle size of sediment, and nutrient (phosphate and nitrate) were collected. The objective is to identify characteristics of mangrove landscape and vegetation, it is environment, and it ecosystem services in term of aboveground carbon stocks. The study showed that the characteristics of landscape and vegetation of mangrove varied among hydrodynamic conditions. The bay is important habitat for 8.5% (17 species) of mangrove species in Indonesia. Rhizophora apiculata and Bruguiera gymnorrhiza were the most dominant mangroves. The environmental conditions of Weda Bay particularly northern part of the bay were suitable for mangrove growth. Substrate of mangrove did not vary significantly with distance from the seaward which was mainly dominated by mud and clay (3.9 - 63 μm). Mean water temperature in the mangrove area was 29.3°C, salinity 34.1 psu, mean water suspension was 46 mg l−1, mean dissolved oxygen was 3.2 mg l−1, and water current was 10 m s−1. Aboveground carbon stock was considerable (752 ± 17.6 Mg C ha−1). Change in aboveground carbon stocks over the distance from the seaward edge to landward edge was not significantly different. In contrast, aboveground carbon stocks varied among hydrodynamic conditions: estuarine, delta, and riverine mangroves. Delta mangrove contained the highest carbon stock (993 ± 27.7 Mg C ha−1), followed by estuarine mangroves (645 ± 12.2 Mg C ha−1) and riverine mangroves (244 ± 8.6 Mg C ha−1). However, this ecosystem faced some threats such as mangrove extraction and plastic pollution. Better mangrove management e.g. reducing mangrove extraction and pollution are required to protect the functions and ecosystem services of mangroves. In addition, conserving mangrove forests will allow the government to achieve blue economy goals and to mitigate climate change through carbon sequestration.

Urban Tree Species Identification and Carbon Stock Mapping for Urban Green Planning and Management

Recently, the severe intensification of atmospheric carbon has highlighted the importance of urban tree contributions in atmospheric carbon mitigations in city areas considering sustainable urban green planning and management systems. Explicit and timely information on urban trees and their roles in the atmospheric Carbon Stock (CS) are essential for policymakers to take immediate actions to ameliorate the effects of deforestation and their worsening outcomes. In this study, a detailed methodology for urban tree CS calibration and mapping was developed for the small urban area of Sassuolo in Italy. For dominant tree species classification, a remote sensing approach was applied, utilizing a high-resolution WV3 image. Five dominant species were identified and classified by applying the Object-Based Image Analysis (OBIA) approach with an overall accuracy of 78%. The CS calibration was done by utilizing an allometric model based on the field data of tree dendrometry—i.e., Height (H) and Diameter at Breast Height (DBH). For geometric measurements, a terrestrial photogrammetric approach known as Structure-from-Motion (SfM) was utilized. Out of 22 randomly selected sample plots of 100 square meters (10 m × 10 m) each, seven plots were utilized to validate the results of the CS calibration and mapping. In this study, CS mapping was done in an efficient and convenient way, highlighting higher CS and lower CS zones while recognizing the dominant tree species contributions. This study will help city planners initiate CS mapping and predict the possible CS for larger urban regions to ensure a sustainable urban green management system.

Expected carbon emissions from a rubber plantation in Central Africa

The development of agriculture on degraded lands is increasingly seen as a strategy to boost food availability and economic productivity while minimizing environmental degradation and loss of forests. To understand the effects of agricultural production on forest carbon, we quantify the aboveground carbon (AGC) of a degraded forest in northeast Gabon (the Olam Rubber Gabon concession) designated for development to a rubber plantation. Combining field measurements from 19 1-ha tree plots and aerial LiDAR, we estimate forest AGC stocks and emissions under four development scenarios: no development, 30-year rubber rotation, extended rubber rotation (replanting of plantation in stages at 30 and 40 years), and 30-year oil palm rotation. On average, the degraded forest in the study area stored 123.8 Mg C ha−1, a mean AGC lower than the Gabon average (141.6 Mg C ha−1) but substantially higher than the 75 Mg C ha−1 threshold recommended by the High Carbon Stock protocol. Converting secondary forest to plantation might incur high environmental opportunity costs from lost carbon sequestration through forest succession and growth. In this study, we estimate that a rubber plantation can sequester similar amounts of AGC as secondary forest by the end of a 30-year rotation; however, the time-averaged AGC of regenerating secondary forests under no development would be 184% higher than a mature rubber plantation with a 30-year rotation, 169% higher than an extended rubber rotation, and 512% higher than a 30-year oil palm rotation. When degraded forest is developed for agriculture, measures should be taken to avoid emissions and prolong carbon retention. We specifically estimate carbon retention from extended harvest rotations and conserving high carbon value areas as set-asides and highlight recommendations from the literature such as minimizing soil disturbance and creating rubber timber products (e.g. furniture). To minimize carbon emissions from agriculture, crop plantation area should be minimized at national and regional scales in highly forested countries, and new plantations should be coupled explicitly with effective forest restoration actions, through suitable regulation and planning, to mitigate or compensate for their climate and biodiversity impacts.

Analysis of Carbon Stock in Seagrass Enhalus acoroides in Benan Island, Lingga Regency

This research was conducted in Benan Island, Katang Bidara Subdistrict, Lingga Regency, Riau Islands Province in February 2020. This study aimed to determine the value of density, biomass and carbon stock in seagrass E. acoroides. The method used in this study is a survey method, where the data collected is considered to represent the waters of Benan Island. The density of seagrass E.acoroides in the study location ranged from 22.67 to 31.22 individuals/m2. E.acoroides seagrass is divided into two parts, namely the top of the substrate or above ground biomass (Agb) and the bottom of the substrate or bellows biomass (Bgb). The average value of biomass seagrass ranged from 1,113.27-4,412.24 g/m2. The highest carbon stock was in the rhizoma section at Station I (2,134.46 gC/m2) and the lowest was in the leaf section at Station II (363.08 gC/ m2). Biomass and carbon stock in the Bgb section is higher than the Agb portion

Biomass carbon stock and water yield of teak catchments

Rehabilitation of degraded forests and lands using the vegetative method can be used to improve the environmental condition and sequestered carbon dioxide from the atmosphere. However, improper plant selection may create water shortage in dry season. Based on the background, the research was conducted in order to study the relationships of biomass carbon stock, evapotranspiration, and water yield of five catchments covered by various teak areas. The study was conducted in Blora Regency, Central Java, Indonesia. The percentage of mature teak plantation areas in the catchments were 82, 82, 73, 70, and 53%. The biomass carbon stock in each catchment was estimated using previously published data. The water yield of the catchments was calculated from the conversion of the stream water level at the outlet of each catchment. The evapotranspiration was calculated based on a simple water budget of a catchment. The results showed that the highest carbon stock was 64 t/ha and found in Modang Catchment (82% mature teak). The lowest carbon stock was 22 t/ha and measured in Gagakan Catchment (53% mature teak). In parallel with the amount of carbon stock, the highest evapotranspiration was measured in Modang Catchment, and the lowest was found in Gagakan Catchment. The observation of water yield during 2008- 2019 showed that the higher the carbon stock in the catchments, the lower the water yield. Synergy in reducing CO 2 emission and sustaining water flows can be achieved by considering land suitability for plant growth and applying water conservation in forests and lands rehabilitation.

High soil organic carbon stocks under impervious surfaces contributed by urban deep cultural layers

Rapid urbanization has created large areas of impervious surface areas globally. As there is little carbon input by plants into soils under impervious surfaces, soil organic carbon (SOC) stocks under impervious surfaces generally have been overlooked in the urban carbon budgets. Here we investigate SOC stocks under impervious concrete surfaces and vegetative surfaces across soil profiles to a depth of 5 m in urban housing complexes in Seoul, Republic of Korea. In the top 1 m of the profile, SOC stocks under vegetative surfaces were three times greater than those under impervious surfaces. However, we discovered that unexpectedly high SOC stocks appeared in deeper soil layers under both surface types, which led to comparable SOC stocks at a depth of 5 m beneath the impervious surface (16.9 ± 1.9 kgC m−2) and at the vegetative surface (22.3 ± 2.2 kgC m−2). Consequently, the ratio of SOC stocks at depths of 1 m to 5 m were 16% in impervious surfaces and 34% in vegetative surfaces, suggesting conventional soil sampling at 1 m depth could miss large SOC. Stable isotope data (δ13C and δ15N) combined with historical aerial photographs revealed that cropland that existed until the 1970s formed the high SOC cultural layer in deeper soils. Our results highlight that deep soils under impervious surfaces could be overlooked carbon hotspots in urban ecosystems. We believe this finding could help city planners and policy makers to assess regional carbon budgets and to reduce carbon footprint by recycling the deep SOC excavated from various construction projects towards sustainable urban development.

Linking Forest Vegetation and Soil Carbon Stock in Northwestern Russia

Research Highlights: It was found that both tree species and ground vegetation affected soil carbon stock in boreal forests. Carbon stocks in the mineral layers were related negatively to the C/N ratio in the organic horizon and pine proportion in the growing stock volume, and positively to the share of herbaceous plants and the proportion of spruce. Background and Objectives: Existing research showed the effects of tree species on soil carbon stocks in organic horizons, but these effects were less clear in mineral horizons. Little is known about the effects of ground vegetation on soil carbon stock. This study aims to identify associations between the forest vegetation composition and soil carbon stocks in northwestern Russia. Materials and Methods: Research data from 109 pine, spruce and birch forests of different Cajander’s and Sukachev’s types with different functional compositions of ground vegetation at autonomous positions are discussed in this paper. The V-test was used to assess the impact of vegetation on soil carbon stocks. Results: Variations in Carbon stocks in the mineral layers were associated with the soil types and vegetation composition. Carbic Albic Podzols accumulated the least amount of carbon in the mineral profile. Carbon stock in the mineral layers in pine forests was considerably lower than in spruce and birch forests. Spruce forests with the highest share of herbaceous plants were characterised by the highest carbon stocks in the mineral layers, while pine forests with dwarf shrubs and green mosses accumulated more carbon in the organic layers, but carbon stocks in the mineral layers here were the lowest. Conclusions: Differences in soil carbon stocks between and within northern and middle taiga in northwestern Russia were associated not only with soil types but also with the proportions of forest types dominated by different tree species and ground vegetation functional groups.