Tree Biomass Carbon Stocks Research Articles

Tree diversity and carbon stock in a subtropical broadleaved forest are greater than a subtropical pine forest occurring in similar elevation of Meghalaya, north-eastern India

Studies on relationship between tree diversity and carbon stock has not been consistent. The present study was undertaken to quantify and compare the plant diversity and carbon stock in a subtropical broadleaved and a subtropical pine forest of Meghalaya, northeast India. Biomass-based carbon estimation was undertaken in two subtropical broadleaved forest stands viz., Mawnai (MBF) and Nongkrem (NBF) and adjacent Pinus kesiya dominated forest stands (MPF and NPF), occurring in similar topography, climatic conditions and soil type. The aboveground and belowground tree biomass was estimated using existing allometric models. Carbon was estimated as 47.4% of the total biomass. Tree species richness was greater in the subtropical broadleaved forest stands at MBF and NBF (117 and 21 species) than in the adjacent pine forests, MPF and NPF (15 and 16 species). The density values were 1294 and 1127 individuals ha−1 in the broadleaved forest stands, and 894 and 1032 individuals ha−1 in the adjacent pine forest stands, respectively. The broadleaved forest stands, MBF and NBF had tree biomass carbon stock of 140.4 Mg C ha−1 and 133.6 Mg C ha−1, respectively, which were significantly greater (F = 26.6; P 66 cm) to the total biomass carbon was greatest in MBF, while the lower diameter trees belonging to 5–15 cm and 16–25 cm were the major contributors to the total biomass carbon in the pine dominated stands.

Karbon Tersimpan Pada Tegakan Benih Teridentifikasi �Pambelum� di Kota Palangka Raya

This study was carried out on a single observation plot measuring 20 m x 100 m in the Tegakan Benih Tersertifikasi (TBT) �Pambelum in Palangka Raya City to determine of carbon stocks in five carbon sources. The method used in this study is destructive methods to determine the amount of carbon stocks in litter, and understorey, non-destructive to measure carbon stocks in tree biomass, woody necromass, and roots. Total carbon stored in TBT Pambelum is 196.695 tons / ha, where tree biomass contributes carbon at 62.67% (123.264 tons / ha); rooting contributes carbon at 23.19% (45.608 tons/ha); carbon deposits on land at 12.34% (24,281 tons/ha); litter of 1.34% (2.736 tons/ha); understorey of 0.40% (0.785 tons/ha); and woody necromass of 0.01% (0.020 tons/ha).

A comparative assessment of tree diversity, biomass and biomass carbon stock between a protected area and a sacred forest of Western Odisha, India

ABSTRACTFrom September 2015 to January 2016, we studied the tree species diversity, biomass and biomass carbon stock of two different forests in Western Odisha: a wildlife sanctuary and a sacred forest. The wildlife sanctuary is entirely managed by the Forest Department, whereas the sacred forest is jointly managed by the local community and the Forest Department. Our results showed that the sacred forest had a greater species richness, density and diversity compared to the wildlife sanctuary. The density in different diameter classes showed that the sacred forest is regenerating with a good regeneration potential, but the wildlife sanctuary had a poor regeneration potential with lower numbers of saplings than adults. However, the biomass and carbon content of the wildlife sanctuary were higher than in the sacred forest. This may be due to the presence of a higher proportion of old trees in the wildlife sanctuary compared to the sacred forest. Biomass values can be used to emphasize the role of management in maintaining the carbon stock in forest ecosystems. Our results can be helpful in framing conservation strategies and action plans for forest patches in India and globally.

Carbon stock potential of scattered trees on farmland along an altitudinal gradient in Tigray, Northern Ethiopia

IntroductionTrees on agricultural landscape play a vital role in ecosystem services including food security that supports human livelihood. They can further offer synergy between adaptation and mitigation in addressing climate change impact. Understanding aboveground tree biomass and soil organic carbon stocks along the altitudinal gradient provide opportunities for better management of the carbon pools. However, little is known on how altitudinal gradient influences on carbon stock of woody biomass and soil of scattered trees on farmland, particularly in a dry area.MethodsThe study area were stratified in to five class (500–1000, 1000–1500, 1500–2000, 2000–2500, and 2500–3000 m a.s.l). Quadrats (100 m × 50 m) were randomly selected from each of stratified altitudinal gradients. At every sampling point, one composite soil sample was taken at 60 cm soil depth for soil organic carbon analysis. For the purpose of woody biomass estimation, allometric equations developed for a similar area were used. Finally, aboveground biomass carbon (AGC), belowground biomass carbon (BGC), soil organic carbon (SOC), and total carbon stock (TC) status were estimated and variables were compared using one-way analysis of variance (ANOVA).ResultsThe result indicated that AGC, BGC, SOC, and TC varied significantly (p < 0.05) along with an altitudinal gradient. The upper altitude (2500–3000 m a.s.l) AGC, BGC, SOC, and TC stock was estimated as 17.97 Mg C ha−1, 6.53 Mg C ha−1, 23.09 Mg C ha−1, 47.59 Mg C ha−1 respectively, and significantly higher than the other altitudinal gradient.ConclusionsWe conclude that scattered trees on farmland hold a high potential of carbon storage which may greatly contribute to the climate resilience green economy strategy and their conservation should be promoted.

Predicting the Potential Impact of Climate Change on Carbon Stock in Semi-Arid West African Savannas

West African savannas are experiencing rapid land cover change that threatens biodiversity and affects ecosystem productivity through the loss of habitat and biomass, and carbon emissions into the atmosphere exacerbating climate change effects. Therefore, reducing carbon emissions from deforestation and forest degradation in these areas is critical in the efforts to combat climate change. For such restorative actions to be successful, they must be grounded on a clear knowledge of the extent to which climate change affects carbon storage in soil and biomass according to different land uses. The current study was undertaken in semi-arid savannas in Dano, southwestern Burkina Faso, with the threefold objective of: (i) identifying the main land use and land cover categories (LULCc) in a watershed; (ii) assessing the carbon stocks (biomass and soil) in the selected LULCc; and (iii) predicting the effects of climate change on the spatial distribution of the carbon stock. Dendrometric data (Diameter at Breast Height (DBH) and height) of woody species and soil samples were measured and collected, respectively, in 43 plots, each measuring 50 × 20 m. Tree biomass carbon stocks were calculated using allometric equations while soil organic carbon (SOC) stocks were measured at two depths (0–20 and 20–50 cm). To assess the impact of climate change on carbon stocks, geographical location records of carbon stocks, remote sensing spectral bands, topographic data, and bioclimatic variables were used. For projections of future climatic conditions, predictions from two climate models (MPI-ESM-MR and HadGEM2-ES) of CMIP5 were used under Representative Concentration Pathway (RCP) 8.5 and modeling was performed using random forest regression. Results showed that the most dominant LULCc are cropland (37.2%) and tree savannas (35.51%). Carbon stocks in woody biomass were higher in woodland (10.2 ± 6.4 Mg·ha−1) and gallery forests (7.75 ± 4.05 Mg·ha−1), while the lowest values were recorded in shrub savannas (0.9 ± 1.2 Mg·ha−1) and tree savannas (1.6 ± 0.6 Mg·ha−1). The highest SOC stock was recorded in gallery forests (30.2 ± 15.6 Mg·ha−1) and the lowest in the cropland (14.9 ± 5.7 Mg·ha−1). Based on modeling results, it appears clearly that climate change might have an impact on carbon stock at horizon 2070 by decreasing the storage capacity of various land units which are currently suitable. The decrease was more important under HadGEM2-ES (90.0%) and less under MPI-ESM-MR (89.4%). These findings call for smart and sustainable land use management practices in the study area to unlock the potential of these landscapes to sequestering carbon.

Tree biomass quantity, carbon stock and canopy correlates in mangrove forest and land uses that replaced mangroves in Honda Bay, Philippines

Mangrove forests are important carbon (C) sinks in the tropics that are threatened by tropical deforestation and land use conversion, especially in Southeast Asia. Yet quantitative estimates are limited on the biomass (i.e. aboveground, belowground, downed woody debris) and tree C stocks of secondary, and converted mangroves in Southeast Asia. While some related studies have been conducted in Latin America and Central Asia, there is a need to assess different geographical areas and regional ecosystems, as well as to consider the impacts of mangrove conversion to other land use types. In this study, tree biomass and tree C stocks of secondary mangrove forests and four types of land uses that replaced intact mangrove forests (abandoned aquaculture pond, abandoned salt pond, coconut plantation, and cleared mangroves) in the coast of Honda Bay, Philippines were quantified. Their relationships with selected canopy variables were evaluated. Our measurements revealed that mean tree biomass (±SE) of intact mangroves ranged from 22.4 ± 9.0 to 178.1 ± 32.0 Mg ha−1, which store 10–80 MgC ha−1 (mean: 47.9 ± 5.1 MgC ha−1). Leaf Area Index correlated with mangrove tree biomass C stock (r=0.67, p<0.05). In contrast, the biomass and tree C stock of the replacement land uses ranged from 0.1 ± 0 Mg ha−1 and 0.12 ± 0.1 MgC ha−1, respectively, in the abandoned aquaculture ponds to 12.0 ± 4.0 Mg ha−1 and 5.7 ± 1.5 MgC ha−1 in coconut plantation. Our results indicate the importance of mangroves in storing considerable amounts of C in tree biomass in the coastal area, and the C losses (46.5 Mg C ha−1 or 97% decline) in tree C stocks from conversion of mangroves to other land uses.

Plantations of Pinus and Eucalyptus replacing degraded mountain miombo woodlands in Mozambique significantly increase carbon sequestration

Total ecosystem carbon (C) stocks in tree biomass (aboveground and belowground), litter layer and soil (0–50 cm depth) were quantified in mountain miombo woodland and in 34-year-old first-rotation plantations of Pinus taeda and Eucalyptus grandis. The study was performed at three sites (Penhalonga, Rotanda and Inhamacari) in the western highlands of Manica province in Mozambique, bordering Zimbabwe. One 30 m × 30 m sampling plot was established for each forest type per site. Pre-tested allometric equations were used to determine total C stocks within aboveground tree biomass of each forest type and data from the literature on the relationship between aboveground and belowground biomass were used to estimate C stocks in belowground woody biomass (i.e. coarse roots). Measured soil and litter layer C data were taken from a previous study. Carbon stocks in mountain miombo woodland were used as a baseline to estimate C sequestration at the ecosystem scale, i.e. net ecosystem production (NEP) in the plantations, considering 34 years as stand age of the planted forests.Total ecosystem C stocks in miombo woodlands (∼116 Mg ha−1) were significantly lower than in stands of P. taeda (363 Mg ha−1) and E. grandis (∼407 Mg ha−1). Carbon sequestration rate at ecosystem scale (NEP) was 7.24 Mg ha−1 yr−1 in P. taeda stands and 8.54 Mg ha−1 yr−1 in E. grandis stands. NEP was dominated by the increment in biomass (∼80%). This was also reflected in higher ratio between biomass C and soil organic C stocks in the plantations compared with miombo forest. The plantation species showed similar performance with respect to total C stocks and NEP. It was concluded that plantations of P. taeda or E. grandis have significant potential to increase C stocks and C sequestration rate in both soil and tree biomass on replacing degraded mountain miombo woodlands in the western highlands of Manica province.

The imprint of logging on tropical forest carbon stocks: A Bornean case-study

In tropical forests, selective logging generates a significant reduction of above-ground carbon stocks, due to direct removal of a few large merchantable individuals, and the death of smaller injured or smashed trees following harvesting. Several studies have shown a strong correlation between logging intensity and a reduction of biodiversity, wood production, and biomass stocks. However, little is known about the long-term effects of logging on the main forest carbon (C) stocks in above and below-ground tree biomass, deadwood, litter, and soil. In this study we quantified C stocks in 28 0.25-ha plots located in a mixed Dipterocarp forest, Borneo, Indonesia, logged 16 years ago at different intensities ranging from 0 to 57% of initial biomass removed. We investigated the effect of logging intensity, topography, and soil variables on each C stock using linear mixed models. Sixteen years after logging, total C stocks ranged from 218 to 554 Mg C ha−1 with an average of 314 ± 21 Mg C ha−1, of which more than 75% were found in live trees. Logging intensity was found to be the main factor explaining the variability in carbon stored in above- and below- ground biomass of tree DBH >20 cm and deadwood. Simultaneously, the proportion of deadwood increased with logging intensity reaching 13.5% of total C stocks in intensively logged plots (>20% removal of initial biomass). This study confirmed, therefore, the need to limit logging intensity to a threshold of 20% of initial biomass removal in order to limit the long-term accumulation of deadwood after logging, probably due to high post-logging mortality. With more than half of all Bornean forests already logged, accounting for total C post-logging is key to better assess the long-term carbon footprint of commercial logging in the region, and is a necessary step towards the development of C-oriented forest management in the tropics.

Carbon stocks in tree biomass and soils of German forests

Abstract Close to one third of Germany is forested. Forests are able to store significant quantities of carbon (C) in the biomass and in the soil. Coordinated by the Thünen Institute, the German National Forest Inventory (NFI) and the National Forest Soil Inventory (NFSI) have generated data to estimate the carbon storage capacity of forests. The second NFI started in 2002 and had been repeated in 2012. The reporting time for the NFSI was 1990 to 2006. Living forest biomass, deadwood, litter and soils up to a depth of 90 cm have stored 2500 t of carbon within the reporting time. Over all 224 t C ha-1 in aboveground and belowground biomass, deadwood and soil are stored in forests. Specifically, 46% stored in above-ground and below-ground biomass, 1% in dead wood and 53% in the organic layer together with soil up to 90 cm. Carbon stocks in mineral soils up to 30 cm mineral soil increase about 0.4 t C ha-1 yr-1 stocks between the inventories while the carbon pool in the organic layers declined slightly. In the living biomass carbon stocks increased about 1.0 t C ha-1 yr-1. In Germany, approximately 58 mill. tonnes of CO2 were sequestered in 2012 (NIR 2017).

Evaluation of tree biomass carbon stock changes in Andalusian forests: comparison of two methodologies

ABSTRACTCarbon sequestration has become an important issue in forest management in the light of concerns about global warming. The two methods proposed by IPCC to quantify the net carbon sequestered by trees are based either on the estimation of annual gains and losses of carbon due to the growth of trees and their removals (default method), or on the difference in carbon stocks between two consecutive inventories (stock-change method). The objectives of this study are to compare the net carbon sequestered by the tree layer of forest ecosystems in Andalusia estimated by the two methods, and to identify what measured variables contribute the most to the differences in the estimations. Multivariate analysis was performed in order to identify the causes of these variations. The results revealed differences of up to 200% in the estimated net carbon sequestration depending on the methodology employed, and changes in the direction of the capture/emission in some areas. The net carbon sequestration ranged between 0.08 ± 0.01 and 1.93 ± 0.52 Mg C ha−1 year−1 depending on the method used and on the tree species analyzed. In global terms, net carbon sequestration at the regional level reaches 2,101,715 ± 560,906 Mg C according to the default method and 1,693,412 ± 272,529 Mg C using the stock-change method.

Allometric equations and carbon stocks in tree biomass of Jatropha curcas L. in Senegal’s Peanut Basin

In Senegal, numerous initiatives exist to cultivate Jatropha curcas L. (JCL) trees as a multipurpose energy crop, including for fuel. Thus, research on this drought-resistant shrub has been predominately focused on biofuel production from its seeds, while its potential for carbon (C) sequestration, which could be valuable in sink projects (i.e., afforestation, reforestation) under the Clean Development Mechanism (CDM) of the Kyoto protocol, has been largely unstudied. This study was carried out in Senegal’s Peanut basin to develop allometric equations for estimating biomass of individual JCL shrubs, JCL plantations, and determining their respective C storage potential. We discovered a three-stage evolution of JCL biomass accumulation. A slow build-up stage (1–3 years), followed by a fast production of biomass (3–4 years), and a relatively slower stage where certain fractions-root and leaf biomass-reach a plateau (4–5 years). The ratio between belowground and aboveground biomass varies from 53% (1 year after planting) and 26% (5 year after planting), with an average of 41%. We developed allometric models that provide a reliable estimation of the different biomass fractions of JCL and according to tree age. The models revealed that the stocks of biomass and C become relatively important from the fifth year with a storage capacity of 5.07 kg per tree. Most of the biomass and organic C are stored in the aboveground fractions of trees, suggesting that JCL plantations may be valuable for C sink and CDM projects.

Ecosystem carbon stocks in a forest chronosequence in Hunan Province, South China

Forest ecosystems represent an important carbon sink. A few studies have reported carbon stocks in a forest chronosequence, the carbon stock pattern variation and proportion of each compartment remain poorly understood. The objectives of this study were to quantify carbon stocks of each compartment of forest ecosystem and access their contribution to forest carbon stocks with forest succession. Totally, 32 plots (20 m × 50 m) in different stages of forest succession were investigated, including 11 replicates for Masson pine forest at the early stage, 9 for pine-broadleaved mixed forest at the middle stage, and 12 for evergreen broadleaved forest at succession climax, to quantify carbon stocks in trees, shrubs, herbaceous plants, litter and coarse woody debris (CWD), and soil. The total ecosystem carbon stocks ranged from 193 to 257 Mg ha−1, of which vegetation carbon stocks ranged from 94 to 129 Mg ha−1. Tree biomass carbon stocks increased but shrub biomass carbon stocks decreased during forest succession. The increment of tree biomass carbon stocks was far more than that of shrub, resulting in the increases of vegetation carbon stocks during forest succession. Debris carbon stocks ranged from 4.2 to 5.6 Mg ha−1, with no significant variation across the forest chronosequence. The soil carbon stocks (top 100 cm) ranged from 96 to 132 Mg ha−1. Soil carbon stocks increased significantly during the forest chronosequence, of which soil carbon accumulation occured mainly in the topsoil (0–30 cm). There were no significant differences among the proportions of forest ecosystem carbon stocks in the chronosequence. The averages of proportions of vegetation biomass, debris and soil carbon were 46.7 %, 2.1 % and 51.2 %, respectively. Our results present robust evidence for the increasing carbon sequestration across forest succession chronosequence. Furthermore, tree growth and carbon accumulation in topsoil layer contribute equivalently to carbon sequestration during forest succession in subtropical China.

Carbon storage in agroforestry systems in the semi-arid zone of Niayes, Senegal

Agroforestry is an ancient practice widespread throughout Africa. However, the influence of Sahelian agroforestry systems on carbon storage in soil and biomass remains poorly understood. We evaluated the carbon storage potential of three agroforestry systems (fallow, parkland and rangeland) and five tree species (Faidherbia albida, Acacia raddiana, Neocarya macrophylla, Balanites aegyptiaca and Euphorbia balsamifera) growing on three different soils (clay, sandy loam and sandy) in the Niayes zone, Senegal. We calculated tree biomass carbon stocks using allometric equations and measured soil organic carbon (SOC) stocks at four depths (0–20, 20–50, 50–80 and 80–100 cm). F. albida and A. raddiana stored the highest amount of carbon in their biomass. Total biomass carbon stocks were greater in the fallow (40 Mg C ha−1) than in parkland (36 Mg C ha−1) and rangeland (29 Mg C ha−1). More SOC was stored in the clay soil than in the sandy loam and sandy soils. On average across soil texture, SOC stocks were greater in fallow (59 Mg C ha−1) than in rangeland (30 Mg C ha−1) and parkland (15 Mg C ha−1). Overall, the total amount of carbon stored in the soil + plant compartments was the highest in fallow (103 Mg C ha−1) followed by rangeland (68 Mg C ha−1) and parkland (52 Mg C ha−1). We conclude that in the Niayes zones of Senegal, fallow establishment should be encouraged and implemented on degraded lands to increase carbon storage and restore soil fertility.

Aboveground carbon in Quebec forests: stock quantification at the provincial scale and assessment of temperature, precipitation and edaphic properties effects on the potential stand-level stocking.

Biological carbon sequestration by forest ecosystems plays an important role in the net balance of greenhouse gases, acting as a carbon sink for anthropogenic CO2 emissions. Nevertheless, relatively little is known about the abiotic environmental factors (including climate) that control carbon storage in temperate and boreal forests and consequently, about their potential response to climate changes. From a set of more than 94,000 forest inventory plots and a large set of spatial data on forest attributes interpreted from aerial photographs, we constructed a fine-resolution map (∼375 m) of the current carbon stock in aboveground live biomass in the 435,000 km2 of managed forests in Quebec, Canada. Our analysis resulted in an area-weighted average aboveground carbon stock for productive forestland of 37.6 Mg ha−1, which is lower than commonly reported values for similar environment. Models capable of predicting the influence of mean annual temperature, annual precipitation, and soil physical environment on maximum stand-level aboveground carbon stock (MSAC) were developed. These models were then used to project the future MSAC in response to climate change. Our results indicate that the MSAC was significantly related to both mean annual temperature and precipitation, or to the interaction of these variables, and suggest that Quebec’s managed forests MSAC may increase by 20% by 2041–2070 in response to climate change. Along with changes in climate, the natural disturbance regime and forest management practices will nevertheless largely drive future carbon stock at the landscape scale. Overall, our results allow accurate accounting of carbon stock in aboveground live tree biomass of Quebec’s forests, and provide a better understanding of possible feedbacks between climate change and carbon storage in temperate and boreal forests.

The global potential for carbon capture and storage from forestry.

BackgroundDiscussions about limiting anthropogenic emissions of CO_2 often focus on transition to renewable energy sources and on carbon capture and storage (CCS) of CO_2. The potential contributions from forests, forest products and other low-tech strategies are less frequently discussed. Here we develop a new simulation model to assess the global carbon content in forests and apply the model to study active annual carbon harvest 100 years into the future.ResultsThe numerical experiments show that under a hypothetical scenario of globally sustainable forestry the world’s forests could provide a large carbon sink, about one gigatonne per year, due to enhancement of carbon stock in tree biomass. In addition, a large amount of wood, 11.5 GT of carbon per year, could be extracted for reducing CO_2 emissions by substitution of wood for fossil fuels.ConclusionThe results of this study indicate that carbon harvest from forests and carbon storage in living forests have a significant potential for CCS on a global scale.

Assessing current stocks and future sequestration potential of forest biomass carbon in Daqing Mountain Nature Reserve of Inner Mongolia, China

Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha, this nature reserve currently stores an estimated 2221 GgC in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 GgC by 2020 and nearly double to 4092 GgC by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development. The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems.

Mangrove biomass carbon stock mapping of the Karimunjawa Islands using multispectral remote sensing

ABSTRACTAmong vegetated coastal habitats, mangrove forests are among the densest carbon pools. They store their organic carbon in the surrounding soil and thus the sequestered carbon stays in the sediment for a long time and cannot be easily returned to the atmosphere. Additionally, mangroves also provide various important ecosystem services in coastal areas and surroundings. Accordingly, it is important to understand the distribution of biomass carbon stock in mangrove habitats in a spatial and temporal context, not only to reduce CO2 concentrations in the atmosphere, but also for their sustainability. The objectives of this research are to map the mangrove carbon stock and estimate the total biomass carbon stock sheltered by mangrove forests, with the Karimunjawa Islands as a study site, using the widely available passive remote sensing system ALOS AVNIR-2. The modelling and mapping of mangrove carbon stock incorporates the integration of image pixel values and mangroves field data via empirical modelling. Vegetation indices and PC bands at different levels of radiometric corrections were all used as the input in the mangrove carbon stock modelling so that the effectiveness and sensitivity of different image transformations to particular radiometric correction levels could be analysed and understood. Afterward, the accuracy and effectiveness of each mangrove carbon stock-mapping routine was compared and evaluated. The accuracy of the best mangrove above-ground carbon stock (AGC) map modelled from vegetation index is 77.1% (EVI1, SE 5.89 kg C m−2), and for mangrove below-ground carbon stock (BGC) it is 60.0% (GEMI, SE 2.54 kg C m−2). The mangrove carbon stock map from ALOS AVNIR-2 PC bands showed a maximum accuracy of 77.8% (PC2, SE 5.71 kg C m−2) and 60.8% (PC2, SE 2.48 kg C m−2) for AGC and BGC respectively. From the resulting maps, the Karimunjawa Islands are estimated to shelter 96,482 tonnes C of mangroves AGC with a mean value of 21.64 kg C m−2 and 24,064 tonnes C of mangroves BGC with a mean value of 5.39 kg C m−2. Potentially, there are approximately 120,546 tonnes C of mangrove biomass carbon stock in the Karimunjawa Islands. Remote-sensing reflectance can successfully model mangrove carbon stock based on the relationship between mangrove canopy properties, represented by leaf area index (LAI) and the tree or root biomass carbon stock. The accuracy of the mangrove carbon stock map is subject to errors, which are sourced mainly from: (1) the absence of a species-specific biomass allometric equation for several species present in the study area; (2) the generalized standard conversion value of mangrove biomass to mangrove carbon stock; (3) the relationship between mangrove reflectance and mangrove LAI; (4) the relationship between mangrove reflectance and above-ground mangrove biomass and carbon stock due to its relationship with LAI; (5) the relationship between mangrove LAI and mangrove below-ground parts; (6) the inability to perform mangrove carbon stock modelling at the species level due to the complexities of the mangrove forest in the study area; (7) background reflectance and atmospheric path radiance that could not be completely minimized using image radiometric corrections and transformations; and (8) spatial displacement between the actual location of the mangrove forest in the field and the corresponding pixel in the image. The availability of mangrove biomass carbon stock maps is beneficial for carrying out various management activities, and is also very important for the resilience of mangroves to changing environments.

Forest thinning impact on carbon stock and soil condition in Southern European populations of P. sylvestris L.

An important aspect of sustainable forest management is to assess the impact of forest operations on ecosystem services. This work analyzed the long-term effect of two standard thinning regimes on carbon stocks both in tree biomass and soil compartments as well as its effect on soil condition. The target population was a 90-year-old Scots pine (Pinus sylvestris L.) stand in southwestern Europe. Soil condition was measured as dry mass of the forest floor and concentration of carbon, nutrients in the forest floor as well as exchangeable cations, effective cation exchange capacity, pH and bulk density in the mineral soil. Repeated thinnings from below in a southern European population of Scots pine led to a reduction in current on-site carbon stock in tree biomass of 28% in moderately thinned stands (D grade: average residual basal area of 65–79% relative to the control plots) which was consistent with an observed loss of volume production. However, the inclusion of the amount of carbon exported off-site with harvested biomass reduced the decrease in stock to 4.8%. Nutrient concentrations in the forest floor increased in moderate thinned stands (P, K, Mg and Mn) or were unchanged (C, N and Fe). The selected thinning regime did not alter mineral soil condition. A decreasing pattern of Ca and Mn stocks with depth was consistent with a high reduction of nutrient concentration of elements and higher bulk density with depth. However K, Mg and Na showed stable stocks across depths because of a much smaller reduction of nutrient concentrations in deeper layers relative to the surface layer. We hypothesized that this stable pattern with soil depth was due to leaching. The sustainability of forest thinning is a trade-off between loss of standing biomass and increasing stand stability as long as other indicators, like soil condition, do not significantly change.

Impacts of the Wenchuan earthquake on tree mortality and biomass carbon stock

The Wenchuan earthquake caused tremendous damages to forests, which could increase tree mortality, disrupt forest carbon cycling, and pose serious challenge to sustainable forest management. In this study, we analyzed data from 871 permanent forest plots from the Sichuan forest inventory (SFI) system to quantify the impacts of 2008 Wenchuan earthquake on tree mortality and forest biomass carbon. Our results showed that the 5-year tree mortality had significantly increased from 2.26 to 3.52 % in the region with seismic intensity of ≥VII (VII and above), and even more dramatically in the hardest hit zone with seismic intensity of X and XI, which showed an increase from 3.77 to 8.96 %. It is estimated that the Wenchuan earthquake had killed as much as 34.5 million trees and mobilized a dead carbon pool of 1050 Gg C (7.87 Mg C/km2/a) in the region with seismic intensity of ≥VII. Our results suggested that the earthquake was the main cause of this risen tree mortality and the loss of huge amount of forest biomass carbon. This study demonstrated that tree mortality derived from forest plots can be used to estimate disaster-induced forest carbon loss for the purpose of hazard assessment.

Organic Carbon Storage in Evergreen Oak Forest Ecosystems of the Middle and High Moroccan Atlas Areas

We report carbon stock in biomass, litter and soil estimated for six locations in natural Quercus ilex L. stands of the Middle and High Moroccan Atlas. Twenty trees at each location were selected according to their diameter classes and felled to measure the biomass of trunk, branches, twigs and leaves and determine allometric relationships. Soil was sampled in five depths (0 - 15, 15 - 30, 30 - 50, 50 - 70 and 70 - 100 cm) and litterfall production measured in all tree stands. The total carbon stock in above-ground biomass ranged between 17 Mg&#183ha&#451 in A&#239t Aamar stand (High Atlas) and 91 Mg&#183ha&#451 in Ksiba stand (Middle Atlas). Perennial organs (trunk, branches and twigs) stored over 95% of the tree carbon stock. Soil organic carbon concentrations ranged from 0.01% (in 70 - 100 cm in all stands) to 8.1% (in 0 - 15 cm in the Ajdir stand in Middle Atlas). The total organic carbon stock in the soil ranged between 141.4 t&#183ha&#451 in Ajdir and 24.6 t&#183ha&#451 in Asloul. The litter contained 0.2 Mg C ha&#451 in the clearing (C2) stand of High Atlas and 14.3 Mg C ha&#451 in (Ajdir) of carbon. The best fitted model for predicting carbon stock in tree biomass was obtained by applying the allometric equation Y = aXb for each biomass fraction and stand, where Y is the aboveground biomass (dry weight) and X is the DBH (Mean diameter at breast height, 1.30 m). These previous data obtained in the present study confirm the important function of these natural forests as longterm C sinks, in forest biomass, litter and soil. The potential long term C storage of these systems is moderately high, especially in less-intensively managed forests that include large trees. The established relationship between DBH and carbon stock in different tree organs can be used for forest carbon accounting, and also synthesize available information on oak forest as a sink for atmospheric CO2, and identify the management options that may enhance the capacity for C capture/ storage in forest soils.