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Mangroves are under immense anthropogenic pressures globally which are further exacerbated by their accessibility to humans. To minimize human access hence pressures to the ecosystem, establishment of protected areas is often employed. However, the ecological effectiveness of protected areas, which influences their legal durability, is rarely assessed beyond curbing deforestation. Furthermore, little is known about whether protection could still provide a positive ecological impact if the sites are easily accessible, i.e., adjacent to urban areas, near roads, small in area and/or fragmented. To improve our understanding thereon, this study compares anthropogenic disturbance severity, forest structures and ecosystem carbon (C) stocks of protected and unprotected mangroves near Barranquilla, Colombia's largest coastal city. The outcomes suggest that accessible, yet protected mangrove has a mean disturbance index of 5.3, lower than unprotected mangrove (mean 11). Protected mangrove also has higher mean (± SD) tree basal area (26.5 ± 15.6 m2 ha−1), mean densities of tree, sapling and seedling (899 ± 398, 5155 ± 7860, and 68,837 ± 73,899 individual ha−1, respectively) and biomass C stock (mean 89.5 ± 39 Mg ha−1) than those of accessible unprotected mangrove (mean basal area 19.3 ± 5 m2 ha−1; mean tree, sapling and seedling densities 823 ± 215, 749 ± 94, and 33,727 ± 44,882 individual ha−1, respectively; mean biomass C stock 60.2 ± 14.5 Mg ha−1). Results suggest that the current sediment C stocks, that is higher in unprotected than protected mangroves (396.8 ± 552.6 and 142.4 ± 205.7 Mg ha−1, respectively), are not primarily driven by conservation status, but by long-term processes that likely pre-date the protected status designation. Mangrove protection, however, could help maintain carbon stocks in soils and biomass and the potential for further soil carbon sequestration, and thus are pivotal in determining future trajectories of mangrove climate mitigation potential. This study shows that even imperfect protection offers ecological benefits to highly accessible ecosystems. Hence, focus should be placed on optimizing these benefits and minimizing their vulnerability to downgrading, downsizing and degazettement. • influence of protection on mangroves is assessed beyond curbing deforestation. • protection effectively limit anthropogenic disturbance on mangroves. • protection promotes mangrove biomass C and regeneration potential. • mangrove sediment C stocks is largely influenced by sediment properties. • mangrove protection is ecologically beneficial even for highly accessible systems. [ABSTRACT FROM AUTHOR]

Thinning, a major measure of forest management, is known to alter carbon sequestration by affecting the forest microclimate and soil environmental conditions. However, how thinning effect on forest ecosystem carbon stocks have presented inconsistent results. Therefore, we conducted 1776 pairs of thinning experiment observations worldwide to explore how thinning affects forest vegetation and soil carbon stocks. The results showed that overall thinning significantly increased total tree aboveground biomass carbon stocks (AGC total , +23.9%, +1.3 Mg ha-1 yr-1), understory vegetation carbon stocks (UVC, +68.3%, 0.12 Mg ha-1 yr-1), and soil organic carbon stocks (SOC stocks , +4.8%, 1.0 Mg ha-1 yr-1) at the global, but exhibited significantly decreased carbon stocks of litterfall (LBC, –9.6%, –0.03 Mg ha-1 yr-1). Belowground biomass carbon stocks remained unchanged under thinning. The sensitivity of carbon sequestration to thinning gradually disappeared after 6 years, except for AGC total , as they were jointly subject to stand density and thinning intensity and not just recovery ages. The response to UVC was more positive in medium-density (1500 – 3000 trees ha-1) and moderately thinned (30 – 50%) stands, and the thinning effects on UVC and SOC stocks were more noticeable in the subtropical and temperate zones. In summary, thinning enhanced forest ecosystem carbon sinks (+2.4 Mg ha-1 yr-1) but reduced carbon stocks in low-density stands (≤ 1500 trees ha-1). Soil moisture content (SMC, +6.6%) and bulk density (BD, –1.5%) dynamics after thinning were important factors regulating vegetation growth and soil carbon cycling processes. • The response of forest carbon stock to thinning was explored by meta-analysis. • Overall increase in forest carbon stocks from thinning. • Post-thinning changes in carbon stocks depend on climate and soil moisture. [ABSTRACT FROM AUTHOR]

Increasing soil N availability is an effective way to enhance soil organic carbon (SOC) sequestration and biomass production in N-limited ecosystems such as boreal Norway spruce forests. Alder has a root nodule symbiosis with Frankia , an N 2 -fixing bacterium, and can thus add considerable amounts of N to soil mainly through its N-rich leaf litter. The objective of this study was to determine whether the presence of grey alder at the regeneration stage had any long-term effects on soil C and N cycling and stocks and spruce growth. The study sites were two relatively fertile 40-year-old Norway spruce stands (Luhdansuo and Porkkola) in Southern Finland. At both study sites, half the spruce stand had an admixture of grey alders for approximately 10–15 years after regeneration (alder treatment), but no alder had been present in the other half (control treatment). Alders were cut from the alder treatment 25 (Luhdansuo) or 30 (Porkkola) years before the measurements. At Porkkola, alder treatment received ash fertilisation 13 years ago. We observed no significant differences in the plant-available N fluxes, measured with a microdialysis technique, or SOC stocks between treatments. The total N stock (organic horizon + 0–30 cm mineral soil) and organic horizon thickness were larger, while the microbial biomass C:N and C mineralisation rate were lower in the alder versus the control treatment at Luhdansuo. The annual ring widths of spruces were larger in the alder versus the control treatment for up to six years after alder removal at both sites, but no differences were observed in the current tree diameters or diameter increments. In conclusion, most of the current soil or tree properties did not differ significantly between treatments, possibly because the effect of alder had faded out over the 25–30 years since its removal, and because the sites were initially relatively fertile. • We studied the effects of alder on soil properties 25-30 years after its removal. • The past presence of grey alder increased soil N stock of a Norway spruce stand. • Alder had increased the organic horizon thickness in one of our study sites. • Soil organic C stock was not significantly affected by the past presence of alder. • Alder caused an increase in spruce ring widths, lasting for six years. [ABSTRACT FROM AUTHOR]

• 1964–65 harvests were whole-tree, and stem-only with and without prescribed burning. • Stand structure and carbon stock did not differ among treatments 50 years later. • Hardwoods were most prevalent on sites where prescribed burning was conducted. • Pinus strobus was most prevalent on sites that had been whole-tree harvested. • Clearcutting resulted in composition shifts regardless of biomass removal treatment. Whole-tree harvesting (WTH) is increasingly used to extract forest biomass for energy and commercial wood products. Slash burning, which is used for fuels reduction and site preparation, also reduces aboveground biomass. Yet effects of incremental biomass reduction, from either WTH or slash burning, on long-term forest productivity and composition are poorly understood. This research uses data from a 50-year-old study in northern mixedwood (Picea – Abies – hardwood) stands on the Penobscot Experimental Forest in Maine, U.S.A., to address these concerns. Clearcutting was conducted in 1964–65 with WTH, stem-only harvesting (SOH), and SOH with post-harvest prescribed burning of logging residues (SOHB). Growing stock, composition, and soil properties (O horizon thickness and soil drainage) were measured 50 years after treatment. Hardwood composition (percent of total basal area) increased from pre-treatment levels in all treatments but was greater in SOHB than SOH and WTH. Eastern white pine (Pinus strobus), though a minor species, was significantly more abundant in WTH than SOH or SOHB. Results indicated no other significant differences in species composition, or in stand structure or productivity (total basal area, stem density, dominant height, quadratic mean diameter, and total above-ground carbon stock) among treatments. Independent of treatment, we observed relationships between soil properties and stem density and quadratic mean diameter (qmd), such that lower stem density and greater qmd were observed on sites with greater O horizon thickness. These findings suggest that relative to SOH, WTH and SOHB do not degrade northern mixedwood stand productivity as expressed by stand structure and stocking 50 years after a single treatment, even on a site with low to moderate production potential. Nevertheless, species shifts associated with clearcutting (i.e., shade-tolerant conifer to intolerant hardwood composition) and prescribed burning in this forest type should be considered in light of the potential application of either for intensive silviculture treatments. [ABSTRACT FROM AUTHOR]

• A poplar clone was exposed to two O 3 and two water treatments. • Drought stress protected poplar growth from O 3 damage. • E-O 3 reduced the total C stock, while it didn't affect the total N stock of poplar. • Drought stress reduced the total C and N stocks of poplar. • There were no interactions between O 3 and drought on most C and N parameters. Ozone (O 3) pollution and drought are frequent in summer, which adversely affects plant growth. In this study, we investigated the interactive effects of O 3 and water deficit on growth parameters, and carbon (C) and nitrogen (N) stocks and their allocation to different organs in poplar saplings in the summer of 2017. The saplings were subjected singularly and in combination to two chronic O 3 treatments (charcoal-filtered air [CF] and ambient air + 40 ppb of O 3 [E-O 3 ]) and two watering regimens (well-watered [WW] and reduced watering [RW]). The results showed that both O 3 and drought inhibited poplar growth, whereas the effects of drought were greater than those of O 3. Moreover, drought stress protected the saplings from O 3 damage, suggesting that some previous studies on well-watered plants might have overestimated the damage caused by O 3. Inconsistent with the general trend, RW significantly increased the light-saturated rate of CO 2 assimilation (A sat) in this study, whereas it reduced the total leaf area. E-O 3 significantly increased the N concentration and reduced the C/N ratio of each organ as well as the total C stock (CS total), while it did not significantly affect the total N stock (NS total). Drought significantly increased the C and N concentrations and reduced the C/N ratio in most organs, and significantly reduced the C stock of each organ, CS total , and NS total. CS total was positively correlated with the total leaf area and the photosynthetic rate of the whole plants (A plant). However, there was no significant relationship between CS total and A sat , suggesting that A plant can better reflect the growth of the whole plant than A sat. In addition, NS total was positively correlated with the root biomass. Both O 3 and drought had no significant effect on the ratio between the root and shoot N stocks, and there were also no interactive effects of O 3 and drought on most C and N parameters. These findings will facilitate better understandings of C and N metabolisms future environment with higher O 3 and more frequent droughts. [ABSTRACT FROM AUTHOR]

Highlights • Soil nutrients decreased over a 14-year period in a degraded forest on sandy soil. • Biomass recovery was very slow compared to secondary forests on clay-rich soil. • Leaching caused reductions in soil nutrient than nutrient uptake by regrowth trees. • Forests on sandy soils should be carefully managed to avoid severe degradation. Abstract Heath forests which are tropical forests on sandy soils are widely distributed in Borneo and provide many ecosystem services, such as carbon storage and non-timber forest products. Over the past several decades, such forests have been disturbed by non-traditional shifting cultivation, which is usually conducted in unsuitable land with short fallow duration. Anthropogenic disturbances in forests growing on sandy soils that have low nutrient retention capacities may promote further reductions in soil fertility. Long-term monitoring of soil nutrients and biomass accumulation is rare in degraded tropical rainforests growing on sandy soils despite the known negative effects of non-traditional shifting cultivation practices on soil fertility, vegetation and biomass recovery, and the growth of trees planted to rehabilitate forests. The objective of the current study was therefore to elucidate changes in soil fertility and biomass recovery potential in degraded forests on sandy soils in Borneo. We monitored soil nutrients and chemical properties in fifty-four 12 × 12 m plots located on different topographical positions along upper and lower slopes. Samples were collected in plots aged 7 and 14 years after abandonment of shifting cultivation. The biomass of secondary forest trees in all plots 12 years after the abandonment was also measured to determine the relationship between biomass accumulation and changes in soil nutrients. We found that soil pH and cation exchange capacity, and the concentrations of most nutrients, including nitrogen, magnesium, and phosphorus, had decreased significantly 7–14 years after abandonment; biomass accumulation in the plots was also limited 12 years after abandonment (<0.8 Mg ha−1 year−1). These changes in soil traits within the study plots were similar regardless of topographical position, and the changes were not related to the amount of biomass. Soil nutrients in the plots may have leached out as a result of removal of thick root mats in the surface soil, high sand content, and large amounts of rainfall in the area rather than uptake by recovering trees. These results indicate that it may be difficult to recover soil fertility on steep slopes in sandy soil conditions because of high leaching rates and erosion when the soil surface layer is destroyed by shifting cultivation. It is therefore important to carefully manage shifting cultivation practices in tropical forests on sandy soils in Borneo. [ABSTRACT FROM AUTHOR]

Substantial amounts of carbon have been known to be stored in the miombo woodlands, which are the most widespread dry forests in the African biosphere. Efforts to get precise estimates of carbon stock in the miombo woodlands are limited by a general lack of models for estimating carbon stock. This study aimed at developing species-specific allometric models for estimating aboveground carbon stock (AGC) in Copperbelt miombo woodlands of Zambia. A total of 60 individual trees representing 4 tree species were destructively harvested for carbon analysis by Ash method. Allometric models relating diameter at breast height (DBH), total tree height (H) and basic wood density (ρ) to the AGC in form of Log 10 (AGC) = a + b (Log 10 X 1 ) + c (Log 10 X 2 ) + d (Log 10 X 3 ) were developed using Ordinary Least Squares (OLS) estimation method. Models with DBH alone performed better than those with DBH along with H and/or ρ. Evaluation of model performance was done by using R 2 (Coefficient of determination), AIC (Akaike Information Criterion), Root Mean Square Error (RMSE) and the Mean Percentage Error (MPE%). Computation of MPE%, R 2 and RMSE was based on the results from the k -fold cross validation technique. R 2 , RMSE and MPE% values for the selected models ranged from 77.3% to 98.4%, 0.065 to 0.169 and −6.09 to 1.35% respectively. Model performance and evaluation of other previously developed general and species-specific models in our dataset depicts that the models in the present study are acceptable to be applied to species in areas with similar climatic conditions. The models developed will serve as an important tool for predicting and monitoring carbon pool sizes in long-term studies. They can also be used to establish conservative carbon stock schemes required to determine avoided emissions in performance-based payment schemes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Defining the most important factors related with forest carbon (C) stocks in different forest types is still a controversial topic. In this study we used data from 10,500 plots from The National Forest Inventory of Mexico encompassing the six main forest types in Mexico (conifer, broadleaf, mixed, evergreen and semi-deciduous, dry and semiarid forests) in order to identify the main factors related to the spatial pattern of C stocks, including climate (temperature and rainfall), forest diversity (structural and species richness), topographic and soil characteristics (soil depth, slope and land tenure) and disturbance factors (fires, pests and tree felling). We built two different types of models, one taking all plots into account (global model, R 2  = 0.54, P < 0.001) and others for each forest type separately. Overall, structural richness was the most important variable related to C stock both in the global model and in each forest type model. Tree richness had a strong relationship in tropical forests (both dry and evergreen) but not in temperate forests (conifer, broadleaf and mixed forests), where slope and climate variables had greater effects on C stocks. C stock was strongly and positively correlated with precipitation in almost all forest types, while it was strongly and negatively correlated with temperature in broadleaf and mixed forests. Surprisingly, slope was the second most important factor positively correlated with C stock in broadleaf and mixed forests. Surprisingly, soil depth, land tenure and disturbance variables had a negligible effect in almost all models, partially due to the poor quality of disturbance and soil depth data available from INFyS. The results suggest that, in order to enhance C stock in Mexican forests, management techniques should encourage increases of the number of tree species and, especially, tree size inequality, since both these factors were shown to have a key role in C stock. [ABSTRACT FROM AUTHOR]

Fine roots (diameter ≤ 2 mm) contribute significantly to the forest carbon cycle and are essential for resource acquisition from the soil. We conducted a study to assess the relationships between tree and ground vegetation fine root biomass and tree species diversity (monocultures compared to 2–5 species mixtures), conifer proportion and other site factors (stand basal area, soil carbon stocks and C:N ratio) in the six major European forest types, boreal forest in Finland, temperate forests in Poland, Germany and Romania, thermophilous deciduous forests in Italy, and Mediterranean forests in Spain. We sampled the fine roots of trees and ground vegetation to the depth of 20 cm in the mineral soil and allocated the fine root biomass to individual tree species using near-infrared reflectance spectroscopy (NIRS). We did not find any general positive effects of tree species diversity on the fine root biomass of trees or ground vegetation across the forest types and tree species combinations. However, our results suggest that tree fine root biomass increases with tree species diversity in pure broadleaf forests, but not in pure conifer forests. Species diversity explained 7% of the variation in tree fine root biomass in the broadleaf stands. The narrow tree species diversity gradient (1–2 species) in the conifer forests compared to the broadleaf forests (1−4) may have decreased the probability of conifer species combinations with below-ground functional traits conducive to over-yielding. Some evidence of diversity-mediated changes in the vertical rooting patterns of broadleaf trees and ground vegetation were found within the entire organic and 0–20 cm mineral soil layer although the weighted mean depth of fine root biomass was not affected. Negative diversity effects were found in the organic layer and positive diversity effects in the 0–10 cm mineral soil layer for broadleaf tree fine root biomass. Diversity effects were negative for ground vegetation fine root biomass in the 0–10 cm mineral soil layer. There was a general positive effect of conifer proportion on total fine root biomass in the organic layer, but not in the mineral soil layers. In general conifer proportion and site factors explained more of the variation in tree fine root biomass than tree species diversity. More research covering the annual variation in fine root biomass and deeper soil layers is needed before recommending managing species-rich forest for increasing below-ground biomass and carbon pools. [ABSTRACT FROM AUTHOR]

Expansion of rubber plantations into sub-optimal environments has been a dominating land conversion in continental South-East Asia in the last decade. Regional evaluation of the carbon sequestration potential of rubber trees depends largely on the selection of suitable allometric equations and the biomass-to-carbon conversion factor. Most equations are age-, elevation-, or clone-specific, and their application therefore gives uncertain results at the landscape level with varying age groups, elevation ranges, and clone types. Currently, for rubber-based systems, none of the allometric equations takes environmental factors (e.g. climate, topographic condition, soil properties, and management scheme) into consideration to allow pan-tropical usage. Against this background, 30 rubber trees with a root profile of up to 2 m were destructively harvested and 882 rubber trees were measured non-destructively in 27 plots, covering rotation lengths of 4–35 years, elevation gradients of 621–1127 m, and locally used clone types (GT1, PRIM600, Yunyan77-4) in mountainous South Western China. Allometric equations for aboveground biomass ( AGB ) estimations considering diameter at breast height ( DBH ), tree height ( H ), and wood density were superior to other equations. A simpler model with similar performance ( AGB = 0.0419 DBH 2.316 H 0.478 ) can be used if tree-specific wood density is not available. For belowground biomass ( BGB ) a model using only DBH can provide a robust prediction ( BGB = 0.207 DBH 1.668 ). We also tested goodness of fit for the recently proposed pan-tropical forest model, which includes a bioclimatic factor E , combining indices of temperature and precipitation variability and drought intensity. Prediction of AGB by the model calibrated with the harvested rubber tree biomass and wood density was more accurate than the results produced by the pan-tropical forest model adjusted to local conditions. The relationships between DBH and height and between DBH and biomass were influenced by tapping, therefore biomass and C stock calculations for rubber have to be done using species-specific allometric equations. Based on the analysis of environmental factors acting at the landscape level, we found that above- and belowground carbon stocks were mostly affected by stand age, soil clay content, aspect, and planting density. Increasing planting density to >570 trees per ha according to the regional plantation management strategy had a negative impact on aboveground carbon stock of old rubber plantations. The integration of bioclimatic and regional management factors is a further approach to build widely applicable biomass models for pan-tropical rubber-based systems. The results of this study provide reference for reliable carbon accounting in other rubber-cultivated regions. [ABSTRACT FROM AUTHOR]

Forest biomass is an important variable for calculating carbon stocks and greenhouse gas emissions from deforestation and forest fires in Brazilian Amazonia. Its spatial distribution has caused controversy due to disagreements over the application of different calculation methodologies. Standardized networks of forest surveys provide an alternative to solve this problem. This study models the spatial distribution and original total stock of forest biomass (Aboveground + Belowground + Fine and coarse litter) in Brazil’s state of Roraima, taking advantage of data from georeferenced forest surveys in the region. Commercial volume (bole volume) from surveys was expanded to total biomass. Kriging techniques were used to model the spatial distribution of biomass stocks and generate a benchmark map. All results were associated with phytophysiognomic groups, climatic regions and land uses (protected areas; agricultural use). We estimate forest in the state of Roraima to have an original biomass stock of 6.32 × 10 9 Mg. Forest biomasses in areas with shorter dry seasons were higher as compared to forests in regions with longer dry seasons. The original vegetation in protected areas, independent of phytophysiognomic group, has higher biomass compared to areas currently under agricultural use. Protected areas support 65.8% of Roraima’s stock of forest biomass, indicating an important potential role in REDD projects for conservation of forest carbon. Information on spatial distribution of biomass stocks at a more refined scale is needed to reduce uncertainties about the regional character of carbon pools in Amazonia. [ABSTRACT FROM AUTHOR]

Quantifying forest biomass carbon (C) stock change is important for understanding forest dynamics and their feedbacks with climate change. Forests in the northeastern U.S. have been a net carbon sink in recent decades, but C accumulation in some northern hardwood forests has been halted due to the impact of emerging stresses such as invasive pests, land use change and climate change. The Delaware River Basin (DRB), sited in the southern edge of the northern hardwood forest, features diverse forest types and land-use histories. In 2001–2003, the DRB Monitoring and Research Initiative established 61 forest plots in three research sites, using Forest Service inventory protocols and enhanced measurements. These plots were revisited and re-measured in 2012–2014. By comparing forest biomass C stocks in the two measurements, our results suggest that the biomass C stock of the DRB forest increased, and was thus a carbon sink over the past decade. The net biomass C stock change in the Neversink area in the north of the DRB was 1.94 Mg C ha −1 yr −1 , smaller than the biomass C change in the French Creek area (2.52 Mg C ha −1 yr −1 , southern DRB), and Delaware Water Gap Area (2.68 Mg C ha −1 yr −1 , central DRB). An increase of dead biomass C accounted for 20% of the total biomass C change. The change of biomass C stocks did not correlate with any climatic or topographic factors, but decreased with increasing stand age, and with tree mortality rate. Mortality rates were highest in the smallest size class. In most of the major tree species, stem density decreased, but the loss of biomass from mortality was offset by recruitment and growth. The demographic changes differ dramatically among species. The living biomass of chestnut oak, white oak and black oak decreased because of the large mortality rate, while white pine, American beech and sweet birch increased in both biomass and stem density. Our results suggest that forests in the DRB could continue to be a carbon sink in the coming decades, because they are likely at a middle successional stage. The linkage between demography of individual trees species and biomass C change underscores the effects of species-specific disturbances such as non-native insects and pathogens on forest dynamics, and highlights the need for forest managers to anticipate these effects in their management plans. [ABSTRACT FROM AUTHOR]

Forest fires coupled with logging have now become one of the most extensive causes of forest degradation, affecting the balance between carbon emissions and sequestration in lowland tropical forests in Southeast Asia. Being transient pools of disturbance-killed trees, coarse woody debris (CWD) stocks play a key role in the carbon budget of such disturbed forests. Here, we investigated for the first time how logging affects the CWD input during and following a fire and, consequently, post-fire CWD stocks. Measurements were made at a permanent site in Bukit Soeharto Education Forest (BSEF) in East Kalimantan, Indonesia. This site consisted of plots that had been subjected to three different logging intensities (HF: heavily felled, trees with diameter at breast height (DBH) ⩾30 cm were felled; LF: lightly felled, trees with DBH ⩾50 cm were felled; UF: unfelled), all of which were burned by a fire that occurred during a drought associated with the El Niño Southern Oscillation in 1998, shortly after logging. CWD mass were measured in 2012, following 14 years of monitoring the CWD inputs. The average CWD mass across the three logging treatments was 89 Mg ha −1 , which is higher than the reported values for undisturbed forests but within the recorded range for recently disturbed forests. The amount of CWD inputs due to tree death during the fire was similar among the three treatments. However, there was a large difference in the CWD input in the post-fire period. In UF plots, large CWD inputs lasted for 2 years following the fire due to delayed tree death, whereas in HF and LF plots, where the above-ground biomass had greatly reduced by selective logging, no further large CWD inputs occurred after the fire. Consequently, the CWD stocks in the HF and LF plots were 50–60% lower than those in the UF plots. A simulation predicted that these CWD inputs during and shortly after the fire still constitute a large proportion of the CWD stocks in 2012, suggesting that the CWD pool is a rather durable carbon store in BSEF. In the HF and LF plots, there was few large diameter CWD pieces, reflecting the selective logging of large diameter trees, whereas, in the UF plots, there were large standing dead and uprooted trees. Since the larger diameter CWD pieces are persist in the forest for a longer time continuing to store carbon and to provide habitats for diverse wild life, selective logging could have large impacts on forest ecology and function not only by decreasing the total CWD inputs and stocks but also by decreasing the large diameter CWD pieces. [ABSTRACT FROM AUTHOR]

Integration of the mitigation and adaptation roles of forests is important in addressing climate change issues. Community forests (CFs) have capacity to contribute in both roles as local communities are collectively working to improve forests and to fulfil their own basic forest product needs. Nowadays, an incentive mechanism for Reduced Emissions from Deforestation and forest Degradation, conservation of forests, sustainable management of forests and enhancement of carbon stocks in forests (REDD+) is emerging and already has received considerable attention in achieving climate change mitigation whereas there has been little analysis of its potential contribution to adaptation objectives, particularly at the community level. Therefore the overarching goal of this study was to analyse CFs from a mitigation and adaptation perspective. This study assesses 105 CFs covering a range of forest types managed by socially diverse communities of Nepal. Two point carbon data (2010 and 2013) was analysed to investigate differences in carbon stocks in these forests following the introduction of a REDD+ pilot program in Nepal. Similarly, a document review and focused group discussions were organised to evaluate the livelihood support and adaptation potential of pilot REDD+ CFs. This study found that community forest user groups (CFUGs) have increased forest carbon stocks and that the pilot REDD+ projects are also delivering livelihood benefits which ultimately will help adaptation to adverse climatic conditions. However, the motivation for communities to realise REDD+ carbon incentives may reduce the food supplement capacity of forests by limiting vegetation diversity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ecological restoration needed to address twin climate and biodiversity crises. • We planted species mixes in a woodland restoration experiment. • After ten years, we measured the contribution of plant diversity to carbon storage. • Diverse plantings sequestered as much carbon as monocultures. • Minimal evidence for carbon-diversity trade-off at Peniup. Biologically diverse forest and woodland restoration can mitigate climate change and biodiversity loss. Understanding the trade-off between carbon storage and biodiversity is important to maximise the value of restoration opportunities. Ecological theory suggests biological diversity contributes positively to carbon storage until the relationship plateaus (i.e., species are added with no effect on carbon storage), and yet in practice, tree monocultures are perceived to sequester more carbon than diverse plantings. Here, we measured the contribution of plant diversity to carbon storage in trees and shrubs ten years after planting for yate (Eucalyptus occidentalis) woodland restoration. We found no evidence for a trade-off between carbon storage and plant diversity. We planted yate with mixes of yate woodland species including native grasses, shrubs, and trees. Ten years after planting, grass establishment was poor, and density of trees and shrubs was patchy. There was some unassisted recruitment of woody species. Diversity was measured as observed species richness and observed functional richness, which incorporated taxonomic diversity, structural diversity, and presence/absence of nitrogen-fixing legumes. Carbon stocks measured were above and belowground tree and shrub biomass, leaf and twig litter biomass, and organic carbon (%) in the topsoil. Across all three carbon stocks diverse yate plantings sequestered as much carbon as yate monocultures. Observed species richness had a weak negative effect on tree and shrub biomass in the best linear mixed model but this effect diminished with the removal of an outlier. Tree density had a positive effect on tree and shrub biomass in models with and without the outlier. There was no effect of diversity on litter biomass and soil organic carbon. Instead, linear mixed models of these stocks showed the influence of soil properties. Litter biomass increased with soil potassium and decreased with soil pH. Soil organic carbon increased with initial soil organic carbon and soil nitrogen. There are potential additional biodiversity benefits of diverse plantings that we did not measure (e.g., soil erosion control, wildlife habitat). We call for more field experiments to explore these potential benefits and to generate the ecological knowledge needed to improve the quality of global forest and woodland restoration efforts. [ABSTRACT FROM AUTHOR]

• Carbon stock in 12 major forest types along an elevational gradient (350–3450 masl) in the Indian Himalaya quantified. • A significant effect (p < 0.008) of elevation was observed on the forest structural variables, biomass and carbon stock. • Highest tree biomass and carbon stock values were found in the high-elevation forest types. • Climate-smart tree species suitable to the elevational belts in the region identified. • Our findings have immediate implications for climate change mitigation policy and practice. In an era of climate change, quantifying forest biomass and carbon stock along elevational gradients in mountainous areas assumes immediate relevance for carbon budgeting and forest management. Here, we carried out extensive field studies to quantify the tree biomass and carbon stock of major forest types along a wide elevational gradient (350–3450 m) in Jammu and Kashmir, a region located in the northwestern Himalaya. We adopted a stratified random cluster sampling approach to generate ground-based data on structural variables (diameter at breast height-DBH, stem height, basal area, stem density, species richness), and quantified biomass and carbon stock volume using allometric equations in 12 major forest types in the region. We found a significant difference in all the tree structural variables among the forest types. Our results show a significantly positive correlation between DBH and height, but a significantly negative correlation of stem density with DBH and height. We observed a higher basal area in the forest types between 1750 and 3350 m elevation, with the highest value (104.4 ± 29.0) found in Fir forest. We also found higher stem density values at mid- and high-elevations in comparison to low-elevation, but the trend was inconsistent. To evaluate the influence of elevation on the structural attributes, we fitted a Linear Regression Model (LM) for each variable, followed by F-test. We observed a significant effect (p < 0.008) of elevation on all the forest tree structural variables, species richness, biomass and carbon stock. All these variables, except species richness, showed a positive relationship with elevation. We found the highest aboveground-, belowground-, total biomass, and carbon stock in the forest types at high elevation above 1750 m. The most significant tree species in terms of biomass and carbon stock contribution was Abies pindrow , followed by Cedrus deodara and Pinus roxburghii , thus making them suitable tree species for forest conservation and restoration in this Himalayan region. Principal component analysis of anthropogenic disturbances revealed the fire mostly associated with the forest types dominated by P. roxburghii , stem cutting with those dominated by C. deodara, P. wallichiana and A. pindrow , and grazing with the high-elevation forest types. Overall, our study unravels the patterns of forest carbon stock along a wide elevational gradient in this Himalayan region, with immediate implications for climate change mitigation policy and practice in mountainous landscapes. [ABSTRACT FROM AUTHOR]

By integrating the reflectance of 7 spectral bands of the MODerate-resolution Imaging Spectroradiaometer (MODIS) and forest inventory data with an empirical statistical model, we mapped the spatial distribution of total forest biomass carbon density (BCD) at 1 km resolution in China during the past decade. The empirical statistical model can explain 75% of the variation in BCD across 29 provinces in China ( R 2 = 0.75, P < 0.001), with a root mean square error of 9.3 Mg C ha −1 . The total forest biomass carbon storage was estimated as 6.4 ± 0.6 Pg C, with an average BCD of 42.6 ± 3.9 Mg C ha −1 during the period of 2001–2005, which is close to the estimates solely by forest inventory data. During the 2000s, the forests in China sequestered carbon by 80 ± 103 Tg C yr −1 . Our estimation is close to an independent forest biomass estimation (76 ± 10 Tg C yr −1 ) derived from passive microwave satellites (Liu et al., 2015). Most of the forest biomass carbon sink was attributed to the growth of low- and medium-biomass forests in eastern, central, and southern China. The large area of currently low-biomass forests will retain as a large potential biomass C sink in the next few decades. This implicates that low-biomass forests (most of these forests are planted forests) need well management such as selected wood harvest to keep large forest biomass carbon sinks in China. Plans of sustainable afforestation and forests protection projects by Chinese government could also enhance the forest biomass carbon sinks in the future. Nitrogen deposition in China significantly correlates with forest biomass C sinks across 2392 0.5° × 0.5° grid cells ( R = 0.54, P < 0.001), which indicate the positive impacts of nitrogen deposition on China’s forest biomass carbon sinks. Our results suggest that China forests can continue to act as a large carbon sinks in the near future because of the contributions of management of low- and medium-biomass forests, afforestation and nitrogen deposition. [ABSTRACT FROM AUTHOR]

Carbon (C) stocks in the forests of Reducing Emissions from Deforestation and Forest Degradation (REDD+) participating countries have to be estimated and monitored to determine accurate financial incentives and compensation. The research estimated the distribution of C stock across the different pools and management regimes of tropical Sal forest in the Terai Arc Landscape of Nepal. It applied a field measurement-based forest inventory method combined with the best predictive allometric model available, to increase accuracy and precision. Shrub and litter C were estimated by destructive method and Soil Organic Carbon (SOC) up to a depth of 30 cm. Biomass data and samples were collected from 113 plots distributed throughout four different management regimes on 1.1 million ha of forest in the landscape. The estimated average C stock in aboveground biomass, belowground biomass, shrub, litter, SOC and total were 105.58 ± 17.05, 24.92 ± 4.15, 0.23 ± 0.06, 1.49 ± 0.25, 96.53 ± 8.76 and 228.76 ± 19.61 Mg ha −1 respectively. The mass of total C stock varied from 291.55 ± 42.51 Mg ha −1 in protected areas to 237.15 ± 32.54 Mg ha −1 in community forests to 189.16 ± 26.46 Mg ha −1 in government-managed forests and to 126.76 ± 56.36 Mg ha −1 in other forests. These estimates of carbon stocks differed from earlier estimates based on biome-average datasets. They are consistent with those from similar forest type and site-specific earlier studies. Evidence of strong association of C stock with management regime provides valuable information for policy makers to make informed choice of management regime for the landscape. [ABSTRACT FROM AUTHOR]

Deforestation for urbanization and agriculture expansion drastically reduced the area of the Atlantic forest biome in Brazil. To reverse this process, rehabilitating degraded lands, restoration plantations with native tree species show significant potential to rebuild the forest habitat and promoting carbon sequestration. High input silviculture (intensive fertilization and weed control), similar to those applied in commercial production forest plantations can increase productivity, accelerating forest restoration process. We evaluated the effects of two contrasting silvicultural systems, “traditional” (based on common silviculture of forest reforestation in Brazil – low input) and “intensive” (based on commercial plantations – high input) on carbon (C) stocks of a restoration plantation. We also compared the plantations with a mature forest remnant. Six years after planting, forest C stock (coarse roots and aboveground biomass) under intensive silviculture reached 23.3 Mg C ha −1 , more than 3-fold the stock under traditional silviculture (6.9 Mg C ha −1 ). Under both silvicultural systems, soil showed constant C stock (average of 33 Mg C ha −1 ). The C accumulation in biomass with intensive silviculture reached 12.8% of that stored in the mature forest (181.5 Mg C ha −1 ), compared with just 3.8% for traditional silviculture. Intensive silviculture provided nutrients and reduced competition with weeds, increasing growth and carbon sequestration. Forest plantations aiming at restoration and also carbon sequestration are practicable, and are highly responsive to intensive silviculture. [ABSTRACT FROM AUTHOR]

Woody plantings are increasing across the globe to satisfy ecosystem service markets for carbon and ecological restoration. Assessments of these complex woody systems typically use coarse-scale parameters, based on the climate and soil type of a region, and/or remotely assessed vegetation cover, to estimate carbon in their above- and belowground biomass. However it remains poorly known what factors influence their biomass at finer scales. Here, we investigated biomass variability after five years across a 250 ha environmental planting on a former agricultural property in south-western Australia. We aimed to understand which factors may influence observed biomass variability. The dominant canopy tree, Eucalyptus occidentalis , was planted as seedlings, and other woody species were direct sown in vegetation associations, according to soil type and landscape position, to reflect historic native assemblages. Results from 42 survey plots stratified across these associations showed variable seedling establishment from the seed mix, and that the amount of above- and belowground biomass varied widely (Coefficient of variation = 60%). A site mean and standard error were inadequate to capture biomass distribution. Instead, two modes were evident within the distribution at approximately 5 Mg ha −1 and 15 Mg ha −1 with variation primarily associated with differential seedling establishment and growth across the vegetation associations. Additionally, multiple regression analysis showed that stem density explained a significant amount of biomass variation whilst greater species richness was associated with increased biomass once stem density had been accounted for – models combining soil-vegetation association, number of individuals, and species richness explained between 60% and 80% of biomass variation depending on the response variable (total or live biomass) and choice of allometric equations to predict biomass. There was some evidence for a role of nitrogen-fixing species in determining biomass variation. There was no evidence for biomass variation being explained by the proportional contribution of the dominant canopy tree ( E . occidentalis ) or eucalypts in general once number of individuals had been accounted for, despite their large contribution to plot biomass. The substantial variation we show across the site has implications for carbon accounting practices and cost-benefit analyses guiding investment and regulation of the sector. Our results add weight to emerging evidence that restoring woody plant diversity can be compatible with efforts to maximize biomass and show the potential for diverse restored woodland assemblages to meet developing market demands for carbon. [ABSTRACT FROM AUTHOR]

Highlights: [•] Existing pantropical biomass allometric equations do not rely on African data. [•] The biomass of 101 trees was destructively measured in northeastern Gabon. [•] New site-specific allometric equations were fitted to these data. [•] Chave et al. (2005) equations for moist forest overestimated the biomass by 40%. [•] More data on tree biomass are needed in central African moist forests. [Copyright &y& Elsevier]

Highlights: [•] African tree species does not differ from common allometric patterns. [•] Pantropical multi-species allometric equations are valid in South-eastern Cameroon. [•] Using wood specific gravity from global data base little impacts biomass estimates. [•] Single-species models are not better than multi-species models. [Copyright &y& Elsevier]

Abstract: Subalpine forests in southwestern China were exploited extensively in the second half of the 20th century. Old growth forests (OGFs) dominated by firs had largely been replaced by spruce plantation forests (SPFs), spruce and birch mixed forests (SBMs), natural birch forests (NBFs), and fir and birch mixed forests (FBM). The main objectives of this study are to quantify the ecosystem carbon (C) stock in these five forest types and to estimate their C sequestration capacity. Sixty-nine stands were sampled across the Miyaluo forest region located in the subalpine zone of southwestern China. The C stocks in the tree-layer, understory, herbs, mosses, forest floor, coarse woody debris (CWD) and soil were estimated. The mean total biomass in SPF, SBM, NBF, FBM, and OGF was 125.9, 131.2, 135.7, 191.7, and 651.1t/ha, respectively. The OGF had the highest level of C stock. Total biomass and C density were significantly higher in FBM than those in SPF, SBM and NBF. FBM had a significantly higher mean annual increment (MAI) than all other types. Soil C accounted for a large proportion (68.4–76.5%) of the ecosystem C pools in SPF, SBM, NBF and FBM, but only 40.5% C was stored in the OGF’s soils relative to 51.5% in the biomass. Of the C stock in the upper 0–80cm soil, about 50% was stored in the upper 0–20cm, and more than 74% in the upper 0–40cm. Soil C stock in OGF, NBF and FBM was significantly higher than that in SPF and SBM. Soil disturbance during timber harvest, site preparation and tree planting explains less soil C stock in the SPF and SBM stands compared to other forest types. These results suggest natural mixed forest restoration can be a promising approach for increasing C sequestration capacity in the subalpine region. Also, reducing soil disturbance during forest management practices plays an important role in increasing the soil C stock. [Copyright &y& Elsevier]

Abstract: Tree plantations established on the natural forest lands increasingly expand globally but their significance in sequestering atmospheric carbon (C) is rarely examined. We investigated changes of C stocks in Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations converted from a natural broadleaved forest, based on a typical chronosequence in mountainland of subtropical China, which includes six first-generation Chinese fir stands at different development stages: 2- (recently regenerated), 7- (sapling), 16- (middle-aged), 21- (pre-mature), 40- (mature), and 88-year-old (over-mature), with a natural evergreen broadleaved forest (NF) as a comparison. The tree biomass C pool increased linearly from 2 to 40years old, with no further significant increase from 40 to 88years old. Compared with that in the NF forest, the mineral soil organic C (SOC) pool in Chinese fir plantation was decreased by 38.9% to a minimum at 16years old. The soils reaccumulated C only between 16 and 21years old, and then became neutral to C till to the over-mature stage, attaining an equilibrium SOC pool 30% lower than the pre-harvest level. The contribution of subsoil (below 20cm depth) to total profile SOC loss ranged from 53.2% in the recently regenerated stand to 81.1% in the 16-year-old stand, emphasizing the importance of subsoil for the SOC balance. Both litterfall and fine-root biomass of Chinese fir trees exhibited a decreasing trend during late stand development, while the stand fine-root biomass remained relatively constant due to an increased contribution from understory vegetations. The stagnancy in stand fine-root biomass during late stand development might prevent the accruement of total profile SOC. However, the reduction of tree roots and the increase of understory roots did change the vertical distribution of soil C at the over-mature stage: the surface 0–20cm soils accumulated C while the 20–40cm soils lose C. It is concluded that over-mature tree plantations had a limited role in continuously sequestering C as old-growth unmanaged forests did, and that the SOC pools of tree plantations can be hardly recovered to those of natural forests due to a large initial loss and a low late gain in SOC following tree plantation establishment. [Copyright &y& Elsevier]

Abstract: Forest soils store large amounts of carbon (C), and releases of C from this pool may significantly increase the CO2 concentration in the atmosphere. Organic matter decomposition in soils has been shown to strongly depend on temperature and soil moisture and is, therefore, susceptible to the climate change. Reliable methods are needed to monitor and predict the changes in soil C stocks. In this study, we tested the Yasso07 soil C model by comparing the model predictions to repeated soil C measurements of organic layer and, furthermore, to the estimates of two other C models, namely Yasso and ROMUL. In the model simulations, we used the litter input time series derived from forest biomass estimates based on the national forest inventories. Both the repeated empirical measurements and Yasso07 simulations indicated upland forest soils to be small sinks of C in Southern Finland. The Yasso07 model was able to predict both soil C stock and C accumulation within the error limits of the measured values. Yasso07 and the earlier version, Yasso, predicted very similar soil C stocks close to the measured values, but slightly underestimated C accumulation. The annual soil C changes predicted by the Yasso07 and ROMUL models were reasonably close to each other, even though the models are based on a very different basic structure. However, the differences in the model predictions were at the highest in years with the highest precipitation, indicating that there are still uncertainties in predicting the effects of soil moisture on the soil C stock changes. [Copyright &y& Elsevier]

Abstract: There is a growing need to understand, and ultimately manage, carbon storage by forest ecosystems. Broad-leaved evergreen forests of Taiwan provide an outstanding opportunity to examine factors that regulate ecosystem carbon storage. We utilized data from three Taiwan Forest Dynamics Plots (FS, LHC, and PTY) in which every tree is identified, measured, tagged and mapped, to examine factors regulating carbon storage as estimated from aboveground biomass. Allometric equations were used to estimate the aboveground biomass of each tree, and a model building procedure was used to examine relationships between plot-level aboveground biomass (AGB; Mg/ha) and a suite of topographic and biotic factors. We found that our study sites have AGB values comparable to some of the most carbon dense forests in the world. Across all three sites, maximum biomass was contained in the taxonomic families Fagaceae, Lauraceae and Theaceae. In the FS site, we identified slope convexity (P =0.03) and elevation (P <0.001) as topographic predictors of AGB and found that maximum AGB was found in topographically flat areas. In FS, stem density (P <0.001) was a significant biotic predictor of AGB and the maxima occurred at intermediate densities. In LHC, we found that convexity (P <0.001) and slope (P <0.001) were significantly related to AGB which was maximized along a topographic ridge in the plot. Species richness (P <0.001) was a significant biotic predictor of AGB in LHC, and the relationship indicated slightly higher AGB at higher levels of species richness. The only significant factor related to AGB in PTY was species richness (P =0.02). Further work is needed to seek a mechanistic understanding of topographic factors and species richness as drivers of carbon storage in forests. [Copyright &y& Elsevier]

Abstract: Tropical forests play an important role in the global carbon cycle. Despite an increasing number of studies have addressed carbon storage in tropical forests, the regional variation in such storage remains poorly understood. Uncertainty about how much carbon is stored in tropical forests is an important limitation for regional-scale estimates of carbon fluxes and improving these estimates requires extensive field studies of both above- and belowground stocks. In order to assess the carbon pools of a tropical seasonal forest in Asia, total ecosystem carbon storage was investigated in Xishuangbanna, SW China. Averaged across three 1ha plots, the total carbon stock of the forest ecosystem was 303tCha−1. Living tree carbon stocks (both above- and belowground) ranged from 163 to 258tCha−1. The aboveground biomass C pool is comparable to the Dipterocarp forests in Sumatra but lower than those in Malaysia. The variation of C storage in the tree layer among different plots was mainly due to different densities of large trees (DBH>70cm). The contributions of the shrub layer, herb layer, woody lianas, and fine litter each accounted for 1–2tCha−1 to the total carbon stock. The mineral soil C pools (top 100cm) ranged from 84 to 102tCha−1 and the C in woody debris from 5.6 to 12.5tCha−1, representing the second and third largest C component in this ecosystem. Our results reveal that a high percentage (70%) of C is stored in biomass and less in soil in this tropical seasonal forest. This study provides an accurate estimate of the carbon pool and the partitioning of C among major components in tropical seasonal rain forest of northern tropical Asia. Results from this study will enhance our ability to evaluate the role of these forests in regional C cycles and have great implications for conservation planning. [ABSTRACT FROM AUTHOR]

Abstract: Self-organizing maps (SOMs) are an advanced neural networks application. SOMs were applied for the spatially explicit estimation of forest carbon stocks for a test region in Thuringia (Germany). The approach utilizes in situ national forest inventory data and satellite remote sensing data (Landsat 7 ETM+) and provides maps showing a high-resolution spatial distribution of forest carbon stocks. The generated maps are compared to alternative estimates obtained by the k-nearest neighbour (kNN) method—a remote sensing based carbon assessment. Beside maps the SOM- and kNN-approaches were utilized to calculate statistical estimates of carbon stock and growing stock. The statistical estimates were validated by calculating bias and mean square errors with reference to in situ assessments. SOM- and kNN-approaches have been tested in a forested region in Central Germany. The results show that SOMs are an approach that has the ability to reproduce the spatial pattern of forest carbon stocks. SOMs are—with some restrictions—comparable to spatially explicit estimates generated by the kNN-method. [Copyright &y& Elsevier]

Abstract: Bamboo stands are one of the most important forest types in China, covering an area of about 4.99 million hectares, and estimation of their carbon stocks is vital for China''s national carbon accounting. Bamboo biomass and carbon fraction, as well as soil bulk density and soil organic matter content, data were collated from 40 publications describing conditions at 35 sites in 10 Chinese provinces where most bamboo stands are distributed. Carbon stocks and its changes in the living biomass and soil organic matter in bamboo stands in China in the past five decades were estimated based on these collated data together with the area of bamboo stands and number of bamboo culms derived from the National Forestry Inventory (NFI). Our estimates indicate that the carbon stocks in bamboo stands in China have been increasing since the 1950s with estimated values of 318.55Tg C (1950–1962), 427.37TgC (1977–1981), 463.80TgC (1984–1988), 493.00TgC (1989–1993), 548.79TgC (1994–1998) and 631.58TgC (1999–2003) accompanying the increase of bamboo stand area. Based on correlation between forest area and bamboo area, as well as the trends of forest area predicted in government strategy documents for forest development over the next five decades, the carbon stocks in bamboo stands for 2010, 2020, 2030, 2040 and 2050 are estimated to be 727.08TgC, 839.16TgC, 914.43TgC, 966.803TgC and 1017.64TgC, respectively. [Copyright &y& Elsevier]

Abstract: A mass-based carbon (C) concentration ([C]) of 50% in dry wood is widely accepted as a constant factor for conversion of biomass to C stock. However, the [C] varies with tree species, and few data on [C] are available for the Chinese temperate tree species. In this study, we examined inter- and intra-specific variations of [C] in biomass tissues for 10 co-occurring temperate tree species in northeastern China. The species were Korean pine (Pinus koraiensis Sieb. et Zucc.), Dahurian larch (Larix gmelinii Rupr.), Mongolian oak (Quercus mongolica Fisch.), white birch (Betula platyphylla Suk.), Amur cork-tree (Phellodendron amurense Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Manchurian ash (Fraxinus mandshurica Rupr.), aspen (Populous davidiana Dode), Mono maple (Acer mono Maxim.), and Amur linden (Tilia amurensis Rupr.). The mean tissue [C] across the species varied from 47.1% in fine root to 51.4% in foliage. The mean stem [C] of the 10 species was 49.9±1.3% (mean±SE). The weighted mean C concentration (WMCC) for the species ranked as: Amur cork-tree (55.1%)>Amur linden (53.9%)>Korean pine (53.2%)>Manchurian ash (52.9%)>Manchurian walnut (52.4%)>Mongolian oak (47.6%)>Dahurian larch (46.9%)>Mono maple (46.4%)>white birch (46.1%)>aspen (43.7%). The WMCC of the dominant trees was negatively correlated to mean annual increment of biomass (MAI), suggesting that planting fast-growing tree species for C sequestration in afforestation and reforestation practices sacrifice some C gain from increasing MAI due to decreasing [C]. Failing to account for the inter- and intra-specific variations in [C] will introduce a relative error of −6.7% to +7.2% in estimates of biomass C stock from inventory data, of which >93% is attributed to ignoring the inter-specific variation in [C]. [Copyright &y& Elsevier]

Abstract: Allometric equations can be used to estimate the biomass and carbon stock of forests. However, so far the equations for Dipterocarp forests have not been developed in sufficient detail. In this research, allometric equations are presented based on the genera of commercial species and mixed species. Separate equations are developed for the Dipterocarpus, Hopea, Palaquium and Shorea genera, and an equation of a mix of these genera represents commercial species. The mixed species is constructed from commercial and non-commercial species. The data were collected in lowland mixed Dipterocarp forests in East Kalimantan, Indonesia. The number of trees sampled in this research was 122, with diameters (1.30m or above buttresses) ranging from 6 to 200cm. Destructive sampling was used to collect the samples where diameter at breast height (DBH), commercial bole height (CBH), and wood density were used as predictors for dry weight of total above-ground biomass (TAGB). Model comparison and selection were based on Akaike Information Criterion (AIC), slope coefficient of the regression, average deviation, confidence interval (CI) of the mean, paired t-test. Based on these statistical indicators, the most suitable model is ln(TAGB)= c + αln(DBH). This model uses only a single predictor of DBH and produces a range of prediction values closer to the upper and lower limits of the observed mean. Model 1 is reliable for forest managers to estimate above-ground biomass, so the research findings can be extrapolated for managing forests related to carbon balance. Additional explanatory variables such as CBH do not really increase the indicators’ goodness of fit for the equation. An alternative model to incorporate wood density must be considered for estimating the above-ground biomass for mixed species. Comparing the presented equations to previously published data shows that these local species-specific and generic equations differ substantially from previously published equations and that site specific equations must be considered to get a better estimation of biomass. Based on the average deviation and the range of CI, the generalized equations are not sufficient to estimate the biomass for a certain type of forests, such as lowland Dipterocarp forests. The research findings are new for Dipterocarp forests, so they complement the previous research as well as the methodology of the Good Practice Guidance for Land Use and Land Use Change and Forestry (GPG-LULUCF). [Copyright &y& Elsevier]

Abstract: Species choice is potentially an important management decision for increasing carbon stocks in forest ecosystems. The substitution of a slow-growing hardwood species (Quercus petraea) by a fast-growing conifer plantation (Pinus nigra subsp. laricio) was studied in central France. Simulations of carbon stocks in tree biomass were conducted using stand growth models Fagacées for sessile oak and PNL for Corsican pine. The changes in soil carbon were assessed using the Century model and data from two European soil monitoring networks: 16km×16km grid and RENECOFOR. Carbon in wood products was assessed with life cycle analysis and lifespan of final products. However, only carbon stocks and their variation were accounted for: effects of energy-consuming materials or fossil fuel substitution are excluded from the analysis. To compare the growth of these two types of forest stands, an important part of the study was to assess the productivity of both species at the same site, using National Forest Inventory data. Simulations showed that (i) this species substitution would lead to an additional carbon storage of 1.6tC/ha/year with the conifer plantation during its first rotation (64 years) (ii) at steady state, the time-averaged carbon stock of the conifer plantation over the whole rotation would be 42tC/ha to 47tC/ha lower than that of the hardwood even-aged forest, depending on applied silvicultural scenarios. The time-averaged carbon stocks including vegetation, soil and wood products are 221tC/ha for sessile oak, and around 175tC/ha for Corsican pine. The amount of carbon stored in wood products is low compared to the total carbon stock (5% for sessile oak, 8–8.5% for Corsican pine), mainly due to important losses during early wood processing, and to the short lifespan of wood products compared to the rotation length of forest stands. [Copyright &y& Elsevier]

Abstract: Forest soil organic carbon (SOC) and forest floor carbon (FFC) stocks are highly variable. The sampling effort required to assess SOC and FFC stocks is therefore large, resulting in limited sampling and poor estimates of the size, spatial distribution, and changes in SOC and FFC stocks in many countries. Forest SOC and FFC stocks are influenced by tree species. Therefore, quantification of the effect of tree species on carbon stocks combined with spatial information on tree species distribution could improve insight into the spatial distribution of forest carbon stocks. We present a study on the effect of tree species on FFC and SOC stock for a forest in the Netherlands and evaluate how this information could be used for inventory improvement. We assessed FFC and SOC stocks in stands of beech (Fagus sylvatica), Douglas fir (Pseudotsuga menziesii), Scots pine (Pinus sylvestris), oak (Quercus robur) and larch (Larix kaempferi). FFC and SOC stocks differed between a number of species. FFC stocks varied between 11.1MgCha−1 (beech) and 29.6MgCha−1 (larch). SOC stocks varied between 53.3MgCha−1 (beech) and 97.1MgCha−1 (larch). At managed locations, carbon stocks were lower than at unmanaged locations. The Dutch carbon inventory currently overestimates FFC stocks. Differences in carbon stocks between conifer and broadleaf forests were significant enough to consider them relevant for the Dutch system for carbon inventory. [Copyright &y& Elsevier]

Abstract: The IPCC-GPG on Greenhouse Gas Monitoring offers countries several options for reporting. The current study selected management effects and decay of dead woody material to demonstrate the dependence of different approaches and assumptions for carbon stock and carbon stock change estimates. For a given set of inventory data the reported change of carbon stock varied between 3.1tonnesCha−1 yr−1and 34.4tonnesCha−1 yr−1 for a 10-year period. Based on the available data set from a test area in the federal state of Salzburg (Austria) the effect of different scenarios for harvesting operations and mortality on reported carbon release was studied. The scenarios covered timber utilization at different points in time and two mortality rates (constant and exponential). A proportion of harvesting was assumed to remain inside the forest as logging residues and entered together with mortality a decay process. Two different lifetimes for decay (10 and 50 years) and constant and negative exponential decay rates were simulated. Those decisions affect the amount of carbon released considerably. For a 10-year period between 5% and 80% of the carbon content of dead woody material that accumulated within the period is released to the atmosphere. [Copyright &y& Elsevier]

The 21st century has brought new challenges for forest management at a time when global climate change is becoming increasingly apparent. Additional to various goods and services being provided to human beings, forest ecosystems are a large store of terrestrial carbon and account for a major part of the carbon exchange between the atmosphere and the land surface. Depending on the management regime, forests can thus be either a sink, or a source of atmospheric carbon. Southeast Asia or ASEAN comprises 10 countries of different cultures and political background. Rapid economic development and fast-growing population in the region have raised much concern over the use of natural resources, especially forest resources. This study aims at finding the appropriate measures for sustainable use and management of tropical forests on a long-term basis. Between 1990 and 2000, about 2.3 million ha of forest were cleared every year and lost to other forms of land use. In terms of carbon emissions, a net amount of approximately 465 million t per year were released to the atmosphere over the same period, which amounts to 29% of the global net carbon release from deforestation worldwide.This study provides an approach to analyzing the implications of alternative forest and land management options on forest carbon stocks. This is done in three steps: First, observed trends in land use are expressed in terms of a model in order to create a scenario for the period 1980–2050. Second, forest management practices and timber production rates are analyzed and three management scenarios are created: (1) continuing the current rate of exploitation, (2) management for long-term economic gains, and (3) climate-beneficial management. Third, the impact of the three scenarios on regional carbon storage is estimated on the basis of a carbon balance model. Comparing the additional rate of carbon sequestration of scenario (3) over scenario (2), and taking into account differing management costs, we also discuss a framework for industrialized countries to invest in carbon credits in the region in order to fulfil their commitments under present and future climate protection agreements. [Copyright &y& Elsevier]

Forest inventory data are widely used for broad-scale quantification of forest carbon budgets. Such data usually represent forest wood volume (m3 ha−1), which needs to be converted to biomass carbon value (Mg C ha−1) for carbon stock estimates. Our main objective is to estimate the carbon stock for all sugi (Cryptomeria japonica D. Don) and hinoki (Chamaecyparis obtusa Endl.) plantations in Japan on the basis of age-class-based forestry statistics. To achieve this purpose, we estimated regional wood volume accumulation and biomass allocation over time for sugi and hinoki forests to calculate and map the carbon stock in all sugi and hinoki plantations in Japan on the basis of forestry statistics. Hinoki forests showed smaller accumulation of volume than sugi forests from ca. 25 years old to maturity; the accumulation of wood volume per hectare at 80 years old was <600 m3 ha−1 for hinoki and >600 m3 ha−1 for sugi. Patterns of biomass allocation to forest components varied by forest type; the proportion of branch biomass in 0–20-year-old hinoki forests is 5–10% larger than that of sugi; the proportion of stem biomass in the same age range is 5–10% smaller than that of sugi; the ratio of roots was approximately constant as its average value, 20.4% for sugi and 22.7% for hinoki. The ratios of total biomass to bole biomass (i.e., expansion factor (EF), Mg total biomass Mg−1 bole biomass) decreased with increasing age, and became nearly constant after 30 years old for sugi and hinoki. The mean EFs were the same for the two forest types, with a value of 1.72 Mg Mg−1. Our results suggest that sugi and hinoki plantations in Japan, respectively, store 346.4×106 and 139.2×106 Mg of carbon, with an area-weighted mean of 76.81 and 58.01 Mg C ha−1. High amounts of carbon stock in both sugi and hinoki are located in the southwestern part of Japan. [Copyright &y& Elsevier]

Temporal changes in organic C stock with soil development were assessed by determining organic C stocks in soils on new deposits of andesitic volcanic materials of different ages. The soils included in this study have developed on avalanche debris of 91-year-old at Bandai, 197-year-old at Asama Kanbara, and 1110-year-old at Yatsugatake. Soils at Asama Oiwake had developed on 849-year-old material from pyroclastic flow. All the soils were located in montane zone and had similar cool temperate and humid climate.Organic C in these soils increased with soil age and therefore also in soil depth. However, organic C concentration in the surface 0–10 cm soil varied among sites independent of their age (5.3% in Bandai, 3.4% in Asama Kanbara, 5.5% in Asama Oiwake, and 12.5% in Yatsugatake). The organic C concentration in the surface 0–10 cm depth at Yatsugatake site was similar in the soil developed from the new deposits to that developed in an adjacent area under much older deposit.Organic C contents in 0–100 cm soil depth were: 53±29 t ha−1 (n=11) at Bandai, 55 t ha−1 at Asama Kanbara, 85±18 t ha−1 (n=2) at Asama Oiwake, and 127±36 t ha−1 (n=3) at Yatsugatake sites. Almost half of the organic C in the 0–100 cm depth was present in the surface 10 cm depth. Organic C content in soils on the new deposits was much lower than in those of the adjacent area with much older deposits. Soil organic C at Yatsugatake site maybe approaching a steady-state condition which was supported by the presence of immature soil humic acids in it.Rate of organic C accumulation declined with soil age, with a rapid increase of organic matter occurring during early stages of soil development. Accumulation rates of organic C were 0.10 t ha−1 per year at Asama Oiwake and 0.11 t ha−1 per year at Yatsugatake sites, and these rates were comparable with those reported as maximum values in the literature. [Copyright &y& Elsevier]

The soils of western European forests may be accumulating carbon, because tree biomass has been expanding in these forests already for decades, and the more numerous and larger trees can produce more litter. We calculated the carbon budget of soils and trees in the forests of 14 EU countries plus Norway and Switzerland from 1950 to 2040 by integrating forest resource information (inventory data from 1950 to 1990 and a forest resource forecast from 2000 to 2040), biomass allocation and turnover information, and a dynamic soil carbon model.The carbon stock of the soils increased throughout the studied period. In 1990, the soil carbon sink was 26 Tg per year. This is 32 or 48% compared with our two estimates of the tree carbon sink for that year. Until 2040, the soil carbon sink was estimated to increase to 43 Tg per year. This would already be 61 or 69% compared with the tree carbon sink that year.In 1990, the soils contributed most to the total forest carbon sink in central Europe, where the soil carbon sink was almost as large as the tree carbon sink. The soils were least important in southern Europe, where the soil carbon sink was less than 25% compared with the tree carbon sink. In the future, the contribution of the soils to the total forest carbon sink was estimated to increase everywhere except in southern Europe.The soil carbon stocks increased mainly because litter fall from living trees increased while the other sources of soil carbon, i.e. the residues of harvests and natural disturbances, varied less. This litter fall was also the largest source of soil carbon accounting for 70–80% of the total. The soil carbon stocks in these forests could thus be most effectively controlled by forest management actions, such as the choices of harvest regimes or tree species, which especially affect the litter production of living trees.According to an uncertainty analysis, we may have overestimated the soil carbon sink by 35% or underestimated it by 50% throughout the studied period. The largest uncertainties were related to calculating the litter production of living trees and decomposition in soil. [Copyright &y& Elsevier]

In this study, effects of altered rotation length, nitrogen deposition and changing climate on harvest removal and carbon sequestration of forest, as well as on economic profitability of forestry, were assessed. This study was based on simulations with a gap-type forest succession model in the conditions that represent Scots pine stands in southern Finland.Both warmer climatic conditions and increased nitrogen deposition enhanced forest productivity and timber yield. This also shortened the optimum rotations based on mean annual yield and soil expectation value. The highest carbon stock in forests, i.e. the highest mean annual carbon stock in the forest over a rotation period, was achieved with long rotations and higher nitrogen deposition. However, a warmer climate had an opposite effect on the forest carbon stock, because enhanced decomposition of soil organic matter resulted in a lower carbon stock in the forest soil. [Copyright &y& Elsevier]

• Above ground biomass (AGB) and coarse woody debris (CWD) decreased with elevation. • Size of living trees and CWD decreased with elevation. • The decomposition rate was higher at higher elevations due to smaller CWD. • The ratio of CWD to AGB was lower at higher elevations. • Climate change may alter the balance between CWD and AGB with elevation. In recent years, coarse woody debris (CWD) of deadwood has attracted attention as a long-term carbon pool for global warming problems. Environmental factors such as temperature and precipitation vary greatly with elevation. Hence, it is expected that the carbon storage by CWD varies with elevation. However, few studies have examined the abundance of CWD along elevations. Therefore, we investigated the abundance and decay classes of CWD, aboveground biomass (AGB) and aboveground net primary production (ANPP) of living trees along an elevational gradient (1600–2800 m above sea level) in subalpine coniferous forests, central Japan. AGB, ANPP and CWD decreased with increasing elevation. AGB at 2800 m was about 10% of that at 1600 m a.s.l. On the other hand, CWD at 2800 m was only 2.2% of that at 1600 m a.s.l. Thus, the ratio of CWD to AGB was lower at higher elevations. The relative frequency of small CWD increased with elevation. In addition, smaller CWD tended to decay less. The lower ratio of CWD mass to AGB at higher elevations was probably caused by smaller CWD because small CWD rapidly disappears via the high decomposition rate due to its high ratio of surface area to volume. Therefore, this study suggests that the importance of CWD relative to AGB for carbon storage decreases with elevation in subalpine forests. Climate change may alter the balance between CWD and AGB by changing ANPP and decomposition rates along elevation gradients. [ABSTRACT FROM AUTHOR]

• Human management greatly influenced C stock increment in China's forest plantations. • Vegetation biomass C can be enhanced via implementation of higher management intensity. • Management intensity should be considered in projection of future forest C sink. Characterized by young age and a large area been newly planted, China's forests were projected to have high carbon (C) uptake potential in the future. While such a potential assumes continuous human management, the effects of forest management on C uptake potential are less clear. Using surveyed data collected from a recent nationwide field campaign conducted between 2011 and 2015, we examined human management effects on C stock dynamics in three of the most widely planted forests in southern China, i.e. Pinus massoniana , Cunninghamia lanceolate , and Eucalyptus. Vegetation C accumulation rates were larger under higher management intensities in Pinus massoniana and Eucalyptus , while there was no such a pattern in Cunninghamia lanceolate. Human management has contributed to vegetation C increment by 2.42 Tg C yr−1 and 0.55 Tg C yr−1 in Pinus and Cunninghamia forests. While in comparison, human management impacts on C accumulation were not accountable in Eucalyptus due to lack of naturally regenerated forests. Moreover, we found that potential vegetation C accumulation can be enhanced by 7.86 Tg C yr−1 from higher management intensity with 3.86, 2.17, and 1.83 Tg C yr−1 from Pinus massoniana , Cunninghamia lanceolate , and Eucalyptus , respectively. We also advise that different management intensities should be considered to avoid biases for projection of future C sink from forest plantations regionally or nationally. [ABSTRACT FROM AUTHOR]

• First study applying terrestrial laser scanning in the Brazilian savanna. • TLS effectively estimated aboveground biomass at plot-scales in sparser savannas. • In dense and tall forests, vegetation structure was less adequately characterized. • TLS accurately captured the structural differences between vegetation formations. • Results present a step forward in applying TLS for biomass estimation in savannas. Understanding structural variations in natural systems can help us understand their responses to disturbance and environmental changes and plan for the mitigation of human-induced impacts. Terrestrial laser scanning (TLS) is a technological solution to quickly and accurately capture and model vegetation structure. In the Brazilian Cerrado biome, characterized by highly heterogeneous plant formations and marked seasonality, TLS may help improve aboveground biomass (AGB) estimates. This study aimed to use single-scan TLS-derived metrics to predict plot-scale aboveground biomass for three vegetation types with high structural diversity and biomass content (woodland savanna, forested savanna, and gallery forest). Ten plots were scanned in each vegetation type, and variables related to point density at different strata and height distribution were extracted from the point cloud to predict AGB measured in local field inventories. The woodland savanna provided good fit models with only two metrics (rainy season: proportion of points below 1.37 m and height of the 99th percentile; adj-R2 = 0.92, RMSE (root mean square error) = 2.67 Mg/ha or 12%; and dry season: height of the 20th and the 99th percentiles; adj-R2 = 0.88, RMSE = 3.32 Mg/ha or 15%). The model for the forested savanna had relatively less explanatory power with one influential predictor (forested savanna: height of the 20th percentile; adj-R2 = 0.58, RMSE = 6.85 Mg/ha or 21%). For the gallery forest, however, the canopy structure could not be adequately characterized due to occlusion of laser returns by dense sub-canopy strata. Our study shows the strong potential of the terrestrial LiDAR technology for estimation of plot-based biomass across diverse savanna vegetation types, where the sparse tree structure allows for better laser penetration the accurate generation of height profiles. [ABSTRACT FROM AUTHOR]