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Sustaining forest carbon sinks is a priority in climate change mitigation and forest management strategies. However, several issues confront the role of Philippine forests in climate change mitigation. These include the loss of old-growth cover, unsustainable forest landuse practices, and lack of site-specific modelling. These are the realities in the Quirino Forest Landscape Project (QFLP), a semi-contiguous collection of secondary forests in four municipalities of Quirino Province. This study was undertaken to develop a forecast model for carbon in aboveground of underutilised trees in QFLP. Data were collected through field inventory, the National Mapping and Resource Information Authority Land Cover Databases, and secondary sources. Multiple linear regression, principal components analysis, and biodiversity indices were used to analyse the data collected from different sampling areas to develop a forecast model. Findings suggest that the QFLP forest was secondary, as evidenced by the fact that > 60% of the trees were underutilised. With the ongoing decline in forest cover due to resource use and lack of forestry policy enforcement, it is worth noting that the carbon sequestration potential of underutilised species is not dependent on ecological dominance; that is, species that are more vulnerable to local extinction have higher potential to gain carbon. Given all the variables and their high forecasting power, the study demonstrated that the developed model was precise enough to provide future carbon capture values for QFLP. [ABSTRACT FROM AUTHOR]

The foremost role of forest vegetation in storing biomass and carbon (C) stock constitutes one of the main nature-based solutions to mitigate climate change. In this study, we aimed to quantify biomass and C stock partitioning in multiple vegetation strata (tree, shrub, herb, and ground floor layers) of major forest types in Jammu and Kashmir, Western Himalaya, India. We used a stratified random cluster sampling strategy to collect field data in 96 forest stands of 12 forest types (altitudinal range: 350 to 3450 m) in the study region. We evaluated the degree to which the carbon stock of the entire ecosystem was dependent on the multiple vegetation strata using the Pearson method. Across all the forest types, the average total ecosystem-level biomass was estimated to be 181.95 Mgha−1 (range: 60.64–528.98). Forest strata-wise, the maximum biomass of 172.92 Mgha−1 (range: 50.64-514.97) was found in the tree vegetation, followed by 5.58 Mgha−1 (range: 2.59–8.93) in understory vegetation (shrubs and herbaceous), and 3.44 Mgha−1 (range: 0.97 and 9.14) in the forest floor. The total ecosystem-level biomass showed a peak at mid-elevation coniferous forest types, whereas the lowest was observed in low-elevation broad leaved forest types. At the ecosystem-level, on average, the understory contributed 3% and the forest floor 2% to the total C stock across the forest types. The shrub layer contributed up to 80% of total understory C, with the herbaceous layer accounting for the remaining 20%. The ordination analysis clearly shows that anthropogenic and environmental variables significantly (p ≤ 0.002) influence the forest types' C stock in the region. Our findings have significant implications for conserving natural forest ecosystems and restoring degraded forest landscapes in this Himalayan region, which in turn can lead to better carbon sequestration and climate mitigation outcomes. [ABSTRACT FROM AUTHOR]

Increasing evidence shows that both abiotic and biotic factors affect species richness and stand biomass in forests, yet the relative and interactive impacts of these factors remain debated in different forest ecosystems. We sampled 55 forest plots (600 m2 per plot) on two subtropical mountains with distinct diversity levels in China to explore the elevational patterns of tree species richness and stand biomass and examined how they were affected by climate, stand structure, and dominance of mycorrhizal types. The tree species richness of both mountains decreased with elevation, while the stand biomass exhibited unimodal or no apparent trends. On both mountains, the tree species richness was strongly shaped by climatic factors, especially the mean annual temperature, whereas the stand biomass was mainly affected by the stand structure. Specifically, on the mountain with higher species richness, both the tree height variation and maximum tree size were strongly correlated with the stand biomass. Meanwhile, on the species-poor mountain with higher elevations, only the maximum tree size correlated with the stand biomass. The dominance of ectomycorrhizal trees also had positive effects on the stand biomass of both mountains. These results suggest that climate, stand structure, and mycorrhizal dominance may jointly drive the decoupling between tree species richness and stand biomass, which should be given more attention in further research and forest management to achieve the climate change mitigation goals. [ABSTRACT FROM AUTHOR]

Background: In Ethiopia, highland bamboo has been cultivated in various niches: farmlands, riverbanks, woodlot boundaries, and homesteads, and agroforestry systems. However, the biomass and carbon storage of potential of bamboo forests across niches is not well characterized in Ethiopia. Therefore, this study was conducted to estimate the biomass and carbon storage potential of highland bamboo plantations in northwestern Ethiopia. To this end, a total of 60 circular plots measuring 100 m2 with a radius of 5.64 m were randomly established on the homestead, woodlot, and riverbank plantation niches to conduct the inventory. The biomass storage of bamboo was calculated based on previously published allometric equations. Biomass and carbon stock variations among age-classes and niches of bamboo forests were analyzed using analysis of variance (ANOVA) and subsequent pairwise means comparisons of carbon stocks among niches were performed via post hoc Tukey test at p < 0.05. Results: Results showed that the mean aboveground biomass (AGB) ranged from 150.18 – 191.42 Mg ha−1 in the entire niches. The highest amount of AGB was stored in the homestead niche (191.42 Mg ha−1) followed by the woodlot (180.11 Mg ha−1) and riverbank niche (150.17 Mg ha−1), respectively. The highest carbon stock (111.56 Mg C ha−1) was found in the homestead niche while the smallest amount was recorded in the riverbank niche (87.52 Mg ha−1). The homestead bamboo plantation has the highest biomass storage due to the application of manure and natural fertilizer, regular harvesting and management of culms, and protection from illegal harvesting and grazing. Conclusion: This study highlights the importance of bamboo plantations in climate change mitigation. Hence, bamboo plantation should be promoted; and natural resource management and forestry departments of the government, Universities, research centers, the International Bamboo and Rattan Organization (INBAR), and other partners should work with local communities to expand bamboo plantation on their homesteads and degraded lands. [ABSTRACT FROM AUTHOR]

Forest biomass plays an essential role in forest carbon reservoir studies, biodiversity protection, forest management, and climate change mitigation actions. Synthetic Aperture Radar (SAR), especially the polarimetric SAR with the capability of identifying different aspects of forest structure, shows great potential in the accurate estimation of total and component forest above-ground biomass (AGB), including stem, bark, branch, and leaf biomass. This study aims to fully explore the potential of polarimetric parameters at the C- and L-bands to achieve high estimation accuracy and improve the estimation of AGB saturation levels. In this study, the backscattering coefficients at different polarimetric channels and polarimetric parameters extracted from Freeman2, Yamaguchi3, H-A-Alpha, and Target Scattering Vector Model (TSVM) decomposition methods were optimized by a random forest algorithm, first, and then inputted into linear regression models to estimate the total forest AGB and biomass components of two test sites in China. The results showed that polarimetric observations had great potential in total and component AGB estimation in the two test sites; the best performances were for leaves at test site I, with R2 = 0.637 and RMSE = 1.27 t/hm2. The estimation of biomass components at both test sites showed obvious saturation phenomenon estimation according to their scatter plots. The results obtained at both test sites demonstrated the potential of polarimetric parameters in total and component biomass estimation. [ABSTRACT FROM AUTHOR]

Biomass procured from forests affected by natural disturbances as a bioenergy source is increasingly considered in the context of climate change mitigation. By comparing clearcuts with and without biomass procurement, we aimed to determine the effects of biomass extraction performed alongside lumber harvesting on regeneration density, number of planting microsites, forest renewal costs, and carbon fluxes, in harvested boreal stands affected by spruce budworm. The results showed that biomass procurement increased regeneration density and number of planting microsites. Reduction of downed woody debris due to biomass procurement lowered site preparation costs by 282.07 $CAN·ha−1, equivalent to 14.45 $CAN per oven-dry metric ton (odmt−1) of harvested biomass. Product value from biomass processing had to reach from 13.90 to 76.84 $CAN·odmt−1 to make biomass procurement operations profitable. Since biomass procurement significantly increased stocking and reduced the amount of decaying debris, it also reduced cumulative CO2 emissions relative to scenarios without biomass procurement. However, ensuring forest renewal through site preparation and plantation per se, irrespective of biomass procurement, played a more important role for carbon sequestration and net balance. Integrating biomass harvesting with silviculture could have significant ecological and financial impacts on forest management while supporting mitigation efforts against climate change. [ABSTRACT FROM AUTHOR]

Well managed teak stands can contribute towards mitigation of climate change by storing carbon in their solid wood products. However, spatial estimates of teak's potential carbon stocks is lacking in the support of precision forest management. The aim of this study was to estimate the carbon in above- and belowground biomass of teak stands and predict their spatial variabilities. Tree data were measured biennially in 46 permanent plots of 213 ha, between 2nd and 12th year, in which thinning was performed at 5th, 8th and 11th year. Carbon stocks were estimated using equations, and geostatistical modelling was carried out by semivariance analyses and ordinary kriging method. Above-ground carbon mean values ranged between 2.95 and 59.10 t ha-1, with reduction to 57.61 t ha-1 after third thinning. Minimum and maximum belowground carbon mean values were 0.67 and 8.06 t ha-1 respectively, decreasing to 7.51 t ha-1 after last thinning. Carbon stocks increased over the years and showed spatial dependence, however, they were influenced by the thinning. Teak stands presented potential carbon stores since the carbon remained in their solid wood products, compared to other species used for energy, pulp and paper. This evidence showed the importance of teak in mitigating climate change. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stand spatial structure plays an important role in the fragile natural secondary forest. • Species diversity have a negative impact in changing restored woodlands, thereby reducing productivity. • Stand spatial structure has a stronger impact on forest carbon sink than species diversity. • Stand spatial structure is a prioritized indicator in the regulation of fragile forest ecosystems. Increasing attention for adjusting forest structural and species diversity has been paid to enhance carbon storage. However, the relative importance of stand spatial structural diversity and species diversity to restored stand carbon stocks remains unclear. To address this issue, we conducted a sample plot setup in the Loess Plateau with the aim of exploring the effects of stand spatial structural diversity and species diversity on forest carbon stocks. Therefore, we determined index parameters for species diversity (Simpson, Shannon-Wiener, and Pielou) and spatial structural diversity (Angular scale, Mingling, Aggregation, and Competition) within the oak forest ecosystem. We examined carbon storage in all vegetation organs and different soil layers. Additionally, we employed a structural equation model to develop a model that illustrates the effects of stand spatial structure and species diversity on ecosystem carbon storage. The results reveal that stand spatial structure and species diversity influence the ecosystem carbon storage through biomass (trees and litter) and soil carbon (0–100 cm). Stand spatial structure exhibits positive direct effects (path coefficients: 0.764 and 0.890), while species diversity shows negative direct effects (−0.320 and −0.206) on biomass and soil carbon, respectively. Finally, the total effect of spatial structure diversity on forest carbon storage surpasses that of species diversity. Therefore, stand spatial structure should be adjusted preferentially during forest management in fragile ecological environment. Our results provide important insights into the climate change mitigation potential associated with the structure-based management of forests. [ABSTRACT FROM AUTHOR]

Forest biomass is key in Earth carbon cycle and climate system, and thus under intense scrutiny in the context of international climate change mitigation initiatives (e.g. REDD+). In tropical forests, the spatial distribution of aboveground biomass (AGB) remains, however, highly uncertain. There is increasing recognition that progress is strongly limited by the lack of field observations over large and remote areas. Here, we introduce the Congo basin Forests AGB (CoFor-AGB) dataset that contains AGB estimations and associated uncertainty for 59,857 1-km pixels aggregated from nearly 100,000 ha of in situ forest management inventories for the 2000 – early 2010s period in five central African countries. A comprehensive error propagation scheme suggests that the uncertainty on AGB estimations derived from c. 0.5-ha inventory plots (8.6–15.0%) is only moderately higher than the error obtained from scientific sampling plots (8.3%). CoFor-AGB provides the first large scale view of forest AGB spatial variation from field data in central Africa, the second largest continuous tropical forest domain of the world. Measurement(s) organic material • aboveground biomass Technology Type(s) digital curation Sample Characteristic - Environment forested area Sample Characteristic - Location Central Africa Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12504911 [ABSTRACT FROM AUTHOR]

• Mitigating increasing atmospheric CO 2 includes management of forest carbon stocks. • We observed forest carbon in a long-term non-intervention forest during 20 yrs. • We observed spatio-temporal variation in the five principal forest carbon pools. • We observed no evidence of continued carbon sequestration in old-growth forests. • Our study has implications for strategies related to climate change mitigation. Forest management, including setting aside non-intervention forests, is currently debated as a measure to efficiently mitigate climate change. Temperate, old-growth forests are rare and the long-term effect of setting aside forest reserves, e.g. for habitat conservation, on forest carbon stocks and carbon sequestration remains uncertain. In this study, we assessed the five principal forest carbon pools in a semi-natural, temperate forest in Denmark and evaluated the changes in biomass and dead wood carbon stocks over 20 years. We also benchmarked the current carbon stocks against those in managed beech-dominated forests in the same region. In the most recent inventory, carbon stocks totalled 395 Mg ha−1 of which 47% was in above-ground live biomass, 11% in below-ground biomass, 9% in dead wood, 2% in the forest floor, and 31% in the top 75 cm of the mineral soil. Compared to similar, but managed forests in the same region, carbon stocks in above- and below-ground biomass as well as in dead wood were notably larger. However, analyses of above- and below-ground biomass and dead wood carbon stocks showed remarkable stability during the past 20 years, despite major disturbances in terms of windthrows and various pathogens. Despite the overall stability of carbon stocks we observed some significant spatio-temporal changes. Notably, the observed dynamics illustrate a general retreat of Q. robur and increasing dominance of F. sylvatica under a small-scale disturbance regime. The forest floor and soil carbon stocks averaged 131 ± 4 Mg ha−1 and were very similar to those of managed beech-dominated forests, suggesting little potential for soil carbon sequestration from setting forests aside as unmanaged. Our study has implications for selection of adequate forest management strategies to efficiently mitigate climate change as it confirms the large and persistent carbon stocks in old-growth forests compared to managed forests, but offers no evidence of continued carbon sequestration in old-growth forests. [ABSTRACT FROM AUTHOR]

Human activities have the potential to enhance carbon sequestration by the world's forests and contribute to climate change mitigation. Voluntary carbon trading is currently the only option to pursue and reward carbon sequestration by forestry activities. Carbon credits for enhanced sequestration can be sold to partners wishing to offset their own emissions. Here we illustrate the steps taken to design guidelines for the generation of voluntary carbon credits by improved forest management in Piemonte, Italy. The guidelines have been developed in a joint effort by academia, regional administrations, forest owners and professional consultants. In particular, we show how to compute the baseline and the additionality of credit-generating forest management activities, and how to reconcile the generation of forest carbon credits with law requirements, technical limitations, and the provision of other ecosystem services. To illustrate the profitability of carbon credit generation, we simulated the application of carbon credit guidelines to two forest-rich mountain watersheds in the southern part of the Piemonte region. The two dominating tree species are beech (Fagus sylvatica L.) and chestnut (Castanea sativa Mill.). We computed current forest carbon stock and carbon credits generated in 20 years under business as usual and an alternative biomass retention scenario. The IFM resulted in an avoided harvest of 39,362 m³ for a net total of 64,014 MgCO2e after subtracting harvest emissions, or 38 Mg ha-1 throughout the permanence period of 20 years. These steps can be replicated in other mountain regions where there is interest in promoting this ecosystem service as an alternative or an addition to production-oriented forest management. [ABSTRACT FROM AUTHOR]

Tropical rainforests store enormous amounts of carbon, the protection of which represents a vital component of efforts to mitigate global climate change. Currently, tropical forest conservation, science, policies, and climate mitigation actions focus predominantly on reducing carbon emissions from deforestation alone. However, every year vast areas of the humid tropics are disturbed by selective logging, understory fires, and habitat fragmentation. There is an urgent need to understand the effect of such disturbances on carbon stocks, and how stocks in disturbed forests compare to those found in undisturbed primary forests as well as in regenerating secondary forests. Here, we present the results of the largest field study to date on the impacts of human disturbances on above and belowground carbon stocks in tropical forests. Live vegetation, the largest carbon pool, was extremely sensitive to disturbance: forests that experienced both selective logging and understory fires stored, on average, 40% less aboveground carbon than undisturbed forests and were structurally similar to secondary forests. Edge effects also played an important role in explaining variability in aboveground carbon stocks of disturbed forests. Results indicate a potential rapid recovery of the dead wood and litter carbon pools, while soil stocks (0-30 cm) appeared to be resistant to the effects of logging and fire. Carbon loss and subsequent emissions due to human disturbances remain largely unaccounted for in greenhouse gas inventories, but by comparing our estimates of depleted carbon stocks in disturbed forests with Brazilian government assessments of the total forest area annually disturbed in the Amazon, we show that these emissions could represent up to 40% of the carbon loss from deforestation in the region. We conclude that conservation programs aiming to ensure the long-term permanence of forest carbon stocks, such as REDD+, will remain limited in their success unless they effectively avoid degradation as well as deforestation. [ABSTRACT FROM AUTHOR]

The main objective of the study was to calculate net atmospheric impacts for wood production and utilization in Finnish boreal forest conditions. Net atmospheric impacts were calculated by comparing net CO exchanges of the wood production and utilization to the reference management regime. Net CO exchanges were simulated with a life cycle assessment (LCA) tool for a Scots pine ( Pinus sylvestris L.) stand (MT, Myrtillys-type) in central Finland (Joensuu region, 62°39 N, 29°37 E) over two consecutive rotation periods (100 + 100 years/200 years). Net atmospheric impacts were calculated both for sawn timber and pulpwood, and expressed in kgCOm. According to the results, the production of pulp and sawn timber produced emissions of 0.20 and 0.59 kgCOm over the 200-year period, respectively, when the unmanagement regime was used as the reference management regime. When 50 % of the processing waste of timber was accounted as an instant emission to the atmosphere, the atmospheric impact increased to 0.55 kgCOm in pulpwood and to 1.27 kgCOm in sawn timber over the 200 year period. When turnover rates of sawn timber in the technosystem were decreased by 30 % and the share of energy use was decreased to 30 %, the atmospheric impact decreased by 17 % and 4 % for pulpwood and sawn timber, respectively, compared to the default wood degradation and energy use of 50 %. The utilized LCA approach provided an effective tool for approaching net atmospheric impacts originating from the ecosystem carbon (C) flows and variable wood utilization. Taking the ecosystem production and utilization of wood (i.e. degradation of technosystem C stock) into account, in terms of net CO exchange, the mitigation possibilities of wood compared to other products can be accounted for more precisely in the future and C sequestration credited more specifically for a certain wood product. [ABSTRACT FROM AUTHOR]

• Aboveground biomass across forest strata was controlled by lower species evenness. • Species evenness mediates the divergent effects of stand age and topography on AGB. • Different trait identities depending on forest strata enhance AGB in each stratum. The relationships amongst environmental conditions, stand age, tree diversity, and trait identity with aboveground biomass (AGB) remain highly debated in forest ecosystems, but these relationships across forest strata (i.e., overstory and understory) remain poorly assessed in subtropical – warm-temperate forests. Here, we hypothesized that environmental conditions, stand age, tree diversity and trait identity jointly control AGB, but divergent species' functional strategies regulate AGB in different forest strata of subtropical – warm-temperate forests. To do so, we analyzed datasets from 72 plots across five sites in subtropical – warm-temperate forests of Jeju Island, South Korea. We used multimodel inference tests based on multiple linear regressions models and then piecewise structural equation modeling (pSEM) to assess the relationships amongst topographic factors, stand age, tree diversity (i.e., species, phylogenetic and functional diversity), and trait identity (i.e., community-weighted mean – CWM – of a trait values) and AGB in the overstory, understory, and whole community. The pSEMs showed that lower species evenness increased AGB in overstory and understory, but CWM of tree maximum height and seed mass enhanced overstory and understory AGB, respectively. Moreover, species evenness mediated the divergent effects of stand age and topography on overstory and understory AGB, respectively. This study shows that the effect of low species evenness on AGB is ubiquitous across forest strata, but divergent species' functional strategies also contribute to shaping AGB. We argue that species' functional strategies (i.e., the mass ratio effect) across forest strata and developmental stages should be taken into consideration for sustainable forest management to achieve the biodiversity conservation and carbon sequestration that underpins human wellbeing through climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Highlights: [•] Logging-induced biomass losses were greater in the plot under CL than RIL. [•] By 16years post-logging, the RIL plot recovered 100% of its original ABG biomass. [•] By 16years post-logging, the CL plot recovered 77% of its original ABG biomass. [•] ABG biomass of trees >60cm DBH did not recover by 16years post-logging. [•] Average annual increment in ABG biomass was 6-times higher in the RIL than CL. [Copyright &y& Elsevier]

Abstract: In this study we analyze and compare the climate impacts from the recovery, transport and combustion of forest residues (harvest slash and stumps), versus the climate impacts that would have occurred if the residues were left in the forest and fossil fuels used instead. We use cumulative radiative forcing (CRF) as an indicator of climate impacts, and we explicitly consider the temporal dynamics of atmospheric carbon dioxide and biomass decomposition. Over a 240-year period, we find that CRF is significantly reduced when forest residues are used instead of fossil fuels. The type of fossil fuel replaced is important, with coal replacement giving the greatest CRF reduction. Replacing oil and fossil gas also gives long-term CRF reduction, although CRF is positive during the first 10–25 years when these fuels are replaced. Biomass productivity is also important, with more productive forests giving greater CRF reduction per hectare. The decay rate for biomass left in the forest is found to be less significant. Fossil energy inputs for biomass recovery and transport have very little impact on CRF. [Copyright &y& Elsevier]

Abstract: Industrialized countries agreed on a reduction of greenhouse gas emissions under the Kyoto Protocol. Many countries elected forest management activities and the resulting net balance of carbon emissions and removals of non-CO2 greenhouse gases by forest management in their climate change mitigation measures. In this paper a generic dynamic forestry model (FORMICA) is presented. It has an empirical basis. Several modules trace C pools relevant for the Kyoto Protocol and beyond: biomass, litter, deadwood and soil, and harvested wood products. The model also accounts for the substitution of fossil fuels by wood products and bioenergy. FORMICA was used to first study the model sensitivity and uncertainty based on data from Thuringia, a federal state of Germany, to determine the major sources of uncertainty in carbon accounting at different levels of carbon pool aggregation (biomass, ecosystem, forestry sector and enhanced forestry sector including the accumulated substitution effect). Rotation length and maximum increment contributed most to uncertainty in biomass. The influence of the latter did not diminish with higher level of pool aggregation. Uncertainty in the enhanced forestry sector was to a smaller degree controlled by product and substitution related parameters. Relative uncertainty decreased with the level of aggregation and comprehensiveness of the carbon budget. In a second step the model estimated the sink potential of the Thuringian forestry sector. The projected average biomass sink for the period of 2003–2043 of 0.6tCha−1 year−1 could be increased by 50% by broadening the perspective to the entire forestry sector, including substitution effects. A simulation of forest conservation on 20% of the forest area increased C fixation. However, even in the biomass C pool the expected C stock changes did not exceed the estimated uncertainty of 40%. A higher level of aggregation (i.e. the inclusion of soil and litter, product pool and substitution effects) decreases relative uncertainty but also diminishes differences between different management options. The analysis demonstrates that the choice of management mitigation options under an accounting scheme should include the impacts on forest products and of substitution effects. [Copyright &y& Elsevier]

• carbon uptake by above-ground biomass is higher in unmanaged beech stands. • thinning does not alter growth-climate sensitivity. • resistance to extreme weather events decreases with increasing tree productivity. • close-to-nature forestry may be preferable at sites with higher incidence of heat and drought events. European beech plays a prominent role in the adaptation of European forests to and mitigation of climate change. Forest management may increase the mitigation potential of beech forests by accelerating carbon accumulation in tree biomass, but little is known about the interaction between the rate of biomass expansion in beech and its sensitivity to climate variation or its resistance to extreme drought episodes. A 60-year thinning experiment in beech forests in Central Europe was used to generate tree-ring width series describing past radial growth of dominant, co-dominant and sub-dominant beech trees. Randomisation applied to daily climate data was used to find the period of the year during which climate best explains beech growth. Results show that carbon uptake by above-ground biomass is higher in unmanaged stands and that thinning does not affect beech growth sensitivity to climate. Further, this study shows that average daily temperature amplitude and precipitation in March-July are the best predictors of radial growth in beech at lower-elevation sites. In a key finding, this research shows that site quality and thinning intensity increase tree size, which in turn lowers their resistance to drought. Using forest management to increase the productivity of European beech may thus increase its vulnerability to climate change. [ABSTRACT FROM AUTHOR]

• Climate-sensitive additive stand biomass models were developed. • The difference in biomass estimations when using the new models at a large scale was quantified. • Forecast combination method reduced the uncertainty from the biomass models. • About $8.3 million carbon services were underestimated using traditional models. • Climate-sensitive stand biomass models were recommended for carbon service accounting. Accurate forest carbon service accounting is essential for climate change mitigation. At present, the knowledge about whether and how climate-sensitive stand biomass models could reduce the uncertainty of forest biomass/carbon estimation is lacking. Hence, the aim of this study is to develop climate-sensitive stand biomass models and quantify their differences. Data containing 539 sample plots of larch plantations in northern and northeastern China were utilized to develop two basic and the corresponding climate-sensitive stand biomass models. Owing to the uncertainty from predictors, the forecast combination method was used to combine the two basic models (FCMs) and the two climate-sensitive models (CS-FCMs) and to quantify the difference in biomass estimations at the plot and regional scales. Results showed that the adjusted R 2 values of the stand biomass models were greater than 0.85 and the relative root mean square errors ranged from 5.51% to 22.62%. The CS-FCMs produced more accurate biomass estimates than the FCMs. The difference in biomass estimations derived from biomass models with and without climatic variables was 411,549 tons or 0.27% at the regional scale, but the carbon value difference amounted to about $8.3 million. This study underlined the importance of accurate carbon accounting based on climate-modified stand biomass models for forest carbon management. [ABSTRACT FROM AUTHOR]

• Methodological framework for updating existing jurisdictional forest inventory data. • Integration of Landsat time series, terrain and environmental data. • Wall-to-wall forest attribute maps at sub-stand level for British Columbia, Canada. • Time series remote sensing enables inventory update for four unique attributes. • Overall accuracy of 72% for the species which dominate 80% of the forested areas. Up-to-date forest inventory information relating the characteristics of managed and natural forests is fundamental to sustainable forest management and required to inform conservation of biodiversity and assess climate change impacts and mitigation opportunities. Strategic forest inventories are difficult to compile over large areas and are often quickly outdated or spatially incomplete as a function of their long production cycle. As a consequence, automated approaches supported by remotely sensed data are increasingly sought to provide exhaustive spatial coverage for a set of core attributes in a timely fashion. The objective of this study was to demonstrate the integration of current remotely-sensed data products and pre-existing jurisdictional inventory data to map four forest attributes of interest (stand age, dominant species, site index, and stem density) for a 55 Mha study region in British Columbia, Canada. First, via image segmentation, spectrally homogenous objects were derived from Landsat surface-reflectance pixel composites. Second, a suite of Landsat-based predictors (e.g., spectral indices, disturbance history, and forest structure) and ancillary variables (e.g., geographic, topographic, and climatic) were derived for these units and used to develop predictive models of target attributes. For the often difficult classification of dominant species, two modelling approaches were compared: (a) a global Random Forests model calibrated with training samples collected over the entire study area, and (b) an ensemble of local models, each calibrated with spatially constrained local samples. Accuracy assessment based upon independent validation samples revealed that the ensemble of local models was more accurate and efficient for species classification, achieving an overall accuracy of 72% for the species which dominate 80% of the forested areas in the province. Results indicated that site index had the highest agreement between predicted and reference (R2 = 0.74, %RMSE = 23.1%), followed by stand age (R2 = 0.62, %RMSE = 35.6%), and stem density (R2 = 0.33, %RMSE = 65.2%). Inventory attributes mapped at the image-derived unit level captured much finer details than traditional polygon-based inventory, yet can be readily reassembled into these larger units for strategic forest planning purposes. Based upon this work, we conclude that in a multi-source forest monitoring program, spatially localized and detailed characterizations enabled by time series of Landsat observations in conjunction with ancillary data can be used to support strategic inventory activities over large areas. [ABSTRACT FROM AUTHOR]

Background: Forests and forest products can significantly contribute to climate change mitigation by stabilizing and even potentially decreasing the concentration of carbon dioxide (CO2) in the atmosphere. Harvested wood products (HWP) represent a common widespread and cost-efficient opportunity for negative emissions. After harvest, a significant fraction of the wood remains stored in HWPs for a period that can vary from some months to many decades, whereas atmospheric carbon (C) is immediately sequestered by vegetation re-growth. This temporal mismatch between oxidation of HWPs and C uptake by vegetation generates a net sink that lasts over time. The role of temporary carbon storage in forest products has been analysed and debated in the scientific literature, but detailed bottom-up studies mapping the fate of harvested materials and quantifying the associated emission profiles at national scales are rare. In this work, we quantify the net CO2 emissions and the temporary carbon storage in forest products in Norway, Sweden and Finland for the period 1960-2015, and investigate their correlation. We use a Chi square probability distribution to model the oxidation rate of C over time in HWPs, taking into consideration specific half-lives of each category of products. We model the forest regrowth and estimate the time-distributed C removal. We also integrate the specific HWP flows with an emission inventory database to quantify the associated life-cycle emissions of fossil CO2, CH4 and N2O.Results: We find that assuming an instantaneous oxidation of HWPs would overestimate emissions of about 1.18 billion t CO2 (cumulative values for the three countries over the period 1960-2015).We also find that about 40 years after 1960, the starting year of our analysis, are sufficient to detect signs of negative emissions. The total amount of net CO2 emissions achieved in 2015 are about − 3.8 million t CO2, − 27.9 t CO2 and − 43.6 t CO2 in Norway, Sweden, and Finland, respectively.Conclusion: We argue for a more explicit accounting of the actual emission rates from HWPs in carbon balance studies and climate impact analysis of forestry systems and products, and a more transparent inclusion of the potential of HWP as negative emissions in perspective studies and scenarios. Simply assuming that all harvested carbon is instantaneously oxidized can lead to large biases and ultimately overlook the benefits of negative emissions of HWPs. [ABSTRACT FROM AUTHOR]

Carbon management in forests has become the most important agenda of the first half of the 21st century in China in the context of the mitigation of climate change impact. As the main producer of the inland river basin ecosystem in arid region of Northwest China, the desert riparian forest maintains the regional environment and also holds a great significance in regulating the regional/global carbon cycle. In this study, we estimated the total biomass, carbon storage, as well as monetary ecosystem service values of desert riparian Populus euphratica Oliv. in the lower reaches of the Tarim River based on terrestrial forest inventory data within an area of 100 ha (100 plots with sizes of 100 m × 100 m) and digitized tree data within 1000 ha (with 10 m × 10 m grid) using a statistical model of biomass estimation against tree height (TH) and diameter at breast height (DBH) data. Our results show that total estimated biomass and carbon storage of P. euphratica within the investigated area ranged from 3.00 to 4317.00 kg/ha and from 1.82 to 2158.73 kg/ha, respectively. There was a significant negative relationship (p < 0.001) between biomass productivity of these forests and distance to the river and groundwater level. Large proportions of biomass (64% of total biomass) are estimated within 200 m distance to the river where groundwater is relatively favorable for vegetation growth and biomass production. However, our data demonstrated that total biomass showed a sharp decreasing trend with increasing distance to the river; above 800 m distance, less biomass and carbon storage were estimated. The total monetary value of the ecosystem service “carbon storage” provided by P. euphratica was estimated to be $6.8 × 104 USD within the investigated area, while the average monetary value was approximately $70 USD per ha, suggesting that the riparian forest ecosystem in the Tarim River Basin should be considered a relevant regional carbon sink. The findings of this study help to establish a better understanding of the spatial distribution pattern of P. euphratica forest under water scarcity and can also provide an alternative approach to local decision-makers for efficient and precise assessment of forest carbon resources for emission reduction programs. [ABSTRACT FROM AUTHOR]