Total Forest Biomass Research Articles

ANALYSIS OF THE AVAILABILITY OF URBAN SOLID WASTE AND BIOMASS IN SOUTHERN SANTA CATARINA AIMING AT ENERGY RECOVERY

Alternative treatments to urban solid waste (USW) landfill and its integration with biomass can generate social, economic, and environmental benefits beyond contributing to the just energy transition in the Carboniferous Region of Santa Catarina State (Brazil). In this paper, were collected and analyzed data on generation, quantity processed, and current USW treatment practices, as well as rice and forest biomass, aiming to identify the potential for application in the development of USW-derived fuel and biomass that can be used in the energy and industrial markets. In 2020, 236,272.2 t of USW were produced by the forty municipalities considered, with 50% concentrated in just five of these. With only three landfill sites in this region, many municipalities dispose of their USW at a distant location, which increases the overall cost of waste management for the municipalities. The total forest biomass handled in 2019 was 2,135,704.31 tons, and rice husk and straw (2020/2021 harvest) were 999,750.00 tons. Based on this amount and the analysis of the points of concentration of these materials, alternative treatments are being studied with a focus on adding value to the waste chain and advances in the development of the waste management sector in Santa Catarina and in Brazil.

Effect of warming on ground vegetation in Carpathian Norway spruce stands, exemplified by European blueberry (Vaccinium myrtillus L.) nutrient stoichiometry

Despite its small share of total forest biomass, ground vegetation plays an important role in biogeochemical cycles, being able to modify carbon (C) and nutrients fluxes. Global climate warming may affect plant nutrient uptake and the carbon:nitrogen:phosphorus (C:N:P) stoichiometry, the release of nutrients from the soil and soil organic matter, as well as significantly influence the tree stand nutrient supply. In this context, the response of Norway spruce (Picea abies (L.) H.Karst) stands' ground vegetation to warming is uncertain. An open-top chamber soil-warming simulation, lasting two growing seasons, was conducted in a spruce forest. At the end of each of the two growing seasons, before leaf senescence, European blueberry (Vaccinium myrtillus L.) aboveground biomass (leaves and stems) and mineral topsoil samples were collected from the plots. The C, N, P, micronutrient, and macronutrient concentrations were estimated in the samples. Warming caused significant decreases in C, N, and P in the soil. Warming also decreased the C:P and N:P stoichiometric ratios in the soil and increased the C:P ratio in plant stems. Significant increase in foliar C and decrease in foliar P in warmed plots were observed. The most evident effect was reduction of N and P in the soil, which directly affected the plant C:P and soil N:P stoichiometry. Our results show that warming has caused a significant decrease in the content of some nutrients in the aboveground plant tissues of blueberries. Given that N is a limiting factor of ecosystems productivity, its reduction in the soil caused by warming may be a serious threat to proper nutrient uptake and cause disruption of biogeochemical cycles. The decrease in nutrient content in aboveground tissues due to warming can result in disruptions to physiological processes.

Maps with 1 km resolution reveal increases in above- and belowground forest biomass carbon pools in China over the past 20 years

Abstract. To quantify the ecological consequences of recent nationwide restoration efforts in China, spatially explicit information on forest biomass carbon stock changes over the past 20 years is critical. However, long-term biomass tracking at the national scale remains challenging as it requires continuous and high-resolution monitoring. Here, we characterize the changes in the above- and belowground biomass carbon (AGBC and BGBC) of forests in China between 2002 and 2021 at 1 km spatial resolution by integrating multiple types of remote sensing observations with intensive field measurements through regression and machine learning approaches. On average, 8.6 ± 0.6 and 2.2 ± 0.1 PgC were stored in above- and belowground live forests in China. Over the last 20 years, the total forest biomass carbon pool in China has increased at a rate of 114.5 ± 16.3 TgC yr−1 (approximately 1.1 % yr−1). The most pronounced forest biomass carbon stock gains occurred in central to southern China, including the southern Loess Plateau, Qinling mountains, southwestern karsts and southeastern forests. While the combined use of multi-source remote sensing data provides a powerful tool to assess the forest biomass carbon changes, future research is also needed to explore the drivers of the observed woody biomass trends and to evaluate the degree to which biomass gains will translate into biodiverse, healthy ecosystems that are sustainable. Annual forest above- and belowground biomass maps for China are now available at https://doi.org/10.6084/m9.figshare.21931161.v1 (Chen, 2023).

Forest Total and Component Above-Ground Biomass (AGB) Estimation through C- and L-band Polarimetric SAR Data

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.

A field-based estimation of moso bamboo forest biomass in China

Moso bamboo (Phyllostachys edulis) forests are widely distributed in southern China and have expanded rapidly in recent years. Although some studies have explored bamboo biomass, there are great uncertainties regarding regional- and national-scale estimations of the total biomass of bamboo forests due to a lack of systematic surveys and root biomass sampling. We investigated 322 bamboo stand plots at 48 sites across all distributed areas (15 provinces) in China in 2017–2019. We further measured the biomass of 147 individual shoots and 132 whole plants in Jiangxi Province, and determined the above- and belowground biomass in 11 sample plots using the complete harvesting method. At individual-level, the average biomass of whole-bamboo and shoot were estimated as 15.6 ± 8.3 and 12.8 ± 6.9 kg per individual, respectively. The stand mean aboveground and belowground biomass values were 60.3 ± 25.7 and 21.0 ± 5.6 Mg ha−1, with a total stand biomass of 81.4 ± 31.3 Mg ha−1 and an average root-to-shoot ratio of 0.37 ± 0.07. Using these data, combined with the 9th National Forest Inventory (NFI) dataset, we estimated that the total bamboo biomass of China was 283.0 ± 6.0 Teragrams (Tg) by using individual mean biomass and 349.5 ± 8.3 Tg by using stand mean biomass, which accounted for 1.7–2.1% of the national total forest biomass carbon pool (i.e., 8.5 Pg C). Our results provide an accurate estimation of bamboo forest biomass based on direct field measurements, and these estimates are essential to the parameterization of forest carbon models in China.

Forest carbon sink in the U.S. (1870–2012) driven by substitution of forest ecosystem service flows

Understanding the dynamics behind forest transitions, i.e., shifts from deforestation to forest recovery, is crucial for forest conservation and climate-change mitigation i.e., carbon (C) sequestration. We investigated the drivers of the forest transition in the United States, which was characterized by forest thickening despite surges in industrial wood extraction. We employ the concepts of Human Appropriation of Net Primary Productivity (HANPP) and Material and Energy Flow Analysis (MEFA) to quantitatively assess changes in major provisioning ecosystem services demanded from forests, i.e., industrial wood (comprising biomass used in products such as paper and pulp), grazing, and fuelwood, and analyse substitution processes from 1870-2012 at regional, sectoral, and national scales. The share of industrial wood in total annual forest biomass harvest increased from 23% to 84% over the time-period, while fuelwood and biomass grazed declined from 63% to 13%, and 14% to 3%, respectively. Reductions in demand for fuelwood and biomass grazed were enabled by shifts in feed and energy sources, consequently allowing for increases in both livestock numbers and energy use. Feed crops increased six-fold, alleviating grazing pressure on forest ecosystems, particularly in the Eastern states. Fossil fuels replaced fuelwood, especially in the residential sector. Between 1900-2012 the final energy mix increased seventeen-fold. Thus, the increase in biomass C stocks in U.S. forests was connected to substitution of forest ecosystem services with fossil fuel-based production systems, and with manifold increases in societal resource use and C dynamics. Such shifts need to be considered when assessing the positive environmental effects of forest transitions.

Spatial distribution of carbon dynamics and nutrient enrichment capacity in different layers and tree tissues of Castanopsis eyeri natural forest ecosystem.

Forest ecosystem carbon (C) storage primarily includes vegetation layers C storage, litter C storage, and soil C storage. The precise assessment of forest ecosystem C storage is a major concern that has drawn widespread attention in global climate change worldwide. This study explored the C storage of different layers of the forest ecosystem and the nutrient enrichment capacity of the vegetation layer to the soil in the Castanopsis eyeri natural forest ecosystem (CEF) present in the northeastern Hunan province, central China. The direct field measurements were used for the estimations. Results illustrate that trunk biomass distribution was 48.42% and 62.32% in younger and over-mature trees, respectively. The combined biomass of the understory shrub, herb, and litter layers was 10.46 t·hm-2, accounting for only 2.72% of the total forest biomass. On average, C content increased with the tree age increment. The C content of tree, shrub, and herb layers was 45.68%, 43.08%, and 35.76%, respectively. Litter C content was higher in the undecomposed litter (44.07 %). Soil C content continually decreased as the soil depth increased, and almost half of soil C was stored in the upper soil layer. Total C stored in CEF was 329.70 t·hm-2 and it follows the order: tree layer > soil layer > litter layer > shrub layer > herb layer, with C storage distribution of 51.07%, 47.80%, 0.78%, 0.25%, and 0.10%, respectively. Macronutrient enrichment capacity from vegetation layers to soil was highest in the herb layer and lowest in the tree layer, whereas no consistent patterns were observed for trace elements. This study will help understand the production mechanism and ecological process of the C. eyeri natural forest ecosystem and provide the basics for future research on climate mitigation, nutrient cycling, and energy exchange in developing and utilizing sub-tropical vegetation.

Long-term changes of forest biomass and its driving factors in karst area, Guizhou, China

The spatiotemporal dynamic changes of forest biomass can provide scientific reference and scheme for improving the quality of forest resources and the ecological environment in karst areas. In this article, the China’s National Forest Continuous Inventory data (from 1984 to 2015) was used to analyze the dynamic changes of forest biomass with the univariate linear slope k, barycenter trajectory, improved hot spots detection which was applied in the analysis of forest biomass dynamic change, and geospatial detector method in Guizhou in the first time. The results showed that the total forest biomass had a steady upward trend, 29.3% unit biomass of the forest had significantly increased, while 1.4% decreased dramatically. The forest biomass gravity center shifted from Qiandongnan to Qiannan, with a total distance of 54.1 km. Thus, the following conclusions were drawn: (1) benefiting from the effective implementation of forestry-related policies, the forest biomass had significant increased in a long time series, especially for the artificial shelter forest; (2) the gravity center shifted to the northwest and the number of level 1 forest biomass hot spots increased year by year, which showed a generalized symmetric pattern along the Wujiang River mainstream; and (3) the results of geographical survey showed that the change of forest biomass was greatly affected by topography, climate and human activities, among which terrain factors had the greatest impact.

Residual forest biomass and energy assessment: a case study analysis in the region of Alto Minho (North Portugal) for the creation of BLCs and 2GBLCs

ABSTRACT Recent synergies have increased the use of forest biomass for energy purposes. In addition to high investment costs, low feed-in tariffs, and low operational efficiency, the real potential of forest biomass does not always correspond to the potential that is often claimed in studies. Instead of total forest biomass assessments, it is recommended that sustainable afforestation criteria should be introduced to obtain more reliable and environmentally sustainable scenarios. In this article, the most representative forest species in the Alto Minho region (northern Portugal) are identified, as well as the total forest area available. Based on cartography, forest inventory data, and allometric equations, the annually available usable residual forest biomass (RFB) and corresponding potential energy are estimated. Finally, to promote local forest biomass markets and most efficient thermal use of forest biomass is suggested the creation biomass logistic centres (BLCs) and second-generation biomass logistic centres (2GBLCs) are introduced as well.

Long-Term Heavy Metal Retention by Mangroves and Effect on Its Growth: A Field Inventory and Scenario Simulation.

The ability of mangroves in taking up and storing heavy metal (HM) helps in reducing HM pollution. However, HMs likewise adversely affect the growth of mangroves. We assess the effects of the long-term soil HMs enrichment on the growth of Rhizophora apiculata forest in the Can Gio Mangrove Forest (Southern Vietnam) in different environmental conditions of soil salinity, ground elevation, and tree density based on a novel set of measured data. These data were analyzed and were used to calibrate and validate for a tree growth model with influencing factors salinity, elevation, tree density, and heavy metals content. Three scenario simulations were performed to predict the mangrove dynamics under different levels of heavy metal pollution in combined environmental conditions of salinity and elevation. Simulation results show the decline of total forest biomass from 1,750,000 tons (baseline scenario with no HM pollution) down to 850,000 tons and 350,000 tons for the current HM pollution and double HM pollution scenarios, respectively. Both data analysis and simulations have shown that although mangroves can assist in reducing HM pollution, the quality and health of this ecosystem will be severely affected if the environment is excessively polluted. In addition, a data-and-model driven management tool is devised for the sustainable management of the mangrove environmental resources.

Climate Change Is Likely to Alter Future Wolf – Moose – Forest Interactions at Isle Royale National Park, United States

We evaluated how climate change and variable rates of moose browsing intensity, as they relate to wolf predation, might impact the forests of Isle Royale National Park, MI USA by conducting a simulation modelling experiment. The experiment consisted of contrasting three different scenarios of wolf management and with a static (current conditions) and changing climate (high emissions). Our results suggest that the interactive effects of wolf predation and climate change are likely to be temporally variable and dependent on biogeographic and forest successional processes. During the first 50 years of simulations, when the effects of climate change were minor, higher simulated rates of predation by wolves reduced moose population densities, resulting in greater forest biomass and higher carrying capacities for moose. However, over the longer term, early successional and highly palatable aspen and birch forests transitioned to late successional spruce and fir forests, regardless of climate or predation intensity. After 50 years, the effects of climate change and predation were driven by effects on balsam fir, a late successional species that is highly palatable to moose. High-intensity predation of moose allowed balsam fir to persist over the long term but only under the current climate scenario. Climate change caused a reduction in balsam fir and the other boreal species that moose currently feed on, and the few temperate species found on this isolated island were unable to compensate for such reductions, causing strong declines in total forest biomass. The direct effects of moose population management via reintroduction of wolves may become increasingly ineffective as the climate continues to warm because the productivity of boreal plant species may not be sufficient to support a moose population at all, and the isolation of the island from mainland temperate tree species may reduce the likelihood of compensatory species migrations.

The potential for REDD+ to reduce forest degradation in Vietnam

Natural forests in Vietnam have experienced rapid declines in the last 70 years, as a result of degradation from logging and conversion of natural forests to timber and rubber plantations. Degradation of natural forests leads to loss of biodiversity and ecosystem services, impacting the livelihoods of surrounding communities. Efforts to address ongoing loss of natural forests, through mechanisms such as Reduced Emissions from Deforestation and Degradation (REDD+), require an understanding of the links between forest degradation and the livelihoods of local communities, which have rarely been studied in Vietnam. We combined information from livelihood surveys, remote sensing and forest inventories around a protected natural forest area in North Central Vietnam. For forest-adjacent communities, we found natural forests contributed an average of 28% of total household income with plantation forests contributing an additional 15%. Although officially prohibited, logging contributed more than half of the total income derived from natural forests. Analysis of Landsat images over the period 1990 to 2014 combined with forest inventory data, demonstrates selective logging was leading to ongoing degradation of natural forests resulting in loss of 3.3 ± 0.8 Mg biomass ha−1 yr−1 across the protected area. This is equivalent to 1.5% yr−1 of total forest biomass, with rates as high as 3% yr−1 in degraded and easily accessible parts of the protected area. We estimate that preventing illegal logging would incur local opportunity costs of USD $4.10 ± 0.90 per Mg CO2, similar to previous estimates for tropical forest protected areas and substantially less than the opportunity costs in timber or agricultural concessions. Our analysis suggests activities to reduce forest degradation in protected areas are likely to be financially viable through Vietnam’s REDD+ program.

Decline of large-diameter trees in a bamboo-dominated forest following anthropogenic disturbances in southwestern Amazonia

Reduction in the aboveground biomass of larger trees is the main consequence of disturbances in open forests dominated by bamboo. Because these trees are of central importance both for ecosystem function and for the economic value of the forest for management, the impact on these trees due to the increase of bamboo abundance following anthropogenic disturbances is both an environmental and a commercial concern. Bamboo-dominated forests in southwestern Amazonia are increasingly exposed to the combined impacts of fire and selective logging. Although the climbing bamboos (Guadua spp.) are considered native species of these forests, disturbances contribute to a discontinuous canopy, which is an ideal scenario for an increase in abundance of these opportunistic plants. The regeneration of tree biomass is limited in these cases, decreasing the carbon stock of the forest. This study compares changes in bamboo abundance and forest structure in the face of forest fire and post-burn logging in the municipality (county) of Rio Branco, Acre state, Brazil. The study was conducted on the Transacreana Highway (AC 090) in the eastern portion of Acre state, Brazil. We compared changes in bamboo abundance and aboveground biomass (AGB) of an area of forest with no known recent disturbances to areas in the same forest that had been disturbed by fire and post-burn logging, which are frequent sources of disturbance in this region. The live and dead AGB values were estimated by field inventory in 2016, which was 11 years after a fire and 9 years after selective logging. The AGB values for trees and palms were estimated by allometric equations in three 2-ha areas. Bamboo abundance was expressed both by bamboo biomass (Mg ha−1) and culm density (culms ha−1), sampled by direct measurements in three 200-m2 areas. Bamboo abundance was over 20% higher in forest that had been burned but not logged, as compared to undisturbed forest. Compared to undisturbed plots, aboveground forest biomass (live + dead) was 34% lower in plots exposed to fire but not logging, and 36% lower if exposed to both. Live trees and palms represented 77% of the total forest biomass (live + dead), and almost a half of this contribution (41%) was in individuals in the largest diameter class (diameter at breast height > 50 cm). Increase in the level of impact led to a reduction in aboveground carbon stock of the forest. One of the main consequences of disturbances in open forests dominated by bamboo is reduction of live trees and palms, especially in the diameter at breast height (DBH) class over 50 cm.

Improving resilience of an old-growth urban forest in Southern Italy: Lesson(s) from a stand-replacing windstorm

There is a current concern that the capacity of urban forests to recover from the effects of climate change may be diminishing. New management options are needed so that they can continue to provide ecosystem services to local communities. After a windstorm occurred on June 2014 pre- and post-disturbance stand conditions (years 2010 and 2015, respectively) of the historical old-growth holm oak forest of Parco Gussone were analysed by combining ground- and satellite-based methodologies. Results highlighted that Parco Gussone was primarily valued for its historical importance and, despite the phytosanitary conditions of the trees, no silvicultural treatments were made since 1986, most probably due to conflicts arisen between different stakeholders. Therefore in 2014, the windstorm damaged 406 trees (8.1% of the total aboveground forest dry biomass) and it was stand-replacing on 1.53 ha (9.3 % of the total forest area). Windthrows, heterogeneously distributed and unequally sized (103 canopy gap ranging between ∼6 to 1632 m2), caused, overall, a significant reduction of LAI (∼19%). The presence of large gaps promoted the invasion of non-native herbaceous species whereas native species of the shrubs and herbaceous layers were favoured when felled trees were left on the ground or removed mechanically during harvest, respectively. In this context, urban forests should be considered as ‘complex adaptive systems’, therefore natural processes can be simulated by applying a ‘close-to-nature’ silviculture (e.g. by opening small gaps), vulnerability assessed (e.g. using a tree-by-tree VTA), biodiversity and ecological resilience improved and short- and long term disturbance effects evaluated (e.g. analysis of disturbance attributes and stand dynamics) so that specific conservation goals can be adapted to a specific landscape and biotic community. By implementing and applying the proposed guidelines in urban forest planning, we are confident that the resilience of those Mediterranean urban forest ecosystems could be effectively restored and improved.

From Farms to Forests: Landscape Carbon Balance after 50 Years of Afforestation, Harvesting, and Prescribed Fire

Establishing reliable carbon baselines for landowners desiring to sustain carbon sequestration and identify opportunities to mitigate land management impacts on carbon balance is important; however, national and regional assessments are not designed to support individual landowners. Such baselines become increasingly valuable when landowners convert land use, change management, or when disturbance occurs. We used forest inventories to quantify carbon stocks, estimate annual carbon fluxes, and determine net biome production (NBP) over a 50-year period coinciding with a massive afforestation effort across ~80,000 ha of land in the South Carolina Coastal Plain. Forested land increased from 48,714 ha to 73,824 ha between 1951 and 2001. Total forest biomass increased from 1.73–3.03 Gg to 17.8–18.3 Gg, corresponding to biomass density increases from 35.6–62.2 Mg ha−1 to 231.4–240.0 Mg ha−1. Harvesting removed 1340.3 Gg C between 1955 and 2001, but annual removals were variable. Fire consumed 527.1 Gg C between 1952 and 2001. Carbon exported by streams was <0.5% of total export. Carbon from roots and other harvested material that remained in-use or in landfills comprised 49.3% of total harvested carbon. Mineral soil carbon accounted for 41.6 to 50% of 2001 carbon stocks when considering depths of 1.0 or 1.5 m, respectively, and was disproportionately concentrated in wetlands. Moreover, we identified a soil carbon deficit of 19–20 Mg C ha−1, suggesting opportunities for future soil carbon sequestration in post-agricultural soils. Our results provide a robust baseline for this site that can be used to understand how land conversion, forest management, and disturbance impacts carbon balance of this landscape and highlight the value of these baseline data for other sites. Our work also identifies the need to manage forests for multiple purposes, especially promotion of soil carbon accumulation in low-density pine savannas that are managed for red-cockaded woodpeckers and therefore demand low aboveground carbon stocks.

Biomass losses resulting from insect and disease invasions in US forests

Worldwide, forests are increasingly affected by nonnative insects and diseases, some of which cause substantial tree mortality. Forests in the United States have been invaded by a particularly large number (>450) of tree-feeding pest species. While information exists about the ecological impacts of certain pests, region-wide assessments of the composite ecosystem impacts of all species are limited. Here we analyze 92,978 forest plots distributed across the conterminous United States to estimate biomass loss associated with elevated mortality rates caused by the 15 most damaging nonnative forest pests. We find that these species combined caused an additional (i.e., above background levels) tree mortality rate of 5.53 TgC per year. Compensation, in the form of increased growth and recruitment of nonhost species, was not detectable when measured across entire invaded ranges but does occur several decades following pest invasions. In addition, 41.1% of the total live forest biomass in the conterminous United States is at risk of future loss from these 15 pests. These results indicate that forest pest invasions, driven primarily by globalization, represent a huge risk to US forests and have significant impacts on carbon dynamics.

Mapping global forest biomass and its changes over the first decade of the 21st century

Forests played an important role in carbon sequestration during the past two decades. Using a model tree ensemble method (MTE) to regress the seven reflectance bands of EOS-Terra-MODIS satellite data against country level forest biomass carbon density (BCD) of 2001–2005 provided by United Nations’s Forest Resource Assessment (FRA), we developed a global map of forest BCD at 1 km ×1 km resolution for both 2001–2005 and 2006–2010. For 2006–2010, the total global forest biomass carbon stock is estimated as 279.6±7.1 Pg C, and the tropical forest biomass carbon stock is estimated as 174.4±5.4 Pg C. During the first decade of the 21st century, we estimated an increase of global forest biomass of 0.28±0.75 Pg C yr−1. Tropical forest biomass carbon stock slightly decreased (−0.31±0.60 Pg C yr−1); by contrast, temperate and boreal forest biomass increased (0.58±0.28 Pg C yr−1) during the same period. Our estimation of the global forest biomass carbon stock and its changes is subject to uncertainties due to lack of extensive ground measurements in the tropics, spatial heterogeneity in large countries, and different definitions of forest. The continuously monitoring of forest biomass carbon stock with MODIS satellite data will provide useful information for detecting forest changes.

Variation in Organ Biomass with Changing Climate and Forest Characteristics across Chinese Forests

Forest biomass allocation patterns are important for understanding global carbon cycling and climate change, which might change with environmental conditions and forest characteristics. However, the effects of climate and forest characteristics on biomass allocation fractions (the fraction of total forest biomass distributed in organs) remains unknown. The authors use a large Chinese biomass dataset (1081 forests encompassing 10 forest types) to analyse the responses of biomass allocation fractions to biogeography, climate, and forest characteristics. The authors found that the stem mass fraction significantly increased with age and precipitation and significantly decreased with latitude and temperature. The branch mass fraction significantly decreased with age and density, but significantly increased with temperature and latitude. The leaf mass fraction significantly decreased with age and precipitation and significantly increased with temperature. The root mass fraction significantly increased with latitude and density, and significantly decreased with precipitation. The results suggest that latitude, temperature, precipitation, stand age and density are good predictors of biomass partitioning. These findings support the hypotheses that variation in resource availability constrains organ allocation and provides biogeographically explicit relationships between biomass allocation and both environmental and forest characteristics, which might be used for assessing the impact of changing environmental and forest characteristics on forest carbon dynamics and fixation.

Regional socio-economic impacts of intensive forest management, a CGE approach

The demand for and supply of forest biomass have both been increasing in recent years, which will set new requirements for forest management. Thus, new studies on regionally suitable forest management regimes to fulfill the needs of potential new investments and the impacts on wood supply potential on regional socio-economic welfare are called for. The aim of this study was to examine the impacts of intensive forest management due to increased demand for wood biomass, from the regional economy point of view. In particular, the impact of intensive forest management on 1) regional gross domestic product (GDP), 2) private consumption, and 3) employment were assessed. The study was carried out by using computable general equilibrium (CGE) modelling combined with the requisite statistics and simulation of regional forest potential in the future. The results showed that total regional forest biomass supply with more intensive forest management could be increased annually on average by 26% (1.7 Mm3) by 2030 compared to the business as usual (BAU) scenario. In this study, regional demand was increased by a hypothetical saw mill (0.5 Mm3) and biorefinery (0.7 Mm3). Total regional socio-economic benefits could be 2.8% (€150 M) for GDP, 1.5% (€49 M) for private consumption and 1.6% (780 person-years) for employment, larger by 2030 than in the BAU scenario including multiplier effects. The study demonstrated how much regional socio-economic welfare would increase if regional wood demand with new investments combined with more intensive forest management and wood supply had more attention paid to it.

Future biomass carbon sequestration capacity of Chinese forests

Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon (C) sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in China will evolve as forest age, climate and atmospheric CO2 concentration change continuously. Here, we present a semi-empirical model that incorporates forest age and climatic factors for each forest type to estimate the effects of forest age and climate change on total forest biomass, under three different scenarios based on the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We estimate that age-related forest biomass C sequestration to be 6.69 Pg C (∼0.17 Pg C a−1) from the 2000s to the 2040s. Climate change induces a rather weak increase in total forest biomass C sequestration (0.52–0.60 Pg C by the 2040s). We show that rising CO2 concentrations could further increase the total forest biomass C sequestration by 1.68–3.12 Pg C in the 2040s across all three scenarios. Overall, the total forest biomass in China would increase by 8.89–10.37 Pg C by the end of 2040s. Our findings highlight the benefits of Chinese afforestation programs, continued climate change and increasing CO2 concentration in sustaining the forest biomass C sink in the near future, and could therefore be useful for designing more realistic climate change mitigation policies such as continuous forestation programs and careful choice of tree species.