Species-specific Wood Research Articles

Tree species-specific wood traits control diazotrophic community composition in deadwood

Deadwood is a nitrogen (N) poor environment and its decomposition rate is limited by low N bioavailability. Diazotrophs reduce such N limitations as they are capable of fixing N2 which employs the functional gene nifH. The present study investigates the diazotrophic community composition in deadwood logs of 13 different tree species in temperate forests. Directly after sampling, deadwood was incubated with water (total fraction) or bromodeoxyuridine (BrdU), and latter labeled the metabolically active fraction. Nucleic acid extracts from both fractions were used to assess the nifH gene-based diversity by amplicon sequencing. The active fraction was a subset of the total fraction, which differed in abundance and with a lower richness. Wood traits such as phosphorous, molybdenum, magnesium, glucose concentration, and C:N ratio were positive factors of richness and community composition of the active fraction. Bradyrhizobium and Methylocapsa dominated the total fraction, while the active fraction was mainly governed by Frankia and Treponema regardless of tree species studied, suggesting that they are well adapted to C sources and nutrient-poor conditions in deadwood. The great diazotrophic diversity (50 genera) in the active fraction indicates an enormous potential for biological N fixation during deadwood decay.

Effects of Forest Management Approach on Carbon Stock and Plant Diversity: A Case Study from Karnali Province, Nepal

The mitigation of global warming and conservation of biodiversity are two significant environmental challenges today. Estimating and comparing forest carbon stock and plant diversity under different management approaches provide insight into the choice of management approaches for carbon and plant diversity management. We investigated the variation in carbon stock and diversity of plant species in two forest managements under different approaches: the Kakrebihar protection forest (PF) and Sano Surkhet community forest (CF) in Karnali Province, Surkhet, Nepal. In total, 63 sample plots (30 plots in PF and 33 plots in CF) were laid out systematically across the forests. Dendrometric measurements were carried out for trees, poles, and saplings, and representative leaf litter and herb samples were collected. Soil samples were taken at 10 cm, 20 cm, and 30 cm depths using a soil auger. The existing tree volume equations of tree species of interest were used to estimate tree volume, and species-specific wood density and conversion factors were used to obtain total biomass and carbon content. Soil samples were analyzed using the Walkley-Black method to determine soil organic carbon. PF had higher carbon stock, plant species richness, and abundance at the landscape level than CF; however, the scenario differed at the plot level. At the plot level, PF had significantly higher total carbon stock and biomass carbon stock than CF. However, PF and CF were statistically indistinguishable in term of soil carbon stock. At the plot level, PF and CF were statistically indistinguishable regarding richness, Simpson diversity, and Shannon diversity, but PF had significantly higher plant abundance than CF. In conclusion, the value of PF for carbon stock and plant diversity surpassed those of CF. This study suggests that PF might be a better strategy to enhance carbon stock in forests and maintain habitat for various plant species.

Above-ground biomass mapping in West African dryland forest using Sentinel-1 and 2 datasets - A case study

The Sudanian Savanna (SS) of West Africa is characterized by tropical savannas and woodlands. Accurate estimation of AGB and carbon stocks in this biome is important for addressing sustainable development goals as the information can aid natural resource management at varied spatial scales. Previous AGB mapping efforts focused on humid forests, with little attention on savannas. This study explored the use of annual monthly time-series of Senitinel-1 (S-1) and Sentinel-2 (S-2) data to map AGB in the SS. Backscatter, spectral reflectance, and derivatives (vegetation indices and biophysical parameters) were combined with field inventory data in a Random Forest regression to map AGB. Eight experiments were conducted with different data configurations to determine: (1) the potential of S-1 and S-2 for AGB mapping, (2) optimal image acquisition period for AGB mapping, and (3) contribution of image derivatives to improving the accuracy of AGB mapping. The predicted map was validated with 40% of the inventory data. Uncertainty in the AGB was assessed using mean absolute error, root mean squared error, coefficient of determination and symmetrical mean absolute percentage error. Results show that about 90% of the study area have low AGB stocks of less than 90 Mg/ha. Compared to S-1 (RMSE: 78.6; MAE: 25.6), S-2 achieved better prediction accuracy (RMSE: 60.6; MAE: 19.2), although combination of the two according to seasonality produced the best results (RMSE: 45.4; MAE: 16.3). Images acquired in the dry season were found to be more useful for predicting AGB than those of rainy season. Also, stress-related vegetation indices and a red-edge dependent normalized difference vegetation index not tested in previous AGB studies using Sentinels were found to be significant contributors to the superior performance of S-2. Since biomass is a finite resource, our results can provide valuable information on the sustainable use of biomass and energy security including studies on carbon cycling and ecosystem functions in the region. The demonstrated possibility of using open access earth observation data to map and monitor AGB in data scarce regions is useful and beneficial to attaining SDG indicators 15.2.1 (sustainable forest management) and 15.3.1 (proportion of land that is degraded over total land area). Further work on developing species-specific wood densities and allometric equations is required to improve AGB and carbon stock estimation in the SS.

Impact of timber harvesting on carbon storage in montane forests of central Mexico

Cut stumps are the legacy of forest harvesting and allow for the estimation of carbon loss from the ecosystem. The objective of this study was to estimate aboveground carbon storage and the impact of forest harvesting based on measurements of cut stumps in pine forests within the Area de Proteccion de Flora y Fauna Nevado de Toluca (APFFNT) in the state of Mexico. A total of 1621 circular 0.1-ha sampling plots were established in a 12,924 ha pine forest (1.25% sampling intensity). Biomass was calculated using conventional volumetric equations incorporating species-specific wood densities. Aboveground carbon storage in the biomass was stratified by forest type including dense forest (≥ 336 trees), semi-dense forest ( 150 trees), fragmented forest ( 20 trees), and stands with isolated trees (< 20 trees). In the 12, 924 ha of forest dominated by Pinus hartwegii, 1,695,004 MgC was contained in aboveground biomass. Data on forest harvesting obtained by analysis of recent cut stumps allowed for the estimation of the removal of 42,701 MgC. In addition, we accounted for carbon in wind thrown trees of 14,904 MgC, some of which were removed over time in harvests. Total loss of carbon from the forest corresponded to 211,218 MgCO2 per year. In the APFFNT, forests dominated by pine with high biomass (P. hartwegii and P. montezumae) are being replaced by those with lower biomass (Alnus jorullensis). Changes in these communities will result in lower carbon capture in the APFFNT.

Tropical tree height and crown allometries for the Barro Colorado Nature Monument, Panama: a comparison of alternative hierarchical models incorporating interspecific variation in relation to life history traits

Abstract. Tree allometric relationships are widely employed for estimating forest biomass and production and are basic building blocks of dynamic vegetation models. In tropical forests, allometric relationships are often modeled by fitting scale-invariant power functions to pooled data from multiple species, an approach that fails to capture changes in scaling during ontogeny and physical limits to maximum tree size and that ignores interspecific differences in allometry. Here, we analyzed allometric relationships of tree height (9884 individuals) and crown area (2425) with trunk diameter for 162 species from the Barro Colorado Nature Monument, Panama. We fit nonlinear, hierarchical models informed by species traits – wood density, mean sapling growth, or sapling mortality – and assessed the performance of three alternative functional forms: the scale-invariant power function and the saturating Weibull and generalized Michaelis–Menten (gMM) functions. The relationship of tree height with trunk diameter was best fit by a saturating gMM model in which variation in allometric parameters was related to interspecific differences in sapling growth rates, a measure of regeneration light demand. Light-demanding species attained taller heights at comparatively smaller diameters as juveniles and had shorter asymptotic heights at larger diameters as adults. The relationship of crown area with trunk diameter was best fit by a power function model incorporating a weak positive relationship between crown area and species-specific wood density. The use of saturating functional forms and the incorporation of functional traits in tree allometric models is a promising approach for improving estimates of forest biomass and productivity. Our results provide an improved basis for parameterizing tropical plant functional types in vegetation models.

Allometric equations from a non-destructive approach for biomass prediction in natural forest and plantation in West Africa

Allometric equations are required for a rapid estimation of commercial timber volume and forest biomass stocks. In order to preserve the forest ecosystem, this study applied a non-destructive sampling approach to measure biophysical properties of living trees. From these measurements, volume and biomass models were developed for 11 dominant tree species in a semi-deciduous natural forest and for Acacia auriculiformis in a plantation located in southern Benin. The observations were combined to develop also generic models applicable to non-dominant tree species. Wood samples of the tree species were collected with an increment borer and analysed in the laboratory to determine species-specific wood densities. The sample size was composed of 243 trees in natural forest and 21 trees in plantation. The measurements were conducted in 30 plots of 50 m × 50 m. The graphical assessment of correlation between model outputs (biomass and volume) and variables (diameter and height) and the statistical analysis confirmed that the logarithmic model with two variables had the best predictions. The assessment also confirmed that the model using diameter only as a variable had good predictions when observations on height were unavailable. The comparative analysis of model predictions showed that the generic model in this study over-estimated biomass by up to 74.80% for certain species and under-estimated biomass by 21.18% for other species. The study shows that there are no statistically significant differences between the wood densities in this research and that published in previous studies.

Assessing the availability of forest biomass for bioenergy by publicly available satellite imagery

Abstract: Forest biomass is a renewable energy source, more climate-friendly than fossil fuels and widely available in Europe. The wood energy chain has been suggested as a means to re-activate forest management and improve the value of forest stands in marginalized rural areas. However, wall-to-wall estimates of forest biomass, needed to design the location and size of power and heat biomass plants in any given territory, are notoriously difficult to obtain. This paper tests an algorithm to predict forest biomass using publicly available Landsat satellite imagery in the Liguria region, northern Italy. We used regional forest inventory data to train and validate an artificial neural network (ANN) classifier that uses remotely-sensed information such as three principal components of Landsat-5 TM spectral bands, the Enhanced Vegetation Index (EVI), and topography, to retrieve aboveground live tree volume. Percent root mean square error was -9% and -23% for conifers and broadleaves respectively in the calibration dataset, and -27% and -24% in the validation dataset. The reconstructed volume map was updated to present day using current volume increment rates reported by the Italian National Forest Inventory. A wall-to-wall map of forest biomass from harvest residues was finally produced based on species-specific wood density, biomass expansion factors, volume logged for timber assortments, forest accessibility, and topography. Predicted aboveground forest volume ranged from 81 to 391 m3 ha-1. In forests available for wood supply (70% of the total), planned volume removals averaged 25.4 m3 ha-1, or 18.7% of the average standing stock across. Biomass available for bioenergy supply was 1.295.921 million Mg dry matter or 8.95 Mg ha-1. This analysis workflow can be replicated in all mountain regions with a predominant broadleaved coppice component.

Interspecific variation in tropical tree height and crown allometries in relation to life history traits

&lt;p&gt;&lt;strong&gt;Abstract.&lt;/strong&gt; Tree allometric relationships are widely employed to estimate forest biomass and production, and are basic building blocks of dynamic vegetation models. In tropical forests, allometric relationships are often modeled by fitting scale-invariant power functions to pooled data from multiple species, an approach that fails to reflect finite size effects at the smallest and largest sizes, and that ignores interspecific differences in allometry. Here, we analyzed allometric relationships of tree height (9884 individuals) and crown area (2425) with trunk diameter using species-specific morphological and life history data of 162 species from Barro Colorado Island, Panamá. We fit nonlinear, hierarchical models informed by species traits and assessed the performance of three alternative functional forms: the scale-invariant power function, and the saturating Weibull and generalized Michaelis-Menten (gMM) functions. The relationship of tree height with trunk diameter was best fit by a saturating gMM model in which variation in allometric parameters was related to interspecific differences in sapling growth rates, a measure of regeneration light demand. Light-demanding species attained taller heights at comparatively smaller diameters as juveniles and had shorter asymptotic heights at larger diameters as adults. The relationship of crown area with trunk diameter was best fit by a power function model incorporating a weak positive relationship between crown area and species-specific wood density. The use of saturating functional forms and the incorporation of functional traits in tree allometric models is a promising approach to improve estimates of forest biomass and productivity. Our results provide an improved basis for parameterizing tropical tree functional types in vegetation models.&lt;/p&gt;

Maximum stand density strongly depends on species-specific wood stability, shade and drought tolerance

The Spanish Minister of Economy and Competitiveness (grant number: AGL2014–51964-C2–2-R); the New Hampshire Agricultural Experiment Station (Scientific Contribution Number 2768); the USDA National Institute of Food and Agriculture McIntire-Stennis (Project Accession Number 1007007); and Short Term Scientific Mission provided by COST Action EuMIXFOR (COST Action number FP1206) to A.B.-O.

Generalized biomass and leaf area allometric equations for European tree species incorporating stand structure, tree age and climate

Biomass and leaf area equations are often required to assess or model forest productivity, carbon stocks and other ecosystem services. These factors are influenced by climate, age and stand structural attributes including stand density and tree species diversity or species composition. However, such covariates are rarely included in biomass and leaf area equations. We reviewed the literature and built a database of biomass and leaf area equations for 24 European tree species and 3 introduced species. The final dataset contained 973 equations. Most of the equations were site-specific and therefore restricted to the edaphic, climatic and stand structural conditions of the given site. To overcome this limitation, the database was used to develop regional species-specific equations that can be used in a wide range of stands and to quantify the effects of climate, age and stand structure on biomass or leaf area. The analysis showed considerable inter- and intra-specific variability in biomass relationships. The intra-specific variability was related to climate, age or stand characteristics, while the inter-specific variability was correlated with traits such as wood density, specific leaf area and shade tolerance. The analysis also showed that foliage mass is more variable than stem or total aboveground biomass, both within and between species, and these biomass components have contrasting responses to age and changes in stand structure. Despite the large number of published equations, many species are still not well represented. Therefore, generic equations were developed that include species-specific wood density instead of species identity. Further improvements may be possible if future studies quantify the stand structure of individual tree neighbourhoods instead of using the stand means for all trees sampled with the given stand.

Persistence and loss of tree cavities used by birds in the subtropical Atlantic Forest

An important goal for the conservation of tropical forest biodiversity is to maintain adequate supplies of tree cavities to support diverse communities of cavity-nesting and roosting vertebrates over the long term, especially in human-modified landscapes. The conservation and replacement of nesting cavities depend critically on cavity persistence, which is predicted to decline with increasing anthropogenic impact to the habitat, and to vary according to characteristics of trees and excavators. We used Cox proportional-hazards models to study the factors influencing persistence of 277 cavities used by 43 species of nesting birds in 38 species of trees, across a gradient of human impact in the subtropical Atlantic Forest of Argentina, 2004–2016. Median cavity persistence was 6years, with 79% of cavity losses caused by the collapse of either the whole tree or the section of the tree holding the cavity. Contrary to predictions, cavity persistence did not vary across habitats (primary forest, degraded forest, farm) or excavator types (true woodpecker vs. weak excavator). Persistence was highest (median>10years) for non-excavated cavities in live trunks of healthy trees, and increased with tree size and species-specific wood density. Thus, although logging and conversion to farmland remove most cavities, the cavities that remain in these human-modified habitats provide high quality, multi-annual nest sites for forest birds. Preserving and restoring these cavities should be a priority for conservation of forest vertebrates. The positive effect of species-specific wood density on cavity persistence suggests a trade-off in rates of cavity turnover, whereby cavities are produced early but lost quickly in fast-growing (low wood density) pioneer tree species, and produced late but persist much longer in slow-growing (high wood density) climax species.

Wood species affect the degradation of crude oil in beach sand

The addition of wood chips as a co-substrate can promote the degradation of oil in soil. Therefore, in the present study, the tree species-specific impact of wood chips of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and Western balsam poplar (Populus trichocarpa L.) on the degradation of crude oil was tested in beach sand in a 4-week incubation experiment. The CO2-C release increased in the order of control without wood chips < +spruce < +pine < +poplar. Initial and final hydrocarbon concentrations (C10 to C40), as indicators for the oil degradation, were determined with gas chromatography-flame ionization detection (GC-FID). The degradation increased for the light fraction (C10 to C22), the heavy fraction (C23 to C40) as well as the whole range (C10 to C40) in the order of control without wood chips (fdegrad. = 23% vs. 0% vs. 12%) < +poplar (fdegrad. = 49% vs. 19% vs. 36%) < +spruce (fdegrad. = 55% vs. 34% vs. 46%) < +pine (fdegrad. = 60% vs. 44% vs. 53%), whereas the heavy fraction was less degraded in comparison to the light fraction. It can be concluded, that the tree species-specific wood quality is a significant control of the impact on the degradation of hydrocarbons, and pine wood chips might be promising, possibly caused by their lower decomposability and lower substrate replacement than the other wood species.

Efficacy of generic allometric equations for estimating biomass: a test in Japanese natural forests

Accurate estimation of tree and forest biomass is key to evaluating forest ecosystem functions and the global carbon cycle. Allometric equations that estimate tree biomass from a set of predictors, such as stem diameter and tree height, are commonly used. Most allometric equations are site specific, usually developed from a small number of trees harvested in a small area, and are either species specific or ignore interspecific differences in allometry. Due to lack of site-specific allometries, local equations are often applied to sites for which they were not originally developed (foreign sites), sometimes leading to large errors in biomass estimates. In this study, we developed generic allometric equations for aboveground biomass and component (stem, branch, leaf, and root) biomass using large, compiled data sets of 1203 harvested trees belonging to 102 species (60 deciduous angiosperm, 32 evergreen angiosperm, and 10 evergreen gymnosperm species) from 70 boreal, temperate, and subtropical natural forests in Japan. The best generic equations provided better biomass estimates than did local equations that were applied to foreign sites. The best generic equations included explanatory variables that represent interspecific differences in allometry in addition to stem diameter, reducing error by 4-12% compared to the generic equations that did not include the interspecific difference. Different explanatory variables were selected for different components. For aboveground and stem biomass, the best generic equations had species-specific wood specific gravity as an explanatory variable. For branch, leaf, and root biomass, the best equations had functional types (deciduous angiosperm, evergreen angiosperm, and evergreen gymnosperm) instead of functional traits (wood specific gravity or leaf mass per area), suggesting importance of other traits in addition to these traits, such as canopy and root architecture. Inclusion of tree height in addition to stem diameter improved the performance of the generic equation only for stem biomass and had no apparent effect on aboveground, branch, leaf, and root biomass at the site level. The development of a generic allometric equation taking account of interspecific differences is an effective approach for accurately estimating aboveground and component biomass in boreal, temperate, and subtropical natural forests.

水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响 DOI: 10.5846/stxb201306101572 作者: 作者单位: 中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;哈佛大学,中国科学院西双版纳热带植物园,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院哀牢山亚热带森林生态系统研究站研究基金 The influence of changes in water availability on seedling mortality of a subtropical evergreen broadleaf forest on Ailao Mountain Author: Affiliation: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences,Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Harvard University,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨环境水分条件变化对亚热带森林林下乔木幼苗动态的影响,以及木材密度和幼苗在干旱中死亡率的关系,研究了哀牢山常绿阔叶林2005-2011年的总体和主要树种幼苗(黄心树、多果新木姜子、多花山矾、鸭公树和大花八角)的死亡率,并分析了幼苗死亡率和旱季幼苗根系所在土层土壤质量含水量、旱季降水量、旱季降水日数以及木材密度的关系。结果表明:1)幼苗死亡率与旱季降水日数、旱季浅层土壤平均质量含水量有显著的负相关关系,和旱季降水量无显著相关性;2)总幼苗及5种乔木幼苗的死亡率均在2010年(西南干旱)达到有观测以来最高,是2009年的2-10倍,其中多花山矾、黄心树幼苗的死亡率最高,大花八角幼苗的死亡率最低;3)在种间,幼苗2010年干旱中的死亡率和木材密度显著正相关,即木材密度较大的物种幼苗死亡率更高。研究表明林下幼苗由于根系较浅,对降雨变化较为敏感,因而受到了这次干旱的较大影响。由于木材密度较低的树种在干旱中有较低的死亡率,干旱频度和强度的增加可能使低木材密度幼苗的丰富度增加,森林的组成也将受到影响。 Abstract:In order to understand the influence of changes in water availability on the seedling dynamics of subtropical forests and the relationship between wood density and seedling mortality during a prolonged drought period, we studied seedling mortality patterns across all species and of 5 common tree species from an evergreen broadleaf forest on Ailao Mountain, southwest (SW) China from 2005 to 2011. The five tree species studied were Machilus bombycina, Neolitsea polycarpa, Symplocos ramosissima, Neolitsea chuii, and Illicium macranthum. The relationships between seedling mortality and rainy days, rainfall, soil water mass content (0-20 cm) during the dry season, and wood density were also analyzed. Our results showed that 1) Seedling mortality was negatively correlated with number of rainy days in the dry season and dry season soil water mass content, but not with total dry season rainfall; 2) The seedling mortalities of all species as a whole and of each of the 5 species studied reached a historical maximum in the 2010 SW China extreme drought, which were 2 to 10 times more intense than for 2009 (Machilus bombycina and Symplocos ramosissima had the highest seedling mortalities while Illicium macranthum had the lowest in 2010); 3) Across species, the seedling mortality in the 2010 drought was positively correlated with species-specific wood densities; species with higher wood densities had higher seedling mortalities. Previous studies have shown that trees in this forest did not experience severe drought stress during the 2010 SW China drought. However, the present study suggests that the seedlings were severely influenced by the rainfall anomaly during the 2010 dry season, probably owing to their shallow rooting depths and consequently high sensitivities to changes in rainfall. Additionally, because of the lower seedling mortalities in lower wood density species, the potential increase in drought frequency and severity in the future may increase the relative abundance of low wood density species, which may potentially lead to changes in forest species composition. 参考文献 相似文献 引证文献

Carbon Stock Movements and GHG Emissions in the State Owned Timber Harvesting and Distribution System in Sri Lanka

The importance of terrestrial ecosystems for the global carbon cycle is undoubted (IPCC,1996). The main terrestrial compartments involved with fluxes and storage of C arevegetation and soils. In this context, forest plantations and homegardens play major role inCO2 sink and long term storage. State Timber Corporation (STC) is the authoritative body fortimber harvesting in state owned plantations in Sri Lanka and majority of timber for woodbased industries in the country is coming from the government owned plantations andhomegardens.The main objective of this study was to assess the embedded CO2 flux in harvested timberand the flow of embedded CO2 stock during the processing both as logs and sawn timber andthe study was confined to the timber harvesting and processing operations in the timberdepots of the State Timber Corporation for the ease of obtaining reliable data. Greenhousegas emissions of the main processors were estimated using a “cradle to gate” approach whereharvesting was taken as the starting point and the timber depots/ showrooms as the finaldestination. The study covered the embedded CO2 stock movement of 36 timber species in 18regions covering 559.4 ha of state owned plantations in Sri Lanka between years 2011 and2012. Embedded CO2 of timber stocks of each timber species were estimated using speciesspecific wood specific gravity values and the standard conversion factors. Further theGreenhouse gas (GHG) emissions during the process were accessed. Timber stockmovements and transportation data of timber species were obtained from regional timberdepots. Data on standing stocks and harvest volumes of state owned plantations wereobtained mainly from FORDATA data base and Forest Department’s inventories.In the primary processing, logs removed from the harvested sites represent approximately60% of the total volume. Ten percent of the wood is taken for fuel wood from the pruning,5% is wasted as leftovers at the harvesting site, 23% at the primary processing stage and 2%at the secondary processing phase totalling to 40%. Analysis shows the average monthlyembedded CO2 inflow of timber logs was 20.96 ± 96.74 tons, while out flow was 19.98 ±89.32. Average monthly embedded CO2 inflow of swan timbers were 1.02 ± 5.9 tons whileissuers were 0.91 ± 5 tons.When considering the emissions during the process, 6% of total emissions are at felling stage.Emissions from transportation both inside the site and outside the site made approximately31.25%. Sawmilling was the highest GHG emitting sub process which contributed 48% from sawing and 9% from surfacing. 9% of the total emissions were emitted during the drying andthere were 2.75 % of other indirect emissions.

Structural Changes are More Important than Compositional Changes in Driving Biomass Loss in Ugandan Forest Fragments

Aboveground biomass (AGB) contained in privately-owned forests is less frequently measured than in forest reserves despite their greater likelihood of degradation. We demonstrate how density changes in contrast to species compositional changes have driven AGB changes in privately-owned fragments in Uganda over two decades. Data on tree assemblages in fragments were obtained by re-sampling a 1990 dataset in 2010 and AGB estimated using generalised allometric equation that incorporates diameter at breast height (DBH) and species-specific wood density. AGB were highly variable between fragments and over time. Structural changes contributed a higher proportion of change in AGB than species compositional changes in all forests. Non-pioneer species constituted over 50% of AGB in reserve forest, in contrast to private forests where pioneer species dominated. Our study demonstrates the potential of private forests to hold comparable AGB to plantation. Reduction in exploitation pressure is required if fragments are to mitigate carbon emissions.

Variation in wood density and carbon content of tropical plantation tree species from Ghana

Most research on carbon content of trees has focused on temperate species, with less information existing for tropical trees and very little for tropical plantations. This study investigated factors affecting the carbon content of nineteen tropical plantation tree species of ages seven to twelve and compared carbon content of Khaya species from two ecozones in Ghana. For all sample trees, volume of the main stem, wood density, wood carbon (C) concentration and C content were determined. Estimated stem volume for the 12-year-old trees varied widely among species, from 0.01 to 1.04 m3, with main stem C content ranging from 3 to 205 kg. Wood density among species varied from 0.27 to 0.76 g cm−3, with faster growing species exhibiting lower density. Significant differences in wood density also occurred with position along the main stem. Carbon concentration also differed among tree species, ranging from 458 to 498 g kg−1. Differences among species in main stem C content largely reflected differences among species in estimated main stem volume, with values modified somewhat by wood density and C concentration. The use of species-specific wood density values was more important for ensuring accurate conversion of estimated stem volumes to C content than was the use of species-specific C concentrations. Significant differences in wood density did exist between Khaya species from the wet and moist semi-deciduous ecozones, suggesting climatic and site factors may also need to be considered. Wood densities for these plantation grown trees were lower than literature values reported for the same species in natural forests, suggesting that the application of data derived from natural forests could result in overestimation of the biomass and C content of trees of the same species grown in plantations.

Wood decay resistance moderates the effects of tree mortality on carbon storage in the indigenous forests of New Zealand

The maintenance of carbon (C) storage in indigenous forest is a key component of efforts to manage atmospheric carbon dioxide concentrations. Increased pressures from extreme climatic events and invasive pests and pathogens pose major threats to the future stability of C storage in indigenous forests through elevated canopy-tree mortality. We assessed the potential for interspecific differences in wood decay resistance to moderate decadal-scale net C losses following canopy tree mortality. We recorded tree mortality, growth and recruitment over a period spanning almost 40years in repeatedly surveyed plots spanning a wide range of mortality rates. We combined these survey data with national data on species-specific wood decay resistance (i.e. retention of wood density) to estimate contemporary C lost through decay of trees that died during our study. We also included C losses from CWD contributed by a major synchronous mortality event before the study period (legacy CWD C loss) for a subset of the plots where CWD C storage measurements were available. C flux from live to dead biomass (1.36Mgha−1year−1, s.e. 0.16) was the main factor influencing estimated net contemporary changes in C storage, with the largest net contemporary C losses (−1.5Mgha−1year−1) observed in plots experiencing high mortality. Estimated net contemporary C loss from tree mortality was reduced when the dominant species had highly decay-resistant wood. The ability to predict contemporary changes in C was significantly improved when a plot-level indicator of CWD decay resistance was included in multiple regressions. Mean legacy CWD C loss was 0.39Mgha−1year−1, s.e. 0.16. When legacy losses were incorporated in net C change estimates, both the size of the legacy CWD pool and its interaction with legacy CWD decay resistance explained a significant amount of variation in net C change in multiple regressions. In plots losing large (around 3Mgha−1year−1) amounts of C from live biomass (or with more than 300Mgha−1 C stored in legacy CWD at the start of the study) wood decay resistance altered the net C balance by as much as 1.11Mgha−1year−1, which is a considerable effect given that the mean annual C assimilation rate across plots was 1.38Mgha−1year−1. Thus, our study reveals strong potential for interspecific variation in decay resistance to moderate the impact of canopy tree mortality on C storage in forests. We suggest that research effort on wood decay rates should be prioritised toward areas, such as drought-prone regions of Amazonia, where forests are likely to experience synchronous mortality events more frequently in future.

Estimating species-specific wood density from the genus average in Indonesian trees

To be able to make accurate estimates of the carbon stocks present in the world's tropical forests, there is a growing need for accurate tree biomass estimations on large spatial scales (Chave et al. 2004, Cummings et al. 2002, Nascimento &amp; Laurance 2004). Wood-specific gravity forms an important component of these biomass estimations (Baker et al. 2004, Magcale-Macandog 2004, Nogueira et al. 2005). Even though Chave et al. (2004) found that the most important source of error in above-ground biomass estimation (AGB) is currently related to the choice of allometric model, Baker et al. (2004) show that for two estimates of AGB in Amazonian forests derived using different allometric equations, stand-level specific wood gravity still explained 45.4% and 29.7% of the total variation in AGB.

Growing stock-based assessment of the carbon stock in the Belgian forest biomass

Belgian forests covered 693 181 ha in 2000, representing 22.7% of the total land area. As no biomass or carbon stock data are included in the Flemish and Walloon regional forest inventories, species-specific wood densities, biomass expansion factors s. s. and carbon content values were critically selected from the literature. Based on these conversion and expansion factors, and on data from the forest inventories, the total C-stock in the living biomass of productive Belgian forests was assessed at 60.9 Mt C in the year 2000. The overall mean C-stock amounted to 101.0 t C ha(-1). This value was in the higher range of values reported for the neighbouring countries, mainly due to a high mean growing stock in the Belgian forests (261.9 m(3) ha(-1)). The conversion from wood volume to wood biomass based on wood density values reported in the literature appeared to introduce the largest variability in the assessment of the carbon stocks. Additional measurements of wood densities in Belgian forests could help to reduce the uncertainty related to this factor. Because of the time-consuming and destructive character of the determination of biomass expansion factors s. s. (BEFs), the establishment of new BEFs does not have the highest priority in the framework of improving the assessment of the biomass carbon stock in the Belgian forests. As the median C-content value for all species except beech was equal to the default IPCC-value of 50% carbon in dry matter, it seems appropriate to use this value for future calculations.