Major Tree Research Articles

Carbon stock in major tree species in Ngoba community forest under Paro Dzongkhag

Carbon stock in major tree species in Ngoba community forest under Paro Dzongkhag

Timing of leaf fall and changes in litter nutrient concentration compromise estimates of nutrient fluxes and nutrient resorption efficiency

Nutrient resorption in the canopy and return to soil with litterfall are two major nutrient processes in forested ecosystems. However, leaf-fall phenology and seasonal dynamics of canopy nutrient concentration have not been comprehensively quantified, compromising the confidence in estimates of litterfall nutrient fluxes and nutrient resorption efficiency. Here, we used high-frequency litter collections for 28 species in nine plots for a temperate deciduous broadleaved forest in northeastern China. Based on leaf-fall phenology and temporal shifts in nitrogen (N) and phosphorus (P) concentrations in leaf litter for major tree species, we quantified the errors in canopy nutrient flux and resorption efficiency for 15 species and nine plots. The day of year (DOY) of start of leaf-fall, DOY of peak leaf-fall, and the length of leaf-fall period differed dramatically among tree species. Concentrations of N and P in leaf litter usually declined during the summer and autumn seasons. Annual nutrient fluxes in total canopy litterfall at the ecosystem level were 65.70 ± 6.14 kg N ha−1 and 4.70 ± 0.80 kg P ha−1 of which leaf litterfall accounted for 78 and 76%, respectively. The N (NRE) and P (PRE) resorption efficiencies at the ecosystem level calculated based on the percentage of nutrient pool resorbed from canopy leaves were 49.8 ± 3.9 and 48.0 ± 7.1%, respectively. Calculating nutrient fluxes with species-specific nutrient concentration at the DOY of peak leaf-fall (Nupeak) underestimated N and P fluxes by an average of 11 and 14%; the corresponding errors in N and P fluxes estimated using plot-specific Nupeak were –5 and –7%. In addition, NRE and PRE for major species based on Nupeak were overestimated by an average of 9 and 12%, and those for nine plots by 11 and 17%; using plot-specific Nupeak lowered mean errors in NRE and PRE to 10 and 11%. These results indicate that estimating canopy nutrient fluxes and resorption efficiency using litterfall collected at the DOY of peak leaf-fall can lead to non-negligible errors, and species-specific combined litterfall collected at and slightly before the DOY of peak leaf-fall may be a better metric for estimating nutrient flux and resorption efficiency at both species and ecosystem scales.

Current status of cherry trees (Prunus subg. Cerasus) planted in Korea: A case study of Bundang Central Park and adjacent area

Prunus subg. Cerasus is the most planted street and landscaping tree in South Korea, but it is difficult to identify species according to their macro-morphologies, leading to problems when attempting properly to manage species quantities. The purpose of this study is to understand the current status of plant types and species compositions in Bundang Central Park in Bundang-gu of Seongnam City and to discuss the necessity of the management of landscaping tree planting. In April of 2021, during the cherry blossom season, a total of 5,866 planted cherry trees were investigated within an area of 6 km<sup>2</sup> of Bundang-gu in Seongnam City. As a result, 5,744 trees were sorted into eleven taxa, but the remaining 122 trees were not determined due to their complex morphologies. Prunus ×yedoensis Matsum. accounted for the highest proportion (52.1%), followed by P. serrulata Lindl. var. pubescens Nakai and P. jamasakura Siebold ex Koidz. P. ×nudiflora (Koehne) Koidz., a plant native to Jejudo Island, was not found in this survey. In order to help identify cherry trees based on micro-morphologies, an identification key was presented for the eleven taxa planted as major landscaping trees. It is known that cherry trees frequently form interspecific hybrids in nature. In order to prevent a loss of the genetic originality of native species due to hybridization and gene introgression from foreign cherry trees, it is necessary to manage planting species near the habitats of native taxa and track their origins.

D-Pinitol-Active Natural Product from Carob with Notable Insulin Regulation.

Carob is one of the major food trees for peoples of the Mediterranean basin, but it has also been traditionally used for medicinal purposes. Carob contains many nutrients and active natural products, and D-Pinitol is clearly one of the most important of these. D-Pinitol has been reported in dozens of scientific publications and its very diverse medicinal properties are still being studied. Presently, more than thirty medicinal activities of D-Pinitol have been reported. Among these, many publications have reported the strong activities of D-Pinitol as a natural antidiabetic and insulin regulator, but also as an active anti-Alzheimer, anticancer, antioxidant, and anti-inflammatory, and is also immune- and hepato-protective. In this review, we will present a brief introduction of the nutritional and medicinal importance of Carob, both traditionally and as found by modern research. In the introduction, we will present Carob’s major active natural products. The structures of inositols will be presented with a brief literature summary of their medicinal activities, with special attention to those inositols in Carob, as well as D-Pinitol’s chemical structure and its medicinal and other properties. D-Pinitol antidiabetic and insulin regulation activities will be extensively presented, including its proposed mechanism of action. Finally, a discussion followed by the conclusions and future vision will summarize this article.

Monitoring Colletotrichum Colonization and Reproduction in Different Rubber Tree Clones.

Anthracnose, caused by fungi of the genus Colletotrichum, is present in the major rubber tree crop areas in Brazil, especially in São Paulo, Mato Grosso do Sul, Paraná, Minas Gerais, Espírito Santo, and northern states. This disease can affect different tissues of the rubber tree, leading to production losses. Thus, a better understanding of the pathosystem Colletotrichum x rubber tree can provide evidence to subsequent epidemiological research and phytosanitary management studies of this disease in the field. The present study aimed to investigate C. tamarilloi colonization and reproduction steps in resistant clones (IAC 502, IAC 507, RRIM 937) and in one susceptible clone (RRIM 600) of the rubber tree, verifying the influence of temperature up to 48 h after inoculation of the fungus, under 24 h wetness. Samples were analyzed under a light, a UV and a scanning electron microscope. Data indicated that the fungus had a delay in its development in resistant clones and, although colonization was expressive 48 h after inoculation, the new spore formation rate in the analyzed samples was lower in resistant clones. For RRIM 600, rapid colonization and intensive sporulation could be observed.

Estimating available unused dead wood materials for heat generation in Mongolia: how much coal can unused dead wood materials substitute?

In this study, we estimated the technoeconomic availability of three types of dead trees, namely commercially fallen, normally fallen, and standing, in Mongolian subgroups. For dead trees of three major Mongolian tree species (Siberian larch, Scotch pine, and Asian white birch), lumber, firewood, and unused material as sources of energy were quantified and operational costs (marking, felling, skidding, transporting, loading/unloading, processing, and stumpage prices) were estimated. As a result, most Mongolian subgroups were profitable and suitable for the harvest of unused materials. Moreover, unused materials of dead trees can substitute nearly 5.45 million tons of coal, although it is not sufficient to meet the 0.6years of coal demand across Mongolia. However, in some places, unused dead wood materials can completely substitute coal for decades. Therefore, although the heat utilization of woody biomass is not suitable for Mongolia as a whole, it is feasible in specific regions where forest resources are abundant, such as some Mongolian sub-provinces. Promoting the use of dead trees can reduce the risk of damage caused by wildfires and pests, which are serious problems in Mongolia, and keep the forests healthy. Furthermore, unused materials can generate new income opportunities, and the forest land can be well prepared by removing dead trees to promote planting for sustainable forest management. Finally, dead trees can be used as a resource until transition to sustainable forests with living trees.

Predictors of the Success of Natural Regeneration in a Himalayan Treeline Ecotone

The sensitivity and response of climatic treelines in the Himalayas to climate change is still being debated. Regeneration of tree species in the treeline ecotone is considered a sensitivity indicator and thus of great scientific interest. The aim of this study is to detect predictor variables for regeneration densities of the major tree species in central Himalayan treeline ecotones (Abies spectabilis, Betula utilis, Rhododendron campanulatum), analysing five development stages from seedling to mature tree. We applied negative binomial generalized linear models with predictors selected from a wide range of soil, topography, climate and stand characteristic variables. We found considerably varying predictors across the tree species and their stages of development. Soil conditions, topography and climate, as well as competing and facilitating tree species, had high predictive power for population densities. These predictors were clearly species- and development stage-specific. Predictors’ spatial- and development-specific heterogeneity induce a high degree of complexity and diversify any potentially linear response of tree population densities and treeline position to changing climatic conditions.

PM2.5 reduction capacities and their relation to morphological and physiological traits in 13 landscaping tree species

Fine particulate matter (PM2.5) is emerging as a serious environmental problem worldwide with the increase in anthropogenic emission sources, such as fossil fuels, transportation, and industries. In urban areas, where industrial complexes and human activities are concentrated, PM2.5 poses a threat to human health. Recently, because of their ability to reduce PM2.5, the introduction of landscaping trees as an environment-friendly solution has become popular; however, there remains a lack of research on the selection of species and their management. In this study, we quantified and compared the PM2.5 reduction capacities of 13 major landscaping tree species and analyzed their relationship with the morphological and physiological characteristics of each species. The results showed that the amount of PM2.5 reduction per leaf area differed among species and was the highest in Ginkgo biloba (28 165 ± 5353 # cm−2 min−1) and the lowest in Pinus strobus (1602 ± 186 # cm−2 min−1). Moreover, PM2.5 reduction by the broadleaf species (18 802 ± 1638 # cm−2 min−1) was approximately 8.6-fold higher than that of the needleleaf species (2194 ± 307 # cm−2 min−1). Correlation analysis revealed that differences in PM2.5 reduction were explained by differences in specific leaf area between species (P = 0.004) and by the length of margin per leaf area among individual trees (P < 0.05). Additionally, reduction in PM2.5 correlated with photosynthetic properties such as maximum assimilation and carboxylation rates (P < 0.001), indicating that PM2.5 is reduced not only by physical adsorption but also by physiological processes. These findings emphasize that for effective reduction in PM2.5 using landscaping trees, comprehensive consideration of the morphological and physiological characteristics of the species is essential during species selection, and that continuous management is also necessary to maintain the active physiological conditions of the trees.

Comprehensive study of distributions of residual stress and Young\u2019s modulus in large-diameter sugi (Cryptomeria japonica) log

Aged conifer forests in Japan are expected to produce large-diameter logs, defined as logs with a top-end diameter of 30 cm or more. However, the knowledge and techniques for industrial processing of large-diameter logs of Japanese wood species have not been sufficiently developed. This study was aimed at characterizing the longitudinal component of residual stress distribution of large-diameter logs of sugi (Japanese cedar, Cryptomeria japonica), a major tree species cultivated in Japan, as the processing yield of primary lumber from large-diameter logs is affected by the magnitude and distribution pattern of the residual stress. The radial distributions of the released strain of residual stress, tensile Young’s modulus, and residual stress were measured using 63 logs. The radial distributions of the released strain and residual stress showed typical patterns reported in previous studies: contraction near the bark and elongation near the pith in the released strain, tensile stress near the bark, and compressive stress near the pith. The radial distributions of Young’s modulus showed a typical pattern: low near the pith and high near the bark. The difference between the maximum and minimum released strains in each log varied widely among individuals, which was expected to result in a wide variation in crooking when rip sawing. The longitudinal uniformity and axial symmetry of the radial distribution of the released strain and residual stress were experimentally confirmed, which lays the groundwork for improved understanding of the residual stress in sugi logs.

Water use efficiency and leaf nutrient characteristics of five major tree species in broadleaved Korean pine forest in Changbai Mountains, China

Water use efficiency (WUE) of five dominant tree species (Pinus koraiensis, Fraxinus mandshurica, Acer mono, Quercus mongolica, and Tilia amurensis) was estimated using the stable carbon isotope method in a broadleaved Korean pine forest in Changbai Mountains. Leaf carbon (C), nitrogen (N), and phosphorus (P) contents were measured to analyze nutrient utilization of the dominant species. The relationship between WUE and leaf nutrient contents was systematically assessed. WUE was different due to the variations of micrometeorological factors at different locations in the canopy. The four broadleaved tree species showed upper layer > middle layer > lower layer, while P. koraiensis showed upper layer > lower layer > middle layer. WUE of evergreen coniferous P. koraiensis was higher than that of two broadleaved species with diffuse-porous wood (T. amurensis and A. mono) and lower than that of two broadleaved species with ring-porous wood (F. mandshurica and Q. mongolica). The compound-leaved species (F. mandshurica) had the highest WUE. The WUE of new leaves was significantly higher than old leaves in P. koraiensis. The carbon content and C/N of the old and new leaves of evergreen coniferous P. koraiensis were significantly higher than those of the other four broadleaved tree species, while nitrogen content and N/P were significantly lower than those of the four broadleaved tree species. P content of old leaves of P. koraiensis was significantly lower than that of the four broadleaved tree species. P content of new leaves of current year was not significantly different from that of the broadleaved tree species. The WUE of five tree species had a poor correlation with leaf C content, but a positive correlation with leaf N content. The WUE of evergreen coniferous and deciduous broadleaved tree species was correlated with leaf P content but in opposite direction.

Identification of Aquaporin Gene Family in Response to Natural Cold Stress in Ligustrum × vicaryi Rehd.

Plants are susceptible to a variety of abiotic stresses during the growing period, among which low temperature is one of the more frequent stress factors. Maintaining water balance under cold stress is a difficult and critical challenge for plants. Studies have shown that aquaporins located on the cytomembrane play an important role in controlling water homeostasis under cold stress, and are involved in the tolerance mechanism of plant cells to cold stress. In addition, the aquaporin gene family is closely related to the cold resistance of plants. As a major greening tree species in urban landscaping, Ligustrum× vicaryi Rehd. is more likely to be harmed by low temperature after a harsh winter and a spring with fluctuating temperatures. Screening the target aquaporin genes of Ligustrum × vicaryi responding to cold resistance under natural cold stress will provide a scientific theoretical basis for cold resistance breeding of Ligustrum × vicaryi. In this study, the genome-wide identification of the aquaporin gene family was performed at four different overwintering periods in September, November, January and April, and finally, 58 candidate Ligustrum × vicaryi aquaporin (LvAQP) genes were identified. The phylogenetic analysis revealed four subfamilies of the LvAQP gene family: 32 PIPs, 11 TIPs, 11 NIPs and 4 SIPs. The number of genes in PIPs subfamily was more than that in other plants. Through the analysis of aquaporin genes related to cold stress in other plants and LvAQP gene expression patterns identified 20 LvAQP genes in response to cold stress, and most of them belonged to the PIPs subfamily. The significantly upregulated LvAQP gene was Cluster-9981.114831, and the significantly downregulated LvAQP genes were Cluster-9981.112839, Cluster-9981.107281, and Cluster-9981.112777. These genes might play a key role in responding to cold tolerance in the natural low-temperature growth stage of Ligustrum × vicaryi.

Simultaneous Compatible System of Models of Height, Crown Length, and Height to Crown Base for Natural Secondary Forests of Northeast China

Individual trees are characterized by various sizes and forms, such as diameter at breast height, total height (H), height to crown base (HCB), crown length (CL), crown width, and crown and stem forms. Tree characteristics are strongly related to each other, and studying their relationships is very important. The knowledge of the compatibility and additivity properties of the major tree characteristics, such as H, CL, and HCB, is essential for informed decision-making in forestry. H can be used to represent site quality and CL represents biomass and photosynthesis of crown, which is the performance of individual tree vigor and light interception, and the longer the crown length (or shorter HCB) is, the more vigorous the tree would be. However, none of the studies have uncovered their inherent relationships quantitatively. This study attempts to explore such relationships through the application of appropriate modeling approaches. We applied seemingly unrelated regression, such as nonlinear seemingly unrelated regression (NSUR), which is commonly used for exploring the compatibility and additivity properties of the variables, for the proposes. The NSUR involves the variance and covariance matrices of the sub-models that are used for the interpretation of the correlations among the variables of interest. The data set acquired from Mongolian oak forest and spruce-fir forest in the Jingouling forest farm of the Wangqing Forest Bureau in the Northeast of China were used to construct two types of model systems: a compatible model system (the model system of H, CL, and HCB can be estimated simultaneously) and an additive model system (the sum of HCB and CL is H, the form of the H sub-model equals the sum of the HCB and CL sub-models) from the individual models of H, CL, and HCB. Among the various tree-level and stand-level variables evaluated, D (diameter at breast), Dg (quadratic mean diameter), DT (dominant diameter), CW (crown width), SDI (stand density index), and BAS (basal area of stand) contributed significantly highly to the variations of the response of the variables of interest in the model systems. Modeling results showed the existence of the compatibility and additivity of H, CL, and HCB simultaneously. The additive model system exhibited better fitting performance on H and HCB but poorer fitting on CL compared with the simultaneous model system, indicating that the performance of the additive model system could be higher than that of the simultaneous model system. Model tests against the validation data set also confirmed such results. This study contributes a novel approach to solving the compatibility and additivity of the problems of H, CL, and HCB models through the application of the robust estimating method, NSUR. The results and algorithm presented will be useful for constructing similar compatible and additive model systems of multiple tree-level models for other tree species.

Effect of feature standardization on reducing the requirements of field samples for individual tree species classification using ALS data

The objective of this study was to evaluate the effectiveness of three standardization approaches for airborne laser scanning (ALS) feature values used for individual tree species classification. This study is the first effort to assess the transferability of forest tree species classification models derived using monospectral and multispectral ALS data. Three research questions were asked; (1) How do the ALS features differ for the same species in different though comparable ecological regions? (2) How to train a model with one sub-population and apply it in another sub-population? (3) How to fuse models for two areas into a global model? To answer these questions, both 3D and intensity features were extracted from the ALS data from Canadian boreal forests. The ALS feature values were standardized in two different scenarios, disjoint areas, and partially overlapping areas, across three study areas. Feature standardization approaches were used: histogram matching, median-based standardization, and linear regression-based standardization. A linear discriminant analysis (LDA) and random forest (RF) algorithms were employed to classify the study area’s major tree species. The Bhattacharyya distance and overall accuracy (OA) were used to assess the classification model performance before and after the feature standardization. Three major conclusions were drawn. First, the Bhattacharyya distance confirmed that intensity features varied across study areas and among tree species, while 3D features were relatively less variable. Second, for the disjoint areas (York Regional Forest (YRF)) and Petawawa Research Forest (PRF)), the feature standardization procedure consistently improved the OA classification for both local model and global model approaches. The feature standardization improved the OA from 16% to 54% using LDA, and from 20% to 55% using RF in the local model. The improvement was from 58% to 66% using LDA, and from 63% to 70% using RF in the global model. It can be concluded that intensity features (at YRF and PRF) were most prone to differ between areas because of scanners and acquisition settings. If ALS data were available from both areas, intensity features need to be normalized so that the local model can be transferred. Finally, for the partially overlapping areas (the northern and southern parts of Black Brook Forest), this study suggests that normalization of ALS data is not needed because they were captured using quite similar ALS settings.

Short- to medium-term effects of crown and surface fires on soil respiration in a Canadian boreal forest

Fires are an important perturbation for the carbon (C) dynamics of boreal forests, especially when they are stand-replacing. In North American boreal forests, crown fires are predominant and, therefore, the most studied. However, surface fires can also lead to major tree mortality with substantial implications for the C balance. Here, we assess the short- (hours to days) to medium-term (1–3 years) effects of the different fire types (surface vs. crown) on the postfire soil C effluxes in jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP) forest stands in the Northwest Territories, Canada. We found that while trees were instantly killed by the four crown fires studied, trees also died within 1 year after two of three surface fires studied. Associated with this tree mortality, soil autotrophic respiration decreased after both fire types, although at different timings. The soil heterotrophic respiration was either lower or unchanged when measured 1–3 years after either fire type but was increased when measured immediately after a surface fire, possibly due to the interaction between ash generation and wetting performed to suppress the fire. Our results suggest that both fire types can thus substantially alter C fluxes in the short to medium term, both through changes in vegetation and the soil environment.

Construction of a collection of introgression lines of “Texas” almond DNA fragments in the “Earlygold” peach genetic background

Peach [Prunus persica L. Batsch] is one of the major temperate fruit tree species, the commercial materials of which have a low level of genetic variability. Almond [P. dulcis (Mill) DA Webb], a close relative of peach cultivated for its kernels, has a much higher level of diversity. The species are inter-compatible and often produce fertile hybrids, almond being a possible source of new genes for peach that could provide biotic and abiotic stress tolerance traits. In this paper we describe the development of a collection of peach-almond introgression lines (ILs) having a single fragment of almond (cv. Texas) in the peach background (cv. Earlygold). Lines with few introgressions were selected with markers from successive generations from a “Texas” × “Earlygold” F1 hybrid, initially using a set of SSRs and later with the 18 k peach SNP chip, allowing for the final extraction of 67 lines, 39 with almond heterozygous introgressions covering 99% of the genome, and 28 with homozygous introgressions covering 83% of the genome. As a proof of concept, four major genes and four quantitative characters were examined in the selected ILs giving results generally consistent with previous information on the genetics of these characters. This collection is the first of its kind produced in a woody perennial species and promises to be a valuable tool for genetic analyses, including dissection of quantitative traits, positional cloning, epistasis and as prebreeding material to introgress almond genes of interest into the peach commercial gene pool.

Exotic genes for solving emerging peach production challenges

Peach, a major fresh-market and processing tree crop world-wide, is entering a period of transformation driven by changes in climate, production methods and market trends but where future breeding progress is severely limited by its very narrow genetic base. Peach rootstocks, which are also of global importance, have a long history of utilizing interspecies hybridization to successfully incorporate needed traits for disease, pest and environmental stress resistance. Interspecies hybridizations resulting in commercially successful rootstocks have been made between cultivated peach and its close wild peach relatives, as well as the more distantly related cultivated almond and its numerous and ecologically diverse wild relatives. Hybrids between peach and plum as well as apricot species have also been successful, though more difficult. Recent efforts to further introgress such exotic germplasm for peach cultivar improvement have successfully transferred not only disease and pest resistance but also improved fruit and tree quality as well as greater tolerance to environmental stresses. Associated genetic and genomic studies provide useful information on trait heritability and, in many cases, have identified putative linkage group and possible candidate genes. Heritability of most traits derived from exotic germplasm, however, remains poorly studied, though early research suggests genomic and epigenetic modifications may sometimes be involved in addition to more traditionally studied genetic changes. While exotic gene introgression has the potential for transferring novel traits of value for rootstock and cultivar improvement, undesirable but undetected changes can also occur that, because of the long-lived and high-value nature of peach orchards, can ultimately result in severe economic losses.

Effect of Afforestation Mode on Rhizosphere Soil Physicochemical Properties and Bacterial Community Structure of Two Major Tree Species in Xiong’An New Area

Effect of Afforestation Mode on Rhizosphere Soil Physicochemical Properties and Bacterial Community Structure of Two Major Tree Species in Xiong’An New Area

Morphological traits and root anchorage ability of native pioneer tree species for reforestation of mudstone badlands

ABSTRACT Mudstone badlands occupy a large area in southwestern Taiwan. Mudstone soils with poor cementation property are particularly vulnerable to water erosion and landslides during rainy seasons. Broussonetia papyrifera, Hibiscus taiwanensis and Macaranga tanarius are major pioneer tree species occurring on mudstone badlands. Therefore, these species are beneficial for slope stabilization and forest restoration to control erosion and landslide. Nevertheless, information on their morphological traits and root biomechanical properties are lacking. In this research, root morphological traits of these species were inspected utilizing WinRHIZOPro Image Analysis System. Root anchorage ability and root tensile strength of 1-year-old B. papyrifera, H. taiwanensis and M. tanarius saplings were evaluated using uprooting testing and root tensile testing. The results show, compared to H. taiwanensis, B. papyrifera and M. tanarius plants had markedly greater root traits. Moreover, the root anchorage abilities of M. tanarius and B. papyrifer plants were notably higher than that of H. taiwanensis. In addition, root tensile strength of M. tanarius plants was markedly higher than those of B. papyrifera and H. taiwanensis plants. The results clearly demonstrate that M. tanarius outperforms B. papyrifera and H. taiwanensis, in these traits. Taken together, the priority for selecting these species for reforestation of mudstone badlands follows as: M. tanarius > B. papyrifera > H. taiwanensis. These results, together with the information on ecological succession following erosion and landslide, allow us to develop the reforestation plan and management strategy of mudstone badlands.

Regeneration status and species diversity of major tree species under scientific forest management in Kapilbastu district, Nepal

In Nepal, scientific forest managementhas been practiced as an effective forest management technique to utilize forest resources sustainably. However, the program has faced many controversies such as intentional logging of only high-valued timber species like Shorearobusta. In addition, few believe this program is severely affecting the regeneration productivity and species diversity in the natural forests. In order to address these issues, we examinedthe regeneration condition and plant species diversity in the stands where scientific forest management operations were carried out. The data related to regeneration status and species diversity were collected using a systematic random sampling of the selected stands. Our results showed good regeneration conditions (Seedling &gt;5000, Sapling&gt;2000) in all the studied stands. The tree species community was dominated by S.robusta(Sal) followed by Schleicheraoleosa (Kusum) and Casia fistula (Rajbriksha). The value of diversity indices of different species varied significantly between felling series. The highest diversity was found in the second year felling series with the Simpsons Index of dominance value 0.6934 and the lowest species diversity was in the first year felling series with a value of 0.8448. It can be recommended that the regeneration felling practice has helped in promoting the regeneration condition and growth.&#x0D;

Biomass and Carbon Stock in the Sal (Shorea robusta) Forest of Dang District Nepal

The study was conducted to find the net carbon stock in the Sal (Shorea robusta) forest in Bagdaila Chisapani community forest of Dang district, Nepal. The inventory was done by a stratified sampling technique with 0.5% sampling intensity taking into account the woody plants with ≥ 5cm DBH. A total of 49 sample plots of radius 8.94m and 5.64 were established to measure tree biomass and sapling biomass respectively in the forest. The mean above-ground carbon (AGC) was 160.4 t ha-1 and the mean below-ground carbon (BGC) was 24.1t ha-1. The mean total carbon stock in the study area was estimated to be 99.02 t ha-1; of which maximum carbon stock of 143.51 t ha-1 was found in block number 5. Sal was the major tree species in the CF. The biomass and carbon content in this forest is found quite low as compared to other studies in the Sal forest and other tropical forests which were due to the presence of tree stands of less diameter and height. This study would be helpful in the long-term management of forests, planning, and research purposes. The data from this study could also be taken as a reference document for the participation of community forests in carbon accounting under the REDD+ scheme in Nepal.