Natural Secondary Forest Research Articles

THE ABILITY OF COFFEE AGROFORESTRY SYSTEM TO STORE CARBON STOCK

Each type of forest ecosystem and the species in it have different abilities to absorb CO2 and produce biomass. Coffee-based agroforestry is thought to be able to increase the ability of forests to store carbon as a result of increasing species composition and density of plants in these forest areas. This study aims to determine the composition of plants and carbon stocks stored in coffee-based agroforestry forests in LMDH Paniis RPH Rancakalong BKPH East Manglayang KPH Sumedang Perum Perhutani Regional Division West Java and Banten. This study uses survey and experiment methods. Data obtained through observations in the field and laboratory are in the form of tree names, wood density, tree biomass and carbon stocks from biomass. The result shows that the agroforestry forest composition at LMDH Paniis RPH Rancakalong BKPH East Manglayang KPH Sumedang within 17,14 ha consists of Pine (Pinus mercusii), Big-leaf Mahogany (Swietenia macrophylla), Clove (Syzygium aromaticum) dan Coffee (Coffea arabica). The carbon stock is 1.869,73 kg/ha in agroforestry forest, 2.618,32 kg/ha in primary natural forest, and 1.460,91 kg/ha in secondary natural forest. Agroforestry forest has more carbon stock than secondary natural forest does and agroforestry forest has less carbon stock than the primary natural forest

Anatomical structures of fine roots of 91 vascular plant species from four groups in a temperate forest in Northeast China.

Fine roots of plants play an important role in terrestrial ecosystems. There is a close association between the anatomical characteristics and physiological and ecological functions of plants, but we still have a very limited knowledge of anatomical traits. For example, (1) we do not know if herbs and grasses have anatomical patterns similar to those of woody plants, and (2) the variation among different woody plants in the same ecosystem is unclear. In the present study, we analysed the anatomical structures of the fine root systems of various groups of vascular plants (ferns, eudicot herbs, monocots and woody plants) from the same ecosystem (a natural secondary forest on Mao'er Mountain, Heilongjiang, China) to answer the following questions: (1) How does the anatomy of the fine roots change with root order in various plant groups in the same ecosystem? (2) What is the pattern of variation within group? The results show that anatomical traits can be divided into 3 categories: traits that indicate the root capacity to transport resource along the root (stele diameter, xylem cell diameter and xylem cell area); traits that indicate absorptive capacity cortical thickness, (the number of cortical cell layers and the diameter of cortical cells); and traits that are integrated indicators (diameter and the stele to root diameter ratio). The traits indicate the root capacity to transport resource along the root order is generally similar among groups, but absorptive capacity is very different. The shift in function is the main factor influencing the fine root anatomy. Some traits show large variation within groups, but the variations in other traits are small. The traits indicate that the lower-order roots (absorbing roots) in distinct groups are of the first one or two root order in ferns, the first two or three orders in eudicot herbs, the first (only two root orders) or first two orders (more than three root orders) in monocots and the first four or five root orders in woody plants and the other roots are higher-order roots (transport roots). The result will helpful to understand the similarities and differences among groups and the physiological and ecological functions of plant roots.

Spatial patterns and interspecific associations among trees at different stand development stages in the natural secondary forests on the Loess Plateau, China.

Quercus wutaishansea populations on the Loess Plateau are currently becoming more dominant in natural secondary forests, whereas Pinus tabulaeformis is declining. In the present paper, the diameter class (instead of age) was used to classify the different growth stages as juvenile, subadult, or adult, and the univariate function g(r) was used to analyze the dynamic changes in spatial patterns and interspecific associations in three 1‐ha tree permanent plots on the Loess Plateau, NW China. Our results suggested that the niche breadth changed with the development stage. The diameter distribution curve was consistent with the inverted “J” type, indicating that natural regeneration was common in all three plots. There was a close relationship between the spatial pattern and scale, which showed significant aggregation at small distances, and became more random as distance increased, but in the Pinus + Quercus mixed forests, the whole species were aggregated at distances up to 50 m. The degree of spatial clumping decreased from juvenile to subadult and from subadult to adult. The spatial pattern also differed at different growth stages, likely due to strong intraspecific competition. Associations among different growth stages were positively correlated at small scales. Our study is important to the understanding of the development of the Q. wutaishansea forests; thus, the spatial dynamic change features should be received greater attention when planning forest management and developing restoration strategies on the Loess Plateau.

Bark and Ambrosia Beetle (Coleoptera: Curculionidae: Scolytinae) Diversity in Natural and Plantation Forests in Ecuador.

The Scolytinae is highly diversified in tropical forests, but richness and abundance patterns within most Ecuadorian forest habitat types are not yet characterized. In this study, we assessed patterns of variation in Scolytinae richness, abundance, and species composition in a primary and a secondary natural forest, and a commercial balsa plantation in Ecuador. We conducted a 1-yr survey of Scolytinae communities with baited traps and measured associated environmental variables. In total, 18,169 Scolytinae individuals were captured and comprised 85 species, 16 genera, and six tribes. In the natural forests, main indicator species were Xylosandrus morigerus, Xyleborus affinis, Xyleborus sp.02, and Corthylus sp.01, whereas all species of Hypothenemus were indicator species in the balsa plantation. The exotic Premnobius cavipennis (Ipini), Xylosandrus compactus, and Xylosandrus morigerus were indicator species for the natural forests. We provide evidence that commercial balsa plantations provide abundant favorable resources for native and exotic scolytines in Ecuador, and that scolytine communities in natural forest and in plantations are more likely to differ in their species composition than in their cumulated species richness. In all habitats, species composition, abundance, and species richness showed temporal patterns of variation that coincided with seasonal variations in climatic conditions, with highest records during the coldest and driest months in the primary forest and the balsa plantation. We provide new knowledge on the native Ecuadorian scolytine fauna and a foundation for the monitoring for potential scolytine pest species of natural and planted tropical forest ecosystems.

A graph-based progressive morphological filtering (GPMF) method for generating canopy height models using ALS data

Airborne LiDAR-derived canopy height models (CHMs) have been widely applied in forestry inventory applications and have shown great advantages in obtaining forest-related parameters at different scales. Usually, first echoes are regarded as a representation of canopy surfaces during CHM generation, which may cause data pits and a lack of detail, thus resulting in negative effects for forestry applications. Therefore, we propose a canopy surface point filtering method called graph-based progressive morphological filtering (GPMF) for generating CHMs. The GPMF algorithm applies adaptive morphological filtering to exclude nonsurface points from all LiDAR points in a progressive process. The proposed method was tested in natural secondary forest stands. By comparing the performances of the GPMF method and four other CHM generation methods, namely, first-echo interpolation, Gaussian filtering, pit-filling and the highest points interpolation method, the results showed that the GPMF method produced few pits while retaining canopy details. The CHMs generated with the GPMF method were also obviously better than those generated with the other methods, as evidenced by the lowest average root mean square error (RMSE, 0.92 m) between reference points and the raster surfaces. The CHMs generated using GPMF also performed best overall in individual tree detection (average Fscore = 80.57%) and tree height estimation (average RMSE = 0.21 m) among all the methods. Therefore, the proposed GPMF method can accurately represent the height of canopy surfaces and shows high potential in forestry applications.

Forest restoration approaches affect soil compositions of lignin, substituted fatty acids, and lignin degradation-associated genes

The study of soil microorganisms and the composition of organic carbon is important for understanding the dynamics of soil organic carbon. The means by which forest restoration approaches might affect the soil composition of lignin, substituted fatty acids,11substituted fatty acids, SFA and the lignin degradation genes, remain understudied. We hypothesized that the soils of naturally restored forests have more abundant and stable lignin, SFA, and lignin degradation genes than those of artificially restored plantations. We analyzed the compositions of lignin, SFA, and the lignin degradation genes in soils restored with natural secondary forests, native species plantations, and introduced species plantations. We found that the extractable lignin content, leaf-derived SFA, leaf- to root-derived SFA ratio, and lignin oxidation state were higher in natural secondary forests than in plantations. The abundances of genes involved in glyoxal oxidase, lignin peroxidase, and manganese peroxidase were higher in the soils of natural secondary forests than in those of the two plantation types. No significant differences in the above indices were found between soils of native and introduced plantations. Nutrients and lignin oxidation state, including tree richness, litter stock, available nitrogen, combined clay and silt content, syringyl-based lignin to vanillyl-based lignin ratio, syringic acid to syringaldehyde ratio, and SFA content significantly affected the composition of genes involved in lignin degradation. Nutrients and lignin oxidation state explained 41.9% of the variation in the composition of lignin degradation genes. The lower lignin oxidation state, higher nutrient availability, and higher aboveground inputs led to a higher abundance of lignin degradation genes in the soils of natural secondary forests than in those of the plantations. These results provide insight into the effects of forest restoration approaches on soil carbon sequestration.

Effects of stand type of artificial forests on soil microbial functional diversity.

We explored the changes of soil microbial biodiversity in response to forest ecological restoration. Soil samples were collected from the close-to nature managed Chinese fir plantation (CF), Moso bamboo plantation (MB), and natural secondary forest (NF). Soil microbial community diversity was analyzed by Biolog-Eco micro-plate technique. The results showed that plant diversity was significantly different among the three stands. Plant diversity of NF was significantly higher than MB and CF, and MB was higher than CF. Soil pH and bulk density showed a great difference, while there was no difference of other soil physiochemical properties among the three stands. Avera-ge well color development (AWCD) of soil in various stands followed the order of NF＞MB＞CF, consistent with the changes of utilization of six types of carbon sources. Shannon index of NF was the highest, and the index of MB was significantly higher than that of CF. Soil physical and chemical properties in different stands were not significantly different, except soil pH and bulk density. The Shannon diversity index (H), Shannon species richness index (S), Simpson dominance index (D) and McIntosh index (U) were the highest in NF, second in MB, and the lowest in CF. Results from principal component analysis (PCA) showed that two factors from 31 carbon sources could explain 60.0% and 12.4% of the variation and that carboxylic acids, carbohydrates and its derivatives, amino acids were the main carbon sources of the two principal component factors. Correlation analysis indicated that plant species richness and Shannon diversity indexes, soil bulk density were significantly correlated to soil microbial community diversity. The microbial community of NF was more efficient in carbon utilization than that in MB and CF, while that in MB was more efficient than that of CF. Based on plant diversity and soil microbial carbon utilization, MB is much better than CF in the artificial forest restoration and improvement in South China.

Soil greenhouse gases fluxes and the affecting factors of natural secondary forest from seriou-sly burned area in Greater Khingan Mountains, China.

To learn the intensity of greenhouse gases (GHG) fluxes source/sink from soil and the influence factors of a natural secondary forest from seriously burned area in Greater Khingan Mountains, we used static chamber-GC technique to measure soil GHG (CO2, N2O, CH4) in situ during the growing season (from June to September). The results showed that: 1) The soil of natural secondary forest was atmospheric CO2 and N2O source and CH4 sink. The mean fluxes of soil GHG (CO2, N2O, CH4) during the growing season were 575.81 mg·m-2·h-1, 17.81 μg·m-2·h-1 and -68.69 μg·m-2·h-1, respectively. The CO2 and CH4 fluxes showed an obvious double-peak trend and the change of N2O fluxes was a single-peak pattern during the growing season, with all maximum fluxes occurred in August. 2) Soil temperature was the predominant factor controlling the soil GHG fluxes. The correlation of soil/atmospheric humidity and soil GHG fluxes was complicated and differed between diurnal scale and seasonal scale. 3) The soil GHG fluxes measured at 9:00-12:00 am could represent the diurnal average fluxes on the same day after proper correction in this area. The findings supplemented the soil GHG fluxes data of fired forest ecosystem in Greater Khingan Mountains, which could provide a basis for related research of soil GHG source/sink in this area.

Anatomical features of branchwood and stemwood of Betula costata Trautv. from natural secondary forests in China

To enhance effective wood utilization, knowledge of the anatomical features that impact its service behavior is indispensable. The anatomical features of branchwood and stemwood of Betula costata Trautv. from natural secondary forests in central (Muzhaling mountain) and northeast (Maoershan mountain) China were studied to provide adequate information to enhance their efficient utilization, especially branchwood, whose use could widen the raw material base of the timber industry. Microtomed sections were employed to determine the tissue dimensions and proportions. Analyses of variance were used to test the anatomical feature differences between the two different sites, between the stemwood and branchwood, and between the heartwood and sapwood. The results showed that B. costata wood is diffuse-porous with more but narrower vessels located in the branch than in the stem. The branchwood also had a significantly higher fiber proportion than the stemwood. The sapwood exhibited significantly longer fibers than the heartwood. B. costata from Maoershan had significantly longer fibers, lower fiber proportions, larger fiber lumen diameter, and higher vessel density than that from Muzhaling. The results suggested that B. costata branchwood from Maoershan is suitable for papermaking and glued plates, while stemwood can be used for light construction purposes.

湖南栎类天然次生林幼树更新特征及影响因子

PDF HTML阅读 XML下载 导出引用 引用提醒 湖南栎类天然次生林幼树更新特征及影响因子 DOI: 10.5846/stxb201806061269 作者: 作者单位: 中南林业科技大学,中南林业科技大学,贵州省植物园,中南林业科技大学,中南林业科技大学,中南林业科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31570631）；国家林业局项目（1692016-06） Regeneration characteristics and related factors affecting saplings in Quercus spp. natural secondary forests in Hunan Province, China Author: Affiliation: Forestry College, Central South University of Forest ＆ Technology, Changsha 410004, China,,Guizhou Botanical Garden,,, 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:以湖南典型栎类天然次生林为研究对象，基于51块样地的调查数据，采用k-means聚类分析划分林分类型，研究湖南不同栎类天然次生林幼树更新特征，分析了湖南不同栎类天然次生林幼树更新指标（幼树密度、幼树平均地径、平均高以及平均冠幅）与环境因子、林分因子的相关性，旨在阐明环境因子、林分因子对幼树更新的影响，以期为湖南不同栎类天然次生林的恢复与经营管理提供理论依据。结果表明：（1）利用聚类分析可将研究区内栎类天然次生林划分为5个类型，包括甜槠锥栗混交林（CC）、亮叶水青冈多脉青冈混交林（FC）、石栎樟树混交林（LC）、枹栎甜槠混交林（QC）、青冈栎混交林（CG）。（2）不同类型栎类天然次生林更新幼树优势种分化明显，物种丰富度差异显著（P < 0.05）。5种不同栎类次生林幼树密度均未超过500株/hm2，更新情况较差；幼树数量差异显著（P < 0.05），为亮叶水青冈多脉青冈混交林 > 石栎樟树混交林 > 青冈栎混交林 > 枹栎甜槠混交林 > 甜槠锥栗混交林；生长情况差异显著（P < 0.05），为青冈栎混交林 > 亮叶水青冈多脉青冈混交林 > 枹栎甜槠混交林 > 甜槠锥栗混交林 > 石栎樟树混交林。（3）相关分析结果显示，不同类型次生林幼树更新的主要影响因子存在差异。甜槠锥栗混交林中幼树密度与腐殖质厚度呈显著负相关（P < 0.05）；幼树平均高与灌木盖度呈显著正相关（P < 0.05）；幼树平均地径与草本盖度、灌木盖度呈显著正相关（P < 0.05）。亮叶水青冈多脉青冈混交林中幼树密度与海拔、腐殖质厚度、枯落物厚度呈显著正相关（P < 0.05），与草本盖度呈极显著正相关（P < 0.01）；幼树平均地径与郁闭度呈显著负相关（P < 0.05）；幼树平均高、幼树平均冠幅与坡位呈显著正相关（P < 0.05）。石栎樟树混交林中幼树密度与坡向、土壤厚度呈显著正相关（P < 0.05），其余因子对幼树生长无显著影响。枹栎甜槠混交林中幼树密度与郁闭度、乔木密度呈极显著正相关（P < 0.01），与坡位呈显著负相关（P < 0.05）；幼树平均冠幅与坡度呈显著负相关（P < 0.05）。青冈栎混交林中幼树平均地径与土壤厚度呈显著正相关（P < 0.05），与乔木密度呈极显著正相关（P < 0.01）；幼树平均冠幅与灌木盖度呈显著正相关（P < 0.05）。 Abstract:Quercus forest is a typical forest type in Hu'nan Province, which plays an important role in water and soil conservation, and maintaining ecological stability. However, most of the natural regeneration of Quercus forest in Hunan is poor, because of limited research on Quercus regeneration mechanisms, and ineffective management. Based on field investigation data, we analyzed typical Quercus natural secondary forests in Hunan, and used k-means cluster analysis to classify forest types. In this research, we studied sapling regeneration characteristics of different Quercus natural secondary forests in Hunan and examined the correlation of the sapling regeneration index (density, average ground diameter, average height, and average crown width of saplings) with environmental and stand factors in different Quercus natural secondary forests in Hunan. This study aimed to provide a theoretical basis for the restoration and management of natural secondary forests of different Quercus species in Hunan Province. The results showed that the natural secondary forest of Quercus could be divided into five types by cluster analysis, including Castanopsis eyrie-Castanea henryi mixed forest (CC), Fagus lucida-Cyclobalanopsis multinervis mixed forest (FC), Lithocarpus glaber-Cinnamomum bodinieri mixed forest (LC), Quercus serrata-Castanopsis eyrie mixed forest (QC), and Cyclobalanopsis glauca mixed forest (CG). The dominant species and species richness of the regeneration forests of different types of Quercus secondary forests were significantly different(P < 0.05). The sapling density in five different secondary forests of Quercus was < 500 trees/hm2, and sapling regeneration was poor. The number of saplings of different Quercus secondary forests was significantly different(P < 0.05), in the order of FC > LC > CG > QC > CC. The sapling growth status in different forests was significantly different(P < 0.05), and in the sequence of CG > FC > QC > CC > LC. The results of the correlation analysis showed that there were differences in the main factors affecting sapling regeneration in different types of secondary forests. In CC, there was a significant negative correlation between the sapling density and humus thickness(P < 0.05), a significant positive correlation between the average sapling height and shrub coverage(P < 0.05), and a significant positive correlation between the average sapling basal diameter and herbaceous and shrub coverage(P < 0.05). In FC, there was a significant positive correlation between sapling density and altitude, humus thickness, and litter thickness(P < 0.05), and a very significant positive correlation with herbaceous coverage(P < 0.01), a significant negative correlation between average ground diameter and canopy density(P < 0.05), and the average sapling height and crown width were significantly positively correlated with the slope position(P < 0.05). In LC, there was a significant positive correlation between sapling density and slope direction and soil thickness(P < 0.05), whereas the other factors had no significant effect on sapling growth. In QC, sapling density was extremely positively correlated with canopy and tree density(P < 0.01), and negatively correlated with slope position(P < 0.05), and the average sapling crown width was negatively correlated with slope(P < 0.05). In CG, the average sapling diameter was significantly positively correlated with soil thickness(P < 0.05), and had an extremely significant positive correlation with tree density(P < 0.01), and the average sapling crown width was positively correlated with shrub coverage(P < 0.05). 参考文献 相似文献 引证文献

秦岭山地天然次生林群落MRT数量分类、CCA排序及多样性垂直格局

秦岭山地天然次生林群落MRT数量分类、CCA排序及多样性垂直格局

Spatial patterns of dominant species and their implication for natural secondary forest ecosystem dynamics in a reserved forest of north China

Spatial pattern analysis is useful to elucidate the type and importance of the ecological processes in forest ecosystem. To better understand the dynamics of the natural secondary forest ecosystem and to provide information regarding the interactions between arbors and shrubs, the spatial patterns of dominant species in a natural secondary forest was examined in this paper. We developed a 2 ha secondary forest plot by mapping the location of all woody plants (diameter at breast height ≥1 cm). Univariate and bivariate Ripley’s L(r) functions were utilized to evaluate the spatial patterns and association of the three dominant plants (P. davidiana, B. platyphylla and C. mandshurica). It was found that aggregated distribution was the main pattern in the dominant populations of the total and size-specific individuals of arbors at most scale. The degree of aggregation gradually decreased with size in B. platyphylla due to self-thinning while increased in P. davidiana which may attribute to the effects of logging for large- and medium-size woods in 1940s or 50s. In associations of intra-/interspecies pairs, positive association was the majority of intraspecies, whereas negative association was the domination in interspecies. Remarkable, mutual independence dominated in C. mandshurica vs. size-specific B. platyphylla pairs at most scales, and positive association emerged at greater than 8 m scales in C. mandshurica vs. size-specific B. platyphylla-large, may contribute to different niche occupying that generated less competitions for resources, even the large ones could provide preferable shelter for shrubs.

Diversity and distribution of food plants: Implications for conservation of the critically endangered Hainan gibbon

An understanding of the diversity and distribution patterns of Hainan gibbon (Nomascushainanus) foods is essential to its conservation. We used data from plots in various successional stages and Pinusmerkusii plantations (PF) of Bawangling National Nature Reserve (BNNR) to compare variations in food species diversity and composition amongst forest types. A total of 85 food species and 16,882 food plants individuals were found across forest types. Habitat-exclusive food species were most abundant in old growth natural forest (OGF), followed by mid-aged natural secondary forest (MSF). We did not find exclusive species in PF. For all food species, as well as each stem size class, PF displayed a lower species richness and abundance and, in addition, less similar species composition in each age class compared to secondary forests. The highest stem density and species richness were found in MSF. The abundance of food trees was higher in MSF and OGF than in young natural secondary forest. Results suggested that MSF could serve as an alternative habitat for Hainan gibbons after short-term recovery. Hainan gibbons might be limited to secondary forests older than 25 years old. PF was found to be unsuitable for Hainan gibbons.

Effects of thinning on hydrological properties of the natural secondary Larix gmelinii forest in the Daxing’an Mountains

Effects of thinning on hydrological properties of the natural secondary Larix gmelinii forest in the Daxing’an Mountains

Biomass-dominant species shape the productivity-diversity relationship in two temperate forests

A negative productivity-diversity relationship was determined for biomass-dominant species at the community level. This study thus supports the hypothesis in which the effects of individual species on the productivity-diversity relationships at the community level are related to their biomass density, an important functional trait. The productivity-diversity relationships have been extensively studied in various forest ecosystems, but key mechanisms underlying the productivity-diversity relationships still remain controversial. The objective of this study is to explore the productivity-diversity relationships at the community level, and to investigate the roles of individual species in shaping the community-level relationships between productivity and diversity under different forest types. The study was conducted in two fully stem-mapped temperate mixed forest plots in Northeastern China: a natural secondary forest plot, and an old-growth forest plot. An individual-based study framework was used to estimate the productivity-diversity relationships at both species and community levels. A homogeneous Thomas point process was used to evaluate the significance of productivity-diversity relationship deviating from the neutral. At the species level, most of the studied species exhibit neutral productivity-diversity relationship in both forest plots. The percentage of species showing negative productivity-diversity relationship approaches linearly a peak value for very close neighborhoods (the secondary forest plot: r = 3 m, 38%; the old-growth forest plot: r = 4 m, 42%), and then decreases gradually with increasing spatial scale. Interestingly, only a few species displayed positive productivity-diversity relationship within their neighborhoods. Dominant species mainly exhibit negative productivity-diversity relationship while tree species with lower importance values exhibit neutral productivity-diversity relationship in both forests. At the community level, a consistent pattern of productivity-diversity relationship was observed in both forests, where tree productivity is significantly negatively associated with local species richness. Four biomass-dominant species (Juglans mandshurica Maxim., Acer mono Maxim.,Ulmus macrocarpa Hance and Acer mandshuricum Maxim.) determined a negative productivity-diversity relationship at the community level in the secondary forest plot, but only one species (Juglans mandshurica) in the old-growth forest plot. The productivity-diversity relationship is closely related to the dominance of individual species at the species level. Moreover, this analysis is the first to report the roles of biomass-dominant species in shaping the productivity-diversity relationship at the community level.

Habitat preference and den characterization of Indian Pangolin (Manis crassicaudata) in a tropical lowland forested landscape of southwest Sri Lanka.

The Indian pangolin (Manis crassicaudata) is under threat due to hunting for local consumption and illegal trafficking of scales and meat. The dearth of scientific studies on the ecology of the M. crassicaudata has impaired accurate assessments of its conservation needs. This study investigated the habitat preference and burrow characteristics of M. crassicaudata in a tropical lowland rainforest in southwest Sri Lanka. A total of 75 burrows (54 feeding burrows and 21 resting burrows) of M. crassicaudata in four different habitat types i.e. secondary forest, Pine-dominated forest, rubber cultivations and tea-dominated home gardens bordering forest were observed using fixed-width transects in order to characterize resting and feeding burrows of this species. The highest density of resting burrows was recorded from the secondary forest (4ha-1), followed by rubber cultivations (2.5ha-1) while no resting burrows were recorded in the Pine-dominated forest and the tea-dominated home gardens bordering forest. Feeding burrows were more abundant in the Pine-dominated forest (5.7ha-1). The burrow depth, burrow opening height, and width were significantly larger in resting burrows compared to feeding burrows. Resting burrows were located at higher elevations (75-100m) with moderately high slopes (450−600), dense canopy cover (>75%) and away from human habitation. Feeding burrows showed a greater variability in terms of associated environmental features. The study further revealed that Indian pangolins exclusively prefer habitats with rocks and boulders under which they dig resting burrows while the location of feeding burrows largely overlaps with the distribution of prey species. The resting burrow design consisted of a bending tunnel that initially slopes downward and then gradually inclines at an angle between 20 and 300, leading to the resting chamber. Our study highlights the importance of conserving fragmented secondary natural forests in changing landscapes of the southwest lowlands of Sri Lanka as these habitats appear to be critical to sustaining populations of M. crassicaudata.

Biomass carbon density in natural oak forests with different climate conditions and stand ages in northwest China

ABSTRACTOak forests are major communities in warm temperate forests in northern China. The dependence of biomass carbon accumulation and allocation patterns in above- and belowground on climate and stand age remains unclear. To quantitatively investigate the influence of temperature, precipitation, and stand age on the biomass carbon density (BCD) of each component in the forest and on the above/belowground allocation, field surveys were conducted at 32 plots with dimensions of 20 m × 50 m representing different ages and environmental conditions of natural oak secondary forests. Tree biomass was estimated using allometric biomass equations based on tree height and diameter at breast height (DBH). Biomass of shrubs, herbs, and litter was estimated by harvesting all the components. Carbon concentrations of all the plant components and litter were measured. Biomass carbon densities of trees and total ecosystems increased with increases in precipitation and stand age, but did not differ significantly with changes in air temperature. The ratio of above/belowground BCD showed significant positive correlation with stand age. Understory layers (shrubs and herbs) BCD showed positive relationships with precipitation, but had no obvious relations with stand age and temperature. BCD in litter layer decreased with increasing precipitation and had no definite variation trend along temperature and stand age gradients. The influence of precipitation on plant growth is greater than that of temperature in the forests. These findings indicate that water availability is the dominant environmental factor across these sub-humid climate sites.

Fine Root Dynamics in Three Forest Types with Different Origins in a Subalpine Region of the Eastern Qinghai-Tibetan Plateau

Fine roots play a crucial role in plant survival potential and biogeochemical cycles of forest ecosystems. Subalpine areas of the Eastern Qinghai-Tibetan Plateau have experienced different forest re-establishment methods after clear-cutting primary forest. However, little is known about fine root dynamics of these forests originating from artificial, natural and their combined processes. Here, we determined fine root traits (biomass, production and turnover rate) of three subalpine forest types, i.e., Picea asperata Mast. plantation forest (artificial planting, PF), natural secondary forest (natural without assisted regeneration, NF) and P. asperata broadleaved mixed forest (natural regeneration after artificial planting, MF) composed of planted P. asperata and naturally regenerated native broadleaved species. At the soil depth of 0–30 cm, fine root biomass was the highest in PF and fine root production was the highest in NF, and both were the lowest in MF. Fine root dynamics of the three forest types tended to decrease with soil depth, with larger variations in PF. Fine root biomass and production were the highest in PF in 0–10 cm soil layer but were not significantly different among forest types in the lower soil layers. There were positive correlations between these parameters and aboveground biomass across forest types in soil layer of 0–10 cm, but not in the lower soil layers. Fine root turnover rate was generally higher in mixed forests than in monocultures at all soil depths. In conclusion, the natural regeneration procedure after clear-cutting in the subalpine region of western Sichuan seems to be superior from the perspective of fine root dynamics.

Phosphorus and Nitrogen Drive the Seasonal Dynamics of Bacterial Communities in Pinus Forest Rhizospheric Soil of the Qinling Mountains.

The temporal distribution patterns of bacterial communities, as an important group in mountain soil, are affected by various environmental factors. To improve knowledge regarding the successional seasonal dynamics of the mountain soil bacterial communities, the rhizospheric soil of a 30-year-old natural secondary Pinus tabulaeformis forest, located in the high-altitude (1900 m a.s.l.) of the temperate Qinling Mountains, was sampled and studied during four different seasons. The bacterial community composition and structure in the rhizospheric soil were studied using an Illumina MiSeq Sequencing platform. Furthermore, the edaphic properties and soil enzymatic activities (urease, phosphatase, and catalase) were measured in order to identify the main impact factors on the soil bacterial community. According to the results, all of the edaphic properties and soil enzymatic activities were significantly affected by the seasonal changes, except for the C/N ratio. Although the biomasses of soil bacterial communities increased during the summer and autumn (warm seasons), their Shannon diversity and Pielou’s evenness were decreased. Proteobacteria, Acidobacteria, Actinobacteria, Planctomycetes, and Bacteroidetes were the predominant bacterial groups in all of the soil samples, and the genera of Ktedonobacter, Sphingobium as well as an unclassified member of the Ktedonobacteria were the keystone taxa. The composition and structure of soil bacterial communities were strongly impacted by the edaphic properties, especially the temperature, moisture, ammoniacal nitrogen, available phosphorus and total phosphorus which were the crucial factors to drive the temporal distribution of the soil bacterial community and diversity. In conclusion, the soil temperature, moisture and the nutrients N and P were the crucial edaphic factors for shaping the rhizospheric soil bacterial communities as season and climate change in a P. tabulaeformis forest of Qinling Mountains.

Atributos físicos do solo em quatro sistemas de uso da terra em São Carlos, SP

The objective of this work was to evaluate the effect of four land use systems: two agroforestry systems (agrisilviculture and silvopastoral system), single pasture of Urochloa decumbens and native forest, on the physical characteristics of the soil, in Sao Carlos, SP, Brazil. Soil density, macroporosity, microporosity and total porosity, and the stability of aggregates, in the layers of 0-0.05, 0.05-0.20 and 0.20-0.40 m, we were analyzed in the year 2015. The experimental design was a completely randomized design with four replications. The data were submitted to the F test and the means were compared by the Tukey test. The multivariate analysis was applied using the Ward method and the Euclidean distance with standardized variables. It was verified that the soil under native forest presents better physical conditions than the areas with other forms of land use. The physical characteristics of the soil in the agroforestry systems did not vary according to the distance of the trees. The conventional pasture presented soil compaction in the 0-0.40 m layer. Considering the set of variables studied, it was possible to separate three groups, by similarity of the set of physical attributes of the soil: (1) secondary native forest, (2) agrisilviculture and (3) that formed by conventional pasture and silvopastoral system.