Analysis of soil moisture variation by forest cover structure in lower western Himalayas, India

Soil moisture affects various hydrological processes, including evapotranspiration, infiltration, and runoff. Forested areas in the lower western Himalaya in India constitute the headwater catchments for many hill streams and have experienced degradation in forest cover due to grazing, deforestation and other human activities. This change in forest cover is likely to alter the soil moisture regime and, consequently, flow regimes in streams. The effect of change in forest cover on soil moisture regimes of this dry region has not been studied through long term field observations. We monitored soil matric potentials in two small watersheds in the lower western Himalaya of India. The watersheds consisted of homogeneous land covers of moderately dense oak forest and moderately degraded mixed oak forest. Observations were recorded at three sites at three depths in each watershed at fortnightly intervals for a period of three years. The soil moisture contents derived from soil potential measurements were analyzed to understand the spatial, temporal and profile variations under the two structures of forest cover. The analysis revealed large variations in soil moisture storage at different sites and depths and also during different seasons in each watershed. Mean soil moisture storage during monsoon, winter and summer seasons was higher under dense forest than under degraded forest. Highest soil moisture content occurred at shallow soil profiles, decreasing with depth in both watersheds. A high positive correlation was found between tree density and soil moisture content. Mean soil moisture content over the entire study period was higher under dense forest than under degraded forest. This indicated a potential for soil water storage under well managed oak forest. Because soil water storage is vital for sustenance of low flows, attention is needed on the management of oak forests in the Himalayan region.     

Impacts of soil fauna on nitrogen and phosphorus release during litter decomposition were differently controlled by plant species and ecosystem type

The dynamics of litter nitrogen (N) and phosphorus (P) release could be affected by soil fauna and environmental conditions. The objective of the present study was to investigate the effects of soil fauna on the dynamics of N and P during foliar litter decomposition in three types of ecosystems (i.e., montane forest, ecotone, and dry valley) along an elevation gradient. A field experiment using litterbags with two different mesh sizes (0.04 and 3 mm) was conducted from November 2013 to October 2014. Nitrogen and P release rates in decomposing foliar litter from fir (Abies faxoniana) and birch (Betula albosinensis) in montane forest, oak (Quercus baronii) and cypress (Cupressus chengiana) in ecotone, and cypress and clovershrub (Campylotropis macrocarpa) in dry valley were investigated in the upper reaches of the Yangtze River. Soil fauna strongly affected N and P release across different decomposition periods and ecosystem types. The average release rate of N mediated by soil fauna across the entire year was higher in the dry valley (15.6–37.3%) than in the montane forest (0.5–6.4%) and the ecotone (- 3.7–4.9%). The effects of soil fauna on P release rate were manifest in both the montane forest and the dry valley. Moreover, the impacts of soil fauna can vary substantially among different decomposition periods. Our results indicated that soil fauna can significantly affect N and P release during litter decomposition. The N release rate mediated by fauna was likely to be more sensitive to the effects of plant species (i.e., initial litter chemical traits), while the P release rate mediated by soil fauna might be subject to the effects of local-scale environmental factors (e.g., temperature) to a greater extent.     

Fractal features and infiltration characteristics of the soil from different land uses in a small watershed in a rocky,mountainous area in Shandong Province

We studied infiltration and fractal mechanisms on sloping farmlands in a small watershed in Shandong Province in the rocky mountain areas of northern China.We studied soil fraction and soil water retention curves,and developed a soil infiltration model to analyze its quantitative relationship with soil particle size and pore dimensions under four types of land use,including sloping farmland,abandoned land,natural forest,and forest plantation(Malus pumila,Crataegus pinnatifida).Soil stability infiltration rate ranked as sloping farmland>abandoned land>natural forest>forest plantation.The sequence of soil particle size and pore dimension ranked as natural forest>forest plantation>abandoned land>sloping farmland.There were significant positive correlations between soil particle size and pore dimension,and both were positively correlated with the percent volume of silt and clay.They were negatively correlated with soil infiltration rate.The Horton model and the power function model were more suitable for simulating soil infiltration and the infiltration rate.We concluded that the soil in this area displayed typical fragments of rocky mountainous regions due to the loss of silt and clay caused by cultivation on sloping farmland.The uniformity and fractal dimensions of soil particle sizes and pore distribution decreased,thereby enhancing soil infiltration capacity and decreasing soil water retention capacity.     

Soil pore identification with the adaptive fuzzy C-means method based on computed tomography images

The complex geometry and topology of soil is widely recognised as the key driver in many ecological processes. X-ray computed tomography (CT) provides insight into the internal structure of soil pores automatically and accurately. Until recently, there have not been methods to identify soil pore structures. This has restricted the development of soil science, particularly regarding pore geometry and spatial distribution. Through the adoption of the fuzzy clustering theory and the establishment of pore identification rules, a novel pore identification method is described to extract pore structures from CT soil images. The robustness of the adaptive fuzzy C-means method (AFCM), the adaptive threshold method, and Image-Pro Plus tools were compared on soil specimens under different conditions, such as frozen, saturated, and dry situations. The results demonstrate that the AFCM method is suitable for identifying pore clusters, especially tiny pores, under various soil conditions. The method would provide an optional technique for the study of soil micromorphology.     

A spatially-explicit count data regression for modeling the density of forest cockchafer （Melolontha hippocastani） larvae in the Hessian Ried （Germany）

Background： In this paper, a regression model for predicting the spatial distribution of forest cockchafer larvae in the Hessian Ried region （Germany） is presented. The forest cockchafer, a native biotic pest, is a major cause of damage in forests in this region particularly during the regeneration phase. The model developed in this study is based on a systematic sample inventory of forest cockchafer larvae by excavation across the Hessian Ried. These forest cockchafer larvae data were characterized by excess zeros and overdispersion. Methods： Using specific generalized additive regression models, different discrete distributions, including the Poisson, negative binomial and zero-inflated Poisson distributions, were compared. The methodology employed allowed the simultaneous estimation of non-linear model effects of causal covariates and, to account for spatial autocorrelation, of a 2-dimensional spatial trend function. In the validation of the models, both the Akaike information criterion （AIC） and more detailed graphical procedures based on randomized quantile residuals were used. Results： The negative binomial distribution was superior to the Poisson and the zero-inflated Poisson distributions, providing a near perfect fit to the data, which was proven in an extensive validation process. The causal predictors found to affect the density of larvae significantly were distance to water table and percentage of pure clay layer in the soil to a depth of I m. Model predictions showed that larva density increased with an increase in distance to the water table up to almost 4 m, after which it remained constant, and with a reduction in the percentage of pure clay layer. However this latter correlation was weak and requires further investigation. The 2-dimensional trend function indicated a strong spatial effect, and thus explained by far the highest proportion of variation in larva density. Conclusions： As such the model can be used to support forest practitioners in their decision making for regenerati     

大兴安岭地区森林景观沿主要河流两侧分布的变化

In this paper, the regularity and changes of the forest landscape along the major rivers, namely, Nuomin River, Bila River and Zhawen River in Daxing‘ an Mountains, Bilahe Forestry Bureau based on the interpretation of TM data were studied. The results showed that the regularity has changed a lot due to the gradually stronger human intervention on forest landscape. The most obvious change was the cultivated lands had been expanding alongside the major rivers. With the increasing of population, the only way to satisfy the increasing needs of the local people for subsistence is by expanding cultivated lands because of the backwardness of agriculture productivity. The regularity of conifer distribution along rivers of 1997 has changed in the diverse direction of that of 1988. The proportion of conifer gradually increases with 1 000 m further away from the major rivers. That is due to the favorable availability of conifer alongside river bank, the most populated area in the forest region.     

Revelation from Management System Reform of State-owned Forests of Hessen State in Germany

The paper analyzes the management system reforms of state-owned forest in Hessen State of Germany based on the forestry situation, and draws conclusions which can be used for reference in management system reform of state-owned forest in China. The results are as follows: stepwise reform is the mode, ecology-centeredness is the principle, transparent property right is the precondition, detached function of government and forest industry groups is the key, and integrated law and regulation system is the guar...     

Study on Function of Vegetation''''s Preventing Soil Erosion in Small Watershed of the Loess Area

This paper analyzes the function of preventing soil erosion of the different woodlands according to a long-term fixed-position observation, and points out that the steep slope plantation of uncontrolled measures for soil and water conservation is apt to produce sediment Forestland has very strong effect in soil and water conservation when the biomass of arbor in the hillslope is over 1 4.51t/ha. Through analyzing the function of soil and water conservation about forestland (arbor, bush and the mixed wood of arbor and bush), it can be known that if the high forest coverage reaches 40%, forests will provide better protective function. To vegetation under forest, litter layer, herb and sparse forest land which do not suffer destruction from human beings, they all have good function in preventing erosion, and the amount of soil loss is far less than the tolerance of soil erosion. At the same time, when vegetation coverage and biomass are in an appropriate state, they will have powerful protective function.     

Relationships between native tree species and soil properties in the indigenous forest fragments of the Eastern Arc Mountains of the Taita Hills,Kenya

The relationship between soil properties and spatial distribution of native woody species was studied in three Taita Hills forest fragments which, although degraded, are ranked among 34 biodiversity hotspots of the world due to their high biodiversity of both plant and animal species. This relationship was assessed by using Spearman correlation and principal component analyses (PCA). The results of these analyses should be useful in instituting forest restoration programs that are crucial for the forests. Both the soil and vegetation studied were sampled from 17 subplots in the natural forest fragments of Ngangao (120 ha), Chawia (86 ha) and Mbololo (185 ha). The soil variables measured were: pH, texture, soil nutrients of C, N, Ca, P, K, Mg and Na. In total 36 native tree species from 13 families were identified from the three forest fragments. Ordination results show that axis 1 accounted for 35% and axis 2 for 25% of the total variation in species composition, indicating that the structure of vegetation is related to two major environmental gradients. The correlation analyses of species and soil properties showed that Na and clay particles were the most important determinants of species distribution; pH and soil variables such as C, N, Ca and P also played minor roles. Unexpectedly, some species (e.g. Psychotria petitii) showed positive relationships with Na attributed to possible substitution for K. Relationships with P were both positive (e.g. Craibia zimmermannii) and negative (e.g. Albizia gummifera) with some species, attributable to pH levels. An ANOVA for soil variables showed that there were differences in the Ca content in Mbololo (due to the parent material) and P in Ngangao where a special relationship was observed between some of the species. The presence of gaps accounted for the distribution of seedlings but not for the saplings, whose distribution responded more to factors similar to those to which mature trees respond. Soil-species relationships that were established may be utilized along with soil analyses when choosing native species for restoration.     

Conservation and Sustainable Exploitation of Forest Ecosystem in Upper Reaches of the Yangtze River -Case Study on Gongga Mountain

The deforestation on large scale in the upper reaches of Yangtze River has caused serious problems of ecosystem and environment. Restoration of the degenerated forest ecosystems is one of the main research fields. Taking Gongga Mountain as an example, degeneration features and existing problems of forest ecosystems are analyzed in this paper, and the measures are also proposed.     

城市地区水土流失指标探讨

依据城市森林和城市水土流失的特点，本文提出考查城市水流失率、水土流失率的指标。并对北京、伦敦等城市和河南长江流域山区水土保持林的水流失率进行了计算比较，结果表明水流失率、水土流失率是考察城市地区和一般林地水土流失的较好指标。     

浅谈利用沼气资源解决青海天然林保护区燃料问题

青海省天然林资源主要分布在黄河、长江、澜沧江上游的高山峡谷区。该区域内生态环境十分脆弱,气候严寒,地处偏远山区。由于经济落后、交通不便,给林区职工和广大农牧民群众生产生活带来很大的困难,其中因燃料消耗森林资源和其它不可再生资源是最突出的问题之一。合理开发和利用优质廉价、环保的沼气能源,调整农村能源结构,解决农民生活用能源的问题,促进林业职工增效和林区群众增收,改善林区环境卫生,有利于巩固天然林保护工程成果,具有较高的生态、社会和经济效益。     

长江中游护岸护堤林带建设初探

本文在分析了长江中游自然资源基本特征的基础上 ,根据护岸护堤林体系建设中的主要防护功能和目标 ,将护岸护堤林林种体系划为 4个三级林种和 1 2个四级林种。根据护岸护堤林的适宜性树种和灌草的选择指标 ,采用模糊相似选择法 ,应用微机进行统计分析 ,选出2 8种乔木、1 7种灌木和 6种草本。通过对护岸护堤林结构配置模式的综合效益和功能的评价 ,提出建设护岸护堤林带应采用多树种、多带型和林农复合型等 ,为长江中游护岸护堤林带建设提供科学依据。     

长江三角洲地区森林碳汇的初步估算与分析

利用森林资源清查数据,采用回归模型和含碳系数换算方法,估算了长三角区域的森林生物量和碳储量,分析了该区域森林碳汇的结构、分布及其增长潜力,提出了构建区域协作机制和发展区域碳汇林业的相关建议。     

南埂长江滩地杨树人工林生物量及生长量规律研究

本文利用在安徽省安庆市大观区海口镇南埂长江滩地不同时期所做的杨树解析木资料,较为系统地研究了滩地杨树人工林的生物量及生长量,并建立了其材积生长方程和生物量方程。结果表明：长江滩地杨树林分具有较高的生长量和森林生产力,并且能够维持较长时间的快生长,这有利于长期维持滩地森林生态系统的稳定性,持续有效地发挥“抑螺防病林”的功能,同时也具有较高的经济效益;长江滩地杨树的数量成熟迟于一般杨树林分,约在22年左右;长江滩地杨树树干生物量的分配比例在60％以上,树枝17％左右,树叶3％左右,树根大致在13％-19％之间,树干生物量分配比例随年龄增加而增加,枝叶则略有下降,而树根下降较多。     

Benefit measurement of the soil and water conservation for ecological forestry engineering

IntroductionThelossofwaterandsoilhasbeentheglobatprobIem.Itstotalareais25millionkm'.or16.8%ofgIobalIandarea.ThefertileSurfacesoilof6obiIIiontflowsintoriverseachyeaIBecauseofsoiIcorrosionthelandof21obillionhm2hasIostfertiIityand...,otbeusedasagricuIturalIand.HumanrecognizestheseverityofIossofwaterandsoilwhileheusesjandresources.Thediff6rentmeasuresarebeingtakeninordertoincreasesoilandwaterconservation.Sev-eralecoIogicaIforestryengineeringshavebeencar-riedoutInChinaforenvironmentconserva…     

陕西省长江流域生态地貌功能分区与评价

采用１０个主要生物气候指标，结合地形地貌及相的地带性植被和地带性土壤，对陕西省长江流域３１个县（市）进行动态聚类综合分析，本区可归并为２个森林植物气候带，５个生态地貌功能区。即：低山丘陵区北亚热带常绿落叶阔叶林生物气候区，包括安康盆地，汉中盆地，热暖温带针阔混交林、针叶林生物气候区；包括秦岭南坡东部中山，低山区，秦岭南坡中、西部中、高山区和巴山北坡中山、低山。各生态地貌功能区的生物气候特征明显，符     

湘西北山区“长防林”生态效益研究初报

湘西北山区长江防护林生态效益监测站，分别就“长防林”对小流域小气候、坡面产流量、产沙量、输沙率、林地最大涵水能力及保土效果进行了定位观测，资料分析表明，长防林生态效益十分显著。     

江苏省国家公益林总体布局与结果分析

阐述了江苏省国家公益林的总体布局特征及划分依据,并对划分结果进行了详细分析,指出江苏省国家公益林布局从总体上看,可分为3个部分：一是以长江、淮河、沂(沭、泗)三大河流为主干,以秦淮河、滁河等20余个一级支流及众多二级支流为分支呈“树型”分布的水源涵养林、水土保持林、护岸林等,构成了江苏省国家公益林的主体。二是以沿海特保林、高速公路、国道、铁路等呈“带状”分布的护路林、防风固沙林、农田防护林等,构成了江苏省国家公益林的基本框架。三是以骆马湖、石梁河水库、大丰麋鹿保护区以及中山陵等呈“块状”分布的水源涵养林、水土保护林、自然保护区林、国防林、风景林等,是江苏省国家公益林十分重要的组成部分。     

湖南省"长防林"生态效益监测站设计与布局研究

为了全面、科学评价长江防护林工程的综合效益，根据湖南省林业区划和“长防林”生态功能划分的实际情况，建立2个生态效益监测核心站、30个监测点。通过长期监测、计量，使长防林工程的生态效益价值化、数量化；为其它防护林工程的规划设计、生态公益林效益补偿以及公益林经营管理提供科学依据，为政府部门决策提供参考。