云南高山林区运材汽车车架断裂原因初探

本文针对云南高山林区运材汽车车架断裂的现象.分析了断裂原因.并提出了改进措施与建议.     

基于IPAT等式的草原资源利用与经济增长关系研究——以甘南藏族自治州草原牧区的实证为例

在概述IPAT等式及其发展模型的同时，构建了以草原资源消耗为表征的草原资源利用与经济增长的关系模型，并以甘南藏族自治州草原牧区为例，采用了3种不同方案对不同草原资源利用技术下的牧民经济行为对草原资源压力进行了实证研究。结果表明，只有当单位GDP草资源消耗年降低率高于单位GDP草资源消耗年降低、上升和不变的临界值时，才能实现确保草资源合理利用的经济内涵式增长。同时发现，甘南州草原牧区经过长期的努力，单位GDP草资源消耗年降低率多年平均值t=2.559%，与临界值tk=2.693%的差距仅为0.134%，这说明牧区对草原资源的利用有向可持续利用转变的趋势。     

城市拆迁中的利益冲突及解决途径

从城市拆迁产生利益冲突的相关利益人入手，对拆迁中涉及的各个相关利益者进行利益分析，分析了产生冲突的原因所在，提出了应如何保障各方特别是被拆迁人的利益。     

云南松种子区划的初步研究

云南松是云贵高原的主要用材树种,在林业生产上占有重要的地位。本文以云南松分布区生态条件差异的研究为依据,在总结过去生产经验及参考种源试验初步成果的基础上,划分出六个种子区,从而为今后用种及种子调拔提供依据。     

黄河下游放淤改土固堤技术分析

根据黄河下游滩区放淤改土固堤的实践，对淤临河洼地、淤滩改土、淤村塘洼地、淤串沟等淤类型进行了分析，提出了放淤改土固堤进水口门、输水渠、围堤、退排水工程布置和引水量、放淤量的计算方法。     

Soil-released carbon dioxide from microbial biomass carbon in the cultivated soils of karst areas of southwest China

 Soil microbial biomass and the emission of CO₂ from the soil surface were measured in yellow soils (Ultisols) of the karst areas of southwest China. The soils are relatively weathered, leached and impoverished, and have a low input of plant residues. The measurements were made for a 1-year period and show a reciprocal relationship between microbial biomass and surface CO₂ efflux. The highest (42.6±2.8 mg CO₂-C m^–2 h^–1) and lowest (15.6±0.6 mg CO₂-C m^–2 h^–1) CO₂ effluxes are found in the summer and winter, respectively. The cumulative CO₂ efflux is 0.24 kg CO₂-C m^–2 year^–1. There is also a marked seasonal variation in the amount of soil microbial biomass carbon, but with the highest (644±71 μg C g^–1 soil) and lowest (270±24 μg C g^–1 soil) values occurring in the winter and summer, respectively. The cumulative loss of soil microbial biomass carbon in the top 10 cm of the soil was 608 μg C g^–1 year^–1 soil over 17 sampling times. The mean residence time of microbial biomass is estimated at 105 days, suggesting that the carbon in soil microbial biomass may act as a source of the CO₂ released from soils. Received: 13 July 1999     

Analysis of the distribution of endemic and rare arthropods in high endemism areas of Algarve-South Portugal

The study of several arthropod groups in high endemism areas (HEA) of Algarve, the Southernmost province of Portugal, has revealed endemic species and species not yet recorded for the Portuguese fauna. The list includes 3 species of Isopoda endemic to Algarve, to Portugal or to the Iberian Peninsula, 2 species new to Portugal and 2 species new to the Iberian Peninsula; 2 species of Pseudoscorpiones not yet cited to Portugal; 11 species of Pauropoda new to Portugal, including one new species probably endemic; 15 species of Collembola endemic to the Portuguese or to the Iberian Peninsula faunas (Gama et al. 1997) and 37 species and 5 subspecies of Staphylinidae endemic to Algarve.With the exception of Collembola, which have been studied by us, the remaining groups have been submitted for study to several specialists.These findings heighten the biological richness of these areas of high endemism in terms of conservation of biological diversity. The authors draw attention to the necessity to preserve or restore the biological value of these areas, encouraging the adoption of protective measures and the creation of research programmes that include the implementation of taxonomic studies and co-operation between taxonomists and ecologists in order to preserve the biodiversity of these areas.     

对双鸭山林区森林分类经营的认识

本文对双鸭山林区森林的分类经营提出了几点认识,并做了具体分析。     

辽东山区天然次生林经营现状,存在问题及对策

文章对辽东山区天然次生林经营现状及在生产中存在的主要问题进行了分析、探讨,并就现有的天然次生林中亟待解决的问题提出了几点参与意见,即增强资源与环境意识;实和行森林分类经营;利用天然林环境优势,发展多种经营;停止皆伐,栽针保阔;采取长轮伐期作业,培育大径材;进行封山育林。     

太行山石灰岩低山区水土保持防护林高效空间配置研究

运用层次分析法（Ａｎａｌｙｔｉｃ Ｈｉｅｒａｒｃｈｙ Ｐｒｏｃｅｓｓ,简称ＡＨＰ）对太行山石灰岩低山区水土保持防护林体系林种结构、树种配置优化进行判断。结果表明,该区水土保持林以生态效益为主,兼顾经济效益和社会效益;以山坡水土保持林为主,多林种多树种结合,山坡水土保护林、梯田经济林、山顶防护林、沟头防护林、沟底防护林、沟边固岸林的比例分别为２８．６％、１８．２％、１７．５％、１７．４％、１０．３％