Stand structure and the regeneration ofChamaecyparis pisifera (Sieb. et Zucc.) Endl. on sites with different soil development in an old-growth coniferous forest, central Japan

Stand structure and the regeneration ofChamaecyparis pisifera on sites with and without well-developed soil in an old-growth coniferous forest, Akasawa Forest Reserve, central Japan, were investigated, along with their relationships to other important coniferous species. Of stems ofC. pisifera≥5 cm diameter at breast height, stems with intermediate size were absent in stands on the developed-soil site, while those with smaller size increased in stands on the undeveloped-soil site, which supported a higher density ofC. pisifera. In the stands without recent tree-fall of canopy stems on the developed-soil site, canopy stems ofC. pisifera were distributed uniformly and the understory stems, patchily. On the other hand, both canopy and understory stems ofC. pisifera in stands on the undeveloped-soil site were distributed patchily. In the understory,C. pisifera occurred as clonal patches formed by vegetative reproduction on various types of microsites including bare rocks. However, the clonal patches did not occur in a stand on the developed-soil site with dense saplings of an evergreen conifer,Thujopsis dolabrata, which can expand vegetatively with a well developed soil layer. Gap formation may induceC. pisifera to develop tree-form stems from shrubby clonal patches. On developed-soil sites,C. pisifera stands that survive a long disturbance-free period on this site need catastrophic disturbance for their regeneration, which will eliminateT. dolabrata in the understory and create bare soil for colonization ofC. pisifera from seeds. On undeveloped-soil sites,C. pisifera replaces itself continuously by effective vegetative reproduction. Ground instability and the wet condition of this site may promote the replacement.     

不同立地条件刨花楠天然群落物种多样性比较研究

对建德市寿昌林场绿荷塘林区刨花楠天然林群落结构特征、物种多样性及林木生长与生境的关系进行了研究，结果表明：刨花楠在群落中占主导地位，并以高强度聚集分布方式存在；刨花楠天然群落物种多样性相对较低，且分布不均匀；刨花楠幼时喜荫、湿润环境，成年则喜光，较耐瘠薄，有较强的适应性，在土层深厚、水肥条件相对较好的立地上生长更好。     

The dynamic mating systems of conifers

Conifer mating systems vary among species and within species; both ecological variables and genetic variation cause mating systems to be dynamic. Within species, estimates of rates of outcrossing vary among populations, among loci, and among individuals within stands. The level of outcrossing varies with stand density, age, and the abundance of local and foreign pollen. Variation in the mating success of both males and females violates the assumption that populations are randomly mating and at equilibrium, and justifies more quantitative analyses of mating systems. Allelic frequencies in the pollen pool and in the pool of receptive female surfaces may vary through a season and among seasons, producing positively assortative mating in time. Seed and seedling viability selects against homozygotes for lethal alleles and favors heterozygous genotypes, biasing estimates of outcrossing. Particularly fruitful topics of research include the genetic consequences of polyembryony, differential male and female mating success, and associations between specific genotypes and floral phenology.     

秦皇岛市区园林昆虫种类调查初报

本文作者利用2年时间,对秦皇岛市区园林昆虫区系进行了调查。初步摸清了秦皇岛市区园林害虫种类及天敌昆虫资源情况。共查出园林害虫50科235种,园林天敌昆虫10科22种。为科研、教学及生产提供了依据。     

自然保护区重要过渡带危机及对策研究——基于四川阿坝自治州理县马山村协议保护机制的调研

针对自然保护区重要过渡带管理危机,引入"协议保护"机制,解决其过渡带管理错位和不到位问题。结果显示:"协议保护"机制能有效激励社区农户和社会组织共同参与自然保护区的管理,能够缓解自然保护区过渡带生物多样性危机,维护生态系统的完整性,保障其核心区和实验区的安全,弥补自然保护区管理体制的主体缺位和管理不到位等问题。     

沾益县天然林保护管理地理信息系统建设构想

论述了沾益县天然林保护管理地理信息系统建设的必要性及重要作用，并对该系统建设的软、硬件环境及系统架构、数据传递及更新等方案作了探讨。     

天然动植物色素的特性及其提取技术概况

综述了天然生物色素在动植物体中的分布和特定生理功能。概括了动植物色素的主要提取方法及其发展状况：直接破碎原料、溶剂浸提、物理技术辅助浸提和现代仪器提取分离等;指出超临界流体萃取(SFE)是较具发展潜力的高效萃取方法,有利于提高色素产品质量。     

西双版纳天然林保护与林业可持续发展

西双版纳天然林保护工程的实施对制止区内的环境退化和资源危机,协调人与自然的关系具有重要的作用.在天然林保护工程的实施过程中,对区域的经济、社会和文化造成了一定的影响.为保障社区林业的可持续发展,针对天然林保护给社区带来的影响,提出了发展非木材产品,加强经济林果的发展以及营造速生丰产林和薪炭林的对策,以实现西双版纳的天然林保护和林业可持续发展.     

中国主要人工林树种幼龄材与成熟材及人工林与天然林木材性质比较研究

本文对中国１０种人工林和４种天然林的幼龄材与成熟材及４个树种的人工林木材与天然林木材的构造特征、化学性质、物理性质、力学性质的３３项材性指标差异进行了比较研究。结果表明,在幼龄材与成熟材之间,在统计上表现出差异显著性的为幼龄材比成熟材生长轮宽,管胞列数多,管胞短,直径小,微纤丝角大,密度小,径向干缩小,差异干缩大,流体扩散性高,抗弯强度、抗弯弹性模量、顺纹抗压强度、径面顺纹抗剪强度、径面抗劈力和冲击韧性低等１５项,即４６％的测试项目差异显著;表明在木材加工和用作结构材时应将幼龄材和成熟材视作两个性质不同的总体来考虑,在培育结构材时应研究如何缩短幼年期或改善幼年期材性。在人工林与天然林木材之间,采取人工林幼龄材性质与天然林幼龄材性质相比,人工林成熟材性质与天然林成熟材性质相比,结果表明,多数性质在统计上差异不显著,只有人工林木材比天然林木材胞壁率小、顺纹抗压强度低、差异干缩大、流体扩散性高等４项,即只有１２％的很少数测试项目差异显著;表明有可能通过人工培育的方法培育出与天然林木材性质相近的木材。     

社区自然资源管理的五个基本要素

本文介绍了社区自然资源管理的5个基本要素:①当地人是自然资源管理的主体,充分赋权于当地人,包括项目决策权、实施参与权、知情监督权、管理维护权、监测评估权;②尊重乡土知识、乡土人才,重视能力建设;③关注农村妇女和弱势群体的参与和能力建设,倡导性别平等及公平的发展观;④在当地村规民约基础上建立社区管理制度和管理组织,促进当地村民的自我管理、自我发展;⑤有偿使用、有偿管理、有偿服务,增强当地村民对项目的拥有感,实现项目的可持续性.