新体制下我国城市交通规划工作者所面临的任务

市场经济的迅速发展,推动了城市的发展。作为城市规划重要组成部分的交通规划工作内容亦日益广泛。由于我国的交通规划学科是在计划经济模式下发展起来的,而市场经济的兴起不仅使整个社会生活面貌发生了巨变,也给交通规划创造了新的课题。本文就此问题探讨了城市交通规划师在社会主义市场经济条件下应当注意的一些问题。     

Non-additive Effects of Leaf Litter Mixtures from Robinia pseudoacacia and Ten Tree Species on Soil Properties

ABSTRACT

Litter decomposition plays a critical role in both nutrient cycling and the interspecific relationships between tree species. In this study, leaf litter from Robinia pseudoacacia was mixed with litter from 10 other species, this mixture was then ground and incubated in soil. The soil indexes (i.e., quantity of microbes, activities of enzymes, and chemical properties) were analyzed to study the effects of litter decomposition on soil properties and the interaction between the litters. If mixed separately with Larix principis-rupprechtii or Betula platyphylla, R. pseudoacacia litter exerted synergistic effects on the activities of most enzymes. The mixed litters of R. pseudoacacia and Pinus sylvestris var. mongolica or Ulmus pumila exerted synergistic effects on the soil available P. With regard to the soil properties as a whole, the mixed litters of R. pseudoacacia and B. platyphylla, Pinus tabulaeformis, P. sylvestris var. mongolica, or L. principis-rupprechtii exerted synergistic effects on soil during their decomposition. However, the mixed litters of R. pseudoacacia and Populus simonii, Quercus liaotungensis, U. pumila, or Caragana microphylla did not. This indicated that R. pseudoacacia mixed with the litter of other needle-leaf tree species benefits the development and regeneration of soil and thus can be used for sustainable forest management.     

基于可持续发展观下的我国狩猎旅游发展策略探究

在阐述狩猎旅游与可持续发展的辩证关系的基础上,探讨我国狩猎旅游发展的现状,并且提出狩猎旅游可持续发展的策略。     

森林结构调查最小面积的研究

采用4块100m×100m的天然林样地材料,分别利用角尺度和双相关函数分析4块大样地中不同面积的窗口(小样地)对应林木个体的空间分布格局。结果表明,小样地面积不同其对应林木的空间分布格局也不同,随着样地面积逐渐变大,对应林木的空间分布格局趋于稳定,这意味着森林结构分析必须在一定大小的样地上进行。根据本研究资料,样地面积最小应为2500m2。     

室温粉碎搅拌法从印楝种仁中萃取印楝素的研究

用快速粉碎搅拌的方法从印楝种仁中萃取印楝素,分别研究了萃取时间、溶剂的选择及用量对印楝素萃取产率的影响。优化的工艺条件为:208g去油后的印楝种仁(相当于300g印楝种仁),以750ml甲醇做溶剂,在快速粉碎搅拌下萃取21min即可以达到最高萃取产率,与微波辅助法、超声波法、浸提法相比,具有提取率高、设备和操作简单、节约溶剂、快速等特点。     

广东自然保护区生态旅游SWOT分析及对策研究

在对广东省自然保护区生态旅游资源实地调查的基础上，运用SWOT分析法全面探讨了广东省自然保护区生态旅游的优势、劣势、机遇和挑战，提出了相应的旅游发展策略。     

来自草原深处的天籁之音——内蒙古民族歌舞剧院蒙古族青年合唱团

“草原是牧人的天堂，蓝天是草原的梦想，大山是草地的高尚，流水是草原的纯真，碧野是草原的宽广，长调是草原的流淌，奶酒是草原的醇香，哈达是草原的赤诚，敖包是草原的向往，骏马是草原的奔放，套杆是草原的臂膀，鲜花是草原的芬芳。”     

Forest resources and environment in China

Covering a vast territory, China is rich in forest resources and diversified environments. The changes in forest resources have a direct bearing on environmental quality. This paper gives a detailed account of the dynamic change in forest resources in China, including the overall process of forest evolution, the status quo, and features of the existing forest resources and the development and use of major forest resources. In addition, it analyses the current situation of China’s environment and explores the main contributing factors based on the overall environmental situation. To achieve sustainable management of forest resources and improve the environment in China, the Chinese Government attaches great importance to the protection and development of forest resources as well as to environmental development and improvement. The paper gives an overview of current thinking for sustainable forest resource and environmental development in the future and highlights the current focus of efforts toward this objective.     

山杨小径木超微结构及其与干燥皱缩的关系

前言山杨(Populus Dividiana Dode)小径木是黑龙江省尚志具帽儿山次生林区主要的间伐树种之一。该树种在干燥时易产生皱缩等缺陷,我们设想与其结构有关,故利用扫描电镜观察其超微结构,以期洞悉其中的奥秘。 W.R.Perng研究颤杨(Populus tremuloides)解剖构造与液体传导的关系,在电镜下观察时,指出颤杨心材中存在侵填体,这些侵填体使导管闭塞,因而液体流动困难。他又对此木材进行聚合物渗透,而心材导管中几乎无聚合物沉积,说明心材导管全部被侵填体堵塞,聚合物难以在心材沉积。     

中国实施清洁发展机制造林和再造林项目的可行性和潜力

分析我国实施清洁发展机制(CDM)林业项目的利弊因素,阐述在我国开展CDM造林项目的可行性;通过对影响CDM碳汇市场主要因素的分析,估计了我国CDM造林项目的潜力。结果表明,在我国实施CDM造林项目是可行的,我国在第1承诺期CDM碳汇市场的份额估计最高可达20%。我国应尽快启动CDM造林试验项目,并开展相关的能力建设以及政策和方法学的研究。