干热干旱河谷区和黄土丘陵沟壑区退耕还林还草模式初步研究

为了得出符合中国国情的退耕还林还草模式,针对我国退耕还林还草主要在长江上游、黄河上中游开展的实际,在两大流域分别选取一个典型的植被恢复困难的类型区,即长江上游的干热干旱河谷区、黄河上中游的黄土丘陵沟壑区.利用适地适树理论、正交实验设计和建立半永久全封闭径流观测场的方法,对树种的选择、配置和生态效益进行了研究.最后提出了生态、经济、社会效益有机结合的退耕还林还草模式,包括其类型区域范围、自然资源特点、社会经济特点、主要限制因子、基本技术思路、林草类型结构、植被恢复方式、植被恢复技术、主要树种草种、经营管护方式等.

Study on the models of conversion of cropland to forest and grassland in dry hot and arid river valley subregions ＆ hilly ravine subregions of loess plateau

The areas of the Conversion of Cropland to Forest and Grassland Project(CCFGP) in China are mainly distributed in the upper reach of the Yangtze River and the upper and middle reaches of the Yellow River. To attain the rational models of the CCFGP in accordance with the concrete conditions of the above mentioned areas, the typical subregions with difficulties to rehabilitate vegetations were selected as the study sites, including the dry hot and arid river valley subregion in the upper reach of the Yangtze River and the hilly ravine subregion of the loess plateau in the middle reach of the Yellow River. Studies on tree species selection and allocation and their ecological benefits were conducted, based on the theory of matching species to the sites, orthogonal design and establishment of semi|permanent and totally closed runoff observation plots. The models of CCFGP with the combination of ecological, economic and social benefits in each typical subregion were proposed. The study covered the following aspects of each model: geographical scope, characteristics of natural resources, social|economic features, main limiting factors, basic technical concepts, structure of forest and grass types, styles of vegetation rehabilitation, technologies of vegetation rehabilitation, main tree and grass species, and protection and management patterns, etc.