Study On Species Composing, Community Stratification And Soil And Water Conservation Function Of Different Vegetations In Datong County

Land Converting Program (LCP) plays an active and important role in soil and water conservation and desertification combating. The converted lands are rehabilitated with artificial vegetation by means of imitating native vegetation on the basis of matching trees species to site factors. It is important to know how the composing, structure and function will change after rehabilitation. Only when the species composing is stable and the stand structure is good, the function of soil and water conservation will be fully realized. The study on the essence of vegetation and soil conversion as well as the mechanism of ecological restoration can play a positive theoretic and practical role in developing and optimizing the technology of vegetation restoration.As to Datong County, Qinghai Province, LCP has been initiated successively in the early 1980s, where various artificial vegetation types with different converted time are kept and existed up until now. In the dissertation, the integrated methods of comprehensive field work and lab test, route investigation and standard plots investigation, quantitative analysis and qualitative analysis have been adopted. Based on the method of substituting temporal sequence with spatial sequence, different vegetation types with different converting time together with the contrastive types of natural forest and cultivated farmland have been selected. And species composing, stand structure and soil and water conservation function of different vegetation types in converted lands have been systematically studied so as to comprehensively evaluate the actual effect of LCP. The main result shows as following:(1)"Species diversity"is proposed to comprehensively evaluate species compositing...