Xiang River In The Hilly Small Catchment Area Of ​​ecological And Economic Protection Forest System Layout And Its Effectiveness Studies

The distribution and its benefit of ecological economical type protecting forest system were studied in the small catch- ment in the hill areas in Hunan. The small catchment for 3. 27km2, is lied in the Huantang village of Sengjiang countryside in the Hongnan county. The characteristies of society, economy and environment of the small catcment were investigated. The pro- ject of excellent forest structure of cological economical type protecting forest system were advanced with the view points of ecology-economics , the methods of system forestry science and system project, by the studying the quality decid- ed, quantity stable and location decided, which general goal of the high effect and persisting development were to consti- tute ecological economical type protecting forest system .The computer proceedings of theory I of quantity-changing,mistiness-clustering, analysing of main shares and distinguish- ing analysis were used .acceding to the land conditions , the degree of soil eroded, soil fertility, and so on , of 98 of 146 sample lands which were investigated. 98 sample lands were measured off into 5 ecolgical economical types .The excellent forest seeds and its structure, proper tree seeds were distri- buted in these sample lands. How to utilize soil in reason was resolved. After the protecting forest system of ecological economical type was created, the mathematics models were set up for the relations of rainfall and current, rainfall and producing sands, the reasons of the reducing of soil and water losing in the prophase of the small catchment fathered were analysed.