Study On Evaluation Theory And Method Of Sustainable Development System Of Reverting Farmland To Forest Or Grassland

On the basis of theories of sustainable development, sustainable forest management, ecology, forest ecological engineering and statistics, this paper made a preliminary research of theories and methods for evaluating the system of reverting farmland to forest or grassland. The paper also introduced corresponding appraising indicator system. Moreover, the system of reverting farmland to forest or grassland in Hong-ya county was analyzed as a typical example, ad the conclusions were drawn as follows:(1) Concepts, component, constituent of system of reverting farmland to forest or grassland, and corresponding relation between subsystems were concluded by consulting large commit references and surveying on the spot. Meanwhile, the author also summarized the operational mechanism, function, object and contents of this system and preliminary established the basic theory system of evaluating sustainable development of reverting farmland to forest or grassland system.(2) The guiding ideology of establishing the appraising indicator on above system was put forward according to sustainable evaluation theory of reverting farmland forest or grassland. Based on it, the paper expected the basic criteria of establishing indicator system, the methods of choosing the appraising indicator, the methods of choosing weight for every appraising indicator, the quantitative transition methods of appraising indicator and the calculation methods for the comprehensive appraising indicator. Thus the methodology base was provided for later analyzing example.(3) Based on the above, evaluation appraising indicators, including 4 levels, 26 indexes, was put forward according to the conditions of reverting farmland to forest or grassland in Hong-ya county. Compared with other indicator system in area levels, this paper presented sustainable management indicator system of the particular forest type.(4) On the basis of above indicator system, and considering the characters of local society, economy, resource and environment, especially the difficulty in obtaining the statistics data, the author pointed out the factors need to be surveyed for 26 indicators, corresponding calculation methods and reference value.(5) Applying above appraising indicator system, the author evaluated the present situation and sustainable development trend of reverting farmland to forest or grassland system inHong-ya county. Results showed that the comprehensive index was 0.778 and the total of system development was sustainable. The main problems were that the forests in study region were still young and the forest structure was not reasonable. At the same time, the external economy condition was one of limiting factors.(6) The key of evaluating the system of reverting farmland to forest or grassland was choosing suitable appraising method and indicator (or indicator system) to evaluate the present situation and sustainable development trend of this system. There were different total evaluation results in different area, so adopting corresponding measure was beneficial to sustainable development of system of reverting farmland to forest or grassland. According to the present situation of reverting farmland to forest or grassland in Hong-ya county, improving ecological environment, enhancing the capacity of soil and water conservation and promoting economic development should be treated at the basic object. Adopting corresponding tending methods and reasonable adjusting the stand structure promoted it to space mosaic and mixed structure.