Study On Robinia Pseudoacacia Forest Health Management Technique In Weibei Loess Plateau

The problem of ecosystem health is one of the major problems humanity facing, forest health study has been a focus issue in forestry nowadays.Loess Plateau is one important area of China's ecological environment construction. Forest health assessment is very important to security of ecological environment in Weibei Loess Plateau. Robinia pseudoacacia is the main forestation species in the Loess Plateau, the total area has reached 70000hm2, the growing stock volume accounts for 28.3%of Shanxi's planted forest. Robinia pseudoacacia forests played a significant role in soil and water conservation in the area, but still have some problems to be solved such as Lack of mixed forest, high density, and poor stability and so on. These seriously affect the comprehensive benefit of Robinia pseudoacacia forest.Therefore this paper analyzed the healthy level of Huaiping Forest in Yongshou, Yehe Forest in Fufeng and Fangshan Forest in Baishui of Shanxi province, The results showed that:(1) Stand structure, plant diversity, the stand stability of the forest ecosystems are taken as the indicators to evaluate the healthy ecosystem and selected 7 parameters using composite function index method to assess Robinia pseudoacacia forest ecosystem health in Weibei Loess Plateau. The 7 parameters are site index, canopy density, distribution of diameter grade, the shannon-wiener index, pielou index, severity of pest and disease and proportion of top drying. Use it to assess Robinia pseudoacacia forest health status with better science and practicality.(2) Taking Delphi-AHP to determine the weight of indexs, according to the investigation data of 79 plots Robinia pseudoacia forest in Yongshou, Fufeng and Baishui areas Multi-level fuzzy comprehensive evaluation method is used to assess the ecological health status, The Robinia. pseudoacia forest's sub compartments divide into the health, the sub-health and unhealth three kinds. The healthy condition forest sub compartments account for the proportion 46.84%, the sub health condition forest sub compartments account for the proportion 13.92%, the unhealth condition forest sub compartments account for the proportion 39.24%. Then we used soil and water conservation evaluation model established by Chen Jianjun to verify this result, it showed that evaluation results can objectively reflect the health status of Robinia pseudoacia forest.(3) The sub-health and unhealth condition forest sub compartments account for the proportion in a big way 53.16%. The direct factors affecting the forest health condition are: forest canopy density, stand density, spike top, unlawful felling tree, overgrazing etc. On this basis, according to the situation of plantations of Loess Plateau, we put forward a set of forest health management measures, which divide into standing forest nurture type and reformation type. For these two kinds of types, we establish a set of health management technique for plantation in Weibei Loess Plateau and it was implemented in October 2008.