Vulnerability Assessment Of Forest Ecological Environment Base On GIS

Ecological fragility could well reflect the tolerance degree of the ecological environment facing outside interference. Generally speaking, the fragile ecological environment often leads to two bad result. On the one hand, because of the Law of conservation of energy, ecological system itself emerges irreversible changes and its recovery ability is losing gradually, on the other hand, the deterioration of ecological environment also threatens the human survival and life. It was because of this that the regional ecological environmental quality assessment is becoming more and more significant. This paper makes a study of the ecological fragility evaluation at the county level. According to the influence factors, ecological fragility include geological fragility, water fragility, soil fragility and food fragility. Meanwhile, there has been much mature study of ecological vulnerability evaluation both in domestic and abroad. Especially the interactive development of various disciplines could provide the advanced theory basis for some old problems. In addition, some technologies,such as PC, GIS, RS, have been widely used in all walks of life.Trying to construct evaluation index for the ecological vulnerability of Shehong county based on the Ecology principle by analyzing the topography, climate, hydrology, soil, plants and animals and socio-economic and population. In the research, the study object has been taken as an ecosystem in order to select index from the topography, soils, hydrology, atmosphere, biodiversity and other aspects. Based on above method, this paper achieved the ecological fragility evaluation and the characteristic research of forestland distribution of Shehong county by using the PCA and Fuzzy clustering analysis.This paper has following conclusions:I. AHP:Based on AHP, forest indicators could create reverse affect for ecological vulnerability, the greater areas of forest cover, the public welfare fo rest and the higher index of NDVI, the better ecological environment of fores t, and vice versa. Other indicators of the vulnerability of forest ecosystems is p ositive:the impact of human activities on the ecological vulnerability is the gre atest; the impact of rainfall on the ecological vulnerability is the smallest; terrain comprehensive index and soil indicators of vulnerability of forest ecosystems o ccupy a certain proportion.very low vulnerability accounted for28.65%and1ow vulnerability zone accounted for31.74%, medium-fragile areas accounted for27.56%,11.10%belongs to higher fragile region, a very fragile area accounted for0.95%.II.PCA:Indicator mechanism analysis combining the Analytic Hierarchy Pr ocess in-dicate that transposing forest cover data, woodland structure index a nd NDVI.Through calculating, the paper determines the first six principal co mponents, and takes advantage of the weighted principal component method to c alculate the comprehensive evaluation of the results of the vulnerability of forest ecosystems:a very low vulnerability zone accounted for10.46%, low vulnerable region57.75%of middle-fragile areas accounted for27.70%,3.84%Higher fragi leregion, a very fragile area accounted for0.25%of totalIII. Comparison and Analysis:Base on two evaluation methods, five fragile level and comprehensive comparison of the three terrain factors, the paper analyze the distribution between the DEM, slope, aspect and the ecological fragility: relative area of the very low fragile region is not broadly distributed in the Low Hilly areas,slope in the range (0,2), aspect to the ground; the largest of low vulnerable area broadly distributed in the mound area, slope range of more than6degrees, especially on the range of (6,15), the flat land distribution is less and every other aspect both are distributed; secondary fragile area of relatively few, broadly distributed in the area of the mound, but the area is smaller than the low vulnerability zone, slope range of more than6degrees, especially in the acute slope area, in addition to the ground the other aspect are distributed; higher fragile areas, and very fragile area are relatively small proportion of the general distribution of the higher elevation, steep places, aspect was no obvious.IV. Analysis of forest ecological environment and ecological vulnerability characteristic in Shehong County:analysis based on distribution relationship of single indicators and forest ecological environment can be found that the distribution of forest structure in the DEM, slope and slope upward roughly consistent with the vulnerability of the distribution of forest ecology, and statistics of forest structure in soil erosion and rainfall on the distribution, provide the basis for the adjustment of forest spatial structure and forest structure.V. Systems:confusion of data management and data processing exist inforest ecosystem vulnerability assessment process in Shehong County, the paper design and develop the system of forest ecosystem vulnerability assessment to reduce the intermediate process in the evaluation process.