Study on Fractal Dimension and Stability of Land Use Types in the Area with High-frequency Debris Flow

Base on GIS and the fractal theory,land use types in Xiaojiang River basin in Yunnan Province were divided into six types: cultivated land,forest land,grassland,water body,urban and rural mining resident land,and unutilized land.Then patch shape fractal dimensions of different types of land use were calculated.The results showed that land uses in Xiaojiang River basin relatively intensively distributed in different areas.The grassland was the main type of Xiaojiang Ravine land-use type,followed by the forest land,the cultivated land again with respective shares of the total area of ravine 52.78%,28.07% and 15.77%,and the land use structure was relatively simple.Land use types could be described with fractal structure.Fractal dimension（D）values varied from 1.197 2 to 1.498 4,average value was 1.327 9.Stability order from higher to lower based on fractal dimension was: forest land,unutilized land,urban and rural mining resident land,cultivated land,grassland,and water body.42.66 percent of areas hold the stability indices between 0.2 to 0.5,which showed the total stability was in a bad condition.Furthermore,due to natural and human activity factors,land use in this basin was developing unsteadily;implementation of human disturbance factors was unadvisable.The D of land use types reflected the degree of complexity,stability and developing trend.