Abstract: Based on the forest distribution map(data from the year of 2001 and scale 1∶50000), using the geography information system program ArcGIS and the landscape analysis program FRAGSTATS, we analyzed the spatial pattern and evaluated the degree of fragmentation primarily from the overall landscape properties, the area properties, the perimeter properties, the numbers of patches of landscape elements and the double-logged fractal dimension(DLFD)of Xishui Natural Reserve. The results showed that grassland was the most important landscape type with the biggest area in this region. The mixed forest of poplar and birch, the mixed forest of conifer and broadleaf, the sparse forest, the Farmland and the unforested-land were all distributed fragmentarily in the landscape. The forest of spruce had a large area and perimeter, but its verge density was much larger than grassland and shrub, which indicatesd a high degree of fragmentation. As a whole, the DLFD of landscape elements in this region was low, ranging from 1 and 2, but inclined to 1. Therefore the edges of the landscape were relatively smooth.

Key words: Net primary production (NPP), Soil nitrogen mineralization rate, Plant nitrogen retention