Abstract: Watershed ecosystem is a macro-scale and integrated unit with the comp lexity in coupling of natural, social, and economic factors. Owing to its specia l development condition and evolution process, watershed ecosystem is intensivel y and chronically interfered by human activities. In recent years, the functiona l assessment of watershed ecosystem has been paid more attentions by researc hers, and especially, the degradation of different type watershed ecosystems has been widely studied at various temporal and spatial scales, giving a sound basi s for the integrated management of watershed ecosystems in China. This paper sum marized the research progress on the degradation of watershed ecosystems in Chin a, including evolution mechanism, diagnosis, classification, integrated assessme nt, and monitoring and early-warning, and analyzed the focuses and directions o f further studies.

Key words: Virtual forest landscape, Forest fire spreading, Forest fire model, Particle system, 3D visualization