Abstract: By using litter-bag method, the root decomposition characteristics of Castanopsis carlesii stand in Jian’ou Wanmulin Natural Reserve of Fujian P rovince were studied over two years. Three classes of roots, i.e., 0〖KG-*2〗-〖 KG-*7〗1 mm, 1〖KG-*2〗-〖KG-*7〗2 mm, and 2〖KG-*2〗-〖KG-*7〗4 mm in diameter, were tested. During the 2-year period of decomposition, all classes roots show ed a bi-phase pattern, being decomposed faster in prophase and slower in anapha se. The leaching loss of extractable substances in roots made root decomposition faster in prophase, while the increase of the acid-insoluble substances conce ntration in roots restrained the decomposition in anaphase. In the first year, t he decomposition rate of all classes roots was controlled by the initial concent rations of their extractive substances and N; while in the second year, the deco mposition rate was controlled by the initial C/N and the initial concentrations of acid-insoluble substances, N and P of the roots. During decomposition, all c lasses roots showed an increasing N concentration and a decreasing P concentrati on, and the N showed an enrichment-release pattern, while the P showed a direct release pattern.

Key words: RS, GIS, wetland landscape pattern, landscape pattern index, driving mechanism.