Abstract: The dynamic observation of the mid-montane humid evergreen broad-leaved forest and the community characteristics analysis were conducted in a 4-hm² permanent plot located in ecological corridor in southern region of Gaoligong Mountains National Nature Reserve during 2009-2010. The results showed that there were 10 546 free-standing individuals with DBH≥1.0 cm in the 4 hm² plot, belonging to 95 species, 64 genera and 35 families. The species richness was higher and the proportion of rare species was lower in the plot, compared with other plots of the same kind forest. Lauraceae, Theaceae, Araliaceae, Fagaceae, and Symplocaceae were dominant families in the plot and they comprised 44.21% of all species and 56.70% of all individuals. Symplocas ramosissima, Eurya pseudocerasifera, Gordonia longicarpa, Neolitsea lunglingensis, Lithocarpus hancei, and Cyclobalanopsis lamellosa had more importance value in the plot, but no one had obvious advantage, namely the plot did not contain an obviously dominant species. Floristic characteristics of the community indicated that the tropical elements were much more than temperate elements, implying that this area could be an origin of tropics. The minimal area of the community is 1. 32 hm²,which could comprise more than 80% of all species. The structure of DBH size class of all species and some dominant species in the plot showed a typical pyramid structure with a wide bottom and a narrow top, implying a good regeneration in the community. The survival curve of most of dominant species tended to be of the Deevey-Ⅲ type, with a high mortality rate at small DHB size class and a low and stable mortality rate at large DBH size class.

Key words: community characteristics, geographical distribution, dynamic plot, evergreen broad-leaved forest, Gaoligong Mountains