Objective In order to provide a scientific basis for sustainable management of Betula luminifera plantation, we studied the effects of different stand densities on community structure and species diversity of 20-year-old B. luminifera plantation in Baiyunshan, north Sichuan.

Method Using the typical sampling method, the community structure and species diversity of B. luminifera plantation under low density (1 050-1 150 trees·hm^-2), medium density (1 450-1 550 trees·hm^-2) and high density (2 150-2 250 trees·hm^-2) in Baiyunshan were studied.

Result In total, 110 species belonging to 52 families and 91 genera were recorded. There were 59, 42 and 57 species under high, medium and low densities respectively. In terms of community structure, most species in communities of medium and high densities were of medium diameters 5, 11) cm, while most species in communities of low density were of large diameters 11, 17) cm. Communities of three different densities were composed of species with similar heights, mostly ranged from medium to high height 9, 13) m. The species richness indexes (D), Shannon-wienner indexes (H) and Simpson indexes (H′) were all in the order of tree layer < shrub layer < herb layer. In the tree layer, different species diversity indexes were in the order of medium density>low density>high density, while in the shrub and herb layers, the indexes of D and H were in the order of low density>medium density>high density.

Conclusion Medium density is most conducive to the maintenance of species diversity and the natural regeneration of B. luminifera plantation in Baiyunshan, north Sichuan.