Abstract: Based on the plot investigation data of Yuelu Mountain, a scenic site in South China, the niche breadth and niche overlap of the main plant species in Pinus massoniana forest were measured by applying Levins and Horn indices, respectively, and the age structure of P. massoniana population was analyzed by using size class instead of age method. The results showed that the niche breath of P. massoniana was the biggest in canopy layer while the smallest in shrub layer, and the age structure of P. massoniana population represented a declining pattern. P. massoniana was one of the dominant species in canopy layer, but regenerated poor and declined intensively. The species having larger niche overlap with P. massoniana in canopy layer were Cinnamomum camphora, Liquidambar formosana, Symplocos setchuensis, Ilex crenata, Cyclobalanopsis glauca, and Loropetalum chinensis, while in shrub layer were Castanopsis fargesii and C. sclerophylla.

Key words: Chilling, Low light, PI, SOD, POD, MDA