Abstract: Based on the data collected from the plots investigation along with the implementation Levins, Shannon weiner index and niche overlap formulas in Mt. Qinling Shaanxi, the niche breadth values, niche similarity and niche overlap values of the main tree species were measured in the forestry of Abies chensiensis in this study. The results showed that: with the respective Levins and Shannon weiner index, the results of niche breadths of the main populations were almost the same and the highest value of niche breadth in arbor layer, shrub layer and herb layer were Abies chensiensis, Sinarundinaria nitida and Carex lanceolata, respectively. Abies chensiensis was prone to form mixed forest with populations with high value of niche breadth. In the populations with high value of niche breadth, the niche similarity was generally higher accordingly. Niche overlaps extents of main populations in Abies chensiensis community were correspondingly lower, indicated that the environmental resource could be shared by every population and the community was comparative stable.

Key words: Abies chensiensis, population, niche breadth, niche similarity, niche overlap