Niche Characteristics of Main Tree Populations in Broad-leaved Mixed Forest of Phellodendron amurense in Changbai Mountain Area

Phellodendron amurense is national second-class protected plant. The quantitative analysis on the niche characteristics of dominant tree populations in broad-leaved mixed forest of Phellodendron amurense can provide theoretical basis for the protection of Phellodendron amurense and maintaining species diversity. Based on the 9^th national forest inventory in Jilin Province, the Phellodendron amurense broad-leaved mixed forest community in Changbai Mountain was investigated and the methods of importance value, Levins niche width, Shannon-Wiener niche width and Pianka niche overlap were used to analyze the niche characteristics of dominant tree populations in this region. The results showed that, there were 25 broad-leaved species, accounting for 96.15% of the total, and the important value of Phellodendron amurense in the broad-leaved mixed forest was the largest. The Levins and Shannon-Wiener niche width indices were basically the same in order. The species with the largest niche width was Phellodendron amurense, followed by Juglans mandshurica. The niche overlap value of species such as Phellodendron amurense with Butula costata, Juglans mandshurica and Ulmus laciniata was large. The niche width and niche overlap degree showed obvious consistency. However, the niche width and niche overlap of some species were opposite, such as Carpinus turczaninowii vs. Quercus dentata, Robinia pseudoacacia, and Tilia tuan, Phellodendron amurense vs. Pinus koraiensis, which was related to the ecological habits, habitat characteristics and spatial distribution of the tree species.