Niche Characteristics and Interspecific Associations of Dominant Tree Species in Secondary Evergreen Broad Leaf Forest of Suichang County

In October 2019, 9 sample plots with 50 m×50 m were established in secondary evergreen broad leaf forest in Suichang, Zhejiang province. Investigation was carried out on growth traits of trees and site conditions. The results showed that there were 66 species of woody plants, belonging to 53 genera and 34 families. The dominant species were Castanopsis eyrei, Cunninghamia lanceolata and Schima superba. There were 88 pairs (83.8%) of similarity between the main species and 93 pairs (88.6%) of niche overlap index more than 0.6. In addition, there was a significant negative association among main species, and the positive and negative association ratio was less than 1, indicating that the competition among species was intense and the community structure was unstable. The natural secondary forest in Suichang was a community with Castanopsis eyrei as the constructive specie, but the community structure was unstable, the interspecific competition was fierce, and no dynamic balance among the dominant species.