Abstract:Based on field data,we established 100 quadrats within fourteen tree species in Taiyue Mountain of Shanxi.We analyzed interspecific segregation by using ArcView GIS software and the nearest neighbor method,interspecific segregation was studied with an N×N nearest-neighbor contingency table,a 2×2 nearest-neighbor contingency sub-table,and Pielou coefficient of segregation(S).According to their adapt ability to the environment and relationships between plants and environment,assisting in principal components analysis,the 14 species divided into three ecological species groups (ESG).The results showed:(1)Most of the species pairs are randomly segregated (74.73%),some species pairs are positively segregated (23.07%),and only a few species pairs are negatively segregated (2.20%).(2)There are some differences among different species in the interspecific segregation of all species.The Ulmus lamellosa in the communities tended to be randomly segregated with other species.Positive segregation appeared among dominant species,probably because of their stronger competitive vigor.For example,Carpinus cordata,Acer elegantulum and Populus davidiana are tended to be positively segregated each other.Negative segregation appeared among companion species in the communities,such as Carpinus turczaninowii,Acer grosseri,Koelreuteria paniculata and Acer ginnala.(3)The interspecific segregation is related to the heterogeneity in the communities,in that segregation often occurs between two species which have different habitat requirements;while the aggregation often appears between two species which have same or similar environmentally requirements.(4)In Ulmus lamellosa communities,the 14 species divided into three ecological species groups.On the whole,the 14 species we studied overlapped in distribution and were characterized by overall non-segregation.The interspecific relationships based on different species are adapted and their biological requirements may be one of the mechanisms which allow these species to stably coexist in the U.lamellosa community of the Taiyue Mountain in Shanxi.