Numerical classification and ordination of wild Castanea mollissima communities in Taikuan River Nature Reserve,Shanxi

Based on the data from the field investigation of 42 quadrats with 37 dominant species,the structure,species composition and distribution of wild Castanea mollissima communities in Taikuan River Nature Reserve,Shanxi and the relationship of community and environment were investigated by TWINSPAN and DCA. The results showed that C. mollissima communities were divided into 11 associations by TWINSPAN,and the distribution of the communities could comprehensively reflect the influences of disturbance,slope direction and soil organic matter on the communities. The results by DCA ordination indicated that the important factors impacting the community distribution were slope direction,terrain and soil type. The first axis of DCA ordination mainly represented the influence of the slope and slope direction on the communities. The relationship between the community and the environment,mainly reflected by the second axis,was not obvious; however,the diagonal of DCA ordination reflected the variations of the communities and the thickness of forest floor. Moreover,the DCA ordination analysis showed that the 37 dominant species had similar patterns. To some extent,community type was dependant on the distribution pattern of dominant species.