A RPELIMINARY ECOLOGICAL STUDY OF DAVIDIA INVOLUCRATA COMMUNITIES AT LONGCHI REGION IN DUJIANGYAN COUNTY OF SICHUAN PROVINCE

The Gongtong(D. involucrata)communities at Longchi region in Dujiangyan City of Sichuan Province were surveyed. The compositions of flora of D. involucrata communities are analyzed,and the types of D. involucrata communities are classified andcontrasted by the similarity of the samples on account of their species composition,therank of importance value,and community structure. The relationships among the different layer and structural factors are discussed,and the diameter class structure of usualspecies in tree layer of the communities are used to investigate the relationship betweenthe current status,the regeneration condition of D. involucrata in the communities andthe successive stages of the communities. The characteristics of sexual and asexual regeneration of D. involucrata are also analyzed and a contrast is made with that of D. involucrata population at Hefeng and Wufeng in Hubei Province. In conclusion,Longchi region in Dujiangyan City belongs to the sub-suitable region for the distribution of D. involucrata according to the distribution,growth and regeneration of it. Although D. involucrata can maintain its existence here much stable now,the situation of its population development isn't unreliable.