Abstract:Population structure and spatial distribution pattern were investigated in a 3 600 m plot of forest community dominated by Castanopsis carlesii,C. fabri, Distylium myricoides and Adinandra millettii in Wuyishan State Nature Reserve．Fujian，China．Method ofTally with contiguous grid quadrats was used to analyze field data obtained．The results indicated that the populations ofth e four species had a great amount ofreserve seedlings． Spatial distribution pattern ofthese dominant populations appeared to have clumping distribution，but the clumping intensity showed diferences with K values (negative binomiaI distribution index) from O.2661 to 1.2877 Costanopsis carlesii population at different developmental stages all showed clumping distribution while D myricoides and C. fabri exhibited random distribution for large trees，and clumping distribution for saplings and median trees. As for A dimmdro millettii，population random distribution was shown in median trees,and clumping distribution in saplings． Such differences are due to the biological and ecological characteristics of the species and the competitive exclusion principle Varies plot sizes had also an effect on spatial distribution pattern.