Castanopsis Forest Types,species Diversity And Community Structure In SW Yunnan

We investigated 86 forest forest plots dominated by Castanopis forest species in SW Yunnan.We studied the forests in terms of species composition,diversity,forest structure and regeneration.The main results are as follows:(1)We classified 47 primary Castanopsis forest plots into 7 types and 39 secondary Castanopsis forest plots into 6 types using floristic similarity cluster analysis.Each forest type is named by the dominant species.The 7 primary forest types are Castanopsis echinocarpa forest,Castanopsis fleuryi forest,Castanopsis hystrix forest,Castanopsis calathiformis forest,Castanopsis lamontii-Lindera gracilipes forest,Castanopsis ceratacantha forest,and Castanopsis argyrophylla forest.The 4 forest secondary types are Alnus nepalensis-Castanopsis ceratacantha forest,Castanopsis calathiformis-Schima wallichii forest,Formanodendron doichangensis-Castanopsis fleuryi forest and Schima khasiana-Castanopsis echinocarpa forest.(2)While Castanopsis lamontii-Lindera gracilipes forest had the highest value among the 7 primary forest types.Schima khasiana-Castanopsis echinocarpa forest had the highest value among the 4 secondary forest types.The diversity indices including Shannon-Wiener H′,Pielow J′ and Simpson D between the primary forests and the secondary forests as a whole showed no siglificant difference.(3)Among the primary forests,Castanopsis lamontii had higher mean DBH and mean height than the other Castanopsis species.Primary Castanopsis echinocarpa forest reached the highest basal area on average,while Castnopsis ceratacantha forest had the highest density/ha.In the secondary forests,the valuese of mean DBH,mean height and mean basal area were generally lower than those in the primary forests,while the densities/ha in the secondary forests were generally higher than that in the primary forests.The DBH frequency distribution of representative primary forests indicated that Castanopsis echinocarpa was in the inverse-J type showing excellent regeneration,Castanopsis fleuryi and Castnopsis ceratacantha were in the multimodal type showing possible good regeneration depending on forest gaps formed.In the representative secondary forests,Castanopsis echinocarpa,Castanopsis fleuryi,Castanopsis calathiformis were in a multimodal type showing those species’ regeneration were waiting for chances such as forest gaps formed.Castanopsis species depended on seedlings for regeneration in the primary forests,while they had regeneration modals in both sprouting and seedling in the secondary forests.