Population Structure And Cummunity Characters Of Davidia Involucrate In The Yaoshan,Yunnan

Davidia involucrat is one of China’s existing rare Tertiary relict plant,Yaoshan Nature Reserve in Yunnan save a few pieces of intact natural forest with Davidia involucrat as the dominant species.Therefore,this paper has studied the community of Davidia involucrata.Six plots was set up,study including the species composition,community structure,population structure and renewal pattern of Davidia involucrata forest,and discussed its competition relation and maintenance mechanism.So as to provide scientific basis for the maintenance and protection of the population of Davidia involucrata.Get the following conclusions:(1)The community of Davidia involucrata was distributed in the evergreen and deciduous broad-leaved mixed forest of wild octagonal and southern Yunnan.The species composition of the Davidia community was significantly different from that of the other communities,and the dominant species were more than evergreen species.The dominant species were also associated with Cercidiphyllum,Euptelea and other relict species in the same period.(2)In the vertical structure,the community of Davidia involucrata occupies the dominant position of the upper layer of trees,and many species are composed of Davidia involucrata and deciduous species,and a few are composed of Davidia iinvolucrata and evergreen species.The lower layers of the trees are dominated by evergreen species,showing the trend of succession from deciduous broad-leaved forest to evergreen broad-leaved forest.(3)Comparing the habitat stability of the different communities and the dominance of Davidia involucrata,the dominant degree of Davidia involucrata decreased with the increase of environmental stability,which was related to the ecological habit and competitive ability of Davidia involucrata,and the unstable habitat was beneficial to Davidia involucrata in the competition.(4)Davidia involucrata occupy the upper edge in the community,each height level and individual-level DBH continuous distribution,and there are many young trees,indicating Davidia involucrata can maintain their updates.The largest individual age of Davidia involucrata is not more than 70 years,which may be related to the instability of the community environment or the impact of human activities.(5)Davidia involucrata are formed individual seedling and germination in two ways,both sections of the communities and seedling sprouted seedlings,saplings reach but the stage is more of a young tree-based initiation,the more the volatile environment of the young seedlings formed tree,which is related to the availability of seedling nutrients.