Spatial Structure Characteristics of Keteleeria davidiana Population in the Nanpan River Basin
PAN Ting;YU Sufang;YAO Xianyu;LI Yuangan;YE Shaoming;LI Yuanfa;College of Forestry,Guangxi University;Linduo Forestry Farm;
Keteleeria davidianais tertiary period relict gymnosperm,which is listed as China's endangered tree species,and also is one of the most important tree species compositions of the natural vegetation along the Nanpan River.In this study,a standard permanent plot with 100 m ×80msizes was set up in Guangxi Yachang Orchid National Nature Reserve of Nanpan River basin by the typical sample method.The bivariate distribution of forest stand spatial structural parameters(BDFSSSP)was used to analyze the spatial structural characteristics of the whole population and its big trees(DBH≥15.79cm)and small trees(5cm≤DHB15.79cm)to reveal structural diversity of the K.davidiana population in natural secondary community in Nanpan River basin.The results showed that:(1)K.davidiana population was randomly distributed(W = 0.468)and moderately mixed by other species(M= 0.480),with obvious diameter differentiation among individuals(U=0.472).(2)Most big trees of the population were in a status of dominance(U= 0.204)and moderate mixture(M= 0.436),and their distribution pattern had a state of ran-dom distribution(W = 0.483).(3)Small trees had a similar distribution pattern and mixture with the whole population.The most of the small trees belonged to the inferior individuals(U = 0.75-1.00).The study suggested that the spatial structural diversities existed between K.davidianaand its adjacent populations,and it also could be found in K.davidianapopulation.It may imply that K.davidiana was in a stage of stable development.