Keywords: 
• 植物种群、年龄组、生态位宽度、群落演替

Abstract: Niche breadth of four dominate populations at three age groups was studied by the methods of resource utilization ability and ratio.The result shows that:Symplocos sectchuanensis is a typical gengeration species whi ch resource utilization ability is strong,and distribution is wide.Meanwhile,Go rdonia acuminata,Castanopsis fargesis and Pinus massoniana specialized at some d egree in resource utilizationm,their distribution is limited.Especially,the ju venile of Pinus massoniana specialized outstandingly.With the devlopment of Pinu s massoniana,which is the pioneer population in Mt.Jinyun,the environment become s unfit to it's juvenile.It turns to needle and evergreen broad-leaves mixed fo r est.Because the tolerance toward shading of Gordonia acuminata is lower than tha t of Castanopsis fargesis,Gordonia acuminata will be substituted by Castanopsis fargesis and other evergreen broad-leaves species are the edificators.The popul ation's ability of resource utilization is the inner factor of population distri bution and community succession.The distribution of light and the concentrate of nutrient(such as N)is the outer factors of community succession.