关键词: 常绿阔叶林, 自然恢复, 种群动态, 种群结构, 材积生产力

Abstract:

The present study was conducted in the secondary subtropical evergreen broad-leaved forests at altitude 1 650～1 670 m in Mt.Wawushan National Forest Park,southwestern China.In order to understand stand restoration dynamics,the stand structure in three permanent 004hm² plots for 3～4 times were recorded from 1982 to 1997 and expounded the changes in 15 years about tree composition,important value index,several diversity indices,structure and volume productivity of both communities and populations.The results were followed:11 tree species disappeared and about another 10 species entered into tree layer in the stand,keeping tree layer dynamic equilibrium and developing tree species diversity.The dominant species,Castanopsis platyacantha,assumed the superior status,but its important value(Ⅳ)was decreased.The position of secondary dominant species,Schima sinense and Lithocarpus hancei, are gradually enhanced with gradually increased Ⅳ.The changes of densities,DBH and height distribution of tree populations displayed that the secondary evergreen forest was developed from past single or double dominant tree species to double or three dominant trees,from single tree layer to multiple levels in vertical structure.And the resulting community becomes more complicated and more stable.The growth rates of average height and DBH of all main trees were 24～48 cm·a^-1 and 034～110 cm·a^-1,respectively.According to the differentiation of growth,the main trees could be divided into three growth groups of species:fast-growing group including species of Schima sinense and Acanthopanax evodiaefolius var.gracills,slow-growing group of Machilus pingii and Lithocarpus hancei, and the group in between of Castanopsis platyacantha and Cyclobalanopsis myrsinaefolia. Volume productivity of the dominant population increased firstly and then decreased,but the secondary tree population increased quickly all the time.Volume productivity of all tree population in 1997 was up to between 218 m3·hm^-2 and 235 m³·hm^-2,and the change of dominant population was a key for community productivity.The relations of DBH,height growth and volume productivity in various density of the main tree populations indicated that the densities was one of the most important factors in fluencing productivity of tree populations under common environment with the interactions among tree populations.It is suggested that there is no contradiction between tree species diversity conservation and high volume productivity in forest restoration process.

Key words: Evergreen broad-leaved forest, Natural recovery, Population strcture, Growth dynamics, Volume productivity