Abstract: This paper studied tree layer biomass dynamics of natural Quercus aliena var. acuteserrata community on Mt.Xiaolongshan in Gansu.The results showed that the tree layer biomass of Quercus aliena var. acuteserrata community was 183.66t穐m^-2,in which slow growth trees took 64.89% of total biomass; common-fast growth trees amounted to 33.40%,and pine trees accounted for 1.38%.The organs biomass was in order of trunk>root> branch>leaf.The tree biomass accumulated with the development of community.The total biomass and the biomass of organs was the highest in the mature community and became stable with the community developing further.The relative growth rate of organs was in order of trunk>branch>root>leaf.The biomass ratio of slow growth trees trended to increase and that of common-fast trees to decrease with the community developing,which turned inverse in the decline development stage.The biomass of conifers was very small throughout the development process.

Key words: Camellia rosthorniana, Bionomic strategies, Fitness, Reproductive value