Abstract: The age structure and dynamics of dominant species Heptacodium miconioides at Tiantai Moduntain in Zhejiang Province were analyzed by adopting the method of "spatial series substituting for time series".The results indlicate that the age-class of the Heptacodium miconioides population is incomplete.The population's survival curves are not linear,and its age structure is declining.The age structure for most of the other dominant populations is also declining,which indicates that the Heptacodium miconioides community is unstable.The species diversity of Heptacodium miconioides community consists in the fact that the woody plants are rich,and the species diversity index is higher than that of the herbs.In terms of species richness distribution,both the woody and herbs fix to the logrithmic scale distributions,which means that the number of the sparse species is bigger than the enriched species,and that the community's evenness is relatively small.

Key words: SO₂, flue-cured tobacco, bulk-curing barn cluster, spatial distribution.