Abstract:The density and pattern dynamics of communities and dominant populations for secondary successional seral communities of evergreen broadleaved forests on Jinyun Mountain are studied on the basis of the size class and mean squreblock size graphs using variance analysis ,comparison with the size-structure, size-survivorship during succession. The sequence of dominant populations occur during succession. The dominant species might be divided into three types: pinoeer succession species, pinoeer climax, species, climax species. All of them progressively develop a whole set of size class. It is shown that the size-structure of Imperata association and Masson pine forest are similar to those of single Masson pine population. The structure of the former has only Ⅰ and Ⅱ classes, and that the latter looks like a inverted pyramid except for class Ⅴ. Both mixed needle and broadleaved forest and Schima forest have a typical pyramid with whole size classes. However, they are essentially different in contents. And the pyramid of Castanopsis is somewhat irregular.The size-survivorship curves of communities are vary from an inverted J-shape in Masson pine forest at the initial period to more or less a straightline later. The patterns of population mainly show continous distribution, although they vary with succession. Most of them coorrespond to the pattern of seedlings (I and II class), while the tree classes show largely randomness distribution. It is illustrated that in the course of succession the scale of the smallest pattern increases controlled by the characteristics of plants, wheresa the environmental pattern changes in the following aspects: 1. due to the variation in the type of pattern, the scale and pattern raise and fall corresponding to the growth, mature, and decline of populations; 2. even if the type of pattern does not change, but (a) the scale increases and the intensity descreases (e. g. Schima); (b) both scale and intensity increases (e. g. Neloitsea). The scale and intensity of pattern of soil depth and moisture for seral communities do not parallel with each other. The distribution of higher classes of some populations is related to the depth of soils.