Abstract: Based on field investigations of sample lots, comparison of Casuarina equisetifolia forest was done with the major species groups of natural forest on sandy coast in two important niche characteristics, i.e. niche breadth and niche overlap. Results show that according to the variation of niche breadth of each species group in the two forests, the main species groups could be divided into 4 types, i.e. niche expanding, niche recessing, niche stable and niche sensitive. The dominant species in the succession of the natural forest were also widely distributed in the understory of the Casuarina equisetifolia forest, with quite a large niche breadth, but as the niches in artificial forest were not well differentiated, interspecies competitions were severe and the formation of community was not stable. The niche breadth of most native tree species was wider in the natural forest than in the Casuarina equisetifolia forest, but the niche overlap of other species groups, except for Litsea glutinosa, Sageretia thea and some niche sensitive species groups, was somewhat lower in the natural forest than in the Casuarina equisetifolia forest, which indicates that after long time of concerted evolution, the niche differentiation was high, and the competition among species groups was not so strong in the natural forest. On the whole, niche disposition was more optimal in the native-species-dominated natural forest than in the Casuarina equisetifolia forest, which is more meaningful to stability of the community, therefore realization of rational disposition of native species and Casuarina equisetifolia is of some important reference value to construction of stable coastal shelter forest system.

Key words: Casuarina equisetifolia, natural forest, ecological restoration, succession, niche breadth, niche overlap