Abstract: The limestone mountainous region is the highlight and most difficult point of afforestation. In an investigation of the southern mountain area of Jinan, the importance value, niche breadth and niche overlap of 10 essential species were analyzed. It was founnd that Platycladus orientalis (Linn.)Franco. is the primary dominant species and constructive species in the southern mountain area of Jinan, Vitex negundo L.is the primary dominant species in the shrub layer, and Eriophorum angustifolium Roth. is the primary dominant species in the herb layer. By synthetic assessment result, P. orientalis (L.)Franco.—V. negundo L. (Lespdeza bicolor Turcz.)—E. angustifolium Roth. are the constructive species of treeshrubherb in the limestone mountainous region. Ulmus japonica Sarg. and Ulums macrocarpa Hance. have a lower value of niche overlap (value is 0), so both can be applied in a reasonable arrangement in governing the barren mountainous areas.

Key words: niche overlap , niche breadth, diversity index, tree seed optimization, limestone mountainous region, Jinan