Abstract: Shorea chinensis forest distributing as a relict in the limited habitats of southern Mengia County, Xishuangbanna, Yunnan. Covering about 800hm2, where is a tropical consociation with a single dominant tree species Shorea chinensis ofDipterocarpaceae. The for-est is mainly charactered by evergreen mega and meso phaenerophytes with simple leathy and entire mesophylls. With 3-4 tree layers, butress appearing in the upper trees, cauliflory ap-pearing in the lower trees, abundant woody lianas and epiphytes in the interlayer, the forest is thoroughly a vegetation type of tropical rain forest. Situated on the northern border of main-land SE Asia, the forest grows under the limiting conditions of the climate, latitude and alti-tude of tropical rain forests, therefore, the forest community has some deciduous trees among the upper trees, less megaphaenerophytes and epiphytes, more abundant lianas, meso and microphaenerophytes.

Key words: XIshuangbanna

摘要： 分布和残存于西双版纳勐腊县南部的望天树林是以龙脑香科植物望天树为上层优势树种，外貌以单叶、革质、全缘、中叶为主的常绿大、中高位芽植物组成为特征的一种热带森林群落。该群落层次结构复杂，上层乔木多具板根，下层乔木具茎花，层间木质藤本和附生植物丰富，具有浓厚的热带雨林特点。由于地处具有山原地貌和季风气候特点的大陆东南亚热带北缘，该群落受到气候的季节性干旱和冬季一定的低温影响，上层乔木中具有一定比例的落叶树种存在；在叶级谱上，小叶比例亦较高，表现为一种在水分、热量和海拔上均达到极限的东南亚热带北缘的热带季节雨林类型。本文也对该群落的乔木径级分布、种/个体关系以及种群配置特征作了讨论。

关键词: 西双版纳, 望天树单优群落, 群落生态学