Abstract: Lastly, works haye been done in the comparative study on the features of physiognonly and structure with tropical cquatorial rainforest. The discussion and comparison show that the floristic component of the forest oil horizontal distribution there are some species are the preyalence everywllere, others due to the cvolution and spread of specics, new species cvolve, old species die out or come to occupy more rcstricted areas, and according as the different local geo- morphy, soil, climate are formed diversity society, from the further constituted mosaic. these society and mosaic in the same a forestland are striking too. The vertical structure of forest consists of the seven layers in natural forest, and the species of structure each layer, D layer is more than others layer of which appears that have the major independent charactcr interlayer relationship. The trees layer, the shrubs layer, the herbaceous layer and the grounds layes are fundamental synusia and they make up the skeleton in forest structure.

Key words: Xishuangbanna

摘要： 本文采用群落样方法和剖面图解法对西双版纳季节雨林水平及垂直结构做了初步讨论。依立木高度、树冠形态、．各层植物叶之解剖结构划分层次; 用Raunkiaer的生活型谱统计生活型、叶级、叶质、叶型组成，并对其外貌特点做了讨论，最后跟龙脑香林外貌结构做了比较。通过比较表明：本区大面积混合季节雨林种类组成表现出一些种类分布普遍，另一些种类局限，随地势、地形、土壤和局部气候差异形成多样性组合，这种组合在同一林地也明显，构成嵌镶。在自然地段森林可分七层。组成各层的结构种，幼灌层D多于其他各层，说明D层在结构关系中具较大独立性。乔木、灌木、草本层片是基干层片和构成森林结构的骨架，外貌上以单叶、革质、全缘、中型叶、滴水尖叶为主的常绿阔叶大、中高位芽组成为特征，所有这些表现出与东南亚龙脑香林相似。外貌结构上与具显著干旱季节气候的中印半岛北部更接近。

关键词: 西双版纳, 季节雨林