横断山区干旱河谷植被类型

横断山区干旱河谷植被,按植物群落的生态外貌、种类组成与结构特点,可分为4个类型(即:稀树灌木草丛,肉质刺灌丛,扭曲云南松疏林,小叶刺灌丛)15个群落。按干旱河谷的区域分异、水热状况、山地植被垂直带和利用方向,将本区干旱河谷分为4个类型(即:干热、干暖、干温、干凉)7个区。

VEGETATIONAL TYPES OF THE ARID VALLEYS IN THE HENGDUAN MOUNTAINOUS REGION

There are arid valleys in the Hengduan Mountainous Region universally. The vegetational characters are following. 1. It is only distributed in the botton zone of the river valley, alt. 350 - 3800m; 2. The change of physiognomy with the alternating of dry and wet season in quite obvious ; 3. The vertical stratification of community is single, in which wood plants are short and to grow separatelly; 4. The community composition is main mesophyte, but the structure is xero-morphic.According to physiognomy, composition and structure of the community, the vegetation of the arid valleys in the Hengduan Mountainous Region is divided into 4 types:1. Savanna; 2. Fleshy thorn shrub; 3. Open woodland with crooked Pinus yunnanensis; 4. Shrub, with small leaves and thorn, and 15 communities.Whole area of arid valleys of the Hengduan Mountainous Region may be divided into 4 kinds and 7 regions by regional differentiation, condition of water and heat, vertical zone of mountainous vegetaion and utilizational direction. The 4 kinds are heat-dry, warm-dry, temperate-dry and cold-dry.