黄土高原红桦林分布特征之探讨

A Discussion on Distributional Characteristics of Betula albo-sinensis Stands and Forest Belt on the Loess Plateau

通过实地调查和文献综述,本文全面描述了黄土高原红桦林分布范围、林分类型、群落结构、演替规律及生长状况。用生物学、生态学、演替学的理论分析了黄土高原红桦林在区域植被带谱中水平分布和垂直分布的奇特特征,进一步解读了为什么喜光、喜温凉、不耐庇荫的强阳性树种红桦承担强耐荫性树种云冷杉的角色——亚顶极树种占据顶极树种的地理位置或取代其功能而独立成带的主要原因,即红桦自身特性、环境特点和反复干扰。

Through on-the-spot investigation and historical literature reviewing, this paper does compre- hensively describe the distribution range, stand types, community structure, succession process and growth conditions of the chinapaper birch forests in the Loess Plateau. The peculiar characteristics of the horizontal distribution and vertical distribution in the vegetation spectrum of the chinapaper birch for- ests in the Loess Plateau are theoretically analyzed with biology, ecology and succession. The main rea- sons are further interpreted why chinapaper birch, which is very bright light and thermophilic cool and intolerant tree species, assume the role of the shade-tolerance tree species of spruces or firs, and why chinapaper birches of the sub-climax tree species occupy the position of spruces or firs of the climax tree species or replace its function as an independent vegetation belt. The main reasons are chinapaper birch＇s own biological and ecological characteristics, growing environmental characteristics and interfered over and over again by human.