火地塘林区桦木林的结构及其稳定性的研究

Structure and Stability of Birch Forest at Huoditang Forest Region

该林区的桦木次生林主要有红桦和牛皮桦两个群系，桦叶英—红桦林、箭竹—红桦林、迎红杜鹃—牛皮桦林、箭竹—牛皮桦林等4个群丛组。红桦次生林种类结构不稳定，巴山冷杉是进展种群，红桦通过林窗更新维持其种群的连续性，演替趋向为针阔叶混交林。牛皮桦林的种类结构相对比较稳定。

There was a secondary birch forest which included mainly two forrnations of Betula albo-sinensis and B. utilis and four association groups of B. albo- sinensis-Viburnum betulaefoium, B. albo - sinensis-Sinarundinaria nitida, B untilis - Rhododenaron giraldii and B.un tilis-Sinarundinaria nitida at Huoditang forest region.the species structure of the forest of B.albo -sinensis was unstable but that of B. utilis was relative stable. Abies fargesis population was progressive. The population continuity of B. albo-sinensis was maintained through blank regen-eration and the succession tended to mixed forest between broad leaved and coniferous trees.