四川盆周中低山速生丰产用材林立地分类研究

四川省第二期速生丰产林的造林地主要分布于盆地边缘海拔８００～１６００米的低中山地带，为此采用了多因子综合方法对我省中低山造林地进行了立地分类和评价。针对杉木、柳杉、马尾松等三个主要树种应用多元线性模型筛选确定了划分立地类型的主导因子（海拔、土层厚度）和辅助因子（坡形、坡度），建立了数量化立地指数模型。木着科学和实用的原则，根据我省的地貌、气候和植被分布的特点，在数学分析的基础上建立了四川省速生丰产林的三级立地分类系统：立地类型区─—立地类型组─—立地类型。以地域分异为主要依据划分立地类型区，反映树种适生性的水平地带性分布格局；划分立地类型组的因子是海拔，反映在同一水平地带树种的适生性和生产力在垂直方向上的差鼻；在立地类型这个基础的层次，根据土层厚度并结合坡度等局部地形因子划分出各个类型。该分类系统为指导以县为单位的营造速生丰产林的规划设计提供了科学的立地分类方法。

Site Classification for Timber Plantations in Low-middle Mountain Area surrounding the Sichuan Basin

Afforestation Snot for fast-growing and high-yield timber plantations are mainly situated in mountain area with altitude of 800-1600m surrounding the Sichuan Basin. A multifactor investigation for site evaluation and classification was carried out. The quantified site index models for Chinese fir,cryptomeria and Massion' s pine were developed,using the linear model. Based on the resultS of statistical md,altitude and thickness of soil layer were selected as demarcating factors. A three-grade site classification system was established, namely, site type district-site type group-site type.