桂西北红椿种群年龄结构与空间分布格局研究
Age Structure and Spatial Distribution Pattern of Toona ciliate Population in Northwestern Guangxi

红椿是我国濒危保护物种，针对红椿天然林在广西的分布及种群分布特点，在桂西北红椿分布集中区域设置了9个20 m×20 m的调查样地，采用离散分布理论拟合方法，对该地红椿不同生长发育阶段种群年龄结构和空间分布格局进行分析。结果表明，桂西北红椿种群个体主要集中在Ⅳ、Ⅴ和Ⅶ龄级，而幼龄树（Ⅰ和Ⅱ级）较少或者没有，表明桂西北红椿种群更新比较困难。桂西北红椿在5 m×5 m、5 m×10 m、10 m×10 m的取样面积上，低龄级呈现均匀分布，高龄级呈现聚集分布，并随着取样面积的增大，呈均匀分布的龄级逐渐增加。
Toona ciliate is a nationally endangered and protected species in China. Based on the distribution characteristics of T. ciliate population, 9 sampling plots, designed as 20 m by 20 m were established in the concentrated distribution area in northwestern Guangxi to study the age structure and spatial distribution pattern by using discrete distribution theory. The results showed that most of individuals concentrated in size class Ⅳ, Ⅴ and Ⅶ, relative few or none individuals appeared in size class Ⅰ and Ⅱ, indicating that the regeneration of T. ciliate was difficult. At the different sampling areas, such as 5 m×5 m, 5 m×10 m, 10 m×10 m, T. ciliate performed the pattern of uniform distribution in size class Ⅰ and Ⅱ, performed the pattern of aggregated distribution in size class of Ⅳ, Ⅴ, and Ⅶ, the size class increased in the pattern of uniform distribution along with the increase of the sampling plot area