论文部分内容阅读
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20m×20m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5m×5m、5m×10m、10m×10m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。
Red toon is an endangered species in China. According to the distribution and population distribution characteristics of natural red forest in Guangxi, nine 20 m × 20 m sampling plots were set up in the concentrated distribution area of red toon grass in the northwestern Guangxi Province. Using discrete distribution theory fitting method, The age structure and spatial distribution pattern of the population of Toona sinensis at different growth and development stages were analyzed. The results showed that the populations of Toona sinensis in the northwest of Guangxi were mainly concentrated in the stages Ⅳ, Ⅴ and Ⅶ, while those of the young trees (Ⅰ and Ⅱ) were less or no, indicating that it is more difficult to renew the populations of Toona sinensis in the northwest of Guangxi. In the sampling area of 5m × 5m, 5m × 10m, 10m × 10m, the distribution of red toon in northwestern Guangxi showed a uniform distribution at the younger age stage and a higher distribution at the older age stage. As the sampling area increased, the age distribution gradually increased .