四川九顶山西坡红桦林天然种群空间格局及更新研究

用T-square距离方法，通过空间格局的T形指数C及其检验值Z1，对九顶山西坡红桦种群中选取的3块样地6条样线进行了研究。结果表明，该区红桦种群空间分布格局以随机型分布为主，如样地支部牛场、十二河等，少数地区由于遭到人类的严重干扰和破坏，形成了集聚型分布格局，如样地上堰，通过分布距离指数I的进一步对照分析得出，在样线L4中，在主要的随机格局中也有少部分表现出了集聚型本区红桦树种按其年龄段的不同分为3个年龄级：幼树、成年树、老年树，红桦幼树比较缺乏，仅占红桦树种的12％，而老年树种占24％，年龄结构为衰老型。在九顶山西坡，红桦种群已开始老化，幼树又相当缺乏，使红桦种群的自我更新面临极大威胁，建议加强对红桦林的保护和种群自我更新能力的研究。

T-square study on spatial pattern and regeneration of Betula albo-sinensis Burkill population on west slope of Jiuding Mountain

The T-square study of Betula albo-sinensis population on the west slope of Jiuding Mountain showed that the population was mainly in random distribution, and in aggregated distribution in a few lines because of the negative human activities and severe destructions. In this region, the old trees of Betula albo-sinensis population were accounted for about 24%, and the younger trees only accounted for 12%. There exited a huge difficulty in the self-regeneration of Betula albo-sinensis population. Therefore, some measures should be taken to protect the population and to speed up its self-regeneration.