Abstract: Two national second-class protected plant species, Calocedrus macrolepis and Pseudotsuga sinensis are mainly distributed in Yimen County, Yunnan Province. These two species and two communities dominanted by Calocedrus macrolepis and Pseudotsuga sinensis respctively are believed to be very valuable in conservation. They have become the first nature reserve in China focusing on the conservation of these two species only. The study on the characteristics of community, its floristic constitution and the population composition of these two species shows the urgency of conservaation.The natural distribution has been limited because Calocedrus macrolepis is a shade tolerant tree while Pseudotsuga sinensis is shade intolerant. Calocedrus macrolepis is regarded to be originated from the central and central-southern part of Yunnan based on fossils evidences. The habitat of Calocedrus macrolepis tends to prefer a more tropical climate than that of Pseudotsuga sinensis based on the analysis of distribution patterns of genera of seed plants in two communities. The above statements provide a theoretic foundation for in situ and ex situ conservation of these two species.

Key words: Calocedrus macrolepis

摘要： 国家二级保护植物翠柏(Calocedrus macrolepis Kurz)和黄杉(Pseudotsuga sinensis Dode),仅在云南易门有较大面积的纯林分布,是很有保护价值的2个树种和相应的2个森林群落,现已成为全国唯一的翠柏和黄杉自然保护区.本文从群落特征、区系和种群分布格局的角度,首次较全面地分析了翠柏和黄杉极需保护的重要性.结果表明翠柏幼苗的耐阴性及黄杉幼苗的喜光性都是其分布范围受限制的主要原因之一;根据化石资料得出翠柏可能起源于滇中南;从分析群落中种子植物属的分布区类型得出翠柏的分布地生境比黄杉更趋于热带性.这些研究为翠柏及黄杉的就地保护和迁地保护提供理论依据.

关键词: 翠柏, 黄杉, 群落, 种群, 区系