马尾松近自然改造初期的混交度与分布格局

近自然森林经营被广泛认为是优化森林结构进而实现森林多功能的有效途径。以中国林科院热带林业实验中心（简称热林中心）伏波林场内1993年春季杉木采伐迹地更新造林的马尾松人工纯林为研究对象，按照补植树种的不同，进行4种不同模式的近自然化改造设计和作业，并从林分混角度、林木空间分布格局2个方面对改造效果进行分析。结果表明:近自然化改造后的林分，混交度有了明显的提升，林木空间分布格局从最开始的均匀分布逐渐过渡为聚集分布或随机分布。因此，近自然化改造有利于优化林分空间结构，从而为森林多功能的发挥提供了前提基础。

Minglings and Spatial Distribution of Pinus massoniana Plantation in the Initial Stage of Near-nature Transformation

Near-nature forest management is regarded as the possible alternative to optimize stand structure and hence to realize the multiple forest functions. We transformed the pure Pinus massoniana plantations into near-nature forests with four silvicultural treatments varying with the underplanted tree species. The transformation effects in terms of stand minlings and spatial distribution pattern were analyzed. The result indicated that the stand mingling of transformed stands were significantly improved and the spatial distribution had shifted from even distribution to random or clustered distribution. We concluded that near-nature transformation which optimized the stand structure could provide the basic precondition to realize the multiple forest functions.