马尾松-川灰木人工混交林种内、种间竞争强度

Intra-and inter-specific competition intensities in Pinus massoniana-Symplocos szechumensis mixed plantation

将林木竞争影响空间划分为2部分:距离对象木最近的一圈竞争木所围成的面积称为内圈,主要包括地上部分对光源的竞争和地下部分对土壤资源的竞争;除内圈外,其他6m以内的竞争木所围成的面积记为外圈,主要包括地下部分对土壤资源的竞争。在此基础上,采用Hegyi提出的单木竞争指数模型对嘉陵江流域南充金城山国家森林公园的马尾松-川灰木混交林中种内、种间竞争强度进行定量分析。结果表明:无论是内圈还是外圈,马尾松种内、种间竞争强度随林木径级的增大而减小,竞争强度顺序为:内圈马尾松种内>内圈马尾松与川灰木种间>外圈马尾松种内>外圈马尾松与川灰木种间。

Two 30 m × 30 m plots in Pinus massoniana-Symplocos szechumensis mixed plantation in Jinchengshan National Forest Park of Nanchong, Sichuan Province were installed, and .30 representative individuals of P. massoniana in each plot were chosen as objective trees to measure their diameter at breast height, plant height, branch height, and crown diameter. Such measurements were also taken for all the competitive trees within and out of 6 m from the objective trees. Within an area with radius of 6 m, two circles were divided. The inner one was composed of the competitive trees that were nearest to the objective tree, while the outer one was composed of the rest competitive trees. Hegyi ＇ s simple competition incdex was used. The intra- and inter-specifc competition intensities either in inner or in outer circle decreased with the increasing diameter class of the trees. The competition intensities were in the order of intraspecific competition of P. massoniana in inner circles 〉 interspecific competition between P. massoniana and S. szechumens/s in inner circles 〉 intraspecific competition of P. massoniana in outer circles 〉 interspecific competition in outer circles.