马尾松火力楠混交林生长特性和结构调控技术研究

在马尾松采伐迹地上开展马尾松与火力楠不同比例带状混交造林试验，研究结果表明：马尾松与火力楠混交能改善土壤肥力，提高马尾松林分生长量；混交林中火力楠生长迅速而占据林分上层林冠，马尾松位于主林层之下，呈受压局面，而且马尾松比例愈大，其平均单株产量越小，生长受抑制越严重。在林分10年生左右需对混交林进行结构调整，采用行状间伐，扩大种间距离到4m，减少了种间竞争，使2个树种各自获得充足营养空间，缓解马尾松被压，优化林分结构，提高林分平均单株材积和增加林分大径木比例。

Studies on Structure and Growth Characters of the Mixed Forestry of Pinus massoniana and Michelia macclurei

The experimental results indicated that the mixed forestry of Pinus massoniana and Michelia macclurei was able to improve soil fertility efficiently and raise growth increment of Pinus massoniana; Michelia macclurei growed more quickly than Pinus massoniana, and occupied the upper space of the forestry thus pressed the growth of Pinus massoniana. Moreover, the average individual growth increment of Pinus massoniana became less and less with its proportion increasing in the mixed forestry. The regulation of structure of the belt mixed forestry needs to be carried out in ten years. The competion between the two species should be retarded through row cutting, widening the distance between the two species so as to supply adequate nutritious space for the both species and reduce the depression on Pinus massoniana. As a result, the average individual volume of the stand is improved and the proportion of big trees is increased.