陕西巴山北坡油松林抚育间伐改良效果

Improvement Effect of Tending and Thinning of Pinus tabuliformis Forest on the Northern Slope of Bashan Mountain of Shaanxi Province

为给巴山北坡具有代表性的森林类型——油松林培育提供技术依据,以南郑区国有碑坝林场针阔混交林为对象,对抚育间伐作业前及5 a后油松林木胸径径级分布、林分高度、林分质量、林分健康等状况进行了试验研究。结果表明:本巴山北坡油松针阔混交林择伐抚育作业5 a后,6~12 cm径级小径材树木占比由68.0%大幅下降到44.7%,14~20 cm径级中径材树木占比由26.7%上升到45.9%,22 cm径级以上大径材树木占比由4.3%提高到9.5%;抚育作业后各径级优质木占比由都高于47%上升到都高于79%,优质木树体占比由82.6%提高到92.87%;林地枯损木、病虫危害木等非健康木占比由9.9%下降到2.5%。抚育间伐在调整林木径级分布,提高优质木比例,降低枯死木、病虫害危害木比例,减弱林木分化,为目标树生长提供较多较好生存空间和通风光照条件等方面效果十分显著。

In order to provide technical basis for the cultivation of Pinus tabuliformis forest,the experimental study with the typical forest type on the northern slope of Bashan Mountain was conducted on the distribution of DBH diameter class,stand height,stand quality and stand health of Pinus tabuliformis trees before and 5 years after the treatment and thinning operation in the coniferous broad-leaved mixed forest of state-owned Beiba Forest Farm in Nanzhen.The results showed that after 5 years of tending and thinning,the proportion of 6-12 cm small class diameter trees decreased from 68.0%to 44.7%,the proportion of 14-20 cm middle diameter trees increased from 26.7%to 45.9%,and the proportion of large diameter trees above 22 cm diameters increased from 4.3%to 9.5%.After the operation,the proportion of high quality wood of all diameter classes increased from more than 47%to more than 79%,and the proportion of high quality wood up from 82.6%to 92.87%.The proportion of unhealthy wood such as dead wood and diseases and insects-infected wood down from 9.9%to 2.5%.Tending and thinning have a significant effect on adjusting the diameter class distribution of trees,increasing the proportion of high-quality trees,reducing the proportion of dead trees and trees damaged by diseases and pests,weakening the differentiation of trees,and providing more and better living space and ventilation and light conditions for the growth of target trees.