六盘山水源林林分目标层次结构研究

为适应六盘山水源林可持续经营实践的需求,利用六盘山林业局120个森林连续清查固定样地调查资料,分析了林分郁闭度对林下灌木、草本植物生长影响的规律,建立了适用于当地的数学模型,提出了该区水源林林分的目标层次结构。结果表明:1)该区水源林林分郁闭度影响林下植被的生长,林下灌木层、草本层盖度随林分郁闭度升高而降低;2)该林区水源林林分郁闭度保持在0.5～0.8之间时能够形成明显的乔灌草层次结构,有利于实现水源林经营的生态功能和经济功能的协调;3)该区水源林林分的目标层次结构为,林分郁闭度0.5～0.8,灌木层盖度35%～46%,草本层盖度35%～46%。研究结果可为该区水源林结构调整提供依据。

The Objective Stand Vertical Structure of Watershed Forests in Liupan Mountains

In order to meet the needs of the watershed forest management practice in Liupan Mountains,based on the continuous forest inventory data from 120 fixed sample plots in this area,the law of watershed forest canopy density impact on the growth of the undergrowth shrub and herb was analyzed,the related mathematical models were established,and an objective stand vertical structure of watershed forests in the area was put forward in this study.The results show that,1)canopy density has impact on the growth of the undergrowth plant,the undergrowth shrub and herb coverage decrease with the increasing of canopy density;2)a distinct arbor-shrub-herb vertical structure can be formed when the canopy density is kept in the range of 0.5~0.8,and accordingly the relationship between ecological and economic functions will be well coordinated;3)the objective stand vertical structure in the area shows that the canopy density is kept in the range of 0.5~0.8,each shrub and herb coverage kept in the range of 35%~45%.Therefore,the result provides scientific support for the structure regulation of the watershed forest stands.