陕西省宁东林业局华北落叶松人工林胸径分布规律研究

【目的】研究陕西省宁东林业局华北落叶松人工林林分胸径分布规律，为区内华北落叶松人工林的可持续经营提供理论依据。【方法】在研究区设置华北落叶松人工林样地并进行调查，测定林木胸径，分析其分布规律，用正态分布函数拟合林分胸径分布规律，在此基础上，提出胸径结构调整方案。【结果】研究区华北落叶松人工林胸径分布均呈左偏的单峰曲线，随着林分密度的增大，曲线左偏程度变大，平均胸径变小；应用正态分布函数能较好地描述该区华北落叶松人工林的胸径分布，并可预测林分产量。【结论】研究区华北落叶松人工林胸径结构不合理，小径阶和大径阶林木较少，急需进行调整，以使其达到合理的胸径结构。

Study on diameter structure of Larix principis rupprechtii plantation of Ningdong forestry bureau in Shaanxi Province

【Objective】 The research on the diameter structure of Larix principis-rupprechtii plantation of Ningdong forestry bureau in Shaanxi province was carried out to provide scientific reference for the sustainable management of L.principis-rupprechtii plantation in the research area.【Method】 Based on the data from the sample plots of L.principis-rupprechtii plantation in the research area,this paper studied the diameter structure,used normal distribution to fit,and on the basis of this made the plan of transformation.【Result】 The diameter distribution of L.principis-rupprechtii plantation appeared to be inclined to right side mountain-liking curve.With the increase of stand density,curve to the left deviation became bigger,while the mean diameter became smaller.The normal distribution could describe the diameter distribution well and also could be used to forecast the yield.【Conclusion】 The diameter structure of the L.principis-rupprechtii plantation was unreasonable,the number of small size-class and big size-class was so less that we need to take some measures to achieve reasonable diameter structure.