香格里拉高山松林窗更新影响因子分析

Analysis of the Factors Impacting on Gap Regeneration of Pinus densata in Shangri-la Area

从高山松更新苗木所处的立地环境、林窗边缘木对更新苗木的影响、林下枯落物的影响、灌木的影响以及林窗特征等方面选取12个影响因子,以更新苗木的地径和高度为指标,建立并分析多重线性回归模型,分析各影响因子在高山松林窗更新过程中的影响程度。结果表明:模型拟合程度良好,可以解释要研究的问题;高山松苗木在林窗更新过程中,林窗形成年龄是最重要的影响因子,海拔和最近边缘木高度与高山松更新苗木高度呈负相关,和最近边缘木的距离与更新苗木地径呈正相关。坡度、坡位、坡向、林下枯落物盖度、林下枯落物厚度、灌木平均高、灌木盖度以及最近边缘木平均冠幅等8个因子对香格里拉地区高山松更新苗木生长的影响相对较小。

The linear regressive model with multiple objectives was built by taking the basal diameter and the seedling height as evaluation indexes to analyze the impact of 12 influencing factors on the growth of Pinus densata seedlings in the cause of forest gap regeneration. The 12 influencing factors were chosen from five aspects, i. e. , the site environmental factors where the seedlings grew, the influence of the trees growing around the forest gap on the seedling growth, the impact of forest litter, the shrub effect and the feature of the gaps. The results showed that the model fitted well, and it could solve the study problem reasonably. In the progress of P. densata seedling re- generation, the age of the forest gap formed was the most influential factor, whereas the altitude was a very impor- tant influencing factor upon the basal diameter and height growth of the seedlings. Seven factors, which included the gradient＇, slope position, coverage and thickness of forest litter, shrub coverage and the average height of the shrub storey, and the distance between P. densata seedlings and the nearest bordering trees, were the major factors affecting the growth of seedling basal diameter in the forest gaps. The height of the nearest bordering trees laid im- portant affect on the height growth of the seedlings.