冻拔对辽东山区天然更新红松幼苗的影响

Effects of frost heaving on natural regeneration of Pinus koraiensis seedlings in mountainous area of eastern Liaoning Province

为探明冻拔对天然更新红松幼苗的影响,该研究以辽东山区天然更新红松幼苗为试材,调查不同处理(苗龄、相对土壤水分梯度、覆盖物厚度)的天然更新红松幼苗根系冻拔情况,并应用主成分和相关性方法分析天然更新红松幼苗发生冻拔与环境因子的关系。结果表明:次生林天然更新红松幼苗的冻拔率为14.81%,在次生林与红松人工林交界处天然更新红松幼苗的冻拔率仅为6.35%,次生林内天然更新红松幼苗的冻拔率较高;相对土壤水分梯度是影响天然更新红松幼苗发生冻拔的主要环境因子,随相对土壤水分梯度的增加,幼苗发生冻拔的概率逐渐增大;而且土壤A层厚度、凋落物O层厚度、土壤水分梯度、坡向与天然更新红松幼苗发生冻拔存在交互作用,在次生林内覆盖物厚度、交界处土壤水分梯度与坡度对天然更新红松幼苗发生冻拔存在显著影响。该研究结果可对天然更新红松幼苗的保护与培育提供科学指导。

The roots of Pinus koraiensis seedlings regenerated from seeds affected by frost heaving under different treatments(seedling age,relative soil moisture gradient,coverage thickness)were investigated,so as to figure out the effects of frost heaving on natural regeneration of Pinus koraiensis seedlings in the mountainous area of eastern Liaoning Province,and the relationship between frost heaving and environmental factors was analyzed by principal component and correlation methods.The results showed that the frost heaving rate of Pinus koraiensis seedlings generated from seeds was higher in the secondary forest than the boundary area,which was 14.81%in the secondary forest,and only 6.35%in the boundary area.The relative soil moisture gradient was the main environmental factor affecting the frost heaving of natural regeneration seedlings.With the increase of relative soil moisture gradient,the probability of frost heaving of seedlings increased gradually.In addition,thickness of the A layer of soil and O layer of litter,soil moisture gradient and slope direction interacted with the frost heaving of natural regenerated Pinus koraiensis seedlings.The coverage thickness in secondary forest,soil moisture gradient and slope gradient at the boundary area of secondary forest and Pinus koraiensis plantation had significant effects on the frost heaving of natural regenerated Pinus koraiensis seedlings.The results of present study can provide scientific guidance for the protection and cultivation of Pinus koraiensis seedlings regenerated from seeds.