Zhao Weiwen, Liang Wenjun, Han Youzhi, Wei Xi
College of Forestry, Shanxi Agricultural University, Taigu, China.
PeerJ. 2021 Oct 14;9:e12327. doi: 10.7717/peerj.12327. eCollection 2021.
is an important and widely distributed species in the mountains of northern China. However, it has inefficient natural regeneration in many stands and difficulty recruiting seedlings and saplings. In this study, we selected six plots with improved naturally-regenerated seedlings. A point pattern analysis (pair-correlation function) was applied to identify the spatial distribution pattern and correlation between adult trees and regenerated seedlings mapped through X/Y coordinates. Several possible influencing factors of seedlings' natural regeneration were also investigated. The results showed that the spatial distribution patterns of seedlings were concentrated 0-5 m around adult trees when considering the main univariate distribution type of regeneration. There was a positive correlation at a scale of 1.5-4 m between seedlings and adult trees according to bivariate analyses. When the scale was increased, these relationships were no longer significant. Generally, adult trees raised regenerated seedlings at a scale of 1.5-4 m. Principal component analysis showed that the understory herb diversity and litter layer had a negative correlation with the number of regenerated seedlings. There was also a weak relationship between regenerated numbers and canopy density. This study demonstrated that the main factors promoting natural regeneration were litter thickness, herb diversity, and the distance between adult trees and regenerated seedlings. Additionally, these findings will provide a basis for the late-stage and practical management of natural regeneration in northern China's mountain ranges.
是中国北方山区一种重要且分布广泛的物种。然而，它在许多林分中自然更新效率低下，幼苗和幼树的补充存在困难。在本研究中，我们选择了六个具有改良天然更新幼苗的样地。应用点格局分析（对关联函数）来确定通过X/Y坐标绘制的成年树木与更新幼苗之间的空间分布格局和相关性。还研究了幼苗自然更新的几个可能影响因素。结果表明，考虑到更新的主要单变量分布类型时，幼苗的空间分布格局集中在成年树木周围0-5米处。根据双变量分析，在1.5-4米的尺度上，幼苗与成年树木之间存在正相关。当尺度增加时，这些关系不再显著。一般来说，成年树木在1.5-4米的尺度上促进了更新幼苗的生长。主成分分析表明，林下草本植物多样性和枯枝落叶层与更新幼苗数量呈负相关。更新数量与林冠密度之间也存在微弱关系。本研究表明，促进自然更新的主要因素是枯枝落叶厚度、草本植物多样性以及成年树木与更新幼苗之间的距离。此外，这些发现将为中国北方山区自然更新的后期实际管理提供依据。
