不同密度油松飞播林灌草多样性与林分空间结构关系

林下植被是森林生态系统的重要组成部分,物种多样性和林分空间结构是评估森林生态系统功能和林分经营质量的关键指标。本文以44年生油松飞播林为研究对象,通过典型样地调查,运用单因素方差分析和相关分析,分析林分密度对油松飞播林灌草多样性和林分空间结构的影响。结果表明:(1)林分密度对灌草多样性指数影响差异显著,灌草多样性指数均在低密度的样地中达到最大值。(2)混交度和密集度受林分密度影响显著,而林分密度对乔木胸径和树高的影响体现在林分水平上,而非空间结构单元中。(3)林分空间结构与灌草多样性之间有密切联系,影响林下植被多样性的最主要因子是乔木层混交度。因此,未来在飞播林经营活动中,调整林分密度的同时,应综合考虑林木分布格局,兼顾灌草多样性保护。

Relationship between understory diversity and stand spatial structure in air-drilled Pinus tabulaeformis forests of different densities

The understory plant layer is one of the most important components of the forest ecosystem.Species diversity and forest spatial structure are the key factors in the evaluation of forest management and forest ecosystem function.In this study,based on typical 44-year-old Pinus tabulaeformis air-drilled forest plots,we explored the effects of forest density on understory layer diversity and forest spatial structure by correlation and ANOVA analyses.The results showed that:(a)the shrub and grass diversity was significantly affected by forest density and exhibited the maximum value in the low-density plots;(b)forest density significantly influenced forest spatial structure indexes of mingling degree(M)and crowding degree(C),whereas it affected DBH and tree height at the stand level but not based on structure units;and(c)there were connections between forest spatial structure and understory layer diversity,with the most important impact factor affecting understory plant diversity being the M index of the tree layer.Overall,during air-drilled forest management activities,managers should consider both the spatial distribution of trees and the diversity of the understory layer when adjusting forest density.