华北落叶松林木生长、草本植物多样性及地形因子之间的关系

以河北省小五台山区华北落叶松人工林为对象,通过对林木生长因子和草本多样性指数的调查、计算和分析,对华北落叶松林木生长、草本植物多样性以及地形因子之间的关系进行了研究。结果表明,(1)坡度与树高、胸径、第一活枝高(枝下高)和冠幅呈显著负相关性,而海拔、坡位和坡形与林木生长因子之间的相关性不显著;(2)从相关系数和相关性强度综合分析,林木生长因子对草本多样性影响程度为:郁闭度枝下高胸径树高冠幅;(3)在海拔1 400~2 000 m范围,随海拔高度增加,Shannon—Wiener多样性指数和Pielou均匀度指数表现出较为平稳的变化趋势,而Simpson多样性指数和Menhinick丰富度指数则表现出上下波动的变化趋势;(4)海拔、坡形、坡度对华北落叶松林下草本多样性变化影响程度较小,而坡位与草本植物Menhinick丰富度指数和Simpson多样性指数达到显著负相关水平,表明坡位对草本植物多样性变化影响程度较大。

Relationships Among Growth of Larix Principis-rupprechtii, Herbaceous Plants Diversity and Landform

Taking Larix principis-rupprechtii forest in Xiaowutai Mountain in Hebei Province as the case study, the relationships between forest growth, topography, and herb diversity were studied through field investigation and laboratory analysis. The results showed that:(1) Slope was significant negative correlation with tree height, diameter at breast height, under crown height and canopy size, but tree growth were not significantly correlated with elevation, slope position and slope shape;(2) In terms of correlation coefficients and correlation strength, the effect size of whole forest growth on herb diversity had an order as following:canopy density >under crown height >DBH >height >canopy size;(3) the Shannon-Wiener diversity index and Pielou evenness index showed a relatively stable trend with the increase of altitude from 1400 to 2000 m, and Simpson diversity index and the Menhinick richness index showed a fluctuating trend;(4) The effect of elevation, slope shape and slope gradient on herb diversity was smaller, but slope position showed a significant negative correlation with Menhinick richness index and Simpson diversity index of herbs, indicating that the impact of slope position change on herb diversity was greater.