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为了解影响热带天然次生林稀疏的因素,本研究应用地上生物量模型、多样性指数和O-ring统计对固定样地中植物的地上生物量、物种多样性和空间分布格局进行定量研究,并结合Yoda自疏模型计算林分稀疏指数,分析物种多样性与空间格局对林分稀疏的影响。结果表明:林分地上生物量随着林分密度的减小呈现先增大,后减小,再增大的趋势,在径级Ⅲ或径级Ⅳ处,出现变化拐点,在天然林管理时应加以注意。多样性指数与林分稀疏指数总体上无显著的相关性,但中等多样性指数值却对应最大的稀疏指数。说明物种多样性中等情况下,林分稀疏最为强烈。植物个体聚集分布的最大强度与稀疏指数呈显著线性负相关,二者的回归方程为:α=-1.7873O11(r)max+2.3451(R2=0.798,P=0.003)。结果表明,在热带常绿季雨矮林中,过大的聚集强度不但不能促进稀疏过程的进行,反而会对其产生阻碍作用。
In order to understand the factors influencing the sparseness of tropical natural secondary forests, this study quantitatively studied the aboveground biomass, species diversity and spatial distribution patterns of plants in fixed plots using the aboveground biomass model, diversity index and O-ring statistics Yoda self-sparse model was used to calculate the sparse index of forest, and the effects of species diversity and spatial pattern on the sparseness of forest were analyzed. The results showed that aboveground biomass of forest stands first, then decreases and then increases with the decrease of stand density, and inflection point appears at either path Ⅲ or path Ⅳ. In the management of natural forest Should pay attention. There was no significant correlation between diversity index and stand index, but the value of middle diversity index corresponded to the largest index of sparseness. The species diversity is moderate, the sparseness of the most intense. The maximum intensity of plant aggregation distribution was significantly negatively correlated with the sparse index. The regression equation was: α = -1.7873O11 (r) max + 2.3451 (R2 = 0.798, P = 0.003). The results showed that in the evergreen tropical evergreen rainforest, the excessive accumulation strength not only can not promote the sparse process, but will hinder it.