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通过调查和分析油松林下植被物种组成特征及生物量,运用灰色关联分析、主成分分析和系统聚类方法,研究了各影响因子不同梯度水平下林下生物量所呈现的分布规律。结果显示:油松人工林林下草本生物量大于灌木生物量,草本层植被生物量为0.339 8~1.322 9 t·hm-2,灌木层生物量为0.018 1~0.289 2 t·hm-2;加权后的关联度与原始关联度排序大致相同,关联性最为密切的因子同为林分均高、林分胸径及林龄,但加权后各单因子关联度数值间差异性增加;以样地作为各单因子聚合的系统进行聚类,样地划分为4个类型,分类结果可反映林下生物量的分布格局。
By investigating and analyzing the compositional characteristics and biomass of Pinus tabulaeformis plantations, the distribution of undergrowth biomass under different gradient levels of each factor was studied by using gray correlation analysis, principal component analysis and cluster analysis. The results showed that the biomass of understory plantation was greater than that of shrubs, the biomass of herb layer was 0.339 8-1.2329 t · hm-2, and the biomass of shrub layer was 0.018 1 ~ 0.289 2 t · hm-2. The weighted correlation degree is roughly the same as the original relevance degree. The most relevant factors are the same stand height, stand DBH and age, but the difference between the weighted single factor correlation degree increases; As a single factor aggregation system for clustering, plots were divided into four types, the classification results can reflect the distribution pattern of understory biomass.