A general combined model to describe tree-diameter distributions within subtropical and temperate forest communities
A general combined model to describe tree-diameter distributions within subtropical and temperate forest communities
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描述亚热带和温带森林群落内树木直径分布的通用组合模型
DOI：
10.1111/j.1600-0706.2013.00436.x
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发表时间：
2013-11-01
期刊：
影响因子：
3.4
通讯作者：
Ma, Keping
中科院分区：
文献类型：
--
作者：
Lai, Jiangshan;Coomes, David A.;Ma, Keping
天然林林木的大小分布是森林结构的基本属性。以前尝试使用简单的函数（如功率或威布尔函数）模型树的大小分布有有限的成功，通常高估了观察到的大茎的数量。我们描述了一个模型，假设占主导地位的死亡率过程是不对称的竞争时，树木较小，和大小无关的过程（如干扰）时，树木较大。这种过程的组合导致尺寸分布，其在小树相中采取幂分布的形式，在大树相中采取威布尔分布的形式。对四个大规模数据的分析亚热带和温带森林面积共计99公顷，约40万棵树，各占24公顷，从两个方面支持这一模式：（a）组合函数提供无偏预测，以及（B）拟合到小树的幂律函数具有偏离由代谢标度理论预测的22的普适指数的指数，沿着纬度梯度由亚热带万年青向温带落叶林逐渐减少。
The size distribution of trees in natural forests is a fundamental attribute of forest structure. Previous attempts to model tree size distributions using simple functions (such as power or Weibull functions) have had limited success, typically overestimating the number of large stems observed. We describe a model which assumes that the dominant mortality process is asymmetric competition when trees are smaller, and size-independent processes (e.g. disturbance) when trees are larger. This combination of processes leads to a size distribution which takes the form of a power distribution in the small tree phase and a Weibull distribution in the large tree phase. Analyses of data from four large-scale ( 24 ha each) subtropical and temperate forest plots totalling 99 ha and approximately 0.4 million trees provide support for this model in two respects: (a) the combined function provided unbiased predictions and (b) power-law functions fitted to small trees had exponents that deviated from the universal exponent of 22 predicted by metabolic scaling theory, gradually decreasing from subtropical evergreen to temperate deciduous forests along the latitudinal gradient.