Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
New Phytol. 2010 Dec;188(4):1124-36. doi: 10.1111/j.1469-8137.2010.03444.x. Epub 2010 Sep 6.
Wood density is thought to be an important indicator of plant life history because it is coupled to many aspects of whole-plant form and function. We used a hierarchical Bayesian approach to explain variation in mortality rates with wood density, drawing on data for 765,500 trees from 1639 species at 10 sites located across the Old and New World tropics. Mortality rates declined with increasing wood density at five of 10 sites. Similar negative trends were detected at four additional sites, while one site showed no relationship. Our model explained 40% of variation in mortality on average. Both wood density and mortality rates show a high degree of phylogenetic conservatism. Grouping species by family across sites in a second analysis, we found considerable variation in the relationship between wood density and mortality, with 10 of 27 families demonstrating a strong negative relationship. Our results highlight the importance of wood density as a functional trait in tropical forests, as it is strongly linked to variation in survival. However, the relationship varied among families, plots, and even census intervals within sites, indicating that the factors responsible for the relationship between wood density and mortality vary spatially, taxonomically and temporally.
木材密度被认为是植物生活史的一个重要指标，因为它与整株植物形态和功能的许多方面都有关联。我们利用分层贝叶斯方法，根据来自新旧世界热带地区 10 个地点的 1639 个物种的 765500 棵树木的数据，解释了死亡率与木材密度的变化关系。在 10 个地点中的 5 个地点，死亡率随木材密度的增加而降低。在另外四个地点也检测到了类似的负趋势，而一个地点则没有相关性。我们的模型平均解释了 40%的死亡率变化。木材密度和死亡率都表现出高度的系统发育保守性。在第二项分析中，我们将物种按科分组，发现在 27 个科中，有 10 个科的木材密度与死亡率之间存在很强的负相关关系。我们的研究结果强调了木材密度作为热带森林功能特征的重要性，因为它与存活率的变化密切相关。然而，这种关系在科、地点甚至地点内的普查间隔之间存在差异，这表明导致木材密度与死亡率之间关系的因素在空间、分类和时间上存在差异。
