Predicting the limits to tree height using statistical regressions of leaf traits
Predicting the limits to tree height using statistical regressions of leaf traits
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DOI：
10.1111/j.1469-8137.2007.02017.x
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发表时间：
2007-01-01
期刊：
影响因子：
9.4
通讯作者：
Dawson, Todd E.
中科院分区：
文献类型：
--
作者：
Burgess, Stephen S. O.;Dawson, Todd E.
叶子形态和生理功能在树冠内表现出相当大的可塑性，在非常高的树木中，各种叶子特征通常表现出明显的垂直梯度。有人提出，通过回归方法确定的这些梯度的轨迹可以与理论生物物理极限结合使用，以估计树木可以生长的最大高度。在这里，我们使用来自高针叶树和被子植物物种的已发表的和新的实验数据检验了这种方法。我们表明，高度预测对回归形状的树与树之间的变化以及所选的生物物理端点敏感。我们检查了所提出的终点的适用性及其理论有效性。我们还注意到，地点和环境对高度预测有很大影响。使用单位面积的叶质量或叶水势，加上树枝对空化的脆弱性，给预测树高带来了许多困难。光合速率和碳同位素辨别显示出更多的前景，但在第二种情况下，必须首先表征光、水可用性、光合能力和二氧化碳内电导之间的复杂关系。
Leaf morphology and physiological functioning demonstrate considerable plasticity within tree crowns, with various leaf traits often exhibiting pronounced vertical gradients in very tall trees. It has been proposed that the trajectory of these gradients, as determined by regression methods, could be used in conjunction with theoretical biophysical limits to estimate the maximum height to which trees can grow.Here, we examined this approach using published and new experimental data from tall conifer and angiosperm species.We showed that height predictions were sensitive to tree-to-tree variation in the shape of the regression and to the biophysical endpoints selected. We examined the suitability of proposed end-points and their theoretical validity. We also noted that site and environment influenced height predictions considerably.Use of leaf mass per unit area or leaf water potential coupled with vulnerability of twigs to cavitation poses a number of difficulties for predicting tree height. Photosynthetic rate and carbon isotope discrimination show more promise, but in the second case, the complex relationship between light, water availability, photosynthetic capacity and internal conductance to CO2 must first be characterized.