A dynamic model for water flow in a single tree: evidence that models must account for hydraulic architecture.
A dynamic model for water flow in a single tree: evidence that models must account for hydraulic architecture.
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单棵树中水流的动态模型：模型必须考虑水力建筑的证据。
DOI：
10.1093/treephys/4.3.195
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发表时间：
1988
期刊：
影响因子：
4
通讯作者：
Melvin T. Tyree
中科院分区：
文献类型：
--
作者：
Melvin T. Tyree
建立了东方白柏(Thuja ocsidentalsL.)单株的水流动力学模型。该模型考虑了树冠内树叶蒸发通量的时空依赖性。它还解释了树的定量水力结构，即该模型将树描述为一个由>；4000个树干节段组成的分枝链状结构，其中考虑了树干节段的长度、直径、水力阻力和附着在树干节段上的叶的总面积。运行模型所需的输入值是蒸发通量、茎的水力传导性与茎直径的测量值，以及叶和茎的蓄水容量。输出参数是茎和叶的水势、茎和叶的水分亏缺、树液流速和相对树液速度的空间和时间特征。比较了分枝Catena模型和非分枝Catena模型的输入值和输出值。结果表明，分枝Catena模型比非分枝Catena模型对独立测量场参数的拟合效果更好。在模型预测和田间测量之间，发现了地上部水势、茎内压力梯度、树干下部和上部之间液流速度的滞后以及茎和叶水分亏缺的日变化。从树木的水力结构和该模型在树木形态、生态学、生理学和进化问题上的潜在应用两个方面对该模型进行了讨论。
A model is presented for the dynamics of water flow in a single eastern white cedar tree (Thuja occidentalis L.). The model takes into account the spatial and temporal dependence of the evaporative flux from leaves in the crown. It also accounts for the quantitative hydraulic architecture of the tree, i.e., the model characterizes the tree as a branched catena of > 4000 stem segments in which account is taken of the segment length, diameter, hydraulic resistance, and the total area of leaves attached to the segment. Input values needed to run the model are measurements of evaporative flux, hydraulic conductance of stems versus stem diameter, and leaf and stem water storage capacitances. Output parameters are the spatial and temporal characterization of stem and leaf water potentials, stem and leaf water deficits, sap flow rate, and relative sap velocity. The input and output values of the branched catena model are compared and contrasted to that of an unbranched catena model. It is shown that the branched catena model fits independently measured field parameters better than an unbranched catena model. Close correspondence is found between model predictions and field measurements of shoot water potential, pressure gradients in stems, hysteresis in sap velocity between the lower and upper parts of the tree, and diurnal changes in stem and leaf water deficits. This model is discussed in terms of both the hydraulic architecture of trees and the potential application of the model to questions of tree morphology, ecology, physiology and evolution.