Abstract While the role of stemflow in directing and concentrating water and nutrients at the tree base is rarely in dispute, its mathematical representation remains a subject of inquiry and research. A network model that seeks to estimate stemflow solute concentration and leaching is proposed. The model accommodates the physico-chemical properties of individual furrows embedded within the tree bark and their interconnections. The within-furrow equations for water and solute transport that include leaching are first developed and integrated along a rough-bark network topology to describe solute concentration and fluxes out of the network. The model is parameterized using published data on stemflow, field measurements of bark geometry, and laboratory experiments on bark leaching for potassium, magnesium, and calcium. The parameterization is intended to impose plausibility constraints and not to test model predictions at a particular site, a single event, or an individual experiment. The outflow concentration is then analyzed as a function of the network complexity that includes asymmetry in the lengths or subpaths connecting network nodes. For a symmetric network, an effective ’channel-flow’ analogy may be used to represent solute concentration at the outflow. However, as the asymmetry increases in subpath lengths, the efficiency of the bark network at moving solutes diminishes for the same rainfall input onto the stem. The network representation featured here is by no means offering a ’finality’ to the stemflow mathematical representation. It must be viewed as an embryonic step that opens up the possibility of using modern advances in network theories to link rainfall properties to stemflow water and solute input from a variety of tree species with differing bark microrelief configurations into the soil.

中文翻译：

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茎流溶质运输的网络模型

摘要 虽然茎流在引导和集中树基水和养分方面的作用很少有争议，但其数学表示仍然是探究和研究的主题。提出了一种旨在估计茎流溶质浓度和浸出的网络模型。该模型适应了嵌入树皮内的各个犁沟及其相互连接的物理化学特性。包括浸出在内的水和溶质运输的沟内方程首先被开发并沿粗糙的树皮网络拓扑结构整合，以描述网络外的溶质浓度和通量。该模型使用已发布的茎流数据、树皮几何形状的现场测量以及树皮浸出钾、镁和钙的实验室实验进行参数化。参数化旨在强加合理性约束，而不是测试特定地点、单个事件或单个实验的模型预测。然后将流出浓度作为网络复杂性的函数进行分析，该网络复杂性包括连接网络节点的长度或子路径的不对称性。对于对称网络，可以使用有效的“通道-流动”类比来表示流出处的溶质浓度。然而，随着子路径长度的不对称性增加，对于相同的降雨输入到茎上，树皮网络在移动溶质方面的效率会降低。这里的网络表示绝不是为stemflow数学表示提供“终结性”。