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Tree hydrodynamic modelling of the soil-plant-atmosphere continuum using FETCH3

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journal contribution
posted on 2022-05-09, 23:17 authored by M Silva, AM Matheny, VRN Pauwels, Dimetre TriadisDimetre Triadis, JE Missik, G Bohrer, E Daly
Modelling the water transport along the soil-plant-atmosphere continuum is fundamental to estimating and predicting transpiration fluxes. A Finite-difference Ecosystem-scale Tree Crown Hydrodynamics model (FETCH3) for the water fluxes across the soil-plant-atmosphere continuum is presented here. The model combines the water transport pathways into one vertical dimension, and assumes that the water flow through the soil, roots, and above-ground xylem can be approximated as flow in porous media. This results in a system of three partial differential equations, resembling the Richardson-Richards equation, describing the transport of water through the plant system and with additional terms representing sinks and sources for the transfer of water from the soil to the roots and from the leaves to the atmosphere. The numerical scheme, developed in Python 3, was tested against exact analytical solutions for steady state and transient conditions using simplified but realistic model parameterizations. The model was also used to simulate a previously published case study, where observed transpiration rates were available, to evaluate model performance. With the same model setup as the published case study, FETCH3 results were in agreement with observations. Through a rigorous coupling of soil, root xylem, and stem xylem, FETCH3 can account for variable water capacitance, while conserving mass and the continuity of the water potential between these three layers. FETCH3 provides a ready-to-use open access numerical model for the simulation of water fluxes across the soil-plant-atmosphere continuum. Copyright:


Edoardo Daly was supported by the Australian Research Council through the Discovery Project DP180101229. Gil Bohrer and Ashley M. Matheny were funded in part by NSF award 1521238. Ashley M. Matheny was supported by the Department of Energy TES grant DE-SC0020116 and the National Science Foundation EAR CAREER award #2046768. Gil Bohrer and Justine E. Missik were partially funded through BARD IS-5304-20.


Publication Date



Geoscientific Model Development






(p. 2619-2634)





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© Author(s) 2022. This work is distributed under the Creative Commons Attribution 4.0 License.