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Finite element tree crown hydrodynamics model (FETCH) using porous media flow within branching elements: A new representation of tree hydrodynamics
Author(s) -
Bohrer Gil,
Mourad Hashem,
Laursen Tod A.,
Drewry Darren,
Avissar Roni,
Poggi Davide,
Oren Ram,
Katul Gabriel G.
Publication year - 2005
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2005wr004181
Subject(s) - fetch , scaling , tree (set theory) , transpiration , canopy , mechanics , geometry , hydrology (agriculture) , mathematics , geology , physics , mathematical analysis , geotechnical engineering , ecology , oceanography , photosynthesis , botany , biology
Estimating transpiration and water flow in trees remains a major challenge for quantifying water exchange between the biosphere and the atmosphere. We develop a finite element tree crown hydrodynamics (FETCH) model that uses porous media equations for water flow in an explicit three‐dimensional branching fractal tree‐crown system. It also incorporates a first‐order canopy‐air turbulence closure model to generate the external forcing of the system. We use FETCH to conduct sensitivity analysis of transpirational dynamics to changes in canopy structure via two scaling parameters for branch thickness and conductance. We compare our results with the equivalent parameters of the commonly used resistor and resistor‐capacitor representations of tree hydraulics. We show that the apparent temporal and vertical variability in these parameters strongly depends on structure. We suggest that following empirical calibration and validation, FETCH could be used as a platform for calibrating the “scaling laws” between tree structure and hydrodynamics and for surface parameterization in meteorological and hydrological models.