What can passive electrical signals tell us about tree transpiration? One year of self-potential observation at three test sites in a Mediterranean Climate
Year: 2025
Type: conference-paper
Abstract: Tree transpiration is a critical process of the water cycle and its observation and quantification are essential to better understand terrestrial ecosystem dynamics. While sap flow measurements provide direct estimates of individual tree transpiration, their reliance on empirical calibration and a rather high energy consumption (due to heat generation) can be strong limiting factors. The self-potential (SP) method, a passive geophysical approach, presents a promising alternative for assessing transpiration rates, although the electrophysiological processes driving SP signals in trees remain underexplored (Fig. 1). This study presents a year-long monitoring of SP and sap velocity in three tree species at three Critical Zone Observatories different in a Mediterranean climate (from OZCAR and ICOS research infrastructures). Using wavelet coherence analysis and variational mode decomposition, our findings reveal strong coherence between SP and sap velocity at diurnal time scales, with coherence diminishing and phase shifts increasing under higher water supply conditions. Electrokinetic coupling coefficients, derived from linear regression between SP and sap velocity variations, align with values typical of porous geological media. During dry seasons, the electrokinetic effect dominates SP signals, suggesting its potential as a tool for evaluating transpiration rates. This research demonstrates the feasibility of integrating geophysical techniques into long-term observations of ecohydrological systems to better understand plant-water interactions in the Critical Zone.
Source: ARPHA Conference Abstracts
Institutions: China University of Geosciences, Centre National de la Recherche Scientifique, Sorbonne Université, Milieux environnementaux, transferts et interactions dans les hydrosystèmes et les sols, Université de Montpellier, Laboratoire HydroSciences Montpellier, Institut de Recherche pour le Développement, Ecole Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES), Institut Terre & Environnement de Strasbourg, École & Observatoire des Sciences de la Terre, Université de Strasbourg, Géosciences Montpellier, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Écologie des Forêts Méditerranéennes, University of Lausanne
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4410825773