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Water uptake by trees in a riparian hardwood forest (Rhine floodplain, France)

Sanchez-Pérez, José-Miguel and Lucot, Eric and Bariac, Thierry and Trémolières, Michèle Water uptake by trees in a riparian hardwood forest (Rhine floodplain, France). (2008) Hydrological Processes, vol 22 (n°3). pp. 366-375. ISSN 0885-6087

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Official URL: http://dx.doi.org/10.1002/hyp.6604

Abstract

Water flow in the soil–root–stem system was studied in a flooded riparian hardwood forest in the upper Rhine floodplain. The study was undertaken to identify the vertical distribution of water uptake by trees in a system where the groundwater is at a depth of less than 1 m. The three dominant ligneous species (Quercus robur, Fraxinus excelsior and Populus alba) were investigated for root structure (vertical extension of root systems), leaf and soil water potential (m), isotopic signal (18O) of soil water and xylem sap. The root density of oak and poplar was maximal at a depth of 20 to 60 cm, whereas the roots of the ash explored the surface horizon between 0 and 30 cm, which suggests a complementary tree root distribution in the hardwood forest. The flow density of oak and poplar was much lower than that of the ash. However, in the three cases the depth of soil explored by the roots reached 1Ð2 m, i.e. just above a bed of gravel. The oak roots had a large lateral distribution up to a distance of 15 m from the trunk. The water potential of the soil measured at 1 m from the trunk showed a zone of strong water potential between 20 and 60 cm deep. The vertical profile of soil water content varied from 0Ð40 to 0Ð50 cm3 cm3 close to the water table, and 0Ð20 to 0Ð30 cm3 cm3 in the rooting zone. The isotopic signal of stem water was constant over the whole 24-h cycle, which suggested that the uptake of water by trees occurred at a relatively constant depth. By comparing the isotopic composition of water between soil and plant, it was concluded that the water uptake occurred at a depth of 20 to 60 cm, which was in good agreement with the root and soil water potential distributions. The riparian forest therefore did not take water directly from the water table but from the unsaturated zone through the effect of capillarity

Item Type:Article
Additional Information:The definitive version is available at www3.interscience.wiley.com at URL : http://onlinelibrary.wiley.com/doi/10.1002/hyp.6604/abstract
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > AgroParisTech (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS
Other partners > Ecole Nationale du Génie de l'Eau et de l'Environnement de Strasbourg - ENGEES (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
French research institutions > Institut National de la Recherche Agronomique - INRA
French research institutions > Institut de Recherche pour le Développement - IRD
Other partners > Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > Ecole Normale Supérieure de Paris - ENS Paris (FRANCE)
Other partners > Université Paris-Est Marne-La-Vallée - UPEMLV (FRANCE)
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Deposited By: Florence Amor

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