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Bittner, S. ; Janott, M. ; Ritter, D.* ; Kocher, P.* ; Beese, F.* ; Priesack, E.

Functional-structural water flow model reveals differences between diffuse- and ring-porous tree species.

Agric. For. Meteorol. 158, 80-89 (2012)
DOI
Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
A functional-structural (FS) model of tree water flow is applied for single trees in an old-growth temperate broad-leaved forest stand. Roots, stems and branches are represented by connected porous cylinder elements that are divided into the inner heartwood cylinders surrounded by xylem and phloem. Xylem water flow is simulated by applying a non-linear Darcy water flow in porous media driven by the water potential gradient according to the cohesion-tension theory. The flow model is based on physiological input parameters such as the hydraulic conductivity, stomata] response to leaf water potential and root water uptake capability and, thus, can reflect the different properties of the two diffuse-porous tree species Fagus sylvatica and Tilia cordata and the ring-porous species Fraxinus excelsior. The structure of the canopy is obtained by applying an automatic tree skeleton extraction algorithm from point clouds obtained by terrestrial laser scans allowing an explicit representation of the water flow path in the stem and branches. Supported by measurements of stem sap flow, the model reveals differences of the simulated stomatal closure due to low branch xylem water contents between the tree species. The diffuse-porous species reduced the transpiration by the stomatal closure only at hot days with a high potential transpiration. For the ring-porous ash the simulated reduction is much higher with a mean value of all trees over the observation period of 0.72. The model gives insights to the mechanism that lead to the stomatal closure and can spot the axial xylem hydraulic conductance along the flow pathway as the limiting factor of leaf water supply at days with moist soil water conditions.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter Terrestrial Laser Scanner ; Root Water Uptake ; Tree Transpiration ; Hydrodynamics Model ; Broad-leaved Tree Species
ISSN (print) / ISBN 0168-1923
e-ISSN 1873-2240
Zeitschrift Agricultural and Forest Meteorology
Quellenangaben Band: 158, Heft: , Seiten: 80-89 Artikelnummer: , Supplement: ,
Verlag Elsevier
Verlagsort Amsterdam [u.a.]
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Institute of Soil Ecology (IBOE)