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Stomatal conductance and intrinsic water use efficiency in the drought year 2003: A case study of European beech.
Trees-Struct. Funct. 30, 153-174 (2016)
Key message: Beech trees were able to cope with the drought of 2003. Harmful water shortage has been avoided by an effective stomatal closure while use of carbon storage pools may have prevented carbon starvation and growth reduction.Abstract: We applied hydrodynamic modeling together with a tree ring stable isotope approach to identify the physiological responses of beech trees to changing environmental conditions. The drought conditions of the extreme hot and dry summer in 2003 were hypothesized to significantly influence the radial growth of European beech mainly triggered by the stomatal response towards water scarcity leading, in turn, to a decline in carbon assimilation. The functional–structural single tree modeling approach applied, revealed in fact a strong limitation of water use and carbon gain during drought. However, tree ring width data did not show a clear drought response and no differentiation in radial growth during six subsequent years examined (2002–2007) has been observed. Using integrated results from mechanistic carbon–water balance simulations, tree ring carbon and oxygen isotope analysis and tree ring width measurements we postulate that the suggested drought-induced growth decline has been prevented by the remobilization of stored carbohydrates, an early onset in growth and the relatively late occurrence of the severe drought in 2003. Furthermore, we demonstrate that the stomatal response played a significant role in avoiding harmful water tension that would have caused xylem dysfunction. As a result of the combined investigation with physiological measurements (stable isotope approach) and hydrodynamic modeling of stomatal aperture, we could give insights into the physiological control of mature beech tree functioning under drought. We conclude that beech trees have been operating at their hydraulic limits and that the longer or repeated drought periods would have affected the growth considerably.
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Publication type Article: Journal article
Document type Scientific Article
Keywords Carbon And Oxygen Stable Isotopes ; Fagus Sylvatica ; Hydrodynamic Modeling ; Intrinsic Water Use Efficiency ; Leaf Physiology ; Stomatal Conductance; Fagus-sylvatica L.; Carbon-isotope Composition; Deciduous Forest Trees; Pinus-sylvestris L.; Southern Range-edge; Regional Die-off; Mesophyll Conductance; Climate-change; Leaf Water; Scots Pine
ISSN (print) / ISBN 0931-1890
Journal Trees - Structure and Function
Quellenangaben Volume: 30, Issue: 1, Pages: 153-174
Publishing Place Berlin ; Heidelberg ; New York
Reviewing status Peer reviewed