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| Titel |
Model analysis of the effects of atmospheric drivers on storage water use in Scots pine |
| VerfasserIn |
H. Verbeeck, K. Steppe, N. Nadezhdina, M. Beeck, G. Deckmyn, L. Meiresonne, R. Lemeur, J. Čermák, R. Ceulemans, I. A. Janssens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 4, no. 4 ; Nr. 4, no. 4 (2007-08-14), S.657-671 |
| Datensatznummer |
250001860
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| Publikation (Nr.) |
 copernicus.org/bg-4-657-2007.pdf |
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| Zusammenfassung |
Storage water use is an indirect consequence of the interplay between
different meteorological drivers through their effect on water flow and
water potential in trees. We studied these microclimatic drivers of storage
water use in Scots pine (Pinus sylvestris L.) growing in a temperate climate. The storage
water use was modeled using the ANAFORE model, integrating a dynamic water
flow and – storage model with a process-based transpiration model. The
model was calibrated and validated with sap flow measurements for the
growing season of 2000 (26 May–18 October).
Because there was no severe soil drought during the study period, we were
able to study atmospheric effects. Incoming radiation and vapour pressure
deficit (VPD) were the main atmospheric drivers of storage water use. The
general trends of sap flow and storage water use are similar, and follow
more or less the pattern of incoming radiation. Nevertheless, considerable
differences in the day-to-day pattern of sap flow and storage water use were
observed. VPD was determined to be one of the main drivers of these
differences. During dry atmospheric conditions (high VPD) storage water use
was reduced. This reduction was higher than the reduction in measured sap
flow. Our results suggest that the trees did not rely more on storage water
during periods of atmospheric drought, without severe soil drought. The
daily minimum tree water content was lower in periods of high VPD, but the
reserves were not completely depleted after the first day of high VPD, due
to refilling during the night.
Nevertheless, the tree water content deficit was a third important factor
influencing storage water use. When storage compartments were depleted
beyond a threshold, storage water use was limited due to the low water
potential in the storage compartments. The maximum relative contribution of
storage water to daily transpiration was also constrained by an increasing
tree water content deficit. |
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