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| Titel |
Partitioning of soil water among canopy trees during a soil desiccation period in a temperate mixed forest |
| VerfasserIn |
M. Meißner, M. Köhler, L. Schwendenmann, D. Hölscher |
| 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 ; 9, no. 8 ; Nr. 9, no. 8 (2012-08-30), S.3465-3474 |
| Datensatznummer |
250007258
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| Publikation (Nr.) |
 copernicus.org/bg-9-3465-2012.pdf |
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| Zusammenfassung |
| Complementary resource use is considered an important mechanism in the study
of biodiversity effects. Here we explore how species identity, species
mixture and tree size influence the vertical partitioning of soil water
among canopy trees during a soil desiccation period. In the Hainich Forest,
Germany, the species Fagus sylvatica, Tilia sp. and Fraxinus excelsior were studied in single- and three-species mixed
clusters, each consisting of three co-dominant trees situated within a
larger mixed forest stand. Vertical soil water uptake depth was assessed by
analyzing the hydrogen stable isotope composition (deuterium, δD) of
water from depth intervals throughout the soil profile and in tree xylem
water. For single species clusters, a mixing model suggested that Fagus
distinctively drew water from soil depths of 0.3–0.5 m, Tilia from 0.3–0.5 m and
0.5–0.7 m and Fraxinus mainly used water from 0.5–0.7 m. In mixed clusters, the
uptake patterns of Fagus and Tilia were similar to those of the single-species
clusters (mainly uptake form 0.3–0.5 m), but Fraxinus showed a different uptake
pattern. Fraxinus in mixture had a somewhat homogenously distributed uptake over the
soil depths 0.2–0.7 m. For single species clusters, there was no correlation
between main soil water uptake depth and tree diameter, irrespective of
variations in tree size. In contrast, for mixed clusters there was a
significant decrease in the main uptake depth with increasing tree size
(P<0.001, R2adj = 0.73), irrespective of species mix. In
consequence, soil water partitioning was strongest where species were mixed
and tree size varied. We further analyzed whether single and mixed-species
clusters differed in the level of water uptake, e.g. due to complementarity,
but our soil water budgeting did not indicate any such differences. A
possible explanation might be that the volume of water used is predominantly
governed by properties at the stand level, such as aerodynamic roughness,
rather than by processes acting at the meter scale between neighbouring
trees. With respect to application, we assume that the upcoming
close-to-nature forestry approach for the area, which fosters mixed stands
of heterogonous diameters, may result in enhanced complementarity in soil
water uptake among canopy trees. |
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