EGU22-10902
https://doi.org/10.5194/egusphere-egu22-10902
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Tree water-use recovery after drought-intermittent rainfall events

Ankit Shekhar1, Eugénie Paul-Limoges2, Roman Zweifel3, Nina Buchmann1, and Mana Gharun1
Ankit Shekhar et al.
  • 1Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
  • 2Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
  • 3Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland

Short drought-intermittent rainfall (SDIR) events, i.e., short rainfall events after long dry spells, typically re-wet top few centimeters of soil layer and often has little impact on the water balance of the ecosystem. Nevertheless, these SDIR events could provide the much-needed short-term water supply during dry spells to the terrestrial ecosystem, especially trees. An efficient use of these SDIR events could provide the trees with a buffer to withstand longer drought conditions, which will become more frequent and intense with the upcoming changes in climate.

This study aims to quantify the tree water use (TWU) recovery in terms of sapflow recovery following SDIR events across multiple global forest sites (35 sites) spanning over 250 site-years. SDIR events are identified probabilistically as rainfall periods (1-2 days with daily rainfall < 75th percentile) occurring after an extreme dry spell (> 90th percentile of dry spell duration) during the growing season. For each tree, TWU recovery (RTWU) is estimated based on percentage increase in sapflow rate after the SDIR event (Sa), compared to before the SDIR event (Sb), and standardized by seasonal maximum sapflow (Smax). The inter-species RTWU and intra-species RTWU relationship with tree allometry (height and diameter) is used to explain the recovery rates. The main hypothesis tested here is that the intra-species differences in RTWU are positively related to tree size due to better root development in larger trees. The understanding of RTWU provides a new axis to understand and predict tree recovery after drought events.

How to cite: Shekhar, A., Paul-Limoges, E., Zweifel, R., Buchmann, N., and Gharun, M.: Tree water-use recovery after drought-intermittent rainfall events, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10902, https://doi.org/10.5194/egusphere-egu22-10902, 2022.

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