Tree carbon allocation explains forest drought‐kill and recovery patterns |
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| Authors: | A T Trugman M Detto M K Bartlett D Medvigy W R L Anderegg C Schwalm B Schaffer S W Pacala |
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| Affiliation: | 1. Department of Biology, University of Utah, Salt Lake City, UT, USA;2. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA;3. Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA;4. Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA;5. Woods Hole Research Center, Falmouth, MA, USA;6. Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, USA |
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| Abstract: | The mechanisms governing tree drought mortality and recovery remain a subject of inquiry and active debate given their role in the terrestrial carbon cycle and their concomitant impact on climate change. Counter‐intuitively, many trees do not die during the drought itself. Indeed, observations globally have documented that trees often grow for several years after drought before mortality. A combination of meta‐analysis and tree physiological models demonstrate that optimal carbon allocation after drought explains observed patterns of delayed tree mortality and provides a predictive recovery framework. Specifically, post‐drought, trees attempt to repair water transport tissue and achieve positive carbon balance through regrowing drought‐damaged xylem. Furthermore, the number of years of xylem regrowth required to recover function increases with tree size, explaining why drought mortality increases with size. These results indicate that tree resilience to drought‐kill may increase in the future, provided that CO2 fertilisation facilitates more rapid xylem regrowth. |
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| Keywords: | Carbon metabolism CO2 fertilisation drought hydraulic‐carbon coupling lagged mortality optimality theory plant hydraulics stem respiration vegetation model xylem damage |
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