Triggers of tree mortality under drought

• Published in: Nature (London) Vol. 558; no. 7711; pp. 531 - 539
• Main Authors: Choat, Brendan, Brodribb, Timothy J., Brodersen, Craig R., Duursma, Remko A., López, Rosana, Medlyn, Belinda E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-06-2018; Nature Publishing Group
• Subjects: 14/63; 631/449/1736; 704/158/2455; Acclimatization - physiology; Biomes; Botanical research; Carbon; Catastrophic events; Cavitation; Climate change; Death; Desiccation; Drought; Droughts; Ecosystems; Embolisms; Environmental aspects; Flowers & plants; Forests; Global temperature changes; Humanities and Social Sciences; Hydraulic equipment; Hydraulics; Industrial equipment; Life Sciences; Medical imaging; Mortality; multidisciplinary; Natural Disasters; Net losses; Physiological aspects; Physiology; Picea rubens; Review; review-article; Science; Science (multidisciplinary); Stress, Physiological - physiology; Thresholds; Trees; Trees (Plants); Trees - anatomy & histology; Trees - genetics; Trees - physiology; Vegetal Biology; Water - metabolism; Water - physiology; Xylem - metabolism; forêt tropicale; x-ray microtomography; plasticity; Science & Technology - Other Topics; hydraulic failure; carbon starvation; cavitation resistance; vegetation mortality; phenotypic; changement climatique; vulnerability segmentation; global change; tropical forests; résistance à la cavitation; tropical forest; plasticité; microtomographie; woody-plants; climate-change
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-018-0240-x

Severe droughts have caused widespread tree mortality across many forest biomes with profound effects on the function of ecosystems and carbon balance. Climate change is expected to intensify regional-scale droughts, focusing attention on the physiological basis of drought-induced tree mortality. Recent work has shown that catastrophic failure of the plant hydraulic system is a principal mechanism involved in extensive crown death and tree mortality during drought, but the multi-dimensional response of trees to desiccation is complex. Here we focus on the current understanding of tree hydraulic performance under drought, the identification of physiological thresholds that precipitate mortality and the mechanisms of recovery after drought. Building on this, we discuss the potential application of hydraulic thresholds to process-based models that predict mortality.
Because climate change is expected to intensify regional-scale droughts, it is important to identify the physiological thresholds that precipitate the mortality of trees and the mechanisms of recovery after drought.