PT  - JOURNAL ARTICLE
AU  - Florian Schnabel
AU  - Sarah Purrucker
AU  - Lara Schmitt
AU  - Rolf A. Engelmann
AU  - Anja Kahl
AU  - Ronny Richter
AU  - Carolin Seele-Dilbat
AU  - Georgios Skiadaresis
AU  - Christian Wirth
TI  - Cumulative growth and stress responses to the 2018–2019 drought in a European floodplain forest
AID  - 10.1101/2021.03.05.434090
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.03.05.434090
4099  - http://biorxiv.org/content/early/2021/11/22/2021.03.05.434090.short
4100  - http://biorxiv.org/content/early/2021/11/22/2021.03.05.434090.full
AB  - Droughts increasingly threaten the world’s forests and their potential to mitigate climate change. In 2018–2019, Central European forests were hit by two consecutive hotter drought years, an unprecedented phenomenon that is likely to occur more frequently with climate change. Here, we examine tree growth and physiological stress responses (increase in carbon isotope composition; Δδ13C) to this consecutive drought based on tree-rings of dominant tree species in a Central European floodplain forest. Tree growth was not reduced for most species in 2018, indicating that water supply in floodplain forests can partly buffer meteorological water deficits. Drought stress responses in 2018 were comparable to former single drought years but the hotter drought in 2018 induced drought legacies in tree growth while former droughts did not. We observed strong decreases in tree growth and increases in Δδ13C across all tree species in 2019, which are likely driven by the cumulative stress both consecutive hotter droughts exerted. Our results show that consecutive hotter droughts pose a novel threat to forests under climate change, even in forest ecosystems with comparably high levels of water supply.Competing Interest StatementThe authors have declared no competing interest.