Background mortality drivers of European tree species : climate change matters

Adrien Taccoen (1) , Christian C. Piedallu (1) , Ingrid Seynave (1) , Vincent V. Perez (1) , Anne Gégout-Petit (2, 3) , Louis-Michel Nageleisen (1, 4) , Jean-Daniel Bontemps (5, 6) , Jean-Claude Gégout (1)

1 SILVA - SILVA
2 IECL - Institut Élie Cartan de Lorraine
3 BIGS - Biology, genetics and statistics
4 Ministère de l'agriculture, de l'alimentation, de la pêche, de la ruralité et de l'aménagement du territoire
5 IGN - Institut National de l'Information Géographique et Forestière [IGN]
6 LIF - Laboratoire d’Inventaire Forestier

Increases in tree mortality rates have been highlighted in different biomes over the past decades. However, disentangling the effects of climate change on the temporal increase in tree mortality from those of management and forest dynamics remains a challenge. Using a modelling approach taking tree and stand characteristics into account, we sought to evaluate the impact of climate change on background mortality for the most common European tree species. We focused on background mortality, which is the mortality observed in a stand in the absence of abrupt disturbances, to avoid confusion with mortality events unrelated to long-term changes in temperature and rainfall. We studied 372 974 trees including 7312 dead trees from forest inventory data surveyed across France between 2009 and 2015. Factors related to competition, stand characteristics, management intensity, and site conditions were the expected preponderant drivers of mortality. Taking these main drivers into account, we detected a climate change signal on 45% of the 43 studied species, explaining an average 6% of the total modelled mortality. For 18 out of the 19 species sensitive to climate change, we evidenced greater mortality with increasing temperature or decreasing rainfall. By quantifying the mortality excess linked to the current climate change for European temperate forest tree species, we provide new insights into forest vulnerability that will prove useful for adapting forest management to future conditions.

Mots clés: Broadleaves; France; Europe; Global warming; Dieback; Drought; Temperature increase; Climate change; Tree mortality; European forests; Global change; Forest decline; Forest ecology; Species distribution models; Global change and conservation ecology; environmental science; plant science global change; mortality; temperate forest; tree species; climate change; forest inventory

Domaines: Milieux et Changements globaux; Sylviculture, foresterie; Biodiversité et Ecologie

Adrien Taccoen, Christian C. Piedallu, Ingrid Seynave, Vincent V. Perez, Anne Gégout-Petit, et al.. Background mortality drivers of European tree species : climate change matters. Proceedings of the Royal Society B: Biological Sciences, 2019, 286 (1900), pp.20190386. ⟨10.1098/rspb.2019.0386⟩. ⟨hal-02095574v2⟩