Underestimation of the Tambora effects in North American taiga ecosystems

Fabio Gennaretti (1) , Etienne Boucher (2) , Antoine Nicault (3) , Guillermo Gea-Izquierdo (4) , Dominique Arseneault (5) , Frank Berninger (6) , Martine Savard (7) , Christian Begin (7) , Joel Guiot (1)

1 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
2 UQAM - Université du Québec à Montréal = University of Québec in Montréal
3 ECCOREV - Ecosystèmes continentaux et risques environnementaux
4 INIA-CIFOR
5 UQAR - Université du Québec à Rimouski
6 Université d'Helsinki
7 GSC Québec - Geological Survey of Canada [Québec]

The Tambora eruption (1815 AD) was one of the major eruptions of the last two millennia and has no equivalents over the last two centuries. Here, we collected an extensive network of early meteorological time series, climate simulation data and numerous, well-replicated proxy records from Eastern Canada to analyze the strength and the persistence of the Tambora impact on the regional climate and forest processes. Our results show that the Tambora impacts on the terrestrial biosphere were stronger than previously thought, and not only affected tree growth and carbon uptake for a longer period than registered in the regional climate, but also determined forest demography and structure. Increased tree mortality, four times higher than the background level, indicates that the Tambora climatic impact propagated to influence the structure of the North American taiga for several decades.We also show that the Tambora signal is more persistent in observed data (temperature, river ice dynamics, forest growth, tree mortality) than in simulated ones (climate and forest-growth simulations), indicating that our understanding of the mechanisms amplifying volcanic perturbations on climates and ecosystems is still limited, notably in the North American taiga.

Mots clés: tambora legacy; Eastern Canada; regional climate responses; terrestrial biosphere responses; forest demography; mechanistic understanding; process-based modeling

Domaines: Interfaces continentales, environnement

Fabio Gennaretti, Etienne Boucher, Antoine Nicault, Guillermo Gea-Izquierdo, Dominique Arseneault, et al.. Underestimation of the Tambora effects in North American taiga ecosystems. Environmental Research Letters, 2018, 13 (3), pp.034017. ⟨10.1088/1748-9326/aaac0c⟩. ⟨insu-02269675⟩