Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers

• Published in: Scientific Reports
• Main Authors: Blarquez, Olivier, Ali, Adam, Girardin, Martin, Grondin, Pierre, Fréchette, Bianca, Bergeron, Yves, Hély, Christelle
• Other Authors: Université du Québec à Montréal = University of Québec in Montréal (UQAM), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Canadian Forest Service - CFS (CANADA), MINISTERE DES FORETS DE LA FAUNE ET DES PARCS DRF QUEBEC CAN, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Centre d'Etude de la Forêt (Faculté de foresterie, de géographie et de géomatique), Université Laval Québec (ULaval), Université du Québec en Abitibi-Témiscamingue (UQAT)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Climate change; Fires; Human activities; Paleontology; Plants; Pollen; Seasons; [SDE]Environmental Sciences; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Canada; Tundra
• Online Access: https://hal.umontpellier.fr/hal-03002206; https://hal.umontpellier.fr/hal-03002206/document; https://hal.umontpellier.fr/hal-03002206/file/srep13356.pdf; https://doi.org/10.1038/srep13356

International audience Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series, and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees.