title: Vegetation limits the impact of a warm climate on boreal wildfires.
abstract: Strategic introduction of less flammable broadleaf vegetation into landscapes was suggested as a management strategy for decreasing the risk of boreal wildfires projected under climatic change. However, the realization and strength of this offsetting effect in an actual environment remain to be demonstrated. Here we combined paleoecological data, global climate models and wildfire modelling to assess regional fire frequency (RegFF, i.e. the number of fires through time) in boreal forests as it relates to tree species composition and climate over millennial time-scales. Lacustrine charcoals from northern landscapes of eastern boreal Canada indicate that RegFF during the mid-Holocene (6000-3000 yr ago) was significantly higher than pre-industrial RegFF (AD c. 1750). In southern landscapes, RegFF was not significantly higher than the pre-industrial RegFF in spite of the declining drought severity. The modelling experiment indicates that the high fire risk brought about by a warmer and drier climate in the south during the mid-Holocene was offset by a higher broadleaf component. Our data highlight an important function for broadleaf vegetation in determining boreal RegFF in a warmer climate. We estimate that its feedback may be large enough to offset the projected climate change impacts on drought conditions.
authors.affiliation: Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S, PO Box 10380, Stn. Sainte-Foy, Quebec, QC, G1V 4C7, Canada.|Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Montréal, Québec, H3C 3P8, Canada.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Girardin
authors.affiliation: Centre de Bio-Archéologie et d'Ecologie, Unité Mixte de Recherche (UMR) 5059 Centre National de la Recherche Scientifique (CNRS), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.|Natural Sciences and Engineering Research Council of Canada Industrial Chair in Sustainable Forest Management, Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boulevard de l'Université, Rouyn-Noranda, Québec, J9X 5E4, Canada.
authors.forename: Adam A
authors.initials: AA
authors.lastname: Ali
authors.affiliation: Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Montréal, Québec, H3C 3P8, Canada.|Centre de Bio-Archéologie et d'Ecologie, Unité Mixte de Recherche (UMR) 5059 Centre National de la Recherche Scientifique (CNRS), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.|Paléoenvironnements et Chronoécologie (PALECO), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.
authors.forename: Christopher
authors.initials: C
authors.lastname: Carcaillet
authors.affiliation: Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Montréal, Québec, H3C 3P8, Canada.
authors.forename: Olivier
authors.initials: O
authors.lastname: Blarquez
authors.affiliation: Centre de Bio-Archéologie et d'Ecologie, Unité Mixte de Recherche (UMR) 5059 Centre National de la Recherche Scientifique (CNRS), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.|Paléoenvironnements et Chronoécologie (PALECO), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Hély
authors.affiliation: Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Montréal, Québec, H3C 3P8, Canada.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Terrier
authors.affiliation: Centre de Bio-Archéologie et d'Ecologie, Unité Mixte de Recherche (UMR) 5059 Centre National de la Recherche Scientifique (CNRS), École Pratique des Hautes Études (EPHE), Institut de Botanique, F-34090, Montpellier, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Genries
authors.affiliation: Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Montréal, Québec, H3C 3P8, Canada.|Natural Sciences and Engineering Research Council of Canada Industrial Chair in Sustainable Forest Management, Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boulevard de l'Université, Rouyn-Noranda, Québec, J9X 5E4, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Bergeron
mesh_terms: D002170:Canada; D057231:Climate Change; D017753:Ecosystem; D005390:Fires; D060106:Lakes; D014197:Trees / Q000502:physiology*
keywords: Canada; broadleaf; charcoal; drought; forest fires; multivariate adaptive regression splines; needleleaf; pollen