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Increasing fire and the decline of fire adapted black spruce in the boreal forest

Baltzer Jennifer L., Day Nicola J., Walker Xanthe J., Greene David, Mack Michelle C., Alexander Heather D., Arseneault Dominique, Barnes Jennifer, Bergeron Yves, Boucher Yan, Bourgeau-Chavez Laura, Brown Carissa D., Carrière Suzanne, Howard Brian K., Gauthier Sylvie, Parisien Marc-André, Reid Kirsten A., Rogers Brendan M., Roland Carl, Sirois Luc, Stehn Sarah, Thompson Dan K., Turetsky Merritt R., Veraverbeke Sander, Whitman Ellen, Yang Jian et Johnstone Jill F.. (2021). Increasing fire and the decline of fire adapted black spruce in the boreal forest. Proceedings of the National Academy of Sciences, 118, (45), e2024872118.

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URL officielle: http://dx.doi.org/doi:10.1073/pnas.2024872118

Résumé

Intensifying wildfire activity and climate change can drive rapid forest compositional shifts. In boreal North America, black spruce shapes forest flammability and depends on fire for regeneration. This relationship has helped black spruce maintain its dominance through much of the Holocene. However, with climate change and more frequent and severe fires, shifts away from black spruce dominance to broadleaf or pine species are emerging, with implications for ecosystem functions including carbon sequestration, water and energy fluxes, and wildlife habitat. Here, we predict that such reductions in black spruce after fire may already be widespread given current trends in climate and fire. To test this, we synthesize data from 1,538 field sites across boreal North America to evaluate compositional changes in tree species following 58 recent fires (1989 to 2014). While black spruce was resilient following most fires (62%), loss of resilience was common, and spruce regeneration failed completely in 18% of 1,140 black spruce sites. In contrast, postfire regeneration never failed in forests dominated by jack pine, which also possesses an aerial seed bank, or broad-leaved trees. More complete combustion of the soil organic layer, which often occurs in better-drained landscape positions and in dryer duff, promoted compositional changes throughout boreal North America. Forests in western North America, however, were more vulnerable to change due to greater long-term climate moisture deficits. While we find considerable remaining resilience in black spruce forests, predicted increases in climate moisture deficits and fire activity will erode this resilience, pushing the system toward a tipping point that has not been crossed in several thousand years.

Type de document:Article publié dans une revue avec comité d'évaluation
ISSN:0027-8424
Volume:118
Numéro:45
Pages:e2024872118
Version évaluée par les pairs:Oui
Date:2021
Identifiant unique:10.1073/pnas.2024872118
Sujets:Sciences naturelles et génie > Sciences appliquées > Climatologie et météorologie
Sciences naturelles et génie > Sciences appliquées > Foresterie et sciences du bois
Sciences naturelles et génie > Sciences naturelles > Biologie et autres sciences connexes
Département, module, service et unité de recherche:Départements et modules > Département des sciences fondamentales
Mots-clés:wildfire, ecological state change, resilience, climate change, tree regeneration, Picea mariana
Déposé le:26 avr. 2022 23:39
Dernière modification:26 avr. 2022 23:39
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Creative Commons LicenseSauf indication contraire, les documents archivés dans Constellation sont rendus disponibles selon les termes de la licence Creative Commons "Paternité, pas d'utilisation commerciale, pas de modification" 2.5 Canada.

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