Responsable
Yves Bergeron
Collaborateurs
Alain Leduc, Damien Rius, Sylvie Gauthier, Martin-Philippe Girardin, Hugo Asselin, Igor Drobyshev, Pierre Grondin, Christelle Hely-Alleaume, Adam A. Ali, Olivier Blarquez, Alexander Kryshen, Victor Danneyrolles, Dorian Gaboriau, Raphaël Chavardes
Étudiants
Jonathan Lesven, Marianne Vogel, Nina Ryzhkova, Andy Hennebelle, Augustin Feussom
Problématique
L’aménagement écosystémique vise à recréer des conditions semblables à celles issues des perturbations naturelles. Il est donc essentiel de pouvoir reconstruire les régimes de perturbations et leurs influences sur la mosaïque forestière pour pouvoir fixer des objectifs crédibles.
Objectifs
Reconstruire les régimes de feux et la dynamique naturelle des peuplements dans le but de les utiliser comme objectifs en aménagement écosystémique.
Méthodologie
Comme les régimes de perturbations ont été modifiés par l’action humaine et les fluctuations climatiques, il est nécessaire d’utiliser des approches dendroécologiques (dernier 300 ans) ou paléoécologiques (période Holocène) pour pouvoir bien caractériser les variations naturelles.
Retombées escomptées
Connaissances de base permettant de fixer des objectifs quant à la mise en place d’un aménagement écosystémique.
Applicabilité
Forêt boréale de l'est de l'Amérique du nord surtout mais région circumboréale en général.
Livrables
Martin-Philippe Girardin, Jeanne Portier, Cécile C. Remy, Adam A. Ali, Jordan Paillard, Olivier Blarquez, Hugo Asselin, Sylvie Gauthier, Yves Bergeron, Pierre Grondin. Coherent signature of warming-induced extreme sub-continental boreal wildfire activity 4,800 and 1,100 years BP. 2019. Environmental Research Letters 14(12):124042
DOI : 10.1088/1748-9326/ab59c9
Climate changes are expected to progressively increase extreme wildfire frequency in forests. Finding past analogs for periods of extreme biomass burning would provide valuable insights regarding what the effects of warming might be for tree species distribution, ecosystem integrity, atmospheric greenhouse gas balance, and human safety. Here, we used a network of 42 lake-sediment charcoal records across a ~2000 km transect in eastern boreal North America to infer widespread periods of wildfire activity in association with past climate conditions. The reconstructed fluctuations in biomass burning are broadly consistent with variations in ethane concentration in Greenland polar ice cores. Biomass burning fluctuations also significantly co-varied with Greenland temperatures estimated from ice cores, at least for the past 6000 years. Our retrospective analysis of past fire activity allowed us to identify two fire periods centered around 4800 and 1100 BP, coinciding with large-scale warming in northern latitudes and having respectively affected an estimated ~71% and ~57% of the study area. These two periods co-occurred with widespread decreases in mean fire-return intervals. The two periods are likely the best analogs for what could be anticipated in terms of impacts of fire on ecosystem services provided by these forests in coming decades.
Victor Danneyrolles, Dominic Cyr, Yves Bergeron, Martin-Philippe Girardin, Sylvie Gauthier, Hugo Asselin. Influences of climate fluctuations on northeastern North America’s burned areas largely outweigh those of European settlement since AD 1850. 2021. Environmental Research Letters 6(11):114007
DOI : 10.1088/1748-9326/ac2ce7
There is a pressing need for a better understanding of changing forest fire regimes worldwide, especially to separate the relative effects of potential drivers that control burned areas. Here we present a meta-analysis of the impacts of climate fluctuation and Euro-Canadian settlement on burned areas from 1850 to 1990 in a large zone (>100 000 km2) in northern temperate and boreal forests of eastern Canada. Using Cox regression models, we tested for potential statistical relationships between historical burned areas in 12 large landscapes (reconstructed with dendrochronological data) with climate reconstructions, changes in the Euro-Canadian population, and active suppression (all reconstructed at the decadal scale). Our results revealed a dominant impact of climate fluctuations on forest burned areas, with the driest decades showing fire hazards between 5 to 15 times higher than the average decades. Comparatively, the Euro-Canadian settlement had a much weaker effect, having increased burned areas significantly only during less fire-prone climate conditions. During periods of fire-prone climate, burned areas were maximum independent of fluctuations in Euro-Canadian populations. Moreover, the development of active fire suppression did not appear to reduce burned areas. These results suggest that a potential increase in climate moisture deficit and drought may trigger unprecedented burned areas and extreme fire events no matter the effects of anthropogenic ignition or suppression.
Dorian Gaboriau, Yves Bergeron, Cécile C. Remy, Adam A. Ali, Christelle Hely-Alleaume, Martin-Philippe Girardin, Hugo Asselin. Temperature and fuel availability control fire size/severity in the
boreal forest of central Northwest Territories, Canada. 2020. Quaternary Science Review 250:106697
DOI : 10.1016/j.quascirev.2020.106697
The north-central Canadian boreal forest experienced increased occurrence of large and severe wildfires caused by unusually warm temperatures and drought events during the last decade. It is, however, difficult to assess the exceptional nature of this recent wildfire activity, as few long-term records are available in the area. We analyzed macroscopic sedimentary charcoal from four lakes and pollen grains from one of those lakes to reconstruct long-term fire regimes and vegetation histories in the boreal forest of central Northwest Territories. We used regional estimates of past temperature and hydrological changes to identify the climatic drivers of fire activity over the past 10,000 years. Fires were larger and more severe during warm periods (before ca. 5000 cal yrs. BP and during the last 500 years) and when the forest landscape was characterized by high fuel abundance, especially fire-prone spruce. In contrast, colder conditions combined with landscape opening (i.e., lower fuel abundance) during the Neoglacial (after ca. 5000 cal yrs. BP) were related with a decline in fire size and severity. Fire size and severity increased during the last five centuries, but remained within the Holocene range of variability. According to climatic projections, fire size and severity will likely continue to increase in central Northwest Territories in response to warmer conditions, but precipitation variability, combined with increased abundance of deciduous species or opening of the landscape, could limit fire risk in the future.
Pierre Grondin, Véronique Poirier, Sylvie Gauthier, Patrice Tardif, Yan Boucher, Yves Bergeron. Have some landscapes in the eastern
Canadian boreal forest moved beyond their
natural range of variability? 2018. Forest Ecosystems 5(1):30
DOI : 10.1186/s40663-018-0148-9
In the context of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec (Canada). Using contemporary and long-term fire cycles, each natural forest landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.
Avancement
L’analyse des données récoltées dans les territoires du Nord-Ouest est en cours. Une synthèse des travaux sur les lacs est disponibles (Girardin et al. 2019) et une synthèse des études dendrochronologiques est en voie de réalisation.
Organismes subventionnaires
CRSNG, MITACS, SÉPAQ (Parc Aiguebelle)
Financement annuel
terminé
Durée
2009-2023
Dernière mise à jour :
2022-04-25 08:21:04
