Raphaël Chavardes, Victor Danneyrolles, Jeanne Portier, Martin-Philippe Girardin, Dorian Gaboriau, Sylvie Gauthier, Igor Drobyshev, Tuomo Wallenius, Dominic Cyr, Yves Bergeron. Converging and diverging burn rates in North American boreal forests from the Little Ice Age to the present 2022. International Journal of Wildland Fire 31(12):1184-1193
DOI : 10.1071/WF22090
Warning: This article contains terms, descriptions, and opinions used for historical context that may be culturally sensitive for some readers.Background: Understanding drivers of boreal forest dynamics supports adaptation strategies in the context of climate change.Aims: We aimed to understand how burn rates varied since the early 1700s in North American boreal forests.Methods: We used 16 fire-history study sites distributed across such forests and investigated variation in burn rates for the historical period spanning 1700-1990. These were benchmarked against recent burn rates estimated for the modern period spanning 1980-2020 using various data sources.Key results: Burn rates during the historical period for most sites showed a declining trend, particularly during the early to mid 1900s. Compared to the historical period, the modern period showed less variable and lower burn rates across sites. Mean burn rates during the modern period presented divergent trends among eastern versus northwestern sites, with increasing trends in mean burn rates in most northwestern North American sites.Conclusions: The synchronicity of trends suggests that large spatial patterns of atmospheric conditions drove burn rates in addition to regional changes in land use like fire exclusion and suppression.Implications: Low burn rates in eastern Canadian boreal forests may continue unless climate change overrides the capacity to suppress fire.
Dominic Cyr, Jesus Pascual Puigdevall, Yves Bergeron, Sylvie Gauthier, Nelson Thiffault, Alain Leduc, Tadeusz Splawinski, Osvaldo Valeria. Mitigating post-fire regeneration failure in boreal landscapes with reforestation and variable retention harvesting: At what cost? 2022. Can. J. For. Res. 52(4):568-581
DOI : 10.1139/cjfr-2021-0180
Successive disturbances such as fire can affect post-disturbance regeneration density, with documented adverse effects on subsequent stand productivity. We conducted a simulation study to assess the potential of reactive (reforestation) and proactive (variable retention harvesting) post-fire regeneration failure mitigation strategies in a 1.37 Mha fire-prone boreal landscape dominated by black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.). We quantified their respective capacity to maintain landscape productivity and post-fire resilience, as well as their associated financial returns under current and projected (RCP 8.5) fire regimes. While post-fire reforestation with jack pine revealed to be the most effective strategy to maintain potential production, associated costs quickly became prohibitive when applied over extensive areas. Proactive strategies such as an extensive use of variable retention harvesting, combined with replanting of fire-adapted jack pine only in easily accessible areas, appeared as a more promising approach. Despite this, our results suggest an inevitable erosion of forest productivity due to post-fire regeneration failure events, highlighting the importance of integrating fire a priori in strategic forest management planning as well as its effects on long-term regeneration dynamics.
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.
Qiuyu Liu, Robert Schneider, Changhui Peng, Zelin Liu, Xiaolu Zhou, Daniel Kneeshaw, Dominic Cyr. TRIPLEX-Mortality model for simulating drought-induced tree mortality in boreal forests: Model development and evaluation. 2021. Ecological Modelling 455:109652
DOI : 10.1016/j.ecolmodel.2021.109652
Globally, increasing drought-induced tree mortality rates under climate change are projected to have far-reaching effects on forest ecosystems. Among these forest systems, the boreal forest is considered a ‘tipping element’ of the Earth's climate system. This forest biome plays a critical role in ecosystem services, structures and functions while being highly sensitive to drought stress. Although process-based models are important tools in ecological research, very few have yet been developed that integrate advanced physiological mechanisms to simulate drought-induced mortality in boreal forests. Accordingly, based on the process-based TRIPLEX model, this study introduces the new TRIPLEX-Mortality submodule for the Canadian boreal forests at the stand level, that for the first time successfully incorporates two advanced drought-induced physiological mortality mechanisms (i.e., hydraulic failure and carbon starvation). To calibrate and validate the model, 73 permanent sample plots (PSPs) were selected across Canada's boreal forests. Results confirm a good agreement between simulated mortality and mortality observations (R2=0.79; P<0.01; IA=0.94), demonstrating good model performance in simulating drought-induced mortality in boreal forests. Sensitivity analysis indicated that parameter sensitivity increased as drought intensified, and the shape parameter (c) for calculating percentage loss of conductivity (PLC) was the most sensitive parameter (average SI = -3.51) to simulate tree mortality. Furthermore, the results of model input sensitivity analysis also showed that the model can capture changes in mortality under different drought scenarios. Consequently, our model is suitable for simulating drought-induced mortality in boreal forests while also providing new insight into improving model simulations for tree mortality and associated carbon dynamics in a progressively warmer and drier world.
Eliana Molina, Osvaldo Valeria, Louis De Grandpré, Jorge Andres Ramirez, Dominic Cyr, Yan Boulanger. Projecting future aboveground biomass and productivity of managed eastern Canadian mixedwood boreal forest in response to climate change 2021. For. Ecol. Manage. 119016
DOI : 10.1016/j.foreco.2021.119016
Eastern Canadian boreal forests are mainly influenced by natural wildfires and forest management activities. To evaluate forest dynamics under possible interactions among fire and timber harvest in a future climate warming scenario (RCP 2.6, RCP 4.5 and RCP 8.5) the forest landscape model Landis II was used to simulate the dynamics of the 78000 km2 of boreal forests in eastern Canada. Forest management intensity scenarios were modeled considering the changes in the annual harvested area (0.5%, 1%, and 2%) and the age that conifers and hardwoods can be harvested (50 and 30 years, 70 and 50 years, and 90 and 70 years). The results of the 300-year model projections implied that both forest management intensity and climatic scenarios explained most of the variability in aboveground biomass, aboveground net primary productivity and forest composition. Forest management seems to be the most important factor that modified the landscape in the southern forests because there were scheduled stands with the age and composition required by each harvesting prescription to deal with the annual allowable cut volume. On the contrary, in the northern forests there was a mixed effect of climate change and forest management because many of the areas suitable for harvesting were previously burned limiting the amount of area available for harvesting. Thus, although it is expected an increase in wildfire area burned due to climate change, the intensification of forest management seems to be the most important driver of the increase of hardwoods and mixed stands and the decrease of conifers stands on the mixedwood boreal landscape, mainly in the southern forests. These results suggest that timber supply would be at risk in the Abitibi Plain, therefore, some strategies should be applied to adapt forest management to climate change.
Jean-Pierre Jetté, Yves Bergeron, Tadeusz Splawinski, Dominic Cyr, Sylvie Gauthier. Analyzing risk of regeneration failure in the managed boreal
forest of northwestern Quebec. 2019. Can. J. For. Res. 49:680-691
DOI : 10.1139/cjfr-2018-0278
Les changements dans le régime des feux peuvent affecter le potentiel de régénération après perturbation des espèces d’arbres de la forêt boréale, modifiant ainsi la densité et la fermeture des peuplements forestiers. Cela pourrait nuire à la durabilité de la gestion forestière, en particulier dans les régions caractérisées actuellement par un cycle de feu court et une faible productivité. À titre d’étude de cas, nous utilisons un véritable paysage (1.3 Mha) de la forêt boréale du nord-ouest du Québec, caractérisé par une superficie annuelle brûlée élevée et pour laquelle l’activité des feux devrait augmenter fortement, pour modéliser l’effet des cycles de feux actuel et ceux induits par le climat, et le taux de récolte sur le potentiel de régénération des peuplements purs d’épinette noire (Picea mariana (Mill.) BSP) et de pin gris (Pinus banksiana Lamb.). Des simulations ont été effectuées sur une période de 50 ans selon trois seuils de maturité reproductive par espèce, représentant l’âge auquel un approvisionnement suffisant en semences est atteint afin d’assurer l’auto-remplacement du peuplement. Les résultats montrent une augmentation progressive de la superficie affectée par les accidents de régénération naturelle au cours de la période de simulation dans les deux scénarios climatiques, montrant une perte de 18.5 % (149?210 ha) de superficie productive sous le cycle de feu actuel et de 65.8 % (532?141 ha) sous les cycles de feux futurs. Les variations dans le cycle de feu ont eu le plus grand effet sur le taux des accidents de régénération, suivi par le seuil d’âge de régénération et le taux de récolte. Nous décrivons les pratiques proactives de gestion forestière et la planification stratégique qui inclut le risque de feu peuvent réduire la probabilité par des accidents de régénération après feu. Cela comprend la gestion intensive des peuplements et les stratégies de rétention variable après la récolte. De même un réseau de suivi des sites après feu aiderait à évaluer les accidents de régénération au fil du temps et serait utile pour valider à la fois les résultats du modèle et l’efficacité des stratégies visant à en minimiser la probabilité.
Yves Bergeron, Dominic Cyr, Tadeusz Splawinski, Sylvie Gauthier. Analyse du risque d’accidents de régénération en forêt boréale aménagée. 2017. Rapport remis à la direction de l’aménagement et de l’environnement forestier du MFFP 54 p.
Yves Bergeron, Yan Boulanger, Sylvie Gauthier, Dominic Cyr. Quantifying Fire Cycle from Dendroecological Records Using Survival Analyses. 2016. Forests 7(7):131
DOI : 10.3390/f7070131
Quantifying fire regimes in the boreal forest ecosystem is crucial for understanding the past and present dynamics, as well as for predicting its future dynamics. Survival analyses have often been used to estimate the fire cycle in eastern Canada because they make it possible to take into account the censored information that is made prevalent by the typically long fire return intervals and the limited scope of the dendroecological methods that are used to quantify them. Here, we assess how the true length of the fire cycle, the short-term temporal variations in fire activity, and the sampling effort affect the accuracy and precision of estimates obtained from two types of parametric survival models, the Weibull and the exponential models, and one non-parametric model obtained with the Cox regression. Then, we apply those results in a case area located in eastern Canada. Our simulation experiment confirms some documented concerns regarding the detrimental effects of temporal variations in fire activity on parametric estimation of the fire cycle. Cox regressions appear to provide the most accurate and robust estimator, being by far the least affected by temporal variations in fire activity. The Cox-based estimate of the fire cycle for the last 300 years in the case study area is 229 years (CI95: 162–407), compared with the likely overestimated 319 years obtained with the commonly used exponential model.
Annie Claude Bélisle, Yves Bergeron, Sylvie Gauthier, Dominic Cyr, Hubert Morin. Fire Regime and Old-Growth Boreal Forests in Central Quebec, Canada: An Ecosystem Management Perspective. 2012. Silva Fennica 45(5):889-908
Boreal forest management in Eastern Canada has caused depletion and fragmentation of oldgrowth
ecosystems, with growing impacts on the associated biodiversity. To mitigate impacts
of management while maintaining timber supplies, ecosystem management aims to narrow
the gap between natural and managed landscapes. Our study describes the fire history and
associated natural old-growth forest proportions and distribution of a 5000 km2 area located in
the black spruce-feather moss forest of central Quebec. We reconstructed a stand-origin map
using archival data, aerial photos and dendrochronology. According to survival analysis (Cox
hazard model), the mean fire cycle length was 247 years for the 1734–2009 period. Age-class
distribution modelling showed that old-growth forests were present on an average of 55% of
the landscape over the last 275 years. The mean fire size was 10 113 ha, while most of the
burned area was attributable to fires larger than 10 000 ha, leading to old-growth agglomerations
of hundreds of square kilometres. In regards to our findings, we propose ecosystem
management targets and strategies to preserve forest diversity and resilience.
Yves Bergeron, Dominic Cyr, Sylvie Gauthier. The influence of landscape-level heterogeneity in fire frequency on canopy composition in the boreal forest of eastern Canada. 2012. J. Veg. Sci. 23(1):140-150
DOI : 10.1111/j.1654-1103.2011.01338.x
voir la liste complète
Naveen Verabhadraswamy, Osvaldo Valeria, Dominic Cyr. Understanding forest management as a solution for climate change mitigation : Carbon dynamics modeling at landscape level 24e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2022-11-22)
Yan Boulanger, Annie Claude Bélisle, Yves Bergeron, Marie-Hélène Brice, Dominic Cyr. Impacts des changements climatiques sur les forêts québécoises : ce qu'une analyse intégrée régionale nous a appris 15e colloque annuel du CEF, Université de Sherbrooke, Québec (2022-09-29)
Martin-Hugues St-Laurent, Yan Boulanger, Dominic Cyr, Francis Manka, Pierre Drapeau, Sylvie Gauthier. Abaisser le taux de couper pour atténuer les impacts des changements climatiques sur la qualité d'habitat du caribou forestier au Québec 15e colloque annuel du CEF, Université de Sherbrooke, Québec (2022-09-29)
Tadeusz Splawinski, Dominic Cyr, Sylvie Gauthier, Jesus Pascual Puigdevall, Alain Leduc, Nelson Thiffault, Yves Bergeron. Modéliser le potentiel des pratiques sylvicoles pour limiter l'impacts des accidents de régénération sur la productivité forestière 22e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, complètement virtuel (2020-12-02)
Marin Seto, Jean-Pierre Jetté, Alexis Schab, Tadeusz Splawinski, Dominic Cyr, Sonia Légaré, Véronique Christophe, Alexis Leroux, Mathieu Bouchard, Yan Boucher, Jean-Pierre Saucier, Alain Leduc, Osvaldo Valeria, Sylvie Gauthier, Yves Bergeron. La gestion du risque intégrée à la prise de décision en aménagement forestier: le cas des zones sensibles de la forêt boréale. Carrefour Forêts (2019-04-04)
Dominic Cyr Dominic Cyr Séminaire Ouranos: (2014-11-19)
Dominic Cyr Cycle des feux, vieilles forêts et aménagement en forêt boréale de l'est du Canada. Soutenance thèse (2010-11-29)
Dominic Cyr Le régime des feux de la Côte-Nord
analysé sous l’angle de la norme FSC (11 diapos.) 10e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2008-12-04)
Dominic Cyr 9e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2007-12-05)
Dominic Cyr Une méthode rapide et peu coûteuse permettant d’évaluer la proportion historique des forêts anciennes : un exemple sur la ceinture d’argile ontarienne 22ème colloque CONFOR-Innovation. Parc National du Mont Orford, Orford, Québec, Canada.
Dominic Cyr A cost effective method for estimating the proportion of old-growth forests from a provincial inventory Forest succession workshop. Lake Duparquet Research and Teaching Forest
Dominic Cyr Influence de la topographie sur le risque de feu en forêt boréale : étude de cas sur la Côte-Nord et potentield’intégration en aménagement forestier durable 74ième congrès annuel de l’ACFAS. Université McGill, Montréal, Québec, Canada.