The potential and realized spread of wildfires across Canada

Wang, Xianli; Parisien, Marc‐André; Flannigan, Mike D.; Parks, Sean A.; Anderson, Kerry; Little, John M.; Taylor, Steve

doi:10.1111/gcb.12590

Cited by 54 publications

(61 citation statements)

References 57 publications

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“…However, biotic interactions and feedbacks related to land-cover effects are rarely included in the models used to forecast fire activity. This is because, until recently [6–8], land-cover effects were believed to be negligible relative to fire weather, likely because of the lack of heterogeneity in land-cover data [9, 10]. If land-cover effects are in fact not negligible, then the reliability of these forecasts is questionable.…”

Section: Introductionmentioning

confidence: 99%

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management

2017

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Fire activity in North American forests is expected to increase substantially with climate change. This would represent a growing risk to human settlements and industrial infrastructure proximal to forests, and to the forest products industry. We modelled fire size distributions in southern Québec as functions of fire weather and land cover, thus explicitly integrating some of the biotic interactions and feedbacks in a forest-wildfire system. We found that, contrary to expectations, land-cover and not fire weather was the primary driver of fire size in our study region. Fires were highly selective on fuel-type under a wide range of fire weather conditions: specifically, deciduous forest, lakes and to a lesser extent recently burned areas decreased the expected fire size in their vicinity compared to conifer forest. This has large implications for fire risk management in that fuels management could reduce fire risk over the long term. Our results imply, for example, that if 30% of a conifer-dominated landscape were converted to hardwoods, the probability of a given fire, occurring in that landscape under mean fire weather conditions, exceeding 100,000 ha would be reduced by a factor of 21. A similarly marked but slightly smaller effect size would be expected under extreme fire weather conditions. We attribute the decrease in expected fire size that occurs in recently burned areas to fuel availability limitations on fires spread. Because regenerating burned conifer stands often pass through a deciduous stage, this would also act as a negative biotic feedback whereby the occurrence of fires limits the size of nearby future for some period of time. Our parameter estimates imply that changes in vegetation flammability or fuel availability after fires would tend to counteract shifts in the fire size distribution favoring larger fires that are expected under climate warming. Ecological forecasts from models neglecting these feedbacks may markedly overestimate the consequences of climate warming on fire activity, and could be misleading. Assessments of vulnerability to climate change, and subsequent adaptation strategies, are directly dependent on integrated ecological forecasts. Thus, we stress the need to explicitly incorporate land-cover’s direct effects and feedbacks in simulation models of coupled climate–fire–fuels systems.

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Section: Introductionmentioning

confidence: 99%

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management

2017

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“…Local, instantaneous conditions such as fire weather, topography, and fuel condition at the ignition point are important factors that directly affect fire ignition and spread in particular sites at specific times [40,41], but over the large spatio-temporal scales of this study, variations in weather, topography and fuel condition become so 'smoothed out' that they are no longer useful predictors. Hence such variables were not included in our analysis.…”

Section: Discussionmentioning

confidence: 92%

Ecoregional Patterns of Spruce Budworm—Wildfire Interactions in Central Canada’s Forests

Candau

Fleming

Wang

2018

Forests

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Wildfires and outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), are the two dominant natural disturbances in Canada's boreal forest. While both disturbances have specific impacts on forest ecosystems, it is increasingly recognized that their interactions also have the potential for non-linear behavior and long-lasting legacies on forest ecosystems' structures and functions. Previously, we showed that, in central Canada, fires occurred with a disproportionately higher frequency during a 'window of opportunity' following spruce budworm defoliation. In this study, we use Ontario's spatial databases for large fires and spruce budworm defoliation to locate where these two disturbances likely interacted. Classification tree and Random Forest procedures were then applied to find how spruce budworm defoliation history, climate, and forest conditions best predict the location of such budworm-fire interactions. Results indicate that such interactions likely occurred in areas geographically bound by hardwood content in the south, the prevalence of the three major spruce budworm host species (balsam fir, white spruce and black spruce) in the north, and climate moisture in the west. The occurrence of a spruce budworm-fire interaction inside these boundaries is related to the frequency of spruce budworm defoliation. These patterns provide a means of distinguishing regions where spruce budworm attacks are likely to increase fire risk.

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“…Attribution metrics are not calculated for ISI as the extreme threshold exceeds any regional values realized in either the ALL or NAT simulations FWI index percentiles have been used in other studies (Wotton et al 2010;Parisien et al 2011;Wang et al 2015) and are a better indicator of extreme fire days than a measure of central tendency. We also considered events defined in terms of days with significant spread potential, by using the 90th percentile value of the ROS (Rate of Spread) and also the definition of Wang et al (2014) that determines spread days in a rain-free period as those with FWI (Fire Weather Index) ≥19 and DMC (Drought Moisture Code) ≥20. Spread days are expressed as the number of days per season or the percentage of the fire season length, with thresholds for an extreme season being 38 days (25% of the climatological mean season length) or 25%, respectively.…”

Section: Event Definitionsmentioning

confidence: 99%

Attributing extreme fire risk in Western Canada to human emissions

et al. 2017

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Canada is expected to see an increase in fire risk under future climate projections. Large fires, such as that near Fort McMurray, Alberta in 2016, can be devastating to the communities affected. Understanding the role of human emissions in the occurrence of such extreme fire events can lend insight into how these events might change in the future. An event attribution framework is used to quantify the influence of anthropogenic forcings on extreme fire risk in the current climate of a western Canada region. Fourteen metrics from the Canadian Forest Fire Danger Rating System are used to define the extreme fire seasons. For the majority of these metrics and during the current decade, the combined effect of anthropogenic and natural forcing is estimated to have made extreme fire risk events in the region 1.5 to 6 times as likely compared to a climate that would have been with natural forcings alone. Keywords Event attribution · Fire weather · ExtremesElectronic supplementary material The online version of this article

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The potential and realized spread of wildfires across Canada

Cited by 54 publications

References 57 publications

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management

Ecoregional Patterns of Spruce Budworm—Wildfire Interactions in Central Canada’s Forests

Attributing extreme fire risk in Western Canada to human emissions

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