Generating annual estimates of forest fire disturbance in Canada: the National Burned Area Composite

Hall, Ronald J.; Skakun, Rob; Metsaranta, Juha M.; Landry, Robert J.; Fraser, Robert; Raymond, D.; Gartrell, Michael; Decker, V; Little, John M.

doi:10.1071/wf19201

Cited by 55 publications

(45 citation statements)

References 43 publications

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“…Due to inconsistent availability of fire agency data in national park areas, we used the National Burned Area Composite (NBAC) fire perimeters in these regions. The NBAC polygons are derived from multispectral imagery from the Landsat satellite series [46]. We merged fire perimeters that crossed jurisdictional boundaries that had been mapped as separate fires.…”

Section: Climate and Fire Regime Datamentioning

confidence: 99%

Climate-induced fire regime amplification in Alberta, Canada

Whitman

Parks

Holsinger

et al. 2022

Environ. Res. Lett.

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Acting as a top-down control on fire activity, climate strongly affects wildfire in North American ecosystems through fuel moisture and ignitions. Departures from historical fire regimes due to climate change have significant implications for the structure and composition of boreal forests, as well as fire management and operations. In this research, we characterize the relationship between trends in climate and fire regime characteristics, for a study area predominantly in Alberta, Canada. We examined trends of fire and climate in northwestern boreal forests using time series analysis of downscaled historical annual climate, fire history (1970 – 2019), and fire severity (the impacts of wildfire on plants and organic biomass; 1985 – 2018). We represented fire severity using the relativized burn ratio (RBR) calculated from multispectral Landsat imagery. The climate of the study area has significantly warmed and dried over the past 50 years. Over the same period the annual number of large wildfires, area burned, and fire sizes in the study area significantly increased. Furthermore, the likelihood, area, and number of extreme short-interval reburns (≤ 15 years between fires; 1985 – 2019) also significantly increased. During the study period, the portion of forested unburned islands within fire perimeters significantly declined, and fire severity (RBR) increased in open conifer and mixedwood forests. These fire regime changes are significantly correlated with annual climate variability, and a path analysis supports the hypothesis that annual climate patterns have led to fire regime shifts. The increasing fire activity in this region has implications for forest ecology and habitat availability, as the disruption of the fire regime is likely to alter forest recovery. Managers may face increasing challenges to fire suppression if the observed trends of increasing hotter and drier annual climate in the study area persist, driving extreme fire activity.

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Section: Climate and Fire Regime Datamentioning

confidence: 99%

Climate-induced fire regime amplification in Alberta, Canada

Whitman

Parks

Holsinger

et al. 2022

Environ. Res. Lett.

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“…To tackle these issues, the Canadian Forest Service (CFS) and the Canada Centre for Mapping and Earth Observation (CCMEO) of Natural Resources Canada have produced the National Burned Area Composite (NBAC) [9]. Since 2004, NBAC has been a growing time series of annual maps, where each map consists of a set of GIS polygons representing the area burned by each wildfire event that occurred in that year.…”

Section: Introductionmentioning

confidence: 99%

“…Since 2004, NBAC has been a growing time series of annual maps, where each map consists of a set of GIS polygons representing the area burned by each wildfire event that occurred in that year. Fire events in NBAC are either mapped anew using satellite imagery, or retained from CNFDB if the polygon therein represents a precise delineation of the burn boundary [9]. Each polygon in NBAC contains assigned attributes describing the event, including the amount of area burned, the ignition cause (e.g., lightning or human), the fire start and end dates, and information about how the fire polygon was delineated and from what mapping sources.…”

Section: Introductionmentioning

confidence: 99%

“…The mapping relies on change detection algorithms, either bitemporal or time series [18][19][20][21]. In particular, the Multi-Acquisition Fire Mapping System (MAFiMS) designed specifically for NBAC applies the differenced normalized burn ratio (dNBR) [22] to pre-and post-fire Landsat data [9]. An accuracy assessment of the burned area from MAFiMS exceeded 90% relative to reference data from visual interpretation and delineation of post-fire aerial photography [9].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the Multi-Acquisition Fire Mapping System (MAFiMS) designed specifically for NBAC applies the differenced normalized burn ratio (dNBR) [22] to pre-and post-fire Landsat data [9]. An accuracy assessment of the burned area from MAFiMS exceeded 90% relative to reference data from visual interpretation and delineation of post-fire aerial photography [9]. Despite its high accuracy, its conventional approach to preprocessing (searching for and downloading suitable imagery, masking of clouds, image differencing) and postprocessing (visual quality control and occasional spatial editing of the automated delineations) can be labor-intensive.…”

Section: Introductionmentioning

confidence: 99%

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Extending the National Burned Area Composite Time Series of Wildfires in Canada

et al. 2022

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Wildfires are a major natural disturbance in Canada that are postulated to increase under a warming climate. To derive accurate trends in burned area and to quantify the effects of fire frequency, duration, and extent, a sufficiently long time series of reliable burned area maps is required. With that in mind, we extended Canada’s National Burned Area Composite (NBAC) dataset from its previous start year (2004) back to 1986. NBAC consists of annual maps in polygon format where the area burned in each fire event is represented by the best available delineation among various mapping methods and data sources of varying quality. Ordered from more to less reliability, in the new 35-year time series (1986 to 2020), 10% of the total burned area was derived from airborne and high-resolution (<5 m) satellite imagery, 81% from change detection methods using 30 m Landsat satellite imagery, and the remaining 9% was largely from aerial surveys. Total (Canada-wide) annual burned area estimates ranged from 215,797 ha in 2020 to 6.7 million ha (Mha) in 1989. We computed 95% confidence intervals for the estimate of each year from 1986 to 2020 based on the accuracy and relative contribution in that year of the different data sources, for both the new NBAC time series and the polygon version of the Canadian National Fire Database (CNFDB), a commonly used source of spatially explicit data on burned area in Canada. NBAC confidence intervals were on average ±9.7% of the annual figure, about one-third the width of the confidence intervals derived for CNFDB. The NBAC time series also included nearly 5000 fire events (totalling 4 Mha, with the largest event being 120,661 ha in size) that are missing in the CNFDB. In a regional analysis for the Northwest Territories, retroactive fire mapping from Landsat imagery reduced historical estimates by 3 Mha (16%), which would result in a 1.6 Mha increase in the reported undisturbed critical habitat for threatened woodland caribou. The NBAC dataset is freely downloadable from the Canadian Wildland Fire Information System.

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Wildfire evacuation patterns and syndromes across Canada's forested regions

et al. 2022

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Human exposure to wildfire is increasing in many regions globally—a trend likely to continue as climate change drives increases in wildfire activity and human populations continue to expand into fire‐prone landscapes. In Canada, this trend is reflected by a steady increase in the annual number of wildfire evacuations since the 1980s. Evacuations can be costly and cause severe stress, even when homes remain undamaged. Because many factors driving community vulnerability are likely correlated, classifying at‐risk communities into groups whose members share common drivers of wildfire vulnerability will be helpful in identifying the key wildfire evacuation “syndromes” that are repeated in different parts of the landscape. Understanding these syndromes will aid in anticipating and mitigating the effects of future fire exposure. Here, we classify the populated places across Canada's forested regions into 19 groups using variables describing their potential vulnerability to wildfire, including the surrounding land cover, land use and infrastructure, and the local fire regime. Then, we evaluate the utility of these groups by comparing actual wildfire exposure among the groups using a unique dataset of 1043 wildfire evacuations from 1980 to 2019. We identified three main evacuation syndromes that represent 79% of all evacuations and are distinct in their geographic distribution, the characteristics of the fires that drove the evacuations, the communities exposed, and the likely mode of evacuation. In remote areas dominated by conifer forest, evacuations were driven primarily by lightning‐ignited fires in the summer. Exposed communities typically lacked access to the road network, making it important to plan for evacuation by air. In less remote mixedwood forest areas, evacuations were driven largely by human‐ignited fires in the spring, and most communities had access to major roads. In interior British Columbia, evacuations were mainly in the summer and driven by both lightning‐ and human‐ignited fires. These areas experienced the greatest increase in evacuation frequency over the last two decades, reflecting the local trend of increasing wildfire activity. These differences highlight how the major risk factors vary spatially across the forested regions and temporally over the fire season—knowledge that will facilitate more effective planning for future fire seasons.

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Generating annual estimates of forest fire disturbance in Canada: the National Burned Area Composite

Cited by 55 publications

References 43 publications

Climate-induced fire regime amplification in Alberta, Canada

Climate-induced fire regime amplification in Alberta, Canada

Extending the National Burned Area Composite Time Series of Wildfires in Canada

Wildfire evacuation patterns and syndromes across Canada's forested regions

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