Exploring cartography

I Researchers mapped wildfire risk across four million square kilometres of forest to help inform management actions

In late spring 2016, when a portion of northern Alberta was engulfed in a wildfire that threatened the city of Fort Mcmurray, more than 88,000 residents of the regional municipality of Wood Buffalo fled their homes. In the summer of 2017, it was British Columbia’s turn, where by mid-july about 46,000 people had been evacuated as wildfires burned across the central part of the province. In recent years, Canadians have come to both dread and expect these conflagrations, with an average of 2.5 million hectares burning each year (an area about the size of Vermont) and annual fire suppression costs ranging between $500 million and $1 billion. It’s within this context that researchers from the Canadian Forest Service at Natural Resources Canada created a strategic map of fire risk across Canada, which for the first time provides a visualization that may help experts connect projected fire risk areas to communities. To produce their map, which uses National Forest Inventory, satellite, climate and topographical data, researchers crunched three key datasets together. The first depicts the percentage of area burned annually between 1959 and 1999 in each of Canada’s 16 “homogeneous fire regime zones” (a fire regime describes the patterns of fire seasonality, frequency, size, spatial continuity, intensity, type and severity) and acts as a broad historical baseline ( top left). The second set is modern data on forest composition ( top middle), and shows that forests with a high percentage of coniferous evergreens are more likely than average to burn, while forests with more broadleaf, deciduous species are less likely to burn. The third set is likewise recent data on forest age ( top right), and reveals that the older the forest, the more likely it is to catch fire. By layering these datasets, the researchers produced a version of the large map shown here. It displays the time between fires in defined areas (what researchers term the “fire return interval range”) and makes two things clear: if you live near a deciduous or young forest, there’s less of a chance of fire occurring near you; and if you live near a coniferous or older forest, there’s a greater risk of wildfire.