Ex­plor­ing car­tog­ra­phy

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

Canadian Geographic - - CONTENTS - BY JOANNE PEARCE AND HARRY WIL­SON

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.

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