August 2nd, 2017 ~ Vol. 87 No. 31
Two case studies examine FireSmart effectiveness
Crowsnest Pass Herald Front Page
Archive photo
2003 Lost Creek Fire
Pass Herald Reporter
FireSmart Canada strongly recommends managing vegetation around one’s yard and home as a way to mitigate the risk of wildfire. FPInnovations conducted two case studies in 2005 and 2007 in natural pine stands of the Northwest Territories to evaluate FireSmart treatments and the effectiveness of thinning crown lines and removing surface fuel.

The studies observed how two plots of land reacted to wildfire. One plot was left natural, or untreated. The other plot had the trees thinned to 3 metres between crowns, and all standing dead trees and ground vegetation was removed.

The natural plot was composed of mature jack pine, black spruce and a lot of black spruce vegetation on the ground. Feather moss and reindeer lichen was other surface vegetation in the natural plot. The thinned plot was composed of mature jack pine with little vegetation on the ground, with the exception of some feather moss.
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The treatment of the thinned plot followed the guidelines recommended by FireSmart in their Priority Zones education. In Zone 2, which includes the area 10 to 30 metres away from a home, evergreen trees need to be pruned and there should be at least 3 metres of horizontal space between single or grouped tree crowns. Branches lower than 2 metres from the ground should be removed and all types of dry or dead vegetation should be cleaned up.

Data was collected using video cameras and the observations of FPInnovations researchers.

In both studies, the fire, which was ignited at the edge of the natural plot, changed from a crown fire to a surface fire once it reached the thinned plot. However, even in the thinned plot, certain trees succumbed to candling (when individual crowns are burning) and spot fires. “In both burns,” notes the study, “the thinning treatment was effective at changing a crown fire into a slow-moving surface fire.”
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The study noted that while drastic change were observed in fire behaviours, the treatments did not stop the fire or the spread completely, so thinning should be considered a risk-reduction technique, not a fire prevention technique.

“Surface fires caused by the head fire and flying embers would likely have burned through the thinned plot, and structures not protected against those ignition sources would have been at risk,” indicates the study.

FireSmart has guidelines for Zone 1a and Zone 1b, cumulatively 0 to 10 metres from a dwelling, that recommend steps that would limit the spread of fire or ignition of a home. This includes things like removing combustible material and vegetation from around a dwelling, paying attention to construction materials used and selecting fire-resistant plants.
August 2nd, 2017 ~ Vol. 87 No. 31
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