Mulching is a common method of fuel treatment. However, it is not currently listed by the U.S. Forest Service as a fuel type in its recommendations for fire retardant coverage levels. FPInnovations researchers set up plots with different coverage levels of retardant on a mulch fuel bed and collected fire behaviour data when a fire interacted with these plots. The results are intended to help wildfire agencies understand the effectiveness of retardant on mulch fuels in developing better suppression plans.
This study investigated the effects of applying three mulch treatment intensities on fuel bed characteristics and the resultant fire behaviour. This is a companion report to a previously published report titled Mulching productivity in black spruce fuels: Productivity as a function of treatment intensity. The findings of these fire behaviour trials, in conjunction with productivity results, can assist fuel management practitioners in developing appropriate cost-effective mulching prescriptions.
Modified oxygen consumption calorimetry was used to track the seasonal flammability of black spruce and tamarack. Age class related samples were collected for both species from May to September at research site in central Alberta. These samples were assessed for their differential heat release using test equipment at the Protective Clothing and Equipment Research Facility (PCERF) at the University of Alberta.
The test method was able to successfully quantify the differences in seasonal flammability between black spruce and tamarack. Data showed the age-related flammability differences were less pronounced, with the exception of new growth samples early in the season.
Data was collected within a burned out area on a steep mountain slope as part of FPInnovations’s Survival Zone project. The fire was a prescribed burn carried out by Parks Canada in Jasper National Park. The data collected shows that in this one instance, that temperatures and heat flux values fell within survivable range for firefighters wearing PPE. This report does not condone firefighters above a fire on a steep slope, but rather this PB was used as a data collecting opportunity.