UBC Theses and Dissertations
Fuel treatment efficacy in fire-prone forests of interior British Columbia, Canada Rutherford, Kea
Extreme wildfire seasons have become a central challenge of forest management in western North America. In response to increasing wildfire risk, forest managers are proactively implementing fuel treatments. Although impacts of fuel treatments have been studied in the western United States, comparable research in the fire-prone forests of western Canada is lacking. In this thesis, I used two approaches to assess the efficacy of alternative fuel treatments to mitigate fire behaviour and effects in the seasonally dry forests of southeastern British Columbia, Canada. I partnered with five community forests in the Kootenay region and measured key components of the wildland fuelbed in forest stands before and after treatment. For the first approach, I used the pre-treatment field data as a baseline and simulated 16 alternative fuel treatment scenarios that spanned the range of thinning, pruning, and surface fuel load reduction combinations being implemented in the region. I modelled stand-level fire behavior (i.e., passive and active crown fire) and effects (i.e., tree mortality) under these simulated stand conditions using Fuels Management Analyst Plus (FMA), and fitted meta-models to assess the treatment impacts. For the second approach, I categorized the fuel treatments implemented by the community forests into five different types based on thinning, pruning, and residue fuel management. I examined the variability of key stand attributes within fuel treatment types. Then, I determined the impacts of the five treatment types on fire behaviour and effects metrics obtained from FMA. Based on results from both approaches, removal of small trees reduced risk of passive crown fire, but concurrent removal of larger trees was necessary to reduce risk of active crown fire. Pruning had minimal impact on mitigating potential of passive crown fire. Ameliorating residue fuels through chipping or pile burning reduced risk of passive crown fire; however, the impacts of chipping on residual tree mortality remains a potential concern. This work provides the first insights into the efficacy of fuel treatments in the Kootenay region and will help forest managers make more informed wildfire management decisions.
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