Modeling the effects of forest succession on fire behavior potential in southeastern British Columbia S.W. Taylor, G.J. Baxter and B.C. Hawkes Natural Resources Canada Canadian Forest Service
Historical Background dry forests in western North America were historically exposed to high-frequency, low- intensity fire regimes favoring the development of grasslands and open stands of fire-tolerant tree species: ponderosa pine, Douglas-fir, western larch fire suppression, logging and forest grazing have resulted in forest in-growth and expansion
Rocky Mountain Trench 1900s 1990s
B.C. Government photos
Issues loss of habitat for some wildlife species reduction in forest grazing decline in forest health increased potential for catastrophic crown fires
Temperatures above flame front by fire intensity class Heat Transfer
Crown Fire Initiation *Foliar moisture content = 100% Crown fire Surface fire Crown fire threshold by fire intensity class
l few planning tools to guide ecosystem restoration and fuels management programs l need to develop techniques to project future change and effects of management practises Rationale
Objectives Develop methods to assess historical change and project future change in: forest cover fuel conditions fire behavior potential
Study areas
Methods l crown closure, fuel type, terrain classification l map historic and contemporary air photos l sample stand characteristics l stand projection using PROGNOSIS growth model l fire weather climatology and fire behavior normals l determine fire behavior potential over time
Forest and fuel type classification
Douglas-fir Ponderosa pine Lodgepole pine Western larch Trembling aspen Stand description
Stand projection
Inventory projection
Climatology
Fire behavior normals * level ground
Normal fire season crown fraction burned class frequencies Fire behavior projection
Normal fire season fire intensity class frequencies Fire behavior projection
Results Grassland and open forest decreased by 50% during will be eliminated by 2036 without management Area of closed forest doubled during Area susceptible to crown fire with >50% CFB increased from 7 to 14% during projected to increase to 29% by 2032 * Results are preliminary - regeneration model needs calibration
dynamic fuel and fire behavior models integrate fire behavior and ignition potential in more sophisticated risk measures quantify preparedness and control costs associated with fire risk further develop fuel management planning tools Research Needs
Fuels Management Planning Tools Tactical models fire behavior and effects stand projection and simulation Strategic models inventory projection forest estate landscape level
Tactical Models Fire Behavior Prediction System SCORCH Tree Mortality Model
Tactical Models Forest Vegetation Simulator (PROGNOSIS) Fuel Dynamics and Fire Effects Model
FVS Fuel Dynamics and Fire Effects Model Sample Output
Strategic Models Simulate forest dynamics and management activities on vegetation growing stock and related attributes fssim Woodstock
Acknowledgements Funding for this project was provided in part by Forest Renewal British Columbia We would like to acknowledge the cooperation of: BC Ministry of Forests Cranbrook Forest District, Nelson Forest Region BC Parks Okanagan District, Thompson River Dist.
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