Modeling the effects of forest succession on fire behavior potential in

1. 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

2. 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

4. Rocky Mountain Trench 1900s 1990s

5. 1992 1952 B.C. Government photos

6. Issues • loss of habitat for some wildlife species • reduction in forest grazing • decline in forest health • increased potential for catastrophic crown fires

7. Heat Transfer Temperatures above flame front by fire intensity class

8. 6 5 Crown Fire Initiation Surface fire Crown fire threshold by fire intensity class 4 Crown fire 3 2 *Foliar moisture content = 100%

9. Rationale • few planning tools to guide ecosystem restoration and fuels management programs • need to develop techniques to project future change and effects of management practises

10. Objectives • Develop methods to assess historical change and project future change in: • forest cover • fuel conditions • fire behavior potential

11. Study areas

12. Methods • crown closure, fuel type, terrain classification • map historic and contemporary air photos • sample stand characteristics • stand projection using PROGNOSIS growth model • fire weather climatology and fire behavior normals • determine fire behavior potential over time

13. Forest and fuel type classification

17. Stand description Douglas-fir Ponderosa pine Lodgepole pine Western larch Trembling aspen

18. Stand projection

19. Inventory projection

21. Climatology

22. Fire behavior normals * level ground

23. Fire behavior projection Normal fire season crown fraction burned class frequencies

24. Fire behavior projection Normal fire season fire intensity class frequencies

25. Results • Grassland and open forest • decreased by 50% during 1952-92 • will be eliminated by 2036 without management • Area of closed forest doubled during 1952-92 • Area susceptible to crown fire with >50% CFB • increased from 7 to 14% during 1956-96 • projected to increase to 29% by 2032 • * Results are preliminary - regeneration model needs calibration

26. Research Needs • 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

27. Fuels Management Planning Tools Tactical models • fire behavior and effects • stand projection and simulation Strategic models • inventory projection • forest estate • landscape level

28. Tactical Models Fire Behavior Prediction System SCORCH Tree Mortality Model

29. Tactical Models Forest Vegetation Simulator (PROGNOSIS) Fuel Dynamics and Fire Effects Model

30. FVS Fuel Dynamics and Fire Effects Model Sample Output

31. Strategic Models fssim Woodstock Simulate forest dynamics and management activities on vegetation growing stock and related attributes

32. 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.

33. Thank you ! Time for questions ?