1. Using FFE-FVS to estimate potential fire behavior in early settlement Black Hills ponderosa pine Mike Battaglia, Colorado State University Skip Smith, Colorado State University Peter Brown, Rocky Mountain Tree-Ring Institute Wayne Shepperd, USFS Rocky Mountain Research Station

2. Hayman Fire, CO 2002 Battle Creek, SD 2002 Jasper, SD 2000 Elk Mtn II, SD 2001 Roger Shack, SD 2001 Rodeo-Chediski, AZ 2002 Recent large-scale wildfires

3. Historical Forest Structure Restoration = Low Crown Fire Risk

4. Southwest MFI: 3-12 years Low intensity, Surface fire Ponderosa Pine distribution MFI: – Ecotone: 10 to 12 yrs – Interior: 20 to 35 yrs

5. Abundant regeneration Photos: Graves (1899). USGS 19 th annual report

6. ©Graves 1899 ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos Multi-cohort forests

7. ©Graves 1899 Dense forest ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos Open forest

8. ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos Moderate severity fire Low severity fire ©Graves 1899 High severity fire

9. ©Graves 1899 ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos “Forest continuity was broken by fire…” “Forest interrupted by open parks…” (Graves 1899)

10. Brown and Cook 2006. For. Ecol. Mgmt 223: 284-290

11. Historical Relative Density and QMD (ca.1900) estimated from 112 plots from around the Black Hills Brown and Cook 2006. For. Ecol. Mgmt 223: 284-290

12. Study Objectives What kind of fire regime would lead to this distribution of stand structures across the landscape?

13. Surface Fire Fire burns along the surface

14. Passive Crown Fire (Torching) Fire torches individual trees or groups of trees, but flames don’t jump from tree to tree Photo by Frank Carroll, BHNF

15. Active Crown Fire Fire spreads from tree crown to tree crown Photo by Terry Tompkins, BHNF

16. Mix of them all???

17. Stand data and the model Reconstructed historical stand structure data (Brown and Cook 2006) Entered into Forest Vegetation Simulator –Central Rockies variant v.6.31; rev date 7/5/06

18. Simulation Scenarios Fire Return Interval (FRI) –10, 20, and 30 years Fire Weather –80 th and 97 th percentile weather

19. Fire and Fuels Extension (FFE) to FVS SIMFIRE –Fire return interval x weather scenario Fire behavior Tree mortality by diameter size class POTFIRE –Fire return interval x weather scenario Potential fire behavior by decade

20. Simulating Stand Development Simulate the stand structures that would result from fire regime characterized by fire return interval and percentile weather –Stands grown for 100 years for the various scenarios –Analysis focused on the last 60 years of the simulation (once the FVS model stabilized)

21. Potential fire behavior of these stand structures? 80 th percentile fire weather stands 10 year MFI Surface 40% Passive 60% 97 th percentile fire weather stands Surface 8% Passive 92% 20 year MFI Surface 0% Passive 100% Surface 15% Passive 85% 30 year MFI Surface 1% Passive 99% Surface 30% Passive 70%

22. Severity of fire behavior differed with weather scenario 80 th percentile fire weather 10 year MFI 20 year MFI 30 year MFI Surface: 3.4 ft Passive: 3.7 ft Surface: 2.5 ft Passive: 3.3 ft Surface: 2.2 ft Passive: 3.4 ft Avg. Flame lengths

23. Severity of fire behavior differed with weather scenario 80 th percentile fire weather 97 th percentile fire weather 10 year MFI 20 year MFI 30 year MFI

24. Severity of fire behavior differed with weather scenario 97 th percentile fire weather 10 year MFI 20 year MFI 30 year MFI Surface: 7.6 ft Passive: 10.5 ft Passive: 16.6 ft Passive: 20.7 ft Avg. Flame lengths

25. Summary Passive crown fire was common, but severity was influenced by weather conditions and fire return interval –Moderate weather (the most common fire) Mortality limited to trees <10 inch dbh

26. 80 th percentile fire weather: Impact on forest structure 10 yr MFI 20 yr MFI30 yr MFI Open-canopied forests with large diameter trees Open- to closed- canopied, multi-storied forests with a range of diameters Closed-canopied, multi-storied or even-aged forests

27. Summary Passive crown fire was common, but severity was influenced by weather conditions –Moderate weather (and most common fire) Mortality limited to trees <10 inch dbh –Extreme weather (infrequent, but did occur) Mortality across all diameter size classes

28. 97 th percentile fire weather: Impact on forest structure 10 yr MFI 20 yr MFI 30 yr MFI Meadows, Patches of saplings/poles, or savannas with large diameter trees Open-canopied, even-aged forests with pole-sized trees Open- to closed- canopied forests, with pole-sized trees scattered among larger diameter trees

29. Surface 15% 20 yr MFI Passive 85% 80 th percentile fire weather Likely scenario that explains most of the landscape…. Ca. 1900 structures ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos

30. 10 yr MFI Clearly other scenarios can help explain other portions of the landscape…. Frequent fire that precluded any overstory recruitment 80th percentile fire weather 10 yr MFI 97th percentile fire weather Surface 40% Passive 60% Surface 8% Passive 92% ©Grafe and Horsted (2002) from Illingworth’s 1874 Photos

31. Clearly other scenarios can help explain other portions of the landscape…. Very severe fires with high mortality of large diameter trees 97th percentile fire weather 20 yr MFI 30 yr MFI Passive 99-100% ©Graves 1899

32. 80 th percentile fire weather Clearly other scenarios can help explain other portions of the landscape…. Long fire return intervals that promoted denser pole-sized forests Surface 30% Passive 70% 30 yr MFI 80 th percentile fire weather ©Graves 1899

33. Active Crown Fire Potential POTFIRE (97 th percentile fire weather) –Crowning Index Windspeed required to sustain active crown fire Low Risk : > 50 mph Moderate Risk : 25 to 50 mph High Risk : < 25 mph

34. Historical Active Crown Fire Risk Stand structures resulting from 80 th percentile fire weather Stand structures resulting from 97 th percentile fire weather 10 year MFI 20 year MFI 30 year MFI

35. Summary Historical forest structures capable of surface, passive, and active crown fire Passive crown fire was common –But the weather associated with fire behavior influenced tree-size mortality Active crown fire potential –low to moderate

36. Summary Restoration of full suite of historical forest structures will not eliminate crown fire risk and mortality Fuel mitigation treatments can incorporate SOME elements of historical forest structure that lower active crown fire risk

37. Acknowledgements FVS group –Stephanie Rebain and Chad Keyser Funding –National Fire Plan –Rocky Mountain Research Station, Fort Collins (RWU-4451): Sustaining Alpine and Forest Ecosystems –Colorado State University

39. Fuel treatments Purpose –Reduce fire intensity and severity –Reduce wildfire size –Facilitate suppression activities

40. Fire behavior under 97 th percentile fire weather conditions 80 th percentile stand structures 97 th percentile stand structures Fire Interval (years) Avg. Flame length (ft) Avg. Mortality BA (%) Avg. Flame length (ft) Avg. Mortality BA (%) 10 20 30

41. Fire behavior under 97 th percentile fire weather conditions 80 th percentile stand structures 97 th percentile stand structures Fire Interval (years) Avg. Flame length (ft) Avg. Mortality BA (%) Avg. Flame length (ft) Avg. Mortality BA (%) 108.873.6 203.234.7 303.133.5

42. Fire behavior under 97 th percentile fire weather conditions 80 th percentile stand structures 97 th percentile stand structures Fire Interval (years) Avg. Flame length (ft) Avg. Mortality BA (%) Avg. Flame length (ft) Avg. Mortality BA (%) 108.873.6 10.286.3 203.234.7 13.898.8 303.133.5 16.197.0