Wildfire Risk Analysis and Fuel Treatment Planning

1. Wildfire Risk Analysis and Fuel Treatment Planning Alan Ager, Western Wildlands Environmental Threat Assessment Center, Prineville Oregon, OR USA Mark Finney, Rocky Mountain Research Station, Missoula MT John Anderson, BalanceTech Inc., Missoula, MT Helen Maffei, Deschutes National Forest, Bend, OR

2. The Problem • Landscape fuel treatment planning is a complex process • Multiple scales • Multiple models • Data and model integration is weak • Wildfire occurrence is highly stochastic – we cannot predict future wildfire likelihood with any certainty • We don’t have a well established analysis process and performance metrics

3. Risk analysis as a framework for fuel treatment planning Definition of Risk: Simple case, only consider losses: Expected Loss = probability of event * loss For multiple loss events of different intensities and probabilities Expected loss = Σ (probability j * lossj) Consider both benefits and losses of multiple events (also present and future) Expected Net Value Change = (probability j * net value changej)

4. Wildfire probability is largely a function of wildfire spread Umatilla National Forest Fire History 1970 - 2005 The majority of acres burned are from a few large fires that escape initial attack and spread over long distances

5. Loss Functions are required to link fire intensity with loss

6. Mitigate Risk by: • Reducing wildfire probability • Reducing fire intensity • Change the loss function

7. Wildfire Risk Analysis Process for Fuels Planning • Design stand fuel treatments (FVS, FFE, SVS) • Design landscape treatment package (ArcGIS) • Simulate treatments (PPE) and generate FlamMap landscape files • Calculate Burn probabilities by simulating lots of wildfires (FlamMap) • Calculate loss functions (FVS-FFE) • Calculate expected loss (Access queries) • Compare treatment alternatives

8. Case Studies Oregon Five Buttes Emily Ager

9. Five Buttes Study Area, Deschutes National Forest

10. 0.001 - 0.005 0.005 - 0.010 0.010 - 0.015 0.015 - 0.020 0.020 - 0.025 0.025 - 0.030 0.030 - 0.035 0.035 - 0.040 0.040 - 0.045 > 0.045 Burn Probability - No treatments, 2000 wildfires, 24 hour burn periods

11. Size of fires generated from random ignitions 2500 acre fires 17,000 acre fires

12. Stands selected for fuel treatment, 20% of landscape treated Owl habitat stands treatments

13. 10% treatment 0% treatment 50% treatment 20% treatment

14. Burn probability does not indicate loss • Need to calculate expected loss, the probability of a fire and loss of habitat

15. Out of 1000 simulated fires on pixel X,Y, how many eliminate owl habitat? Lethal flame length ~100 fires have flame lengths that exceed the lethal flame length Expected loss = 100/10000 = 0.01

16. Calculate the lethal flame length for owl habitat stands • Simulated fire in each stand with flame lengths ranging from 0.5 - 15 meters, 0.5 meter increments [FLAMEADJ] • Determine the flame length when the stand at no longer meets habitat requirements • Query these results against the FlamMap output table

18. Expected Loss of Spotted Owl Habitat for 6 Treatment Intensities

19. Summary: Risk Analysis in Fuel Treatment Planning • Provides a quantitative measure of fuel treatment performance • Accounts for fire spread, intensity, and loss • Can incorporate multiple future and present losses and benefits

20. FVS, FFE, PPEFlamMap, Behave, FOFEM, Nexus, The WO-SPOT and R5 Fireshed Assessment Process Quantitative Framework for Wildfire Risk WWETAC, JFSP 06-1-04-06 (Miller, Ager, Finney, Parisien) ArcFuels

21. ArcFuels • VBA macros in ArcMap • Implemented on 2 toolbars • ArcObjects library allows full GIS functionality • Distributed in an .MXD project file • Macro errors do not crash ArcMap • Hooks to Excell, Access, FVS, FlamMap, Farsite, Nexus, SVS, Behave • Interface