1. Fire, Multiple Stressors, Climate Variability and Change, and Ecosystem Impacts Ron Neilson Dominique Bachelet, James M. Lenihan, Raymond J. Drapek

2. Vegetation and Fire Dynamics (MC1 Model) FIRE (Surface, Crown, Rate of Spread) Growth and Nutrient Cycling (CENTURY) Vegetation Distribution (MAPSS) Drought Responses Fire Risks Carbon Sequestration

3. Historical Analyses Development of Understanding Fire, Multiple Stressors, Climate Variability and Change, and Ecosystem Impacts

4. Biomass Consumed 1895-2100 Disturbance Mediates Ecosystem Change MC-FIRE Simulation Biomass Consumed, 1988 1910 1988 Regime Shift 2035 1930s Yellowstone Fire Cornbelt Fires Increase in ‘Background Fire Severity Large, ‘Catastrophic’ Fires High Warming Small Warming Historic Trend Future Trend

5. Extensive Fire Suppression Little Fire Suppression

6. Absolute Change (Kg/m 2 ) Percent Change Fuel Buildup from Fire Exclusion, MC1 Simulation

7. 1976 Ocean-Climate Regime Shift Yearly Change in Leaf Mass With and Without Fire Exclusion

8. May 17, 2003 North of San Francisco Peaks, AZ (courtesy of Craig Allen) Trees are long-lived dominants, once established they have lots of inertia, tend to tolerate environmental stress and persist. So forests are often thought of as slow-changing, gradually adjusting to new climate conditions through competition and establishment.

9. September 20, 2003 North of San Francisco Peaks, AZ (4 months later) (courtesy of Craig Allen) But, once thresholds of environmental stress are exceeded, rapid changes can occur through massive forest dieback.

10. Wet Dry Ocean – Climate Regime Shifts Large El Niño Interdecadal Variability Dominates Historical Climate

11. Interdecadal Climate Regime Shifts 1976 - 771988 - 89 El Niño 19831998 Drought and Fire in the West (Simulated Fire, no Fire Suppression) 1940s

12. Pacific Decadal Oscillation (Mantua and Hare 2002) North Atlantic Oscillation (Hurrell 1995) 1988-891976-77 Arctic Oscillation (Thompson and Wallace 1998 ) Ocean – Climate Regime Shifts 1940s

13. Observed and Simulated Fire Area for the Conterminous U.S. (Millions of Acres) (MC1 Dynamic General Vegetation Model)

14. Near-Term Fire Risk Forecasting Fire, Multiple Stressors, Climate Variability and Change, and Ecosystem Impacts

15. Observed Large Fire Events in 2002 2000 2001 2002

16. Simulated vs. Observed 2003 Fires

17. Fire, Multiple Stressors, Climate Variability and Change, and Ecosystem Impacts Long-Term Forecasting

18. Historical Climate – MC1 Simulation (With Fire) 4/25/05

19. CSIRO_MK2-B 4/25/05

20. HADCM3-A 4/25/05

21. CGCM2-A 4/25/05

22. Biomass consumed by wildfire over North America Past Future Past Future

23. Potential Catastrophic Dieback of North American Forests: What is the Price of Uncertainty? Fire Management

24. North America Total Ecosystem Carbon Gain or Loss Historical and Future MC1

25. North America Total Ecosystem Carbon Gain or Loss Historical and Future MC1

26. CGCM2 CSIRO HADCM3 MC1 (No Fire Suppression) Percent Change in Vegetation Carbon A2B2

27. CGCM2 CSIRO HADCM3 MC1 (Fire Suppression) Percent Change in Vegetation Carbon A2B2

28. Tundra Taiga - Tundra Boreal Forest Maritime Conifer Forest Continental Conifer Forest Cool Mixed Forest Temperate Deciduous Forest Warm Mixed Forest

29. Taiga - Tundra Continental Conifer Forest Warm Mixed Forest Temperate Deciduous Forest Tundra Maritime Conifer Forest Cool Mixed Forest Boreal Forest

30. Yellow Pine Savanna Sagebrush – Steppe Chaparral Semi-Desert Grassland Pinyon – Juniper Woodland

31. Yellow Pine Savanna Sagebrush – Steppe Chaparral Semi-Desert Grassland Pinyon – Juniper Woodland

32. Tundra Taiga – Tundra Boreal Forest Maritime Conifer Continental Conifer Cool Mixed Forest Temperate Deciduous Warm Mixed Forest East U.S. West U.S. Canada & Alaska Browndown Timing with Fire

33. Tundra Taiga – Tundra Boreal Forest Maritime Conifer Continental Conifer Cool Mixed Forest Temperate Deciduous Warm Mixed Forest East U.S. West U.S. Canada & Alaska Browndown Timing with Fire Suppression

34. Potential Catastrophic Dieback of North American Forests: What is the Price of Uncertainty? Future Development Needs Better ignition Links to socioeconomic factors New fuel characterizations Scaling And many more

35. Riparian Floodplain South Facing North Facing Static Topoedaphic and Climatic Constraints Sub-Grid Heterogeneity Water Flows in Red Spatially Explicit Spatially Aggregated

36. 1 year old Old Growth 10 years old 50 years old Dynamic Age Cohorts, Post-Disturbance Sub-Grid Heterogeneity Spatially Implicit Spatially Aggregated

37. Conclusions North American Forests could experience an early greenup followed by a later ‘browndown’ Lower latitude forests begin to die back first, followed by higher latitude forests Fire Suppression could play a major role in mitigating the negative impacts, but can we afford it? Vegetation shifts will be very complex, tearing assemblages apart and creating new ones

38. Management Implications (personal musings) Management goals must look forward to an uncertain context, rather than backward to a presumed, certain ‘historical’ Potential Natural Vegetation Management Goals shift from ‘Desired future condition’ to Management of Change, per se and continuity of function Fire, Carbon and other policies may be antithetical demanding creative management of change Improve resilience of ecosystems to rapid change –Keep forest density below water-limited carrying capacity –Plant diversity as opposed to homogeneous monocultures in a landscape context