1. CLASS UPDATES Office hours: Fridays 9AM-12noon (or email me for an appointment) Powerpoints – on class website Schedule changes: thesis statement, outline, first draft Exams – will be returned on Thursday Quiz Thursday (today’s lecture/discussion only)

2. Fire Ecology: Rocky Mountain Mixed Conifer Forests NREM390 October 5, 2010

3. Fire Regimes: Review Components of fire regimes –Extent –Frequency –Seasonality –Intensity –Duration –Severity Historic vs. Modern Fire Regime?

4. Fire classification: severity and frequency (return interval) Short fire return intervals (<20 years) –Low-severity surface fires are common. –Fire tolerant herbaceous species or shrubs dominate. –Species composition often similar. Intermediate fire return intervals (20-75 years) –Fuel buildup and continuous in distribution –Moderate-severity fires (patchy crown fires) or some high-severity fires –Greater changes in plant composition Long fire return intervals (>100 years) –Very high fuel loads possible –High-severity fire commonly occur (stand-replacing crown fires) –Postfire & prefire vegetation can be very different Mixed-severity fires –Combination of frequent low-severity & infrequent high severity fires

5. How do historical (pre-settlement) and modern (current) fire regimes differ – and why? In ecosystems with high frequency, low intensity fire regimes (e.g., dry forests, grasslands, woodlands, savannas): –Significant changes to fire regime due to: Land use change (agriculture, urban) Fire suppression and fuel accumulation Change in vegetation type and structure Forests with low frequency, high severity stand- replacing fire regimes: –Much less change from historical fire regimes – Why?

6. Lodgepole pine (aspen, spruce-fir) 8,000-9,000 ft Douglas-fir mixed conifer 6,500-8,000 ft. Ponderosa pine 5,500-6,500 ft Alpine Meadows >11,000 ft Spruce-Fir 9,000-11,000 ft Short- grass steppe <5,500 ft Fire regimes in Rocky Mountain Conifer Ecosystems

7. Ponderosa Pine: Ecology Shade intolerant Early successional Fire resistant –Thick bark –Seedlings > 5 yr. old Mast seeding (episodic)

8. Ponderosa pine: fire regime Fire frequency: 5-30 yrs. Light surface fires Regeneration: –Patches of old trees  crown fire & seed bed –Mast year + fire-free period 1900s: grazing & fire suppression –Many seedlings survive –Fuel build up –High severity, stand-replacing fires

9. Ponderosa pine: Low intensity, frequent surface fires (historic) Stand-replacing fires

10. Lodgepole pine (aspen, spruce-fir) 8,000-9,000 ft Douglas-fir mixed conifer 6,500-8,000 ft. Ponderosa pine 5,500-6,500 ft Alpine Meadows >11,000 ft Spruce-Fir 9,000-11,000 ft Short- grass steppe <5,500 ft Fire regimes in Rocky Mountain Conifer Ecosystems

11. Douglas-fir, mixed conifer: Ecology Intermediate shade tolerance Early successional –Seedlings can establish on moist, cool sites Late successional –Understory of Ponderosa Pine –Understory of Lodgepole Pine Intermediate fire resistance –mature trees only

12. Historic: Mixed fire severity –Light surface fires, 20-60 yr. –Severe stand-replacing fires, >60 yr. Fire suppression  shade tolerant species –Douglas-fir seedlings –Hemlock, white spruce, blue spruce (low fire resistance) Shift: increased mixed-conifer forests on landscape Favors high severity, stand-replacing fires Douglas-fir: fire regime

13. Lodgepole pine (aspen, spruce-fir) 8,000-9,000 ft Douglas-fir mixed conifer 6,500-8,000 ft. Ponderosa pine 5,500-6,500 ft Alpine Meadows >11,000 ft Spruce-Fir 9,000-11,000 ft Short- grass steppe <5,500 ft Fire regimes in Rocky Mountain Conifer Ecosystems

14. Lodgepole pine: Ecology Shade intolerant Early successional Intermediate fire resistance Serotiny –Young trees – low serotiny –Old trees – low serotiny (high elevations with low fire frequency –Intermediate age – high serotiny requires intense ground fires Melt resin Exposed mineral soil (seed bed) http://www.cfr.washington.edu/Classes.esc.202/LPBarkBFireRot.htm

15. Lodgepole pine: fire regime Mixed severity fire regime Low-intensity surface fires, 50-100 yr. –Fuel characteristics –Topography & Weather Stand-replacing fires, 100-400 yr. –Climate driven –drought, winds Fire suppression –Understory: spruce, fire (low fire resistance) –Low impact on fire dynamics Altitudinal gradient: Rockies –Moisture, temperature –Biomass accumulation

16. Lodgepole pine (aspen, spruce-fir) 8,000-9,000 ft Douglas-fir mixed conifer 6,500-8,000 ft. Ponderosa pine 5,500-6,500 ft Alpine Meadows >11,000 ft Spruce-Fir 9,000-11,000 ft Short- grass steppe <5,500 ft Fire regimes in Rocky Mountain Conifer Ecosystems

17. Mid-Elevation Lodgepole pine ecosystems (8,000-9,000 ft)

18. Relatively rapid regeneration: - Lodgepole pine - Aspen - Spruce - Fir

19. High-Elevation Spruce-Fir ecosystems (10,000-11,000 ft)

20. Slow regeneration process

22. Alpine meadows and tundra forest

23. Lodgepole pine, Spruce-Fir Short grass steppe / Sagebrush Ecosystems & fire regimes Pinyon- Juniper Tallgrass prairie Ponderosa pine Douglas-fir mixed conifer

24. Fire regimes EcosystemSeverity class Fire intervalDriving factor Tallgrass prairie Short Grass Steppe /Sagebrush Pinyon-juniper (savannas, woodlands) Ponderosa Pine Mixed conifer (Ponderosa pine, Douglas fir, white fir, larch) Lodgepole pine Subalpine (lodgepole pine-spruce-fir)

25. Fire regimes EcosystemSeverity classFire intervalDriving factor Tallgrass prairie Short Grass Steppe /Sagebrush Pinyon-juniper (savannas, woodlands, forests) Ponderosa pine Mixed conifer (Ponderosa pine, Douglas fir, grand fir, western larch) Lodgepole pineMixed severity Subalpine (lodgepole pine- spruce-fir) High severity> 400+ yrs Fuel load Weather, fuel load, topography Weather, fuel load, topography Weather, fuel load, topography < 60 yrs > 100yrs 4-36 yrs < 100 yrs 1-5 yrs 20-50 yrs < 10 yrs < 100 yrs Low severity Low to moderate severity Low to moderate severity Mixed severity Weather 50-100 yrs > 400 yrs Weather, fuel load, topography

26. ElevationLow (< 2,000m)High (>2,300 m) Stand age130 yr.250 yr. % serotiny65%1.9 % Fire return interval~ 180 yrs.~ 300 yrs. Pine seedling density (stems/ha) 211,000 stems/ha600 stems/ha LP regenerationHigh (> 50/m2)Low (< 10/m2) Seed viabilityHigh (ground fires, melt resin, scarify soil) Low (crown fires, serotiny) Stand developmentSimilar to unburned forests High herbaceous density, Slow forest recovery * Effect of patch size on LP regeneration: Large > Small * Effect of fire severity on LP regeneration: ground fires > crown & surface Post-Fire Pre-FireYellowstone LakeCougar Creek Lodgepole Pine regeneration after the 1988 Yellowstone Fires

27. Fire and Ecosystem Heterogeneity Mosaic pattern – “patchiness” –Fire intensity –Burned area Microclimate variation –Light –Moisture –Nutrients Species composition & diversity –Different microclimate requirements –Different regeneration strategies Ecosystem diversity –Successional communities –Dynamic equilibrium (landscape scale)

28. Other examples of post-fire heterogeneity Herbaceous vegetation –Light (larger patches) –Seed dispersal high Aspen –Root suckering (low fire intensity) –Regeneration by seed (woody debris – elk browse) Spruce-fir –Distance to seed trees –Shade, moisture Wildlife –Mosaic of different habitats –Increased abundance of food

29. Initial vegetation cover: Lodgepole pine No fire until 300 yrs. Fire every ~40-50 yrs. Fire every ~100 yrs. Probably surface fires, high survival no new regeneration, dense LP stand Probably ground fires, some mortality, new seedlings, mixed-age LP stand Mixed LP, spruce-fir, crown fire, slow regen