1. ESRM 450 Wildlife Ecology and Conservation ECOLOGICAL DISTURBANCE Concepts, Approaches, and Applications

2. Parameters of Disturbance Regimes From White (n.d.)

3. The Disease Spiral From Manion (1991)

4. Yellowstone Fires of 1988 A shift in biological and management perspectives What are the effects of fire size and pattern?

5. Fire disturbance is an inherent process in forest ecosystems An example from PNW forests From Agee (1993)

6. Low severity fire regimes

7. High severity fire regimes

8. Landscapes with moderate severity fire regimes often have complex spatial patterns Southern Cascade Range, Oregon

9. Wind disturbance

10. Wind disturbance in the Pacific Northwest Cyclonic winds are associated with tropical storms intensified by the jetstream. Significant events are recorded every ~20 years. 1921 windstorm on the Olympic Peninsula

11. Wind and forest harvest

12. From Kimmins (1999)

13. Insects Low vigor trees are at greatest risk

14. Tree Mortality Mountain Pine Beetle Shaded areas show locations where trees were killed. Intensity of damage is variable and not all trees in shaded areas are dead. www.fs.fed.us/r6/nr/fid/data.shtml = Host Type 1980 - 2004 Pacific Northwest Region, Natural Resources, Forest Health Protection Pinus spp.

15. Mountain Pine Beetle outbreaks (1959-2002) Courtesy of Mike Bradley, Canfor Corporation

16. Dying Pinus edulis Jemez Mts., October 2002

17. Jemez Mts., May 2004

18. Interactions among disturbance agents Cascade Range, Oregon From Gara et al. (1985) Fire, mountain pine beetles, and fungi

19. Fire effects on forest landscapes From Swanson (1981)

20. Causes and rates of tree mortality vary with stand age (Douglas-fir, PNW) Regen. Full veg. Closed Mature Old cover canopy forest forest Stand age (yr) 0 – 5 5 – 20 20 – 100 100 – 200 > 200 Mortality rate Very high High High to mod. Mod. to low Mod. to low Mortality Phys. stress, Competition Competition Pathogens Wind causes herbivory phys. stress pathogens wind pathogens pathogens pathogens wind competition physiol. disorders herbivory From Swanson (1981)

21. Fire regimes What is a “fire regime”? –Frequency and severity –Seasonality, vegetation, controls (climate, fuels, ignition sources) Fire frequency –Point fire return interval –Composite fire interval –Fire cycle/rotation Fire severity (low, mixed, high) Baker & Kipfmueller (2001)

22. Fire regime properties PropertiesDrivers Temporal distributionClimate/weatherVegetation/fuelsTopography/landform Frequency or fire interval (mean and variance) Duration Seasonality Ignition availability and flammability Drought or days w/o rain Vegetation recovery / fuel buildup Consumption stages Greenup and leaf fall Interaction of fire size with fuel availability Interaction of topography with fire spread Spatial distribution Extent (mean and variance) Pattern (patch size, aggregation, contagion) Intensity and severity (mean and variance) Fire spread driven by weather From orographic atmospheric instability to apparent chance Micro-climate/weather from topography and fuels Vegetation/fuels connectivity Vegetation/fuel density and configuration Topographic barriers to fire spread Slope/aspect interact with weather

23. Low-severity fire in ponderosa pine and other dry forest ecosystems Pinus ponderosa

24. Pinus contorta High severity, but lots of geographic variation. High-severity fire regimes are associated with more serotinous cones. Serotinous cones Non-serotinous cones

25. N. Snell – California Academy of Sciences At treeline, rare patchy fires Whitebark pine (Rocky Mountains)

26. Sagebrush fires can be mixed to high severity Clint Wright

27. Chaparral fires are associated with synoptic weather (Santa Ana winds) and human ignitions.

28. Climatic change and controls on fire Fuels Climate Topography Temperature increases ENSO? Fire frequency Fire severity Fire area burned Air quality

29. Climate-limited or fuel-limited? Different fuel types respond differently to climate. Two mechanisms: drying of fuels and production of fuels. Drying happens seasonally, whereas production affects fire on scales from years to decades.

30. Managing fire regimes in the context of climatic change and other stresses Examples from forests of Western North America

31. Mixed conifer (Sierra Nevada, southern California) Ozone and particulate pollution Fire exclusion  high stand densities Extended warm period  insects Ponderosa pine, Jeffrey pine, white fir die Fuels accumulate  severe fires Exotic plants increase where fires do occur.

32. Global warming Bark beetles and defoliators Ponderosa and Jeffrey pine mortality Fuel accumulation Large severe fires Changes in species composition (including exotics) Sierra Nevada mixed conifer Fire exclusion High stand densities Ozone Higher temperatures & more severe and extended droughts

33. Lodgepole pine Extended warm period, insects, pines die, fuels accumulate, sets up for large fires.

34. Global warming Higher temperatures & more severe and extended droughts Bark beetles and defoliators Lodgepole pine mortality Fuel accumulation Large severe fires Changes in species composition (including exotics) Interior lodgepole pine Stand-replacing fire regime Extensive mature cohorts (70-80 yrs) Salvage logging

35. Multiple disturbances Fire and insects are modifying different regions (so far). Direct effects of global warming = melting of permafrost.

36. Stand-replacing fire

37. Stand-replacing beetles

38. Stand replacing fire + global warming Stand replacing insect kill + global warming Ecosystem change White spruce Paper birch Black spruce

39. Southcentral forests (non- maritime)/Interior forests on permafrost-free soils Interior forests on permafrost soils Ice-rich lowlands (deciduous forests) Upland coniferous forests Higher temperatures Beetles Large fires Species conversion More deciduous forest Thermokarst ponds Wetlands, fens, and bogs Coniferous and deciduous forest ? More stand- replacing fires Fuel accumulation Permafrost degradation Global warming

40. Managing fire and fuels is mostly a sociocultural challenge Federal fire suppression cost in 2002 = $1.6 billion (~$500 per ha burned)

41. Current conditions Target (historical) conditions

42. Objective: Reduce crown fire hazard Guiding scientific question How can fuel treatments be designed to modify fire hazard and potential fire behavior?

43. Burning Thinning

44. Scientific principles of fuel treatment: Modifying forest structure Raise canopy base height Reduce canopy bulk density Reduce canopy continuity AND reduce surface fuels

45. Principle #1 – Canopy base height Dense stand with understory -------- Canopy base height < 2 m Treated stand after thinning from below -------- Canopy base height > 6 m

46. Principle #2 – Canopy bulk density Dense stand with understory Canopy BD > 0.30 kg m -3 Treated stand after thinning from below Canopy BD < 0.10 kg m -3

47. Principle #3 – Canopy continuity Dense stand with understory Treated stand after thinning from below

48. Surface fuels must be treated following removal of trees

49. Analysis of stand development assists treatment scheduling 200320102015 2020 No treatment Thinning

50. Effective fuel treatment programs must consider large landscapes

51. Many constraints to effective fuel treatments Need lots of tree removal Lack of markets for small wood EIS, EA and other review Litigation Risk of escaped fire Scheduling (~20-year cycle)

52. Toward science-based fire management and policy Develop guidelines that quantify the effects of fuel treatments on fire behavior Integrate scientific information and human values (ecological + cultural restoration) Develop a rational economic approach Educate the public on living with fire

53. Principles of fire-resilient forests ObjectiveEffectAdvantageConcerns Reduce surface fuels Reduces potential flame length Fire control easier, less torching Low surface disturbance Increase canopy base height Requires longer flame length to begin torching Less torchingOpens understory, may allow surface wind to increase Decrease crown density Makes independent crown fire less probable Reduces crown fire potential Surface wind may increase, surface fuels may be drier Retain larger trees Thicker bark, taller crowns, higher canopy base height Increases survivability of trees Removing smaller trees is economically less profitable Adapted from Agee (2002)

54. How do forest harvest practices compare to natural disturbance processes? Standard thinning

55. How do forest harvest practices compare to natural disturbance processes? Variable density thinning

56. How do forest harvest practices compare to natural disturbance processes? Clearcut

57. How do forest harvest practices compare to natural disturbance processes? Multiple clearcuts