Buckle Up: The under-appreciated role of large wildfires in the West Cascades Daniel Donato Washington DNR & University of Washington May 2018
Wind Disturbances About the author Old-growth development J. Walstad Insect Volcano M. Simard Fire R. Van Pelt
Central Premise Very large fires will visit the west side, sooner or later (climate change or not) (management or not)
Eagle Creek Fire ~25,000 acres stand-replacement severity
Historic fire regimes Infrequent high severity Moderate frequency mixed severity Frequent low severity FROM: Draft Synthesis of Science to Inform Land Management Within the Northwest Forest Plan Area (January 2017)
Life & times of a Doug-fir/hemlock forest ~200-600 years Van Pelt (2007)
Circa year 1700 -At least 1 million acres burned on the Olympic Peninsula, and 3 to 10 million acres burned in western Washington -Henderson et al. 1989
Circa year 1700 -At least 1 million acres burned on the Olympic Peninsula, and 3 to 10 million acres burned in western Washington -Henderson et al. 1989
How big are westside fires?
Some background Research Question: How much late-successional habitat should we strive for? Whole landscape? Probably not then what?
Wanna know about old-growth in the West Cascades?
Wanna know about old-growth in the West Cascades? Gotta know about fire
Historic fire regimes Infrequent high severity Moderate frequency mixed severity Frequent low severity FROM: Draft Synthesis of Science to Inform Land Management Within the Northwest Forest Plan Area (January 2017)
Life & times of a Doug-fir/hemlock forest ~200-600 years Van Pelt (2007)
Approach: model the fires & succession on landscape over time ~200-600 years Van Pelt (2007) Halofsky et al. 2013, 2017
West Cascade landscape dynamics Fires 100 Percent of land area 80 60 40 20 0 6000 7000 8000 9000 10000 Years
West Cascade landscape dynamics Fires 100 Percent of land area 80 60 40 20 0 6000 7000 8000 9000 10000 Years
West Cascade landscape dynamics Fires Early-seral 100 Percent of land area 80 60 40 20 0 6000 7000 8000 9000 10000 Years
West Cascade landscape dynamics Fires Early-seral Late-seral 100 Percent of land area 80 60 40 20 0 6000 7000 8000 9000 10000 Years
In the process, we learned something about westside fires
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn)
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If one fire per 500 years Fire size =
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If one fire per 500 years Fire size = 6,000,000 acres
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 2 fires per 500 years (250-year intervals) Fire size =
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 2 fires per 500 years (250-year intervals) Fire size =
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 2 fires per 500 years (250-year intervals) Fire size = 3,000,000 acres
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 5 fires per 500 years (100-year intervals) Fire size =
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 5 fires per 500 years (100-year intervals) Fire size =
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 5 fires per 500 years (100-year intervals) Fire size = 1,200,000 acres
A little fire math West Cascades area = 6,000,000 acres Fire rotation = 500 years (time it takes for whole thing to burn) If 20 fires per 500 years (25-year intervals) Fire size = 300,000 acres
Even more math Fire frequency (annual probability) Fire likelihood 0.05 0.04 0.03 0.02 0.01 0.00 0 500,000 1,000,000 1,500,000 2,000,000 Fire size (acres) Power Law of event sizes
Even more math Fire frequency (annual probability) Fire likelihood 0.05 0.04 0.03 0.02 0.01 0.00 0 500,000 1,000,000 1,500,000 2,000,000 Fire size (acres) Fire frequency (annual probability) Fire likelihood 0.1 0.01 0.001 10,000 100,000 1,000,000 10,000,000 Fire size (acres) Power Law of event sizes
Solving for frequency/size
Solving for frequency/size
100-year flood Solving for frequency/size
Solving for frequency/size 100-year event 500-year event
Solving for frequency/size Event type (interval) Fire Size (acres) 25-year 50-year 100-year 200-year
Solving for frequency/size Event type (interval) Fire Size (acres) 25-year ~27,000 50-year ~110,000 100-year ~445,000 200-year ~1,730,000
Solving for frequency/size Event type (interval) Fire Size (acres) 25-year ~27,000 50-year ~110,000 Eagle Creek Fire 100-year ~445,000 200-year ~1,730,000
Results -- Fire Sizes
Results -- Fire Sizes Maximum fire/episode sizes (acres) More Fire frequency Less Fire rotation Shorter Longer 1,700,000
Results -- Fire Sizes Maximum fire/episode sizes (acres) More Fire frequency Less Fire rotation Shorter Longer 1,700,000 3,500,000 4,700,000 870,000 1,700,000 2,200,000 590,000 1,200,000 1,500,000
Not the first to suggest this Year ~1700 fire episode: >1 million acres on Olympic Peninsula, 3 to 10 million acres in western Washington (Henderson et al. 1989) 1902 Yacolt complex >1 million acres (Natl. Int. Fire Center [nifc.gov]) 1933 Tillamook burn 350,000 acres (Kemp 1960)
Early land surveys Spies et al. in review (summarizing Plummer 1902, etc.)
The M.O. of large westside fires Three factors coincide: 1) 2) 3)
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) 3)
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) Ignition source 3)
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) Ignition source 3) Synoptic east wind event
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) Ignition source 3) Synoptic east wind event 24-72 hours
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) Ignition source 3) Synoptic east wind event 24-72 hours Tillamook Burn: Yacolt Burn: 200,000 acres in 24 hrs 30 miles in 36 hrs
The M.O. of large westside fires Three factors coincide: 1) Exceptional summer drought (e.g. 2015) 2) Ignition source 3) Synoptic east wind event 24-72 hours Tillamook Burn: Yacolt Burn: 200,000 acres in 24 hrs 30 miles in 36 hrs Biscuit Fire
What about Fire suppression? Fuels management? Climate change?
What about Fire suppression? Ineffective on large events Fuels management? Climate change?
What about Fire suppression? Ineffective on large events Fuels management? Climate change? Event type (interval) Fire Size (acres) 25-year 27,000 50-year 110,000 100-year 440,000 200-year 1,700,000
What about Fire suppression? Ineffective on large events Fuels management? Climate change?
What about Fire suppression? Fuels management? Ineffective on large events Largely irrelevant here Climate change?
What about Fire suppression? Fuels management? Climate change? Ineffective on large events Largely irrelevant here Buckle up!
Cascadia Subduction Fires
Black Swan Theory: The world is structured by rare, unpredictable, extreme events that can only be rationalized in hindsight
One event can direct landscape (and management) for next century
Results -- Smaller landscape West Cascades region (2.7 million ha) Landscape (20,000 ha) LSR, timber block, municipal watershed, etc. Percent of land area 100 80 60 40 20 B E 0 6000 7000 8000 9000 10000 Year of simulation 6000 7000 8000 9000 10000
Results -- Smaller landscape West Cascades region (2.7 million ha) Landscape (20,000 ha) LSR, timber block, municipal watershed, etc. Percent of land area 100 80 60 40 20 B E 0 6000 7000 8000 9000 10000 Year of simulation 6000 7000 8000 9000 10000
So What do we do?
So What do we do?
So What do we do? Big events are part of the system; built-in resilience
So What do we do? Big events are part of the system; built-in resilience Climate adaptation management options are few, or ineffective (e.g. fuel management)
So What do we do? Big events are part of the system; built-in resilience Climate adaptation management options are few, or ineffective (e.g. fuel management) Fire suppression is a reasonable strategy
So What do we do? Big events are part of the system; built-in resilience Climate adaptation management options are few, or ineffective (e.g. fuel management) Fire suppression is a reasonable strategy KEY: Post-disturbance plans in place
DRM; oregonhikers.org Thanks