Fuel Treatment Effectiveness Fairbanks-North Star Borough CWPP Risk Assessment Update And Plan Evaluation.

Fuel Treatment Effectiveness

Fairbanks-North Star BoroughCWPP Risk Assessment Update

And Plan Evaluation

2006/7 CWPP Exposure Modeling• High Res Spot

Imagery in Yellow area

• Landsat imagery used in blue areas

• Fire Departments within black boundary (Phase 1)

• Whole Borough mapped eventually

Imagery provides the missing link to emergency services responders.

When responding to a fire, our fire engines only carry a roadatlas, shown here. Some of roads have not been constructed. Note that the fire (shown in red) crosses two pages in the atlas, making it difficult to read and determine your location.

Exposure Model ComponentsWildfire Exposure = Hazard Fuels + Ignition Risk + Values

of Concern + Suppression Ability

• Vegetation/Fuels Information was ground truthed.

• Rating Included Ignition Likelihood, Values at Risk, and Suppression Difficulty

• Fuels Hazard based on static evaluation of each location. Not able to evaluate change based on Fuel Treatments

Zones of Concern IdentifiedWUI areas rated•Red: Extreme•Yellow: Very High

•Green: High•No low or moderate designations

Mitigation Practices Employed• Fuels Reduction

Silvicultural Treatments– Shaded fuelbreaks– Shearing, piling,

burning

• Education and Outreach

• Improved Suppression Resources

• Community Planning and Preparedness

• Evacuation Planning and Implementation

Research: Cache Creek

Shear Blade

Drum Crushing

Mastication

Hand Falling

Grinding –Secondary Process

-Hand felled $ 2,700/ acre + $4,500/acre norm

-Masticating head $4,830/ acre

-Shear blade Single Pass $ 350/ acre Double Pass $ 450/ acre

-Drum Chopper $ 450/ acre

-Grinding $4,900/ acre

Costs

Questions: Where will the Fire occur and will the Fuel Treatment be Effective

Evaluating the CWPP Mitigations

• Original Exposure Model can’t be used to evaluate change in fuel hazard.

• New one needs to consider potential spread factor.

• Review needs to consider changes to the landscape from wildfires as well as fuel treatments

• Can ecological impacts, smoke hazard, and climate change be incorporated into the planned action items?

Evaluating Fuel Treatment Effectiveness

FLAMMAP 5 models fire spread as well as intensity. It includes spotting spread (as well as spread from surface fires and active crown fire), an important vector in Black Spruce that can breach fuel treatments.

Burn Probability models spread for many fires (e.g. 10,000) and identifies the relative probability for all areas on the landscape.

Stuart Creek

Wood River

LANDFIRE Landscape above and CWPP based landscape to the right using the same color schemes to represent

fuel models

2011 Hastings fire perimeter in red

•LANDFIRE landscape over-represents the aspen/birch (light green) spread and intensity

•CWPP landscape recognizes greater torching and crown fire potential in black spruce (brown).

LANDSCAPE SELECTION

LANDFIRE Landscape above and CWPP based landscape to the right using the same color schemes to represent

fuel models

2011 Hastings fire perimeter in red

Modeled growth for first 3 days of Hastings Fire (5/30 to 6/1) using same inputs.•LANDFIRE Analysis (left) spread was limited by light green fuel areas

•CWPP Analysis (below) filled out 6/1 perimeter effectively

LANDSCAPE CALIBRATION

Winds in the Fairbanks North Star Borough

• Composite of 7 RAWS stations in the borough

• Predominately S, SW, and W winds

• 2004 fires moved to the west, indicating potential for high risk winds from the NE

• 4 Analysis wind directions (NE, S, SW, W)

Other Environmental Inputs• Dead Fuel Moistures (no conditioning)

– 1hr = 5% – 10hr = 7% (FFMC of 93)– 100hr = 8%

• Live Fuel Moistures– Herbaceous = 100% to represent reduced flammability

in grasses and forbs soon after greenup– Woody = 90% to represent flammability in leatherleaf

and spruce seedlings– Foliar Moisture = 85% to represent spring dip conditions

in Black Spruce• Windspeed 20mph (Midflame winds partially

sheltered 6mph, unsheltered 8mph)

Before and After Treatment Analyses• Comparing burn

probability from before and after treatments are completed can identify areas of reduced risk (green shading).

• With 20 mph NE winds, some treatments and fire scars are more effective than others.

• Why?

Fire Sizes(distribution of the 10,000 fires from NE wind direction)

2006 (Before Fires & Treatments)

• Average Size 837.7 • Median Size 574.4 • Minimum Size 2.0 • Maximum Size 6559.1

2014 (After Fires & Treatments)

• Average Size 686.8 • Median Size 408.3 • Minimum Size 2.0 • Maximum Size 6609.1

20% reduction in average size30% in median size

Further Analysis

• Calculation and comparison of Fire Length/Fire Intensity for each grid cell in the Landscape (LCP)– Not only maximum intensity (as provided in first

analysis), but average and conditional values as well

• Combination of burn probabilities from the 4 wind directions.

• Addition of concentrations of human caused ignitions to further burn probability analyses.