2007 SHRUG GIS Workshop

Modeling Fire Behavior and Assessing Post Fire Burn Severity for the 2007

Big Turnaround Fire Complex Joe Noble

Joshua Picotte

2007 SHRUG GIS Workshop

Project Overview

BackgroundProject QuestionsResultsConclusions

Mark Jamieson May 31, 2007

2007 SHRUG GIS Workshop

Background-Burn Severity and Joint Fires Science Program (JFSP)

Burn Severity-ecosystem change and landscape changeSystem developed in 1996 by Carl Key and Nate Benson Started in the Western United States

Initial Fires Assessed-1994 Glacier National Park FiresNeeds more work in East

JFSP was formed in 1998 to provide support for fuel and fire management programs

Key and Benson 1995

Key and Benson 1995

2007 SHRUG GIS Workshop

Background-Composite Burn Index (CBI) and Normalized Burn Ratio

(NBR)NBR-Remote sensing of burn severityLandsat R4 (NIR, Veg) and R7 (SWIR, Soil)

NBR = (R4-R7)/ (R4+R7)dNBR=NBR prefire-NBR postfire

CBI-Ground measure of burn severity30 m plot

CBI should validate NBR values

2007 SHRUG GIS Workshop

Background-deltaNormalized Burn Ratio (dNBR)

dNBR: Change in reflectance between pre-fire (1 year pre-fire) and post-fire NBR values

dNBR=NBRprefire-NBRpostfire

Weighted dNBR = Average of plot center and corners (N=5)

30m

30m

30m

659 - 1300High

439 - 659Moderate-High

269 - 439Low-Moderate

99 - 269Low

-100 - 99UnburneddNBRSeverity

2007 SHRUG GIS Workshop

Background-Composite Burn Index (CBI)

Burn Index: 0-30-Unburned3-Severe Burn

Five Strata4-5 Ratings FactorsAveraged

CBI ScoreAverage of Five Strata

2007 SHRUG GIS Workshop 0 20 4010 Kilometers

²

Background-Big Turnaround Fire Complex Burn Severity

UnburnedLowLow-ModerateModerate-HighHigh

Burn Severity

2007 SHRUG GIS Workshop

Background-Assessed Habitats Within the Big Turnaround Fire Complex

A. Flatwood Pineland• Palmetto• Long-Leaf/Slash Pine

B. Depression Swamp• Cypress• Titi• Pond Pine• Ilex sp.

A.

B.

2007 SHRUG GIS Workshop

Background-Plot Locations

_ Plot Locations

UnburnedLowLow-ModerateModerate-HighHigh

Burn Severity

0 7 143.5 Kilometers

²

Plots:

89 CBI

32 “Virtual”

2007 SHRUG GIS Workshop

Project Questions

1) Does this system adequately describe burn severity within ecosystems affected by the Big Turnaround Fire Complex?

2) Are there differences in the effectiveness of using CBI and dNBR to categorize burn severity in flatwood and depression swamp community types?

3) What are the appropriate dNBR breakpoints for a given burn severity categories?

2007 SHRUG GIS Workshop

Results-Correlations Between CBI and dNBRWithin Flatwoods

y = 0.0022x + 0.09R2 = 0.7493

0

0.5

1

1.5

2

2.5

3

-100 0 100 200 300 400 500 600 700 800 900 1000

dNBR

CB

I

2007 SHRUG GIS Workshop

Results-Correlations Between CBI and dNBRWithin Depression Swamps

y = 0.0016x + 0.691R2 = 0.5419

0

0.5

1

1.5

2

2.5

3

-200 0 200 400 600 800 1000 1200

dNBR

CB

I

2007 SHRUG GIS Workshop

Results-Flatwood Vs. Depression Swamp dNBR Breakpoints

660690974High

440496662Moderate-High

270303349Low-Moderate

10010937Low

<100<109<37Unburned

WesternAverageCalculatedSeverity

660690982High

440496755Moderate-High

270303527Low-Moderate

100109300Low

<100<109<300Unburned

WesternAverageCalculatedSeverity

2007 SHRUG GIS Workshop

Conclusions

dNBR images accurately represented the burn severity of the 2007 Big Turnaround Complex dNBR Breakpoints differed between vegetation typesdNBR Breakpoints calculated per vegetation type differ from suggested Western Breakpoint range of ± 100If possible, dNBR breakpoints should be calibrated with CBI plots for each fire

Increased accuracyMore research needs to be done

Effects of time since fireAccuracy of extended assessments

2007 SHRUG GIS Workshop

Acknowledgements

Dave BrownlieJason DrakeSue GraceJohn Bethay State ParkSusan KettShia MucciMatt Mueller Don OhlenOsceola National Forest Okefenokee National Wildlife RefugeKevin Robertson