• Immediate Changes

Carbon Emissions, Tree Mortality

• Short Term Changes

Erosion, Water Quality, Nutrient Availability

• Long Term Changes

Future Flammability, Animal Browse

• Immediate Changes

Carbon Emissions, Tree Mortality

• Short Term Changes

Erosion, Water Quality, Nutrient Availability

• Long Term Changes

Future Flammability, Animal Browse

Fire Severity: Amount of Change Following Fire (Percent Combusted)

• Reconstructed Organic Matter (C&N) Pools

Plot Scale; Quantitative; Effort=High

• Composite Burn Index (CBI)

Plot Scale; Semi Quantitative; Effort=Medium

• Normalized Burn Ratio (NBR)

Remote Sensing; Semi Quantitative; Effort=Low

• Reconstructed Organic Matter (C&N) Pools

Plot Scale; Quantitative; Effort=High

• Composite Burn Index (CBI)

Plot Scale; Semi Quantitative; Effort=Medium

• Normalized Burn Ratio (NBR)

Remote Sensing; Semi Quantitative; Effort=Low

Fire Severity: Amount of Change Following Fire (Percent Combusted)

How do we measure something that burned away?

Fire Severity: Amount of Change Following Fire (Percent Combusted)

Biomass Reconstruction

• Adventitious roots on black spruce trees grow at the surface of the organic soil

• Roots are still visible after fire• Post-fire measurements can reconstruct pre-fire organic soil

depth and C and N pools• Aboveground tree measurements, visual estimates, plus

allometric equations used to reconstruct canopy

green mossdead mossfibric humic

Mean offset between adv. root

and moss surface = 3.2 ± 0.3 cm

Adventitious root

Organic Soil Reconstruction

• Measure depth & horizons of remaining post-fire organic soil

• Adventitious root collar: height above burn (correct for deeper burning under trees)

• soil core samples analyzed by horizon for bulk density, [C] and [N]

(burned layers reconstructed from soil measurements in unburned)

Organic Soil Reconstruction

• Measure tree density and basal area

• Visually estimate %Combustion for: needles, fine branches, coarse branches and cones

•Black spruce allometric equations used to estimate quantity of canopy fine fuels

• ~50% C• 0.4 - 1% N

Canopy Reconstruction

• A scaled index to visuallyquantify and standardizefire effects over largeareas.

• Five strata

• CBI scale: Low (0.5-1)Moderate (1.0-2.0)High (2.0-3.0)

Composite Burn Index (CBI)

How does CBI compare to

%combustion estimates?

Organic soil Canopy

R2= 0.63, P<0.001R2= 0.14, P<0.02

• Mean combustion was 64%

• CBI better correlated with organic soil combustion

0

20

40

60

80

100

1 1.5 2 2.5 3

%m

ass

com

bu

stio

n

Total CBI scores

• CBI significantlypositively related to % mass combustion

How does CBI compare to C emissions?

• CBI significantlypositively related to % C lost

• CBI better correlatedwith organic soil C emissions

• mean canopy and soil C emissions were 0.4 and 1.5 kg/m2

0

2

4

6

8

1 1.5 2 2.5 3

C e

mis

sion

s kg

/m2

Total CBI score

Organic soil

Canopy R2= 0.44, P<0.001

R2= 0.14, P<0.03

How well does CBI correlate with our fire severity estimates?

measurement CBI Equation R2 P- value Organic soil % mass combustion Total -39.7 + 45.0 (CBI- Tot) 0.63 <.0001 Understory (U) -13.0 + 34.7 * (CBI - U) 0.63 <.0001

% C combustion Total -66.3 + 52.56 * (CBI- Tot ) 0.54 <.0001

Understory (U) -36.6 + 41.1 * (CBI - U) 0.56 <.0001 C emissions (kg/m2) Total -3.0 + 2.60 * (CBI- Tot) 0.44 <.0001 Understory (U) -1.42 + 1.97 * (CBI - U) 0.43 <.0001 Tree canopy fine % mass combustion Total 34.3 + 16.51 * (CBI- Tot) 0.14 0.02 fuels Overstory (O) 9.6 + 2.83 * (CBI- O) 0.44 <.0001 (branches, needles, % C combustion Total 48.6 + 14.15 * (CBI- Tot) 0.15 0.02 cones) Overstory (O) 8.39 + 28.7 * (CBI- O) 0.44 <.0001 C emissions (kg/m2) Total -0.25 + 0.28 * (CBI Tot) 0.14 0.03 Overstory (O) -0.74 + 0.45 * (CBI - O) 0.27 0.002 Ecosystem % mass combustion Total -37.0 + 43.9 *(CBI – Tot) 0.64 <.0001 % C combustion Total -61.1 + 50.6 * (CBI - Tot) 0.56 <.0001 C emissions (kg/m2) Total -3.26 + 2.85 * (CBI - Tot) 0.45 <.0001

Summary• Adventitious root method is a good proxy for

pre-fire organic soil height

• Correct adventitious root measurements for deeper burning at tree, and for offset between root and organic soil surface height

• CBI is a great estimator of % mass lost, and pretty good for C emissions

• CBI is a better predictor for organic soil mass and C emissions, explaining from 45-64% of the variation

2 Upland Black Spruce Burns

Yukon Charley 1999

• Fire start mid-June• NBR 9-Sept

CBI-NBR trend:• R2 = 0.81, n=32• R2 = 0.64, n=47

Boundary 2004

• Fire start mid-June• NBR 6-Sept

CBI-NBR trend:• R2 = 0.30, n=32• R2 = 0.43, n=28• R2 = 0.29, n=73

dNBR = 797dNBR = 672

dNBR = 913

Lessons Learned

• Remote sensing estimates best across wide

range of severity

• Unreliable to estimates at high fire severity

• Estimates should be calibrated by vegetation

type

• Solar elevation/topography problems

Field Estimates : CBI (0 to 3)

Using the adventitious root method to measure fire severity

How do we measure something that burned away?

MeasurementsMeasurementsat burned sites: at burned sites:

understoryunderstory• Depth of post-fire

organic soil including horizons

• adventitious root collar height above burn

• soil core samples analyzed by horizon for bulk density, [C] and [N]

1. Dead moss1. Dead moss

2. Fibric2. Fibric

3. Humic3. Humic

MeasurementsMeasurementsat unburned sites: understoryat unburned sites: understory

Root collar height

Adventitious root offset:Adventitious root offset: Distance between high Distance between high adventitious root andadventitious root and green mossgreen moss

Mineral Mineral soilsoil

unburned sitesunburned sitesfour horizons:four horizons:

3. Fibric3. Fibric

4. Humic4. Humic

2. Brown moss2. Brown moss

1.1. Green mossGreen moss

• Root collar height corresponds to organic soil height

• add 3.2 cm

• pre-fire organic soildepth= post-fire depth + Root collar height + Root Collar offset

> 0 0

<0

to -

1

<-1

to -

2

<-2

to -

3

<-3

to -

4

<-4

to -

5

<-5

to -

6

<-6

to 0

2

4

6

8

Frequ

ency

Root collar offset values (cm)

Does the adventitious root method work?

+Adventitious root height

+ Depth of post-fire soil organic layer

= Pre-fire soil organic layer depth

Moss

Fibric

HumicMineral

soil

Adventitious root height

Adventitious roots

Brown Moss

FibricHumicMineral

soil

Green Moss

• Adventitious roots on black spruce trees grow at the surface of the organic soil

• Roots are still visible after fire• We can reconstruct pre-fire

organic soil depth and C and N pools