ALFRESCO• State-transition type vegetation succession model

• Focuses on system interactions and feedbacks

• User-defined spatial resolution (currently operational at 1 km pixels)

• User-defined temporal resolution (currently operational on annual time step w/ monthly fire-climate relationship)

• Pixels are randomly “ignited” and fire “spreads” as a function of climate and vegetation state

Climate• GS Temp.• GS Precip.• Drought

Disturbance• Fire• Insects• Browsing

Deciduous Forest

Black Spruce Forest

Upland Tundra

Dry Grassland

White Spruce Forest

Colo

niza

tion

Fire

+ E

xtre

me C

old

Extreme Cold

Fire

+ D

roug

ht

Succession

Fire

Fire + Drought

Fire + Drought

Fire

+ S

eed

Sour

ce

Fire

Succession

Fire + Extreme C

old

Fire Fire Fire

Fire Fire

Probability of Burning

Vegetation Type

Stand Age

ClimateSuppression

HumanIgnitions

Individual Cell Flammability

Recursive Fire Spread Algorithm

1950 2000 2050 2100

0e+0

01e

+05

2e+0

53e

+05

4e+0

55e

+05

6e+0

5

Year

Cum

aliti

ve A

rea

Burn

(km

^2)

Historical FireCRU + GCM CompositeECHAM5HADCM3MIROC3.5GFDL2.1CGCM3.1

Simulated Cumulative Area Burned

1900 1950 2000 2050 2100

020

000

4000

060

000

8000

0

Year

cells

bur

nAreaBurn/Year: Replicate 43

Simulated AB/YearHistorical AB/YearBackCast

ECHAM5

Simulated Annual Area Burned – Best Replicate

1900 1950 2000 2050 2100

020

000

4000

060

000

8000

0

Year

cells

bur

nAreaBurn/Year: Replicate 43

Simulated AB/YearHistorical AB/YearBackCast

CGCM3.1

Simulated Annual Area Burned – Best Replicate

Time Since Last Fire at 2099

ECHAM5 CCCMA

1900 1950 2000 2050 2100

0.5

1.0

1.5

Year

Inte

rior C

onife

r to

Dec

id R

atio

Ratio.cccmaRatio.echam5Ratio.hadRatio.gfdl21Ratio.miroc2001 Ratio

Interior Spr/Decid Ratio 1860:2099 (GCM Comparison)Simulated Conifer to Deciduous Ratio

Management Implications• Alaska will likely experience substantial burning

over the next 3 decades in response to projected warming and drying.

• As a result the Alaska boreal forest will likely transition to a new landscape equilibrium dominated by deciduous vegetation.

• The age structure of this new landscape will likely be considerably younger, including the remaining spruce forest cover as a result of continued frequent burning events.