Global Warming, Forests, and Fire: What Might We Expect

8/3/2019 Global Warming, Forests, and Fire: What Might We Expect

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Climate Change, Forests, & Fire

What Might We Expect?

Carl N. SkinnerProject Leader

USFS Pacific Southwest Research StationRedding, CA

PSW


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Climate Change?Statistical Proof?

There i s on ly one ea r t h !


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Climate Change?Statistical Proof?

4 x CO2Control .5 x CO2 2 x CO2

Study the Past Monitor the PresentModel the Future


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Piecing Together a Picture ofClimate History

Piecing Together a Picture ofClimate History

Ice CoresGas, Isotopes, Dust Sediment Cores

Pollen, Charcoal, Fossils Pack-rat Middens Tree-rings

Ring width, Ring density,Isotopes, Fire scars

Instrumental Record

Ice CoresGas, Isotopes, Dust Sediment Cores

Pollen, Charcoal, Fossils Pack-rat Middens Tree-rings

Ring width, Ring density,Isotopes, Fire scars

Instrumental Record


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Climate is always

changing.

Just sometimes faster

than at other times.


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380

1960-1990

Ice core data


7/54From: Jones et al. 2001 Science 292: 662-667

Globa l Tem pera t u re Trends

Black = Instrumental Record 1861-1990Others = Reconstructed from tree rings


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Global Temperatures8 warmest yrs on record are since 1998


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Climate ChangeTemperatures

Warming

Night vs. Day

Winter vs. Summer

Elevation

Latitude Poles vs. Equator

Warming

Night vs. Day

Winter vs. Summer

Elevation

Latitude Poles vs. Equator


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Water

Snow melt

Earlier / more rapid Stream flow

Dominated more by rain rather than snowMore rapid rain related peaks

Less summer flows


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Climate Change&

Fire

What might we expect?


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The most potent factor in shaping the forest of the region has been, and still is, fire. The general character of the forest,

... in fact almost every phase of its condition has been determined by ...

fire.

J. B. Leiberg1902

Forest conditions in the northern Sierra Nevada, California.

Professional Paper 8, Series H, Forestry, 5.US Geological Survey, GPO, Washington, D.C.


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Havent Fire Regimes and Forestshad to adjust to a warming climate

before?

Havent Fire Regimes and Forestshad to adjust to a warming climate

before?

Neverwhen accompanied by

nearly a century offire suppression!


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Where are we headed?

Fire season getting longer. Fuels keep growing. Greater probability of intense fires.

H e a t O x y g e n

Fuel

FireTriangle

FireTriangle


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Annual Area BurnedWestern States

0.0

0.51.0

1.5

2.02.5

3.0

1915 1925 1935 1945 1955 1965 1975 1985 1995 2005

Millions of Hectares

0.0

0.51.0

1.5

2.02.5

3.0

1915 1925 1935 1945 1955 1965 1975 1985 1995 2005

Millions of Hectares

From: Arno & Allison-Bunnell 2002 (1915 to 2000) &National Interagency Fire Center http://www.nifc.gov/fire_info/fire_stats.htmFrom : Arno & Allison-Bunnell 2002 (1915 to 2000) &National Interagency Fire Center http://www.nifc.gov/fire_info/fire_stats.htm

5 *

2.5 **Millions

of Acres

7.5 *


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Mediterranean Climate

Cool/wet Wintersvegetation/fuel

Warm/dry Summerannual fire season

Lightning


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Fire Climate - Precipitation Patterns

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

2

4

6

8

10

12

14

16

18

20

NORTH PLATTE, NE


2

4

6

8

10

12

14

FLAGSTAFF, AZ

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0.0

0.5

1.0

1.5

2.0

2.5

YELLOWSTONE LAKE, WY


5

10

15

20

REDDING, CA


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Red dots = Lightning Caused FiresBlue dots = Human Caused Fires


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33 Fire Scars


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Taylor & Skinner 2003


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California ~ 4.5 to 12 million acres/yrStephens et al. 2007 FEM


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Of the hundreds of persons who visit the Pacific slope in California every summer to see the mountains, few see more then theimmediate foreground and a haze of smokewhich even the strongest glass is unable to

penetrate.

C. Hart Merriam1898 Visit to Siskiyou CountyChief, Division of Biological Survey

From: Morford 1984


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Stand Structure & Species CompositionChanges over 20th Century

Stand Structure & Species CompositionChanges over 20th Century

Fire exclusion has helpedlead to increasing stand

density.

Fire exclusion has helpedlead to increasing stand

density.

OriginalStandStructure

OriginalStandStructure


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Forest Restoration? What Time Period?

What is your goal?StructureProcess/FunctionResilience


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From: Jones et al. 2001 Science 292: 662-667

Tree-ring Based Fire HistoriesTree-ring Based Fire Histories

Mostly cover the period of~1600 to 1900

Much colder than 20 th Century.


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Tree-ring Evidence of Fire/Climate RelationshipsSkinner, Taylor, Carleton, Stephens

Regions adapted from

Trouet, Taylor,Carleton, & Skinner 2006 GRL

Since 1600, tree-ringevidence suggests that

average temperatureswere associated with fireactivity the higher the

temperature, the morewidespread were thefires across the study

regions.


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Resilience the capacity of a system toabsorb disturbance and

reorganize w hile undergoingchange so as to retain

essentially the same function,structure, identity, andfeedbacks

Folke, C. and others 2004. Regime shifts, resilience, andbiodiversity in ecosystem management. Annual Review

of Ecology, Evolution, and Systematics 35: 557-581.


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ResilienceForested systems characterized byfire regimes of frequent, mostly

low-moderate intensity fires,

dominated by large, long-livedtrees, are considered resilient ifthe forested landscape exhibits a

generally forested condition,including larger trees, shortly

following an event such as fire.


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Surface Fuels Ladder Fuels

Crown Fuels Large Fire Resistant

Trees

Agee & Skinner 2005Basic principles of forest fuel reduction treatments.

Forest Ecology & Management 211: 83-96

Stand ScalePriorities for Fuels Assessments


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19821982

19921992

19941994


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Climate Change, Fire,

&

CarbonZhang, Powers, Skinner

The following slides are based on preliminary,unpublished data. It is subject to further revision

before publication.


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Com ponent s o f C in fo res t ec osys t em s above ground

Deadt r e e sDeadt r e e s

U n d e r s t o r y Do w n w o odDo w n w o od

L i v e t r e e sL i v e t r e e s


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Carbon in fo res t f loor and be low ground .

Forest FloorForest FloorCoarse RootsCoarse Roots

Lateral RootsLateral RootsMineral SoilMineral Soil


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The Whi t m ore Garden o f Eden St udyW.M Beaty & Associates

F

HI

Ctrl

HFI

FI

F

HF

H

F

I

HFI HF HF

H H Ctrl Ctrl

F

HF

H

F

HF

H

H

FCtrl

Ctrl

HF


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F

Destructive

sampling at 21 years


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Whole St and Carbon a t Age 21

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

C F H HF

C

b

(Mg

h

Fores t f l oor U nders t o ry Live t ree


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Message #1:

Managed s t ands s t o r em o re l i ve t r ee c a rb on

t h an u nm a na ge d s t a nd s


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What about climate change?

Pr e c i p i t a t i o n d e c r e as e Tem p e ra t u r e i nc r e as e B o t h


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Cl im at e Change Effec t s on

Aboveground B iom ass a t age 21

C(43.4)

F(89.7)

H(125.2)

HF(148.7)

-16

-12

-8

-4

0

C

(%)

-25% ppt


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C(43.4)

F(89.7)

H(125.2)

HF(148.7)

-16

-12

-8

-4

0

C

(%)

-25% pp t +2C


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-1 6

-1 2

-8

-4

0

C

(%)

-25% ppt +2C -25%ppt +2C

C(43.4)

F(89.7)

H(125.2)

HF(148.7)


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Message #2:

Unm anaged s t ands a r em o re s en s i t i ve t o g lo ba lw a rm i ng in t e rm s of l i ve

t r ee c a rb on

Fores t f loor U nders t ory Live t ree


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What about

WholeS tandCarbon

af t e r Fi r e?

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

C F H HF

C

b

(Mgh

U nders t o ry L iv e t ree

2644

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

C F H HF

Cb

(Mgh


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Message #3:

Managed s t ands a r e m orer es i l ie nt t o w i ld f i re int e rm s of t o t a l s t and

c a r b o n


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Conclusions

Managed s t ands w i l l seques t e r m o r e c a r bo n i n t h e t r e esrega rd les s o f s t and ages . Treec a rb on i s m u c h m o re s t a bl e in

r e sp o ns e t o f i r e an d c l i m a t ec hange t han ot he r abovegrounde c o s ys t e m c o m p o ne nt s

Managing fo re s t s appear s t o be ap ar t i c u la r l y i m p or t a nt t o ol t o

m i t i g at e c l i m a t e c h an ge


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Where are we headed?

Fire season getting longer. Fuels keep growing.

Greater probability of intensefires.

C l i m a t

e W e a t h e r

Vegetation

FireTriangle

FireTriangle

Fi


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Fire:A Catalyst

For Change?

From M RitchieFrom M. Ritchie


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Thank You!Thank You!

1 2 i n c h e s

From M. Ritchie& T. Hamilton

From M. Ritchie& T. Hamilton

Documents

Global Warming, Forests, and Fire: What Might We Expect