Alan Tepley and Jane Kertis May 28, 2009 Fire Regimes and Successional Pathways in the Western...

Alan Tepley and Jane KertisMay 28, 2009

Fire Regimes and Successional Pathwaysin the Western Cascades of Oregon

• Fire-regime gradients in the Western Cascades

– Gradients of driving factors

– Location and severity of recent fires

• Fire effects and successional trajectories

– Warner Creek post-fire stand structure

– Age structure in the central western Cascades

• Topographic influences on fine-scale variability

• Influence of fire-severity mosaics on subsequent burn patterns

– 2008 Rattle Fire reburn of the 1996 Spring Fire

Fire Regimes in the Western Cascades as a Context for Restoration

Fire Regimes Based on Kuchler’s Potential Natural Vegetation Types

Stand-Replacement Fires 500+ yrs

Stand-Replacement Fires 201–500 yrs

Understory Fires 0–34 yrs

Mixed-Severity Fires 0–34 yrs

Brown et al. 2000Wildland Fire in Ecosystems:Effects of Fire on Flora

Data from NIFMID and ODF, Compiled by Ray Davis

NotModeled

High

Low

Density of Lightning Ignitions(1970–2002)

Mean Annual Precipitation(1961–1990)

Gradients of Fire Regime Drivers

Oregon Climate ServicePRISM Project

< 7070-9595-120120-150150-175175-200200-230230-270270-320320-390> 390

AnnualPrecipitation

(cm)

Frequency of Large

Fires (≥1,000 acres)

(1970-2008)1 burn

2 burns

3 burns

Ray Davis, Unpublished

DryFire-Prone Provinces

Frequency of Large

Fires (≥1,000 acres)

(1970-2008)1 burn

2 burns

3 burns

Ray Davis, Unpublished

Low

Moderate

High

Fire Severity

Severity of Recent Fires in the

Western Cascades

0 1 2km

Clark 2003 4,905 acres

0 1.5 3km

Warner Creek 1991 8,960 acres

0 1.5 3km

Spring 1996 15,960 acres

0 2.5 5km

Apple 2002 19,139 acres

0 3 6km

Boulder 2002 48,505 acres

0 1.5 3km

Shady Beach 1988 5,174 acres

Clark

WarnerCreek

ShadyBeach

SpringApple

Boulder

0 20 40Kilometers

60N

Morrison & Swanson 19900.50 1

km

Cook-Quentin Study AreaCumulative Effects of

19th-Century Fires

Low severity (< 30% mortality)

High severity (> 70% mortality)

Moderate severity (30–70% mortality)

Comparison to Historical Fire

Severity

0 30 60Kilometers

90N

Cook-Quentin

ClarkWarnerCreek

ShadyBeach

SpringApple

Boulder

Comparison of Two Recent Fires

Seral Stage Distribution

Pre-Fire Post-Fire (%) (%)

Early 5 30Mid 5 5Late 90 65

Fire SeverityLow 61% Moderate 13% High 25%

Kertis 2000

Spring Fire 1996 15,960 acres

0 3 6Kilometers

9N

Kushla and Ripple 1998

Fire SeverityLow 48% Moderate 12% High 40%

Warner Creek Fire 1991 8,960 acres

0 2 4Kilometers

6N

Seral Stage Distribution

Pre-Fire Post-Fire (%) (%)

Early Seral/Rock 14 46Sapling/Pole 9 4Open Mature/Old 0 18Closed Mature/Old 77 32

Pre-fire Density of Small Trees (5–30 cm dbh)

Pre-fire Density of Small & Medium Trees

(5–60 cm dbh)

Pre-fire Densityof Large Trees (> 100 cm dbh)

R2 = 0.010p = 0.410

R2 = 0.024p = 0.197

R2 = 0.002p = 0.399

Bas

al A

rea

Mo

rtal

ity

(%)

0 100 200 300 400

Density (stems/ha)

0

20

40

60

80

100

Summarized from data of Larson and Franklin (2005)

Warner Creek Fire Severity was Weakly Related to Stand Structure at a Plot Scale

0 200 400 600

Density (stems/ha)

0

20

40

60

80

100

0 20 40 60 80 120

Density (stems/ha)

0

20

40

60

80

100

100

Low Severity< 30% BA Mortality

(n = 31)

Den

sit

y (t

rees

/ha)

05

10152025

25

2015105

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

Shade-Tolerant

DBH (cm)

0

10

20

30

20

20

10

0 20 40 60 80 100120140160

Survival

Mortality

Den

sit

y (t

rees

/ha)

Moderate Severity30–70% BA Mortality

(n = 23)

0

5

10

15

20

Den

sit

y (t

rees

/ha)

20

15

10

5

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

DBH (cm)

50

403020

10

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

01020304050

Survival

Mortality

Shade-Tolerant

High Severity> 70% BA Mortality

(n = 14)

DBH (cm)

Survival

Mortality

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

Shade-Tolerant

010203040506070

10203040506070

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

10203040506070

010203040506070

Data from Jane Kertis, Prepared by Stuart Johnston

Plot Burned at Low Severity


Plot Burned at Moderate Severity


Plot Burned at High Severity

Elevation (m)High: 3,196

Low: 45

Transect Location

Willamette National Forest

Study Area

N 0 10 30 50Kilometers

20 40

Oregon

Eugene Bend

FallCreek

BlueRiver

Cre

sto

fth

eC

asca

des

WarnerCreekFire

DBH (cm)

Den

sit

y (t

rees

/ha)

0 40 80 120 160

Survival

Mortality

20

40

60

0

20

40

60


Den

sit

y (t

rees

/ha)

05

10152025

25201510

5

0 40 80 120 160

Survival

Mortality

DBH (cm)


Den

sit

y (t

rees

/ha)

0

5

10

15

20

20

15

10

5

0 40 80 120 160

Survival

Mortality

DBH (cm)


0

50

100

150

200

250

300

Den

sity

(tr

ees/

ha)

No Evidenceof Fire(n = 18)

LowSeverity(n = 19)

ModerateSeverity(n = 33)

HighSeverity(n = 15)

Before 1800After 1800

Establishment Date

62 6243

70 4

108

210

Using the Past to Infer Successional TrajectoriesComparing Warner Creek to Sites Burned in the 19th Century

Warner Creek post-fire data

(shade-intolerant only)

Sites burned in the 19th Century

(shade-intolerant only)


Den

sit

y (t

rees

/ha)

05

10152025

25

2015105

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

Shade-Tolerant

DBH (cm)

0

10

20

30

20

20

10

0 20 40 60 80 100120140160

Survival

Mortality

Den

sit

y (t

rees

/ha)

Succession Following Low-Severity Fire

% o

f S

amp

led

Tre

es

0

4

0

4

8

12

1500 1600 1700 1800 1900 2000

Shade Tolerants (n = 340 trees)

Shade Intolerants (n = 103 trees)

Composite for 19 Sites

2 Representative Transects

0

10

20

30

1500 1600 1700 1800 1900 2000

0

10

20

30

1500 1600 1700 1800 1900 2000

Establishment Date

% o

f S

amp

led

Tre

es

Shade-TolerantShade-Intolerant

with charred bark Hardwood

% o

f S

am

ple

d T

ree

s

0

4

0

1500 1600 1700 1800 1900 2000

4

8

12Shade Tolerants (n = 304 trees)


Establishment Date

No Evidence of 19th-Century Fire(composite of 18 transects)

0

4

0

% o

f S

am

ple

d T

ree

s

1500 1600 1700 1800 1900 2000

4

8



Establishment Date

19th-Century Low-Severity Fire(composite of 19 transects)

Effects of Low-Severity Fire

Shade-Tolerant

ShadeIntolerant

Shade-Intolerant withcharred bark


(n = 23)

0

5

10

15

20

Den

sit

y (t

rees

/ha)

20

15

10

5

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

DBH (cm)

50

403020

10

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

01020304050

Survival

Mortality

Shade-Tolerant

Succession Following Moderate-Severity Fire

05

10152025

1500 1600 1700 1800 1900 2000

01020304050

1500 1600 1700 1800 1900 2000

Establishment Date

% o

f S

amp

led

Tre

es


% o

f S

amp

led

Tre

es

0

4

8

12

0

4

1500 1600 1700 1800 1900 2000



Composite of 33 Transects




(n = 14)

DBH (cm)

Survival

Mortality

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

Shade-Tolerant

010203040506070

10203040506070

Den

sit

y (t

rees

/ha)

0 20 40 60 80 100120140160

Survival

Mortality

Shade-Intolerant

10203040506070

010203040506070



% o

f S

amp

led

Tre

es

0

4

8

12

0

4

1500 1600 1700 1800 1900 2000




0

10

20

30

1500 1600 1700 1800 1900 2000

010203040

1500 1600 1700 1800 1900 2000

Establishment Date

% o

f S

amp

led

Tre

es


Succession Following High-Severity Fire

High-Severity Fire

Low-

Severity

Fire

Moderate-SeverityFire

Stand Development

Douglas-fir (> 200 yrs old)

Western hemlock

Western redcedar

Douglas-fir (< 200 yrs old)

Successional in Douglas-fir Forests

1-4 DecadesSince Fire

100–200 YearsSince Fire

300–500 Years Since Fire

Stand Development

Underburn

Low-severity fire

Moderate-severity fire

Douglas-fir (> 200 yrs old)

Western hemlock

Western redcedar

Douglas-fir (< 200 yrs old)

Successional Pathways in Douglas-fir Forests

% o

f S

amp

led

Tre

es

0

4

0

4

8

12

1500 1600 1700 1800 1900 2000






0

10

20

30

1500 1600 1700 1800 1900 2000

Establishment Date

0

10

20

30

1500 1600 1700 1800 1900 2000


% o

f S

amp

led

Tre

es

Age Structure of Fire-Prone Stands

with at least 3 Douglas-fir Cohorts

% o

f S

amp

led

Tre

es0

4

0

1500 1600 1700 1800 1900 2000

4

8



Establishment Date

No evidence of fire for > 350 yrs(composite of 18 transects)

% o

f S

amp

led

Tre

es

Establishment Date

0

4

0

1500 1600 1700 1800 1900 2000

4

8



At least 3 fires in the last 400 yrs(composite of 13 transects)

Shade-Tolerant

ShadeIntolerant

Shade-Intolerant withcharred bark

Comparison of Stand and Age Structure in the Most and Least Fire-Prone Sites

1,6001,5001,4001,3001,2001,1001,000 900 800 700

RidgetopElevation (m)

Terrain Shape

Pro

bab

ility

of

Occ

urr

ence

0 30 60 90 120 150 180 2100.0

0.1

0.2

0.3

0.4

0.5

Concave Convex

Topographic Context for Stands with no Evidence of Fire for at Least 350 yrs

% o

f S

amp

led

Tre

es

0

4

0

1500 1600 1700 1800 1900 2000

4

8



Establishment Date

Composite of 18 transects

Shade-Tolerant

Shade-Intolerant

Probability of Occurrence for

the Least Fire-Prone Stands

< 0.050.05–0.100.10–0.150.15–0.200.20– 0.250.25–0.300.30–0.350.35–0.400.40–0.450.45–0.50

Probability of Occurrence

Present

All OtherTransects

TransectLocation

20151050Kilometers

N

Blue River

Fall Creek

12 9630Kilometers

N

129630Kilometers

N

3350 3820 4290 4760 5230 5700Insolation

0.0

0.1

0.2

0.3

0.4

Pro

bab

ility

of

Occ

urr

ence

66605448423630241812

SlopeGradient (%)

3350 3820 4290 4760 5230 5700Insolation

0.0

0.1

0.2

0.3

0.4

0.5P

rob

abili

ty o

f O

ccu

rren

ce

1,6001,5001,4001,3001,2001,1001,000 900 800 700

RidgetopElevation (m)

% o

f S

amp

led

Tre

es

Establishment Date

0

4

0

1500 1600 1700 1800 1900 2000

4

8



Composite of 13 transects


with charred bark

Topographic Context for the Most Fire-

Prone Stands

Probability ofOccurrence

< 0.050.05–0.100.10–0.150.15–0.200.20–0.250.25–0.300.30–0.350.35–0.400.40–0.450.45–0.60

Present

All OtherTransects

TransectLocation

Probability of Occurrence for

the most Fire-Prone Stands

20151050Kilometers

N

Blue River

Fall Creek

129630Kilometers

N

129630Kilometers

N

Clearcut

High Severity

Low SeverityModerate Severity

Natural Opening

Road

Spring Fire Severity

Spring Fire 1996 15,960 acres

Rattle Fire 2008 19,771 acres

Clearcut

High Severity


Natural Opening

Road


Rattle Fire Perimeter

September 14

September 152,202 acres burned



The Biggest Fire Days

48% of the Rattle Fire (9,453 acres) burned from 9/14 to 9/17

Clearcut

High Severity


Natural Opening

Road


Increasing

• annual precipitation

• mean fire intervals

• proportion of fire covered by large high-severity patches

• influence of fuel moisture on fire extent and severity

Increasing

• proportion of landscape covered by multi-cohort stands

• average number of cohorts per stand

• proportion of fire covered by large low-severity patches

• influence of fuel amount and continuity on fire extent and severity

Summary and Conclusions• An understanding of fire-regime gradients is useful in guiding restoration

Questions?

Alan Tepley and Jane Kertis May 28, 2009 Fire Regimes and Successional Pathways in the Western...

Documents

Transcript of Alan Tepley and Jane Kertis May 28, 2009 Fire Regimes and Successional Pathways in the Western...