climate change, forests and fire: issues in current …climate change, forests and fire: issues in...
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Climate change, forests and fire: issues in
current and future resource management in
the California National Forests
Hugh Safford
Regional EcologistRegional Ecologist
USDA Forest Service
Pacific Southwest Region
1323 Club Drive
Vallejo, CA 94592
Department of Environmental Science
and Policy
University of California
Davis, CA 95616
707-562-8934
I. I. Review of climate trends and projectionsReview of climate trends and projections
II. II. Review of fire trends and projectionsReview of fire trends and projections
III. III. Ecological implications for resource mgt.Ecological implications for resource mgt.
-- Biological: Biological:
VegetationVegetation
Outline
VegetationVegetation
Plant diversityPlant diversity
Wildlife habitatWildlife habitat
-- Physical: Physical:
CarbonCarbon
Water and soilWater and soil
IV.IV. ConclusionsConclusions
Not a focus of my
presentation
California: mean
annual temps,
1920-2005
Temperatures are climbingC L I M A T E
Tahoe City:
number of days
below freezing,
1910-2009
Moser et al. 2009
TERC 2009
C L I M A T E
C L I M A T E
Precipitation is ~steadyC L I M A T E
100+ year record shows modest increase in mean
annual ppt in most California climate regions
WRCC 2009
C L I M A T E
4
6
8
10
12
14
16
18
20
yr sta
ndard
devia
tion in a
nnual pre
cip
itation
5-yr running standard deviations in
mean annual precipitation
Lake Tahoe
Interannual variability in ppt. is up*, and
snow:rain proportion is downC L I M A T E
0
2
4
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
5-y
r sta
ndard
devia
tion in a
nnual pre
cip
itation
Year
Tahoe City: snow as
a fraction of
total precipitation
* but not at all stations
WRCC 2009
TERC 2009
C L I M A T E
Winter snowpack is down across most of California
Trends in the amount
of water contained in
the snowpack (“snow
water equivalent”) on
April 1, for the period
1950-1997.
C L I M A T E
Summer moisture in California montane
forests is primarily snowpack-derivedMoser et al. 2009
C L I M A T E
Future climate: models project more of the same
California mean annual temperature
C L I M A T E
Historic and projected annual mean temperature for California, from three
GCMs using the A2 and B1 IPCC emissions scenarios
Moser et al. 2009
Future climate: snowpack
California:
C L I M A T E
California:
predicted snow-
pack trends from
2010 to 2100
CalFire-FRAP, draft 2010
C L I M A T E
Climate summaryC L I M A T E
1.1. It’s getting warmer, especially at nightIt’s getting warmer, especially at night
2.2. Mean annual precipitation appears to be Mean annual precipitation appears to be
holding steadyholding steady
3.3. InterannualInterannual variability in precipitation is variability in precipitation is
increasing in many places (higher highs, increasing in many places (higher highs,
C L I M A T E
increasing in many places (higher highs, increasing in many places (higher highs,
lower lows)lower lows)
4.4. Snow:rainSnow:rain ratio and snowpack are ratio and snowpack are
decreasingdecreasing
5.5. Combination of these factors is resulting in Combination of these factors is resulting in
drier summersdrier summers
F I R E
Area burned by wildfire is increasing across
California in many ecosystemsF I R E
CalFire-FRAP, draft 2010
California: annual acres burned by decade and
lifeform 1950’s-2000’s
0
20
40
60
80
100
120
140
1900 1920 1940 1960 1980 2000 2020
Year
Hecta
res (th
ousands)
A
0
500
1000
1500
2000
2500
1900 1920 1940 1960 1980 2000 2020
Year
Hecta
res
B
Mean fire sizeAnnual burned area
Fire
suppression
Compare to
+/- 180,000
ha per year
pre-1800
Sierra Nevada: trends in fire area and severity
Total burned area 10yr Moving Avg A Average Fire Size 10yr Moving Avg B
0
10
20
30
40
50
60
70
1900 1920 1940 1960 1980 2000 2020
Year
Hecta
res (th
ousands)
Maximum Fire Size 10yr Moving Avg C
All Forest Types
0
10
20
30
40
50
60
70
1982 1987 1992 1997 2002 2007
% H
igh S
everi
ty
100
1000
10000
100000
Ha
% High Severity 10Yr Moving Avg Mapped Burned Ha
R2 = 0.465, P(lin.) = 0.006
All Forest Types
0
10
20
30
40
50
60
70
1982 1987 1992 1997 2002 2007
% H
igh S
everi
ty
100
1000
10000
100000
Ha
% High Severity 10Yr Moving Avg Mapped Burned Ha
R2 = 0.465, P(lin.) = 0.006
Max. fire size Forest fire severity
Miller et al. 2009
0
20
40
60
80
100
120
140
1900 1920 1940 1960 1980 2000 2020
Hecta
res (th
ousands)
Total burned area 11 yr Moving Avg
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
1900 1920 1940 1960 1980 2000 2020
Hecta
res
Mean fire size 11 yr Moving Avg
Annual burned area Mean fire size
1987:
185,851 ha
2008:
212,819 ha
Klamath Mountains: trends in fire area and severity
Total burned area 11 yr Moving Avg Mean fire size 11 yr Moving Avg
0
10
20
30
40
50
60
1900 1920 1940 1960 1980 2000 2020
Hecta
res (th
ousands)
Max fire size 11 yr Moving Avg
1
10
100
1000
10000
100000
1000000
0
10
20
30
40
50
60
70
1985 1990 1995 2000 2005 2010
Ha
% H
igh S
everity
Forest Fire Severity
% High Severity 10Yr Moving Avg Total Burned Area
NSMax. fire size
Miller , Ramirez & Safford, in prep.
F I R E
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
1900 1920 1940 1960 1980 2000 2020
Hecta
res
Mean fire size 11 yr Moving Avg
Fire trends have clear
links to climate, but also
to fuels, and to changing
federal fire management
policies and practices
F I R E
Miller and Safford 2008, Miller et al. 2009; Miller, Ramirez & Safford, in prep
80
90
100
Wetter and higher elevation forest types are not
experiencing an increase in fire severity
“Fuels-limited” forests:
strong current departure
from characteristic fire
regime
“Climate-limited” forests:
no discernable departure
from characteristic fire
regime
0
10
20
30
40
50
60
70
Current
Ref.
Current
Ref.
Current
Ref.
Current
Ref.
E-side Pine Pond. Pine White Fir Red Fir
% o
f burn
ed a
rea
Low
Moderate
High
NationalAtlas.gov 2009
Klamaths are much
wetter and more
topographically
complex than the
Sierra Nevada
Miller and Safford 2008
F I R E
Future fire trends: Models project increases in fire
activity, but there are projected decreases in some parts of the State
Sierra
Nevada
Klamath
Mtns
F I R E
Lenihan et al. 2008
PCM-A2: no change in ppt., +2.5 to 3° C; GFDL-B1 scenario: slightly drier, +2.5 to
3° C; GFDL-A2: much drier, +4 to 5° C
Future fire trends: Increasing probabilities of large wildfires
except in areas of climatic extremes (very wet, dry, or cold)
State of California 2009
Future fire trends: increasing fire intensity,except in Klamaths under drier future scenario
Lenihan et al. 2003
= increased
intensity
HADCM2: much wetter than today, +3.5 to 4° C; PCM: slightly drier, +1.5 to 2.5° C
Fire summary
1.1. Wildfires in California forests are becoming Wildfires in California forests are becoming
more frequent and larger more frequent and larger
2.2. Annual burned area is increasing across Annual burned area is increasing across
most vegetation typesmost vegetation types
3.3. Fire severity is increasing in semiFire severity is increasing in semi--arid arid
F I R E
3.3. Fire severity is increasing in semiFire severity is increasing in semi--arid arid
forestlands (“fuelforestlands (“fuel--limited” types), but not limited” types), but not
changing in wetter and/or higher elevation changing in wetter and/or higher elevation
forests or in southern California chaparral forests or in southern California chaparral
(“climate(“climate--limited” types)limited” types)
4.4. Future projections are for more frequent, Future projections are for more frequent,
larger, and more intense wildfireslarger, and more intense wildfires
F I R E
no change in
ppt., +2.5 to
3° C;
much drier,
+4 to 5° C
Ecological implications of future fire regimes I. Vegetation
Lenihan et al. 2008
Sierra
Nevada
Interactions between climate change and fire are projected
to have major effects on California vegetation
Sierra Nevada Ecoregion
15
20
25
30
35%
of la
ndscape
subalpine forest and
alpine
evergreen conifer forest
mixed evergreen forest
mixed evergreen
woodland
shrubland
V E G E T A T I O N
Much drier
& much
warmer
Same ppt.
& warmer
Slightly drier
& warmer
0
5
10
15
Current
(1961-
1990)
GFDL-B1
(2071-
2100)
PCM-A2
(2071-
2100)
GFDL-A2
(2071-
2100)
% o
f la
ndscape
shrubland
grassland
arid lands
Lenihan et al. 2008
Increase in hardwood types, loss in conifer forest; increase in
grassland; major loss of subalpine forest
V E G E T A T I O N
30
40
50
60
70%
of la
ndscape
subalpine forest and
alpine
evergreen conifer forest
mixed evergreen forest
mixed evergreen
woodland
shrubland
Sierra Nevada Foothill EcoregionV E G E T A T I O NMuch drier
& much
warmer
Same ppt.
& warmer
Slightly drier
& warmer
0
10
20
30
Current
(1961-
1990)
GFDL-B1
(2071-
2100)
PCM-A2
(2071-
2100)
GFDL-A2
(2071-
2100)
% o
f la
ndscape
shrubland
grassland
arid lands
“Complete” loss of conifer forest; possible increase in semi-desert;
hardwood coverage increases or decreases depending on ppt.
Lenihan et al. 2008 V E G E T A T I O N
1934 2000
Projected changes in vegetation are already underway
(1) Loss of yellow pine dominated forest
(logging X fire suppression X climate)
(2) Increase in hardwood density and
forest cover (climate X disturbance)
(3) Loss of subalpine forest (climate)
plus
(4) Loss of blue oak woodland (urban &
ag expansion)Thorne 2008
V E G E T A T I O N
Interactions among fire, insects, disease, drought, pollution, and other
stressors are provoking vegetation changes across California
Forestland to shrubland and grassland
V E G E T A T I O N
Jeffrey pine killed by fire near San Diego,
6 yrs post-fire with no regeneration: fire X
temperature X drought X pine beetles
Loss of piñon pine near Topaz Lake, western
Great Basin: invasive species X fire X pine
beetles
V E G E T A T I O N
Shrubland to grasslandForestland to shrubland
V E G E T A T I O N
Frequent anthropogenic fire reducing coastal
sage scrub to grassland: fire X exotic species
X drought
Repeated wildfire reducing forest to
shrubland: fire X temperature X drought
PIPOPIPO
PIJEPIJE
ABCOABCO
Sensitivity to air pollution (N and ozone)
Susceptibility to insect/disease PIPOPIPO
PIJEPIJE
PILAPILA
Sensitivity to increased temperatures
ABCOABCO
PILAPILA
Sensitivity to water stress
ABCOABCO
Sensitivity to fire (adult)
CADECADE
ABCOABCO
California forests are under major ecological stress: the
example of southern California
CADECADE
Sensitivity to air pollution (N and ozone)
Susceptibility to insect/disease
CADECADE
ABCOABCO
Sensitivity to increased temperatures
PIPOPIPO
CADECADE
Sensitivity to water stress
PIPOPIPO
PIJEPIJE
CADECADE
Sensitivity to fire (adult)
PIPOPIPO
PIJEPIJE
Who wins?
Pollution FireInsects/disease H2O stressTemps
Trends in high severity patch size
In conifer vegetation, the size of
high severity patches in Sierra
Nevada fires has increased over
the last two decades
Mean patch radius = 130 m
Average Patch Size
0
2
4
6
8
10
12
14
He
cta
res
R2 = 0.325, P = 0.011
400
Mean distance to nearest living seed
tree, Angora Fire
Sierra Nevada: mean high severity patch size
0
1980 1985 1990 1995 2000 2005
Year
Average Patch Size 10yr Moving Avg
These patterns have
important implications for
forest fragmentation, postfire
regeneration, vegetation
succession, soil erosion, etc.
0
50
100
150
200
250
300
350
400
Mete
rs Treated
Untreated
Miller and Safford 2008
Safford et al., in prep.
V E G E T A T I O N
Meadow to forestlandPine forest to fir forest
In many places, lack of fire is just as serious an ecosystem
disturbance as uncharacteristically frequent or severe fireV E G E T A T I O N
Meadows being invaded by conifers: lack of
fire X decreasing snowpack X grazing
Loss of large pine dominance in many montane
forests: lack of fire X water stress
V E G E T A T I O N
Vegetation summary
1.1. Fire will interact with climate and other factors to Fire will interact with climate and other factors to
provoke major changes in vegetation; projected provoke major changes in vegetation; projected
changes are already occurringchanges are already occurring
2.2. As high severity area and patch size increase, and as As high severity area and patch size increase, and as
summer droughts deepen, regeneration of many conifer summer droughts deepen, regeneration of many conifer
species will become progressively more difficultspecies will become progressively more difficult
3.3. Given sufficient Given sufficient precipprecip., hardwood species will replace ., hardwood species will replace
V E G E T A T I O N
many lower elevation conifer forests after disturbancemany lower elevation conifer forests after disturbance
4.4. Many areas of persistent Many areas of persistent shrublandshrubland that succeeded to that succeeded to
conifers under fire suppression may return to shrubsconifers under fire suppression may return to shrubs
5.5. Major expansion of grassland is projected for much of Major expansion of grassland is projected for much of
California due to frequent fires in forests and California due to frequent fires in forests and shrublandsshrublands
6.6. Densification of subalpine forests and expansion of Densification of subalpine forests and expansion of
subalpine trees into previously “permanent” snowfields subalpine trees into previously “permanent” snowfields
may increase continuity of subalpine fuelsmay increase continuity of subalpine fuels
High
B I O D I V E R S I T Y Species adapt to fill niches created by an ecosystem’s
“characteristic” disturbance regime.
Ecological implications of future fire regimes II. Biodiversity
Characteristic disturbancefrequency
Relative diversity
Time since last disturbanceLow
HighShort
Long
B I O D I V E R S I T Y
Denslow 1985, Milchunas et al. 1988, Huston 1994
High
B I O D I V E R S I T Y
Strong departures from the characteristic regime will
negatively impact the diversity of species native to the
ecosystem in question
Characteristic disturbancefrequency
Relative diversity
Time since last disturbanceLow
HighShort
Long
B I O D I V E R S I T Y
Denslow 1985, Milchunas et al. 1988, Huston 1994
Too much disturbance
Too little
disturbance
B I O D I V E R S I T Y
100
120
140
160
180
200
Presettlement: FRI
(yr)
Subalpine
Yrs since fire
suppression
In the Sierra Nevada, fire suppression and climate change have
greatly changed fire regimes in many low-middle elevation forests B I O D I V E R S I T Y
0
20
40
60
80
1000 1500 2000 2500 3000
Elevation (m)
(yr)
Yellow pine Mixed conifer White fir-Red fir
Red fir-White pine
suppression
Fire return interval
departures are greatest in
fuel-limited forests, but low
to nonexistent in climate-
limited forests
Miller et al. 2009; Safford, in prep.
B I O D I V E R S I T Y
100
120
140
160
180
200
Presettlement: FRI (yr)
Presettlement: High
severity fire (%)
Subalpine
When fire does occur, it burns at uncharacteristically high
severity in many low-middle elevation forestsB I O D I V E R S I T Y
0
20
40
60
80
1000 1500 2000 2500 3000
Elevation (m)
severity fire (%)
Current: High severity
fire (%)
Yellow pine Mixed conifer White fir-Red fir
Red fir-White pine
Stephens et al. 2007, Miller et al. 2009,
Safford, in prep.
Increases in fire severity
vary from high in fuel-limited
forests to low or none in
climate-limited forests
B I O D I V E R S I T Y
100
120
140
160
180
200
Presettlement: FRI (yr)
Presettlement: High
severity fire (%)
Subalpine
When fire does occur, it burns at uncharacteristically high
severity in many low-middle elevation forestsB I O D I V E R S I T Y
0
20
40
60
80
1000 1500 2000 2500 3000
Elevation (m)
severity fire (%)
Current: High severity
fire (%)
Yellow pine Mixed conifer White fir-Red fir
Red fir-White pine
Stephens et al. 2007, Miller et al. 2009,
Safford, in prep.
Increases in fire severity
vary from high in fuel-limited
forests to low or none in
climate-limited forests
B I O D I V E R S I T Y
California yellow pine forests are adapted to frequent fires of
predominantly low to moderate severityFire Suppression
Most species are best adapted to this fire regime
B I O D I V E R S I T Y
Fire Suppression
B I O D I V E R S I T Y
6
8
10
12
14
16
18
Treated
Untreated
Large contiguous areas of high severity fire in yellow pine
forests are uncharacteristic of the ecosystem, and are
usually less biodiverse than areas of low and mixed severity
In the Angora Fire (Lake Tahoe,
2007), open-canopied stands in
fuel treatments burned at low to
moderate severity, untreated
forest burned at high severity
P = 0.025
P = 0.002
B I O D I V E R S I T Y
0
2
4
Understory species Herb species
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12 13
Specie
s
Plots
Untreated
Treated
Alpha diversity (810 m2 plots)
Beta diversity (spp./area curves)
Both graphs from
one year postfire
B I O D I V E R S I T Y
Large contiguous areas of high severity fire in chaparral are
characteristic of the ecosystem, and are usually more
biodiverse than areas of low and mixed severity
20
25
30
35
40
Specie
s/2
50 m
2
Sandstone
In the Sixteen Fire (Lake County,
1999), dense canopy chaparral
on fertile sandstone substrates
burned at higher severity than
more open canopied stands on
infertile serpentine substrates
B I O D I V E R S I T Y
0
5
10
15
20
Prefire Postfire
Specie
s/2
50 m
Sandstone
Serpentine
Alpha diversity (250 m2 plots)
After fire, species richness rose
by 140% in the more productive
chaparral, vs. only 35% in the
serpentine chaparral . Since fire
is characteristically less
frequent and less severe in the
serpentine vegetation, fewer
plant species fill “regeneration”
niches
Safford and Harrison 2004
Biodiversity summary
1.1. For a given ecosystem, ecological theory predicts that For a given ecosystem, ecological theory predicts that
species diversity should be highest under some species diversity should be highest under some
“characteristic” regime of disturbance, due to evolutionary “characteristic” regime of disturbance, due to evolutionary
responses to disturbance selectionresponses to disturbance selection
2.2. Continued and exacerbated departure from historically Continued and exacerbated departure from historically
“characteristic” disturbance regimes will have negative “characteristic” disturbance regimes will have negative
consequences for native biodiversityconsequences for native biodiversity
3.3. The occurrence of uncharacteristically The occurrence of uncharacteristically infrequentinfrequent and and
B I O D I V E R S I T Y
3.3. The occurrence of uncharacteristically The occurrence of uncharacteristically infrequentinfrequent and and
severesevere fire in yellow pine and mixed conifer forests is the fire in yellow pine and mixed conifer forests is the
most important land management issue in the Sierra most important land management issue in the Sierra
Nevada; it will require major economic and political Nevada; it will require major economic and political
investment, and the reinvigoration of fire as a major investment, and the reinvigoration of fire as a major
ecosystem processecosystem process
4.4. The occurrence of uncharacteristically The occurrence of uncharacteristically frequentfrequent fire in fire in
chaparral and coastal sage is a major land management chaparral and coastal sage is a major land management
issue in S. California; it will require major economic and issue in S. California; it will require major economic and
political investment, and continued implementation of nopolitical investment, and continued implementation of no--
holds barred fire suppression policiesholds barred fire suppression policies
B I O D I V E R S I T Y
Two stories:
Old forest obligates
Postfire specialists
Ecological implications of future fire regimes III. Wildlife habitatW I L D L I F E
W I L D L I F E
Old forest obligates: projected outcomes of climate
change for Fisher (Martes pennanti)
absent (100% )
stable (100%)
expansion (< 50%)
contraction (50-70%)
expansion (50-70%)
expansion (>70%)
contraction (< 50%)
contraction (> 70%)
Projection (% agreement across 10 GCM projections)
Most GCM-based climate
niche models predict
strong contraction of fisher
habitat in California…
Lawlor, Safford, & Girvetz, in prep.
W I L D L I F E
…but these projections ignore the effects of future
fire regimes
0
10
20
30
40
50
60
% o
f la
ndscape
-50 to -75%
-25 to -50
-10 to -25
-5 to -10
-5 to +5
+5 to 10
10 to 25
25 to 50
50 to 100%
= higher frequency fire
Ranges
Coast
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Klamath
population
Southern Sierra
Nevada population
Ranges
Coast
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Ranges
Coast
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Ranges
Coast
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Klamath
population
Southern Sierra
Nevada population
Fire frequency
projections
W I L D L I F E
HAD (2099) PCM (2099)A
0
10
20
30
40
50
60
70
80
HAD (2099) PCM (2099)
% o
f la
ndscape
-50 to -75%
-25 to -50
-10 to -25
-5 to -10
-5 to +5
+5 to 10
10 to 25
25 to 50
50 to 100%
BLenihan et al. 2003
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Nevada population
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d aCoast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Nevada population
Most scenarios project
higher fire frequencies in
California fisher habitat
W I L D L I F E
0
10
20
30
40
50
60
70
HAD (2099) PCM (2099)
% o
f la
ndscape
-50 to -75%
-25 to -50
-10 to -25
-5 to -10
-5 to +5
+5 to 10
10 to 25
25 to 50
50 to 75%
ACoast R
anges
Ranges
Coast
Fresno
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Klamath
population
Southern Sierra
Nevada population
Coast R
anges
Ranges
Coast
Fresno
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d aCoast R
anges
Ranges
Coast
Fresno
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d aCoast R
anges
Ranges
Coast
Fresno
Sacramento
Redding
Klamath
Mountains
S i e r r a N
e v a d a
Klamath
population
Southern Sierra
Nevada population
Fire intensity projections
88% of landscape
with = or higher
intensity fire
52%
W I L D L I F E
HAD (2099) PCM (2099)A
0
10
20
30
40
50
60
HAD (2099) PCM (2099)
% o
f la
ndscape
-50 to -75%
-25 to -50
-10 to -25
-5 to -10
-5 to +5
+5 to 10
10 to 25
25 to 50
50 to 75%
B
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Coast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d aCoast R
anges
Los Angeles
Bakersfield
Fresno
San Diego
S i e r r a N
e v a d a
0 100 200kilometers
N
Most scenarios project
higher fire intensities in
California fisher habitat
Lenihan et al. 2003
76% 87%
W I L D L I F E
Mixed Conifer
40
50
60
% H
igh S
everity
10000
100000R2 = 0.356, P (lin.) = 0.025
Predicted increases in fire intensity/severity are well-
underway in the Sierra NevadaW I L D L I F E
0
10
20
30
1982 1987 1992 1997 2002
% H
igh S
everity
100
1000
Ha
B
5-10% belt(probable historic
average – Stephens
et al. 2007)
Miller et al. 2009
Stephens et al. 2007, Miller & Safford 200830000
35000
40000
45000
50000
Acre
s
High Severity AreaArea of high severity fire in the Sierra Nevada, 1984-2007
W I L D L I F E
Post-fire specialists: temporal trends in the creation of
snag habitat
Stephens et al. 2007, Miller & Safford 2008
0
5000
10000
15000
20000
25000
1980 1985 1990 1995 2000 2005 2010
Acre
s
Mean +/- 33% for
annual area of high
severity fire in
presettlement Sierra
Nevada forests
Trend: strongly increasing over the last quarter century, and
well within (or beyond) presettlement bounds
W I L D L I F E
Wildlife summary
1.1. Current trends in fire regimes pose a growing Current trends in fire regimes pose a growing
challenge to species that require dense, old challenge to species that require dense, old
forest habitat during some part of their life cycleforest habitat during some part of their life cycle
2.2. Other direct and indirect effects of climate Other direct and indirect effects of climate
warming will increase stress on these specieswarming will increase stress on these species
3.3. At the level of the Sierra Nevada as a whole, At the level of the Sierra Nevada as a whole,
W I L D L I F E
3.3. At the level of the Sierra Nevada as a whole, At the level of the Sierra Nevada as a whole,
current production of snag habitat through high current production of snag habitat through high
severity fire is at levels characteristic of the preseverity fire is at levels characteristic of the pre--
EuroamericanEuroamerican settlement period, and trends in settlement period, and trends in
high severity habitat creation are strongly upwardhigh severity habitat creation are strongly upward
4.4. If current climate and fire trends continue, habitat If current climate and fire trends continue, habitat
for old forest obligate species will retract, and for old forest obligate species will retract, and
habitat for postfire specialists will expandhabitat for postfire specialists will expand
W I L D L I F E
Concluding thoughts
1.1. Current USFS priorities focus on “ecological Current USFS priorities focus on “ecological
restoration”, ecosystem services, and climate restoration”, ecosystem services, and climate
change adaptation and mitigationchange adaptation and mitigation
2.2. Mgt. focus on “restoration” requires some real Mgt. focus on “restoration” requires some real
critical thinking: past reference conditions may critical thinking: past reference conditions may
not be an appropriate target for future not be an appropriate target for future
ecosystems. Focus must be on ecological ecosystems. Focus must be on ecological
processes and not patternsprocesses and not patterns
3.3. Fire management, a variety of ecological Fire management, a variety of ecological
disturbances, and climate warming are disturbances, and climate warming are
interacting to create “threshold conditions” in interacting to create “threshold conditions” in
many vegetation types in the California National many vegetation types in the California National
ForestsForests
4.4. Unless we can reverse climate warming, Unless we can reverse climate warming,
dramatic changes in forests and other dramatic changes in forests and other
vegetation in the California mountains are vegetation in the California mountains are
inevitable. Many of these changes are already inevitable. Many of these changes are already
underwayunderway
Concluding thoughts
5.5. Habitat for old forest obligate species will be Habitat for old forest obligate species will be
very difficult to maintain under likely future very difficult to maintain under likely future
climate and fire regimes. There is currently little climate and fire regimes. There is currently little
consensus on what to doconsensus on what to do
Concluding thoughts
6.6. Past emphasis on allPast emphasis on all--out fire suppression is out fire suppression is
waning, but use of waning, but use of wildlandwildland fire for ecological fire for ecological
benefit is still the exception rather than the rule. benefit is still the exception rather than the rule.
Use of purely mechanical means to reduce Use of purely mechanical means to reduce
forest fuels and increase forest resilience to forest fuels and increase forest resilience to
warming and disturbances will never come close warming and disturbances will never come close warming and disturbances will never come close warming and disturbances will never come close
to solving the problemto solving the problem
7.7. Response to all of these issues will require Response to all of these issues will require
unprecedented integration of science and unprecedented integration of science and
management. We need your help!management. We need your help!
Thank you