SUPPORTING INFORMATION
Climatic stress increases forest fire severity across the western United States
Phillip J. van Mantgem, Jonathan C. B. Nesmith, MaryBeth Keifer, and Eric E. Knapp
Average temperature

anomaly ( C)
2
A
1
0
-1
-2
Average precipitation
anomaly (mm)
600
B
400
200
0
-200
-400
Average water deficit
anomaly (mm)
150
C
100
50
0
-50
-100
-150
1980
1985
1990
1995
2000
2005
Year
Figure S1. Temperature (A), precipitation (B) and climatic water deficit (C) anomalies averaged
across study sites from 1965 to 2005. The heavy black line represents a five-year running average
for each climate variable.
Figure S2. Trend in pre-fire climatic water deficit anomaly by year of prescribed fire ignition at
each study plot. The blue line represents a loess smoother.
Table S1. Characteristics of forest plots within management units, with among plot averages and
range (in parentheses) for year of prescribed fire ignitions, and coniferous tree stem diameters, fire
injuries, and species composition.
Management
unit*
Latitude Longitude
BAND
35.78
-106.33
BRCA
37.58
-112.18
ELMA
34.88
-108.00
FFS3
46.90
-113.43
GLAC
48.68
-113.80
GOGA
37.79
-122.55
GRCA
36.18
-112.67
JODA
44.63
-119.88
LABE
41.76
-121.52
LAVO
40.49
-121.41
PINN
36.49
-121.18
REDW
41.37
-124.03
ROMO
40.36
-105.70
SEKI
36.51
-118.58
WHIS
40.61
-122.60
YOSE
37.85
-119.56
ZION
37.30
-113.03
Plot
count
10
13
16
3
12
7
74
2
4
32
2
1
2
20
14
22
17
Live tree
count†
203
378
144
1228
139
195
1924
11
56
1233
3
8
55
548
272
489
231
Ignition
year
1995
1997
2000
2002
1999
1998
1998
2002
1991
1997
1998
1996
1998
1991
1996
1995
1998
Table S1. Continued.
Management
unit
BAND
BRCA
ELMA
FFS3
GLAC
GOGA
GRCA
JODA
LABE
LAVO
PINN
REDW
ROMO
SEKI
WHIS
YOSE
ZION
DBH (cm)
26.6 (15 to 60)
28.6 (15 to 80)
29.6 (15 to 67)
23.6 (10 to 68)
28.8 (15 to 80)
61.1 (15 to 236)
33.2 (15 to 120)
24.4 (15 to 57)
34.2 (16 to 80)
32.3 (15 to 170)
25.3 (22 to 32)
131.2 (46 to 320)
24.5 (15 to 44)
41.9 (15 to 296)
34.9 (15 to 143)
40.7 (15 to 179)
31.8 (15 to 97)
Crown scorch (%)
37 (0 to 100)
28 (0 to 100)
32 (0 to 100)
14 (0 to 100)
41 (0 to 100)
54 (0 to 100)
23 (0 to 100)
10 (0 to 40)
21 (0 to 100)
25 (0 to 100)
0 (0 to 0)
0 (0 to 0)
25 (0 to 100)
22 (0 to 100)
20 (0 to 100)
27 (0 to 100)
13 (0 to 100)
Scorch height (m)
1.5 (0 to 11)
1.1 (0 to 18)
1.4 (0 to 12)
1 (0 to 7.62)
5.3 (0 to 18)
9.4 (0 to 32)
2.5 (0 to 30)
0.1 (0 to 0.6)
2.1 (0 to 11.3)
2 (0 to 20)
0 (0 to 0.1)
4.5 (0.1 to 15)
1.7 (0 to 12)
2.4 (0 to 27)
1.8 (0 to 20)
1.4 (0 to 13)
1.3 (0 to 9)
Table S1. Continued.
Management
unit
BAND
BRCA
ELMA
FFS3
GLAC
GOGA
GRCA
JODA
LABE
LAVO
PINN
REDW
ROMO
SEKI
WHIS
YOSE
Species comprising ≥1 % of stems††
PINPON 89%, ABICON 6%, PSEMEN 4%
ABICON 49%, PSEMEN 23%, PINPON 22%, PINFLE 5%, JUNSCO 2%
PINPON 92%, PINEDU 6%, JUNMON 1%, PSEMEN 1%
PINPON 62%, PSEMEN 35%, PINCON 2%, LAROCC 1%
PINCON 40%, PINPON 39%, PSEMEN 10%, LAROCC 9%, PICENG 1%
SEQSEM 77%, PSEMEN 23%
PINPON 70%, ABICON 10%, PINEDU 10%, JUNOST 7%, PICENG 2%,
ABILAS 1%, PSEMEN 1%
JUNOCC 100%
PINPON 100%
ABICON 50%, PINPON 28%, PINCON 12%, CALDEC 5%, PINJEF 4%
PINSAB 100%
SEQSEM 90%, ABIGRA 10%
PINCON 71%, PINPON 24%, PSEMEN 6%
ABICON 44%, CALDEC 17%, PINLAM 15%, SEQGIG 13%, PINPON 9%,
ABIMAG 2%
PINATT 41%, ABICON 26%, PINPON 17%, PINLAM 13%, CALDEC 1%,
PSEMEN 1%
ABICON 39%, CALDEC 21%, PINPON 21%, ABIMAG 8%, PINLAM 8%,
PINJEF 1%, PSEMEN 1%
*Management
unit acronyms refer to the following; BAND = Bandelier NM, BRCA = Bryce Canyon
NM, ELMA = El Malpias NM, FFS3 = Fire and Fire Surrogate site 3 (Lubrecht Forest, MT), GLAC
= Glacier NP, GOGA = Golden Gate NRA, GRCA = Grand Canyon NP, JODA = John Day Fossil
Beds NM, LABE = Lava Beds NM, LAVO = Lassen Volcanic NP, PINN = Pinnacles NM, REDW
= Redwood NP, ROMO = Rocky Mountain NP, SEKI = Sequoia and Kings Canyon NP, WHIS =
Whiskeytown NRA, YOSE = Yosemite NP, ZION = Zion NP.
†Count
of live trees pre-fire.
††Species
composition for stems ≥15 cm DBH pre-fire. Percentages may not add to 100 due to
rounding. ABICON = Abies concolor, ABIGRA = Abies grandis, ABILAS = Abies lasiocarpa,
ABIMAG = Abies magnifica, CALDEC = Calocedrus decurrens, JUNMON = Juniperus
monosperma, JUNOCC = Juniperus occidentalis, JUNOST = Juniperus osteosperma, JUNSCO =
Juniperus scopulorum, LAROCC = Larix occidentalis, PICENG = Picea engelmannii, PINATT =
Pinus attenuata, PINCON = Pinus contorta, PINEDU = Pinus edulis, PINFLE = Pinus flexilis,
PINJEF = Pinus jeffreyi, PINLAM = Pinus lambertiana, PINPON = Pinus ponderosa, PINSAB =
Pinus sabiniana, PSEMEN = Pseudotsuga menziesii, SEQGIG = Sequoiadendron giganteum,
SEQSESM = Sequoia sempervirens.