Table S1. Geographic descriptions and the associated climate data for 7 regions where coast Douglas-fir (Pseudotsuga menziesii var. menziesii) seeds
were collected.
Population
Latitude
(N)
Longitude
(W)
Elevation
(m)
Calif. (high)
Oreg. (high)
Oreg. (low)
Oreg. (coast)
Wash. (high)
Wash. (low)
Wash (coast)
39.87
42.54
42.90
42.70
47.06
46.92
46.95
120.73
122.87
123.08
124.18
121.72
121.92
123.67
1475
1063
483
299
1071
445
179
Photoperiod
(min)
671
666
665
666
656
656
656
MAT
(°C)
MCMT
(°C)
eFFP
(DOY)
PAS
(mm)
MWMT
(°C)
TD
(°C)
CMD
(mm)
MAP
(mm)
8.9
9.1
11.8
12.9
5.5
7.8
9.8
0.4
0.3
4.7
6.8
-1.6
0.6
4.0
267
272
314
341
262
285
310
131
69
26
27
493
191
59
18.8
19.6
20
19.8
13.5
15.7
16.3
18.4
19.3
15.4
13
15.2
15
12.3
671
693
487
322
122
159
197
1080
618
1256
2933
2074
1971
2014
Climate data derived from ClimateWNA; abbreviations: MAT=mean annual temperature; MCMT=mean cold month temperature; eFFP
(DOY)=ending day of year of the frost free period; PAS=precipitation as snow; MWMT =mean warm month temperature; TD=continentality
(MWMT-MCMT); CMD=aridity (Hargreaves climatic moisture index); MAP=mean annual precipitation.
Table S2. Geographic descriptions and the associated climate data for 35 populations of coast Douglas-fir (Pseudotsuga menziesii var. menziesii).
Population
Latitude
(N)
Longitude
(W)
Elevation
(m)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
39.83
39.84
39.85
39.85
39.97
42.05
42.08
42.29
42.36
42.47
42.63
42.67
42.81
42.83
42.86
42.90
42.92
43.04
43.22
43.38
46.37
46.49
46.62
46.74
46.78
46.90
46.94
47.00
47.06
47.11
47.12
47.28
47.32
47.40
47.42
120.65
120.67
120.79
120.66
120.90
124.28
123.55
122.53
123.02
123.12
122.98
124.37
124.29
122.92
124.06
122.48
123.03
123.92
123.01
123.21
122.62
123.57
121.68
122.28
123.55
122.03
121.47
123.40
121.70
123.85
121.84
121.74
123.91
121.55
121.41
1602
1415
1509
1744
1080
17
961
1378
667
491
1002
732
122
835
154
1103
442
407
566
288
242
469
326
833
158
547
1405
61
1105
66
1000
603
139
495
924
Photoperiod
(min)
671
671
671
671
671
625
667
667
666
666
666
666
665
665
665
665
665
665
665
664
658
657
657
657
657
656
656
656
656
656
656
655
655
655
655
MAT
(°C)
MCMT
(°C)
eFFP
(DOY)
PAS
(mm)
MWMT
(°C)
TD
(°C)
CMD
(mm)
MAP
(mm)
9.4
9.7
9.9
8.5
10.4
12.1
10.7
7.4
11.3
12.3
10.7
11.5
12.4
10.1
12.3
6.6
11.5
11.8
11.8
11.8
9.9
8.7
9.0
8.0
10.1
8.1
4.2
10.7
5.3
10.4
6.4
8.5
10.0
7.9
4.8
1.2
1.4
1.2
0.3
1.6
8.7
3.6
-0.4
3.4
4.1
2.5
6.3
7.3
3.1
6.7
0.1
4.3
6.4
4.6
4.8
2.9
2.3
1.3
0.9
4.0
1.0
-2.7
4.3
-1.9
4.7
-0.5
1.5
4.0
0.4
-3.2
272
275
274
268
266
348
297
277
297
309
308
329
337
309
320
290
307
318
312
310
297
292
286
284
309
283
264
308
259
321
273
296
312
287
266
95
80
110
126
76
10
52
165
22
17
50
53
21
53
16
236
25
22
29
20
55
175
124
229
60
144
753
42
525
48
370
146
83
299
964
19.1
19.5
19.6
18.5
19.9
15.9
19.6
16.7
20.3
21.5
20.5
18.1
18.4
19.1
18.8
16.8
19.9
18.2
19.7
19.6
17.3
15.7
17.4
16.0
17.0
15.9
12.7
18.0
13.4
16.6
14.3
16.2
16.6
16.2
14.3
17.9
18.1
18.4
18.3
18.3
7.3
16.1
17.2
16.9
17.3
18.0
11.7
11.0
15.9
12.1
16.7
15.6
11.8
15.1
14.8
14.4
13.4
16.2
15.1
12.9
14.9
15.4
13.7
15.3
11.8
14.8
14.7
12.6
15.8
17.5
670
701
649
662
762
245
594
419
668
692
533
182
282
466
468
365
542
369
476
497
273
121
303
187
257
190
153
310
129
157
93
115
135
119
114
1004
941
1349
927
1130
1912
1351
1080
663
712
1012
3895
2550
1162
1582
1214
1039
1809
1401
1129
1588
3119
1592
2354
2078
1747
1958
1701
2057
2249
2330
2137
2854
2747
2640
Climate data derived from ClimateWNA; abbreviations are same as Table S1.
Supplementary Methods 1: Experimental design
Supplementary Methods 2: Freeze-test protocol and LT50 calculations.
Four test temperatures were used to produce a range of damage scores, which required using test
temperatures below actual field temperatures. Test temperatures were determined during a pretest at each test site seven days prior to each of the sampling dates for actual tests. Branch
samples that were collected after each sampling event were grouped by block from each test site,
wrapped into packets of moist cheesecloth and covered with aluminum foil. Sample packets were
placed in a programmable freezer (Forma Scientific Model 8270/859M) with a built-in
temperature controller (model WestM3750) overnight at -2°C to equilibrate them. The following
day, freezer temperatures were lowered by 1-3°C per hour until the warmest test temperature was
reached (-14 and -18°C on the first and second sampling date, respectively). The temperature
was maintained for one hour and then three packets (one from each test site) were removed from
the freezer. The process of reducing temperature by 1-3°C, maintaining for one hour and then
removing packets continued for the second, third and fourth test temperatures (-20 and -23°C on
the first and second sampling date, respectively). Immediately upon removal from the freezer,
the packets were placed in a 4°C refrigerator overnight to allow samples to slowly thaw. The
packets were then kept at room temperature for 6-7 days to allow symptoms of cold damage to
develop. The whole process was repeated identically for the second, third and fourth blocks on
subsequent days.
The freeze-treated samples were visually scored for cold damage as the percentage of
each type of tissue (bud, needle and stem) showing injury (yellowing or browning). Stems and
buds were tangentially cut to assess percent damage. Scoring was between 0 (no damage) and 10
(100% damage). By taking the mean damage score of the four test-temperatures, we increased
the precision of our cold hardiness assessment for each population (Aitken & Adams, 1996,
Aitken & Adams, 1997, Anekonda et al., 2000). In addition, by taking cold damage
measurements across a range of temperatures, we could also calculate the temperature at which
50% of tissues were visually damaged (LT 50) from a linear regression of damage as a function of
freezer temperature. Calculated LT50 temperatures corresponded well with mean damage scores
(Supplementary Fig. S1). However, many samples had low variation in damage scores among
the four temperatures due to high damage scores at the warmer test temperatures, leading to
missing LT50 values for each of the three tissue types. Bud LT 50 had the least missing values and
the strongest correlation to damage scores compared to stem LT50 or needle LT50 (Supplementary
Fig. S1); thus, we present results only for bud LT 50.
Aitken S, Adams W (1996) Genetics of fall and winter cold hardiness of coastal Douglas-fir in
Oregon. Canadian Journal of Forest Research, 26, 1828-1837.
Aitken S, Adams W (1997) Spring cold hardiness under strong genetic control in Oregon
populations of Pseudotsuga menziesii var. menziesii. Canadian Journal of Forest Research, 27,
1773-1780.
Anekonda T, Adams W, Aitken S (2000) Cold hardiness testing for Douglas-fir tree
improvement programs: Guidelines for a simple, robust, and inexpensive screening method.
Western Journal of Applied Forestry, 15, 129-136.
Figure S1. Relationships between the temperature that 50% of tissue damage (LT50) and mean
damage of bud (a,b), needle (c,d) and stem (e,f) tissue for 35 coast Douglas-fir (Pseudotsuga
menziesii var. menziesii) populations growing across all three common garden test sites in early
(4 Oct. 2012, a,c,e) and late (30 Oct. 2012, b,d,f) fall. All relationships are significant at P <
0.001