Apr. X4.1923 Physiological Requirements of Rocky Mountain Trees 151 
TabI/E XXI .—Miscellaneous wilting coefficients —Continued 
ENGEEMANN SPRUCE 
Sam¬ 
ple 
No. 
Station or forest. 
74 
75 
76 
76 
35 
33 
34 
no 
III 
X12 
632 
6 
243 
331 
332 
SOS 
306 
333 
33X 
Fremont F-3... 
-do. 
... .do. 
... .do. 
Fremont F-s... 
-do. 
— .do. 
Wagon Wheel 
Gap D. 
-do. 
-do. 
Wagon Wheel 
Gap A-x. 
Fremont. 
Arapaho. 
Leadville. 
Battlement.... 
....do.•.... 
Bighorn. 
... .do. 
Gunnison. 
-do. 
Origin and character of soil. 
Granitic gravel. 
-do. 
-do. 
-do. 
-do. 
....do. 
....do. 
Quartz latite sandy loam. 
-do. 
-do. 
_do. 
Granitic sandy loam. 
Transported ^e sandy loam... 
Granitic loam.. 
Lava loam. 
-do. 
Granitic sandy loam. 
-do. 
Limestone silt loam. 
Limestone loam. 
Moisture 
equiva¬ 
lent. 
Wilting 
• coeffi¬ 
cient. 
Ratio of 
wilting 
coeffi¬ 
cient to 
moisture 
equiva¬ 
lent. 
Conditions of test. 
7.87 
1- 54 
0.196 
Without paraffin. 
6 . S 3 
I-51 
- 231 
Do. 
3-99 
X. 50 
-364 
Do. 
3-99 
X. 40 
-351 
With p£lraffin. 
6. 74 
2.12 
•315 
Without paraffin. 
7. 62 
2. 64 
-347 
Do. 
6.68 
X. 98 
- 297 
Do. 
20. so 
7- 56 
•369 
17-38 
3- 59 
. 207 
17- 72 
4-14 
• 234 
18.43 
6.93 
•376 
10. 43 
3-73 
•358 
13- 65 
3- 22 
. 236 
45-40 
7. 60 
.x68 
Da 
30. x6 
4-93 
. 163 
Da 
2 X. 83 
3- 73 
• 171 
Do. 
17-40 
2.88 
. x66 
Do. 
13-63 
2.17 
.159 
Do. 
28. x6 
3-31 
.1x8 
Da 
22. 78 
2. 69 
. X18 
Do. 
In Table XXI there are presented all the wilting coefficients which have 
not been given in the two preceding tables, and for which the correspond¬ 
ing moisture equivalents are available. On examining the data, how¬ 
ever, it is readily seen that in each group those tests which have been 
made without coating the soil with paraffin give much lower coefficients 
than those in which the soil was coated. This is as might be expected 
and, since the proportion of such tests is variable in the different groups, 
it seems best to discard all data obtained in this way. We then obtain 
the following averages: 
Species. 
Num¬ 
ber 
oftests. 
Mean 
moisture 
equivalent. 
Mean ratio 
wilting co¬ 
efficient to 
moisture 
equivalent. 
Yellow pine.... i. 
16 
15 
13 
7 
Per cent. 
8. 42 
12. 90 
8. 76 
14.58 
0.382 s 
.3468 
• 3065 
■ 3044 
bodgepole pine.... 
Douglas fir. 
Kngelmann spruce.. 
When allowance has been made for the fact, which is evidenced by the 
mean moisture equivalents, that three-fourths of the usable data for 
yellow pine and half of that for Douglas fir were obtained with granitic 
gravel, or sand soils, although these soils do not much effect the other 
two groups, it is definitely decided that wilting coefficients are much lower 
for Douglas fir than for yellow pine, probably somewhat lower for yellow 
pine than for lodgepole, and certainly lower for Douglas fir than for 
spruce. 
