700 
Jour nal o f Agricultural Research 
Vol. XXX, No. 8 
Month 
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LEGEND 
E7] - Months in whicn less than one-twelfth of the annual precipitation falls 
- Months in which about one-twelfth of the annual precipitation falls 
□ - Months in which more than one-twelfth of the annual precipitation falls 
Numoers refer to the regions outlined in Table V. 
Fig. 3.—Distribution of precipitation by months, for the several forest regions 
Table V.— List of subregions and forests, with the classification of forest types a 
Region 
Forests 
1. Northern Rocky 
Mountains. 
Lewis and Clark, Helena 
(except west end), Jeffer- 
j son, Gallatin (northern 
j part), Absaroka (northern 
part). 
2. Western Montana.| Blackfeet, Bitterroot, Flat- 
head, Missoula, Helena 
(W.), Deerlodge (N.), 
Kootenai (E. of range 31 
W.), Cabinet (E. of range 
29 W.), Lolo (E. of line 
from NE. of T. 19-28 to 
NW. of T. 17-29). 
Kaniksu, Pend Oreille, St. 
Joe, Coeur d’Alene, Koo¬ 
tenai (W.), Clearwater, 
Cabinet (W.), Selway 
(Lochsa drainage), Lolo 
(W.L 
Colville, Okanogan, Chelan, 
Wenatchee, Rainier (E.), 
Columbia (E.). 
3. Northern Idaho_ 
4. Eastern Washing 
ton. 
Representative 
weather stations 
Helena, Great Falls. 
Kalispell, Missoula. 
Forest types 
Douglas fir, lodgepole pine, 
subalpine (including En- 
gelmann spruce), open 
(grass, sage, etc.). 
Western yellow pine, Doug¬ 
las fir-western larch, lodge- 
pole pine, spruce-cedar- 
hemlock-white fir, west¬ 
ern white pine, subalpine, 
open (grass, sage, etc.). 
Same as Region 2, with Priest River, Port- 
“open” separated into hill, Murray, Wal- 
“brush n and “grass.” lace, Sandpoint, 
Spokane. 
Same as Region 3, except 
that western white pine 
not used. 
Ellensburg, Colfax, 
Lakeside, Spokane, 
Lyle. 
a Common and botanical names for the species listed here and mentioned elsewhere in this article are 
as follows: Western yellow pine ( Pinus pcnderosa), sugar pine (P. lambertiana), jack pine (P. banksiana), 
western white pine (P. monticola), lodgepole pine (P. contcrta), eastern white pine (P. strobus), red or 
Norway pine (P. resinosa), Jeffrey pine (P. jeffreyi), pinon pine (P. edulis), digger pine (P. sabiniana), 
Douglas fir ( Pseudotsuga taxifolia ), bigcone spruce (Ps. matrocarpa), lowland white fir (Abies grandis), 
red fir (A. magnified), balsam (.4. balsamea), Engelmann spruce ( Picea engelmanni), white or eastern 
spruce (P. canadensis), black spruce (P. mariana), western larch ( Larix occidentalis), tamarack ( L. laricina), 
western hemlock, ( Tsuga heterophylla), juniper ( Juniperus spp.), redwood ( Sequda sempervirens), incense 
ceder (Libocedrus decurrens), red cedar ( Thuja plicata), aspen (Populus tremuloides). 
