De I. VNER VEW D Forest Trees of the Pacific Slope

46
FOREST TREES OF THE PACIFIC SLOPE.
at 6.000 to 7,000 feet; Middle Fork of Kaweah to Buck Canyon at 7,500 feet; Sequoia
National Park, at 5,000 to 6,000 feet; Middle Fork of Kings River at mouth of Crown
Creek; South Fork of Kings River, from mouth of Bubbs Creek 2 miles up, and from
Copper Creek 2 miles up, at 8,700 feet; Kern River canyon to point above Soda Springs;
South Fork of Tale River from East Tule Indian Reservation eastward. Greenhorn
Mountains; Piute Mountains and Mount Breckenridge at 6,000 to 7,000 feet. Tehachapi
Mountains on most of ridges above 6,000 feet; noted in Tejon Canyon, south of which it
has not been detected. Coast ranges, abundant in Stony Creek National Forest at 3,000
to 6,000 feet; scarce in Sonoma County, common in Napa County, especially on Howell
Mountain plateau south of Angwins, bitt unknown on inner ranges bounding Solaun and
Yolo counties. In San Francisco Bay region, recorded only from Mount Hamilton.
Santa Cruz Mountains and northward in seaward coast range to Woodside. Southern
Santa Lucia Mountains, at 1,000 to 5,000 feet. Santa Barbara National Forest, only
between Thorn Meadows and I'ine Mountain Lodge, on San Rafael and Big Pine mountains,
Mount Medulce, and in part of Alamo Mountain region, at 4,750 to 6,750 feet;
near Mount Pinos (S. 12, T. 6 N., R. 22 W.), above 5,750 feet. San Gabriel National
Forest, at 5,500 to 9,000 feet from head of Sheep Creek throughout Upper Swarthout
Valley, as well as to some of higher parts of San Gabriel and San Antonio watersheds;
also on Mount Wilson, Pine Flats, Brown Flats, and in Mount Gleason country. San
Bernardino National Forest, in Little Bear Valley to Sawpit Canyon, and less abundantly
nearly to Cleghorn Pass and I)eep Creek; usually at 4,500 or lower, to 9,000 feet,
but sometimes at 9,800 on the range fronting Mohave Desert; Santa, Ana Range at about
1,600 feet. San Jacinto Mountains, at 3,000 to 9,000 feet; Tahquitz Valley at 6,000 to
9,000 feet, Onstatt and Strawberry valleys; Palomar Mountain, in Doane Valley only.
Farther south, noted about Julien and in San Luis Rey Canyon.
IDAHo.a-Northern and central parts generally at 2,000 to 7,000 feet. Priest River
National Forest, at 2,000 to 4,000 feet. Coeur d'Alene Mountains, valleys, bottoms,
benches, and lower slopes, up to 4,9)O0 feet. Bitterroot National Forest, slopes and flats
up to 7,500 feet; also about west and south boundaries, including a deep extension into
the reserve near south and middle forks of Clearwater River. Thatuna Hills (near Pullman,
Wash.). Sawtooth National Forest slopes and ridges at 2.500 to 5,000 feet
MONTANA.-Mainly west of Continental Divide up to 3,300 feet; Flathead Valley region,
up to 4,125 feet. Valley of North Fork of Flathead River, between Indian and
Logging creeks, and Kootenai Valley (small areas). Bitterroot Valley ulp to 5,800 feet.
Northern part of State, but not on east side of Continental Divide, nor on Whitefish
Mountains. Farther south, east of Divide, sparingly on Little Belt Mountains between
6,000 and 6,500 feet; in Elkhorn Mountains at 4,000 to 5,500 feet, and in Absaroka
Division of Yellowstone National Forest at 5,500 to 6,'00 feet.
The pine occurring mainly east of the Itockies and throughout the region
southward to Texas and Arizona is Piouts pondcrosa scopulorunt, the detailed
range of which will be dealt with in a later bulletin,
OCCURRENCE.
On dry and moist slopes, on tops of ridges, and in canyon bottoms. Very moderate in
soil requirements. Grows on all soils from glacial drift and volcanic ash to deep, loose
sands and stiff clays ; dry, well-drained sandy or gravelly soils most characteristic. Requires
very little soil moisture ; its enormously deep roots enable it to thrive in soils
nearly as dry as those in which pifion pines and junipers grow.
Occurs in pure extensive stands and in mixture with other conifers and broadleaf
trees. Pure large, but interrupted, forests are found on east slopes and foothills of the
Cascades in Washington and Oregon ; open, grassy park lands intervene; little or no underbrush
or even grass occurs in these forests, on account of continued fires. Occasionally
with western larch and Douglas fir. In Sierras, in scattered smaller pure stands, or,
more often, variously mixed with sugar pine, incense cedar, Douglas fir, white fir, and
smaller numbers of California red fir. Often associated with Kellogg oak, occasionally
with bigtrees, and at lower elevations sparsely mingled with gray pine. Mixed forests
usually with brushy ground cover and considerable young growth.
CLIMATIC CONDITIONs.-Great seasonal and daily variations of temperature are endured
Seasonal range between about 28° and 110° F. _Mean annual rainfall in region
of principal occurrence from 10 to 50 inches; an annual rainfall of less than 20 inches
probably limits its occurrence in commercial quantities.
- The north Rocky Mountain range of this tree is given in order to complete the distribution
of what must be regarded as the ordinary form of western yellow pine. Southward
and eastward it passes imperceptibly into P. ponderost scopulorum.