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

FOREST TREES OF TI-IE PACIFIC SLOPE. 115
on Sauk River near Monte Cristo; head of Early Winter Creek. Both sides of Cascades
in southern Washington National Forest, in valleys of Skykomish, Tolt, Snoqualmie,
Green, White, Yakima, Wenache, and Entiat rivers, up to an elevation of 5,400 feet.
Noted in Wenacbe Mountains and range between Columbia River and Yakima River,
at 5,000 feet. Mount Rainier National Forest, both sides of range generally to 4,200
feet, but sometimes to 5,2l00 feet. Noted in Upper Nisqually Valley ; Upper Klickitat
River, at 4,200 feet; mouth of IHellroaring Canyon, at 3,800 feet; about Mount Adams
and Eagle Mountain; on Goose Prairie along Bumping River, at 3,520 feet; on Dewey
Lake (head of American River), at 5,200 feet. In Olympic Mountains from sea level
to lower slopes. Locally noted at Tacoma, Port Ludlow, Lake Cushman, on shores of
Puget Sound, and about I)ryad, at 304 feet elevation. In Colville National Forest,
Blue Mountains (Wenaiche National Forest), at 2,.500 to 5,000 feet.
OREGON.-Stream bottoms and lower slopes of Cascade and coast ranges, Blue and
Powder Itiver mountains. In northern Cascade National Forest, on both sides of range
and generally up to 4,100 feet; lower slopes of Mount flood. Farther south (R. E to 17
S.) it reaches 200 to 6,000 feet. In southern Cascades National Forest, extending southward,
on west slopes of Cascades, to headwaters of Umpqua River, and on east slopes
to Mount Jefferson. Exact southern limit imperfectly known. In Coast Range southward
into California. Locally noted in vicinity of Portland; coast of Clatsop County;
from lower Clackamas River bottoms to point about 6 miles above " Hot Springs " in this
canyon; Blue Mountains, at 2,500 to 6,000 feet.
CALIFORNIA.-In fog belt of northern coast, extending inland 10 to 30 miles, and
southward to north of Fort Ross (Sonomna County). Locally noted in Del Norte County
at Crescent City, and in bottoms of Smith River. Humboldt County: Inland to iloopa
Valley and ridge east of Hoopa Valley, at 3,700 to 5,500 feet; lower Mad River;
Eureka; from Ilydesville inland nearly to Bridgeville and Little Van Dusen River (10
miles cast of Bridgeville) ; Ferndale to Bear Valley : between Capetown and I'etrolia
and thence to Upper Mattole. Mendocino County: Along coast from Kenny to Westport
and inland along Laytonville road to point 15 miles from Westport; gulches close
to coast from Fort Bragg to Gualala; Mendocino inland, on road to Ukiah, nearly to
Orris Hot Springs; Navarro River up to a point 12 miles from mouth; Elk Creek, near
Greenwood (12 miles south of Navarro River).
Ross with Pinus atericata.
eontena County: Coast north of Fort
The detailed range of this fir in
described in a later bulletin.
Idaho, Montana, and Wyoming will be
OCCURRENCE.
A tree of moist situations. On alluvial stream bottoms and their border valleys, lower
gentle mountain slopes, depressions, and gulches. Best and most abundant growth in
coast region on stream bottoms at low levels; small at high elevations. Its deep root
system demands fairly deep, preferably moist, porous, well-drained soils. With favorable
moisture and climatic conditions, it grows wvell on rather poor, thin soils, but better
quality is necessary in soils deficient in moisture and subject to rapid evaporation.
Rarely in pure stands; usually in mixture. Most commonly with Douglas fir, and
dominant over western red cedar, western hemlock, Pacific yew, and vine maple. At low
levels in Oregon and Washington, with latter trees and sparingly also with amabilis and
noble firs, broadleaf maple, red and Sitka alders, and black cottonwood; in low coast
region with Sitka spruce, and in California with redwood.
CLIMATIC CONDITIONS.-Climate of range favorable to tree growth. Summers comparatively
cool and humid; winters ordinarily mild, and changes of temperature rather
gradual ; in Bitterroot Mountains (.Idaho) and northward, temperature falls occasionally
to -30' F'. irecipitation, well distributed, except in July and August, which are usually
rainless over greater part of range. Forest floor is then dry, and destructive fires often
occur. Annual precipitation, from less than 20 inches to over 100 inches in different
parts of range.
TOLEttANCE.-For a fir only moderately tolerant of shade, being less so than amabilis
fir, western red cedar, western hemlock, and California yew, but more tolerant than
noble fir, Douglas fir, western white pine, western larch, and yellow pine. Seedlings
endure considerable shade, but in later life full overhead light is needed for best growth.
Young growth under ordinary shade remains dwarfed and dies within a few years, unless
overhead light is admitted. With overhead light, but Ehaded from side, height growth is
rapid, trunks are readily cleared of branches, and long, clean stems are formed. Shade
endurance varies in general with age, moisture of soil and air, exposure, quality and
quantity of soil, altitude, and latitude. With sufficient moisture, soil, and heat this fir
thrives in full sunlight, and also endures considerable shade. On poor, dry soils in
warm exposed places, shelter and some shade are beneficial to reduce soil evaporation