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

62. FOREST TREES OF THE PACIFIC SLOPE.
Knobcone Pine.
Pinus attenuate Lemmon.
DISTINGUISHING CHARACTERISTICS.
The form and size of knobeone pine varies considerably, according as it grows
in exposed or in sheltered situations. It is commonly from 15 to 30 feet high
and from 6 to 12 inches in diameter. Exceptionally large trees are from 60 to
80 feet high and from 18 to 20 inches in diameter. Except in very dense stands,
trees of these sizes have broad, pyramidal crowns, the slender branches curving
outward and upward toward the stem; the branches grow from the trunk in
distant circles, giving an open aspect to the crown. Old trees are peculiar in|
having the trunk forked near its middle, thus forming a thin-foliaged, open,
narrow crown. The bark of old trunks is thin, dull brown, and shallowly fur-
rowed and ridged, mainly near the ground; the ridges have large, loose scales.
The bark of young trunks and of branches and upper stems of old trees is
smooth and light brown. The foliage is nearly always light yellow-green. The
leaves (fig. 22), 3 in a bundle, are slender, often with a twist, and from 3 to
sometimes 7 inches long, but mainly from 32 to 5 inches. Leaves persist for
about four or five years. The cones (figs. 22, 23) mature by September of the second
season. Clusters of them, rigidly attached and bent down, encircle the main
stems of even small trees (from 5 to 8 feet high) and are the most striking
character of this pine. They adhere to the branches and trunk indefinitely;
many trees showing that they have retained their cones for nearly fifty years
(embedded in the trunk). Moreover, the cones very rarely open until the tree
is killed or they are cut from it; then they open only slowly. In collecting the
seed it is necessary to force the cones open by moderate artificial heat. When
ripe they are a light yellow or clay brown. The seed (fig. 23, 5) is blackish.
Seed leaves, 5 to 7, sometimes 8.
Wood rather light and soft, coarse-grained, brittle, pale yellowish brown, and
usually with a thick layer of sapwood.
Longevity.-But little is known of the age limits of this tree. It is commonly
killed by the recurring fires which run over the dry slopes it inhabits.
Considering the unfavorable conditions (barren and dry soils) under which it
grows, its diameter growth, as well as its height growth, is rather rapid during
early life (from 15 to 25 years old). Trees from 10 to 12 inches in diameter
are from 40 to 60 years old. Probably it does not attain an age of over 100 or
150 years. Further study of its longevity is needed.
RANGE.
Throughout Coast Mountains of southern Oregon, of California, and also in southern
Cascades of Oregon and northern California Sierras.
OREGON.-Southwestern part south of McKenzie River, and eastward to western slopes
of Cascades, where It occurs ft 1,000 to 2,000 feet elevation.
CALIFORNIA.-Ilamath National Forest, at about 5,000 feet; Trinity National Forest,
above 5,000 feet, extending eastward to Shasta and Whiskeytown (near Redding) and
southward throughout the coast ranges. Siskiyou County: East slope of Scott Mountain,
between Gazelle and Scott Valley, at about 4,000 feet, and thence to near summit;
west slope of Marble Mountain Divide (west of Scott Valley), and thence into Russian
Creek basin, scarce on North Fork of Salmon River, especially west of Sawyers Bar;
extreme western Siskiyou County (between Salmon and Trinity summits, on trail from
forks of Salmon River to Hoopa) up to about 5,400 feet. Humboldt County: West slope
of Trinity Mountain (east of Iloopa Valley) between 3,700 and 4,100 feet. In Trinity
County on Canyon Creek near Dedrick. Shasta Cosnty: Common on Sacramento River
about Redding (westwvard also 10 or 12 miles, reaching Clear Creek), ard sparingly
up river to Gregory (Baird Switch) ; also along lower McCloud River near Baird. north-