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

FOREST TREES OF THE PACIFIC SLOPE. 101
situations appear to have rougher and harder bark than those in the moist,
deep forest. Trees of the high, very dry interior mountain slopes, particularly
young trees, may have soft, cork-like, gray-brown bark. (This may well be a
result of the excessively dry atmosphere, for one or two firs of that region have
similar bark). Otherwise these trees are not different from those with the
ordinary bark. Mature foliage is usually deep yellow-green. In the drier parts
of its range Douglas fir sometimes has blue-green foliage of varying shades,
especially in Rocky Mountain forms. This color is particularly pronounced
during the early maturity of the leaves. Foliage of a season's growth remains
on the tree about eight years, when it is shed at irregular intervals. The leaves
(fig. 36) are flat, slightly grooved above and commonly blunt, or very occasionally
pointed. Cones ripen early in August and by September they begin
to open and shed their seed. A few weeks later the cones drop from the trees.
The cones fig. 36), which are cinnamon or reddish-brown, furnish easy and
reliable means of identifying this tree. Their simplest distinction is the 3pointed,
trident-like thin bracts protruding from among the cone-scales. Cones
vary from 14 to 47 inches in length, but they are commonly about 2A to 3
inches. The seeds (fig. 36, a) are dull russet-brown, with areas of white.
Seed-leaves, about three-fourths of an inch long, are 6 to 7. Wood varies
widely in character and grain, which may be very coarse, medium, or fine.
Coarse-grained wood is usually distinctly reddish-brown, the "red fir" of lumbermen.
Fine-grained wood is a clear yellowish brown, the "yellow fir" and
"Oregon pine" of lumbermen. The botanical characters of trees furnishing
these dissimilar qualities of wood are the same, and there is no foundation for
the popular belief that these woods come from two different "varieties" or
"species" of trees; indeed the two grades of wood may sometimes be obtained
from the same tree. For the first stage of from 50 to 100 or more years
diameter growth is rapid, giving coarse-grained wood, while the later stages
of growth are, as a rule, slower and give fine-grained wood. The invariable
difference in color between these two grades of wood is often attributed to the
character of the soil, but this explanation ignores the fact that both grades
may come from the same tree. The true explanation is yet to be found. Grades
intermediate between these are also common, especially in trees grown outside
of the humid northwestern range, from which the bulk of "red" and "yellow"
timber is derived. Both grades are exceedingly important commercially, but
the finer-grained, yellow wood is now being worked up for the finest grades of
finishing lumber, for which it competes with high-class pine.
LONGEVITY.-Long-lived. Trees from 3 to 4 feet in diameter are from 150
to 200 years old, while those from 4 to 8 feet in diameter are from 200 to 375
years old. One tree 9 feet through showed an age of 435 years. The ages of
rare trees larger than this are probably from 400 to 500 years.
RANGE.
Western North America from British Columbia southward to central California, to
northwestern Texas, southern New Mexico, Arizona, and northern Mexico.
BRITISH COLUMBIA.-From east side of Rocky Mountains westward to Pacific coast
and northward to Tacla Lake (lat. 55' 10') and Skeena River (lat. 540 20') ; in southern
part, from sea-level to 6,000 feet; farther north, at general elevation of country,
but absent from valleys of southern part of central plateau, as also from higher parts
of Rocky, Gold, and Selkirk Mountains. From Rocky Mountains eastward to Calgary
and Porcupine Hills; northward to head of Athabaska and Grand Fork Fraser rivers,
but absent from Cariboo Range; northward in Fraser River Valley to McLeods, Tacla,
Babine, and Frangois lakes; absent from headwaters of Salmon River, but on coast
range northward to Skeena River. Northward on Pacific coast only as far as north end
of Vancouver Island, not on coast archipelago, and rare on west coast of Vancouver
island.