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

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FOREST TREES OF THE PACIFIC SLOPE.
and transpiration; therefore in regions with such conditions the tree confines itself
mainly to cooler, sheltered sites.
REERoDUCTION.-Moderately prolific seeder; ; est In open stands. Seed of rather low
rate of germination and with only transient vitality. Seeding habits not folly determined.
Cones produced mainly at irregular intervals (two to three years). Occasionally
few cones borne by trees about 20 years old (in open), production increasing to old age.
Under favorable conditions some seed germinates soon after it is shed and seedlings may
become established before cold weather. Moderately burnous and shaded soils most
favorable to germination, but with sufficient moisture and light, seeds sprout and seedlings
thrive in humus acM in min eral soils. Seedlings come up hoth in open and in shade.
White Fir.
Abies ctacolor (Gord.) Parry.
DISTINGUIS1tING CHARACTERISTICS.
White fir, a massive tree, is fitly and widely called by this name from the ashy
hue of its bark. All of its other common names refer to its silvery or whitish
appearance. It grows to its largest size in the Pacific region, where it is fre
quently from 140 to 180 feet and, occasionally, over 200 feet high, with a
diameter of from 40 to 60 inches, rare trees being from 5 to 6 feet through. In
its Rocky Mountain range it is much smaller-from 80 to 100 feet high, or rarely
more, and from 20 to 30 inches in diameter. The massive trunks are conspicuously
rough, with great deep, wide furrows and ridges in the ash-gray bark,
which is from 4 to 60 inches thick, and very hard and horny. The smooth,
unbroken bark of the upper stem, and of young trees, is grayish, with a brownish
tinge. The dense crown of heavily foliaged, short branches is aD irregular,
round-topped cone, extending to the ground on trees in open stands, and in dense
stands covering only a third or a half of the upper stem. The trunks are straight
and taper very gradually. Young trees have beautifully symmetrical, sharp
crowns down to the ground, the lower limbs standing out horizontally and those
above slanting upward. On old trees the lower crown branches droop conspicuously,
as do also those of the middle crown; while branches above this remain
upright. In old age the more rapid growth of upper side branches than of the
leader forms a rounded top. Young foliage of the year is yellow-green, with a
bluish cast, but later it turns to a pale yellow green, with a whitish tinge. The
leaves are flat, straight, and full and pllump on the upper side, blunt or
pointed-usually not prickly, but sometimes prickly on the lower crown
branches of old trees. They stand out distinctly from two sides of the lower
branches by a twist in their base (fig. 43) ; but very commonly the lower
branches of young trees have their leaves curved and standing erect, somewhat
in two lines, from the upper sides of the twigs. Leaves of the upper crown.
especially on the topmost branches, are strongly curved or sickle-shaped, and
appear to grow from the upper sides of the branchlets (fig. 44). These leaves
and those on leaders are sharp-pointed. Lower branch leai es are usually
longer (,a to 3 inches long) than those of the upper branches, which are commonly
about 1 to fl inches long. There is very great variation in the length
form, and thickness of leaves of this fir in different parts of its wide
range. The changes in form from horizontally flattened leaves to vertically
flattened ones, or to those resembling a sickle-blade, are curious; they are unexplained,
except perhaps by the fact that the latter form is best adapted to
the dry climate in which it most often occurs. Some authors hold that Rocky
Mountain trees bear longer leaves, and more ecommonly pointed ones, than do
trees of the Pacific forests. The writer has seen trees in the latter region with
quite as long leaves, while long blunt leaves are not infrequent on trees of the