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

84 FOREST TREES OF THE PACIFIC SLOPE.
changes of temperature, gradual ; summers generally mild and winters not severe. Nevertheless,
average daily, monthly, and yearly temperatures and average annual precipitation
and humidity vary greatly from southern limits of range in California to northern
limit in Alaska. Precipitation ranges from about 20 inches in California to over 100
inches in Alaska. The temperature drops to -3:5a F. toward north limit; while over a
great part of range, notably at south, and along coast, light frost occurs and temperature
goes to zero.
TOLERANCE.-Tolerant, but less tolerant than western red cedar and western hemlock.
Seedlings endure dense shade, competing successfully with young hemlock. Endures considerable
side shade in later life, but must have overhead light for best growth after
seedling stages. Grows rapidly in height after first few years, and overtakes the slower
western hemlock. Alone or in mixture it maintains a dense stand. Permanently overtopped
seedlings or older trees remain stunted and grow but jittle, but if shade he dense
and persistent they die eventually.
REPRODrUCTION.-Prolific seeder, especially heavy seed years occurring at intervals of
two or three years, while some seed is usually borne locally nearly every year. Seed with
high rate of germination and of persistent vitality. Germination and growth of seedlings
best on any wet or constantly moist soil ; muck, moss, duff, or decaying wood common
to its habitat. Seedlings are sensitive to frost for first few years, but not in later
life. Root system, shallow; in moist ground running near surface beneath moss, duff,
and other debris; in drier soils, going deeper, when, for good growth, a deep, porous soil
is necessary.
Weeping Spruce.
Piecea brcweriatna Watson.
DISTINGUlIS1iING CHARACTERIS'IC5S.
Weeping spruce is a little-known tree, and a comparatively recent discovery.
It was permianently brought to light in 1884 by Thoinas Howell, but the first
discovery plrobably dates from 1813, when Prof. William H. Brewer, in honor of
whom the tree was afterward named, preserved leaves and a branchlet from a
weeping spruce tree growing at the west base of Mount Shasta, California. The
species has not been rediscovered in that locality. Professor Brewer's speei-
mens can be likened only to those from weeping spruce, but the confirmatory
evidence of cones, which were not collected, is required to make the identification
sure.
The maklled weeping habit of its lower branches distinguishes this tree from
its associates. It is thickly branched to the ground, formuing a long-pointed,
conical crown. The trunk is greatly swelled at the base and tapers rapidly to
the top. The usual height attained is from 50 to 75 feet, with a diameter of
18 to 30 inches. Trees 100 feet or more in height occur, but they are excep-
tional. The thin, spike-like point of the crown bears short upturned branches,
while on the lower crown the branches stand out straight, becoming more and
more drooping near the ground. The unique characteristic of the middle and
lower crown branches is their numerous, very long, strilg-like branchlets, which
hang down froni 4 to 8 feet in length. These also have numerous pendulous side
branehlets. Bark of large trunks is about three-fourths of an inch thick, dark
reddish brown, and with thin, long, firmly attached scales. The dense foliage
has a somewhat bright but deep yellow-green hue. The leaves (fig. 31) are ftat-
tisli and obscurely triangular, the sharpest angle on the lower side. Two resin
ducts are shown on cross-section of the leaf near its upper border. The cones
(fig. 31) mature in one season, shedding their seed late in September or in Octo-
ber. When full grown, and before opening, they are dark purplish green;
after shedding their seed, they are dull russet-brown. They fall from the trees
slowly, many adhering until the end of the second autumn. The seeds are dark
chocolate brown. Seed-leaves, as a rule, 6. Wood, little known; pale yellowish
to very light brown, rather heavy, and fine-grained.