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

FOREST TREES OF THE PACIFIC SLOPE.
Approximately 75 species occur on this continent, while about 20 are trees,
13 of which inhabit the Pacific region, into which one extends from the Atlantic
States. The willows are of very ancient origin. Remains of them exist in
the Cretaceous formations of our Middle West, while willows appear to have
flourished extensively on this continent and in Europe during the Miocene
period.
With few exceptions the various species of willows, which, as a class, are
nearly always distinguished as willows from other trees and shrubs by laymen,
are exceedingly difficult to identify, especially before they become trees. When
they have attained tree size most of the important ones can be distinguished
by a careful study of their mature leaves, bark-, twigs, and habit of growth.
But individual trees are likely to be found which will baffle attempts at identification
without a close examination of the minute characters of the male and
female flowers and the tiny seed capsules, all consideration of which is here
omitted. Such an examination requires a strong magnifying lens and a good
knowledge of plant morphology.
Black Willow.
Salix nigra Marshall.
DISTINGUISHING CHARACTERISTICS.
Black willow is the largest and most widely known of our tree willows, but
much less abundantly represented in the Pacific country than in its eastern
range. It is more distinctly a tree throughout its range than almost any of our
other tree willows, and for this reason it is probably the most commonly recognized.
Several trunks grow close together. Its usual size is from 25 to 50 feet
in height and from 10 to 20 inches in diameter. Trees from 60 to 80 feet high
and from 2 to 3 feet in diameter are of rather rare occurrence. The trunks
(rarely straight) are usually somewhat bowed and leaning, but are clear of
branches for a third or a half of their length in the open, and for two-thirds of
it in close stands. The branches trend somewhat upward, forming a wide,
round-topped, open crown. Rough, furrowed, blackish-brown bark, with wide,
thick-scaled ridges and narrower connecting ridges, is a marked character.
The slender, drooping branchliets are very easily snapped off at their bases.
The leaves-very variable in size and form-from straight to scythe-like (figs.
85, 86), are from 2j to 5 or sometimes 6 inches long, and pale yellow-green.
They may be somewhat shiny above and smooth beneath, or minutely hairy on
the veins of the under surface. Wood, pale red-brown, light and soft, rather
fine-grained, but firm. It has little or no actual or possible economic value,
except for fuel and charcoal.
LONGEVITY.-Not much is known of its age limits, which in trees from 12 to
18 inches in diameter are from 35 to 60 years. Occasional large trees are estimated
to be from 125 tc 150 years old. Further study of its longevity is
required.
RANGE.
New Brunswick to southern Florida and west to eastern Dakota, Nebraska, Kansas,
Indian Territory, southern Arizona, southern and central California, and south Into
Mexico.
CALIFORNIA.-Western foothills of Sierras, San Joaquin and Sacramento valleys, north
to eastern foothills of crast ranges in Colusa County, and south through southern cross
ranges.
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