The black oak, which gives its name to the large group of
biennial-fruited oaks, is one of our handsome, sturdy forest trees. It
grows from Maine to Florida, and west to Minnesota, Kansas, and Eastern
Texas. Its bark is very dark grey or brown, and thick, with rough, broken
ridges and deep furrows. Under this outer layer is a yellow belt, rich in
tannin. This gives the tree the name “yellow oak,” and since its bark is
valuable in tanning leather, it is some times called the “tan bark oak.”
The tree is not graceful nor symmetrical, but there is a picturesqueness
and strength about it that redeems its coarseness and irregularity. This
species would be planted oftener for shade, were there not so many
beautiful oaks to choose from. In the wild, however, a giant black oak is
a noble feature of the landscape.
In early spring the large downy winter buds begin to swell, and soon the
leaves push rapidly out. The whole tree top flushes crimson in the
sunshine. The red glow is from the crinkly, half-awake baby leaves, whose
brilliance is softened by a silky covering of white hairs. In a day the
leaves turn green, and most of their silky covering is shed.
The bloom of the black oak consists of a fringe of yellow catkins at the
base of each shoot, and pairs of red-tongued acorn flowers in the angles
of some of the leaves. Back of the new shoot the half-grown acorns of the
previous season are seen. In autumn the new crop is well along and the
full-grown acorns, which have taken two seasons to ripen, are ready to be
shed. Each kernel sits in a straight-sided cup of loosely shingled
scales, which form a fringe at the margin. The kernel is bitter, and
yellow, as it is in most of the species of the Black Oak Group.
[Illustration: Leaves, mossy-cup acorns and warty twigs of the bur oak]
[Illustration: The horizontal limbs of the pin oak form a regular
pyramidal head]
The large, downy, pointed buds of this oak will often determine its name
for us when we are confused by the shapes of the leaves. Often the red
oak and the black oak “run together” in their leaf forms. To determine
the tree’s name we must call in the buds, the acorns, and their cups, and
the general shape of the trees, and consider all these points together.
Black oak leaves are thick, coarse, and leathery. Crumple one in your
hand, and you cringe at the harsh scratching noise it makes. They vary
from four to ten inches in length, and from two to six inches in breadth.
The margins are deeply cut into seven or nine broad, bristly-toothed
lobes, with rounded bays between. The upper surface is dark green in
summer, shining and smooth, or sometimes hairy. The lining is brownish
and a remnant of the scurfy down is found in the neighbourhood of the
veins. In autumn these leaves turn brownish-yellow, but rarely show a
tinge of red.
The bark of black oak is stripped and carried to the tan-yards. Or it
furnishes a yellow dye, used in the printing of calicoes. The wood is
used in house-building, and in the manufacture of furniture.