The Red Oak
Nature Bulletin No. 316-A October 12, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation
THE RED OAK
The oak has long been a symbol of rugged strength and nobility. Of all
our hardwood trees, the oaks are unsurpassed in grandeur, size, length
of life, numbers and commercial value. There are more than 80 kinds
in the United States, including the evergreen live oaks, and probably
20 of them are found in Illinois, but some are difficult to identify and
tell one from the other. Moreover, the same common name may be
used for two different kinds, depending upon the locality.
There are two general classes: the White Oak group, and the Red Oak
or Black Oak group. In the first, the ends of the leaves and their lobes
are rounded without any spines or bristles at the tips. Their acorns,
which are relatively sweet and edible, mature and fall off the same
year they are formed, so that there are none on the branches in winter.
In the Red Oak or Black Oak group, the leaves and their lobes, if any,
have bristly hairs or spines at the tips. The acorns, which are bitter
with tannin, do not mature and fall off until the second year, so that
small ones may be seen on the branches in winter.
Unfortunately for us ordinary folks, there is commonly a considerable
variation in the size and shape of the leaves on any given kind of oak,
especially on young seedlings, on sprouts from stumps, and also on
vigorous new shoots on older trees. Furthermore, some oaks cross-
pollinate and the leaves of such hybrids can be a puzzle. The expert
forester or botanist may identify an oak by its leaves and other
characteristics but he depends chiefly upon the size and shape of its
acorns, and the size, shape and texture of the shell or cup that holds
In the Red Oak group are the species commonly and best known as
northern red, southern red, pin, scarlet, black, Hill's black, scrub,
blackjack, willow, shingle and laurel. They and their relatives make up
more than half of the total stand of oaks in the United States and are
all usually marketed as "red oak".
The Northern Red Oaks are the most important, fastest growing, and
attain the greatest size. They extend from Nova Scotia to central
Minnesota and south to Arkansas, northern Louisiana, Tennessee and
northern Georgia. In Illinois we have only the larger two varieties.
Ordinarily, the older trees are from two to four feet in diameter and 70
to 90 feet in height, but in the Chio valley and the Appalachian
regions some have become 150 feet tall and six feet in diameter.
Red Oak lumber, altho not equal to white oak, is extensively used for
the same purposes: such as general construction, flooring, interior
finish, and furniture. It is not durable in the soil, however, and red oak
posts or railroad ties should be pressure-treated with a preservative.
The leaves, smooth dark green above and paler below, have from five
to eleven bristle-tipped lobes. In autumn they turn deep red or orange,
then brown, and on some trees may hang on until midwinter. The
acorn is usually an inch or more in length and is held in a shallow
saucer-like cup which is covered with closely fitting scales. These
acorns are very nutritious. They are important food for squirrels, foxes,
deer and many other kinds of wildlife. Hogs, in wooded pastures,
gobble them greedily and grow fat. The Potawatomi and other Indians,
who knew how to remove the tannin, ground them into meal for food.
It takes a mighty red oak to make a Potawatomi pancake.
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Update: June 2012