Forest Preserve District of Cook County, Illinois
Nature Bulletins
Newton Home Page

Introduction and Instructions

Search Engine

Table of Contents



The Oaks
Nature Bulletin No. 73   July 6, 1946
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation

The oak is celebrated in history and fable. Great forests of oak once covered much of England and central Europe. The ancient Druids held the oak especially sacred and performed their mysterious rites in the depths of the oak forests. Our modern oaks, of which there are more than 275 species distributed over the world -- largely in temperate regions -- are descendants of prehistoric trees. Some 20 or 30 forms have been identified from fossils as existing during the Ice Age.

The oaks dominate our upland woods in the Middle West. Of 54 species in the United States, Illinois has 19. Cook County has 9, of which only 6 are common: the white, the swamp white, the bur, the black, the red and Hill's black ( or northern pin oak). Less common are the true pin oak, the shingle oak and the chinquapin.

All oaks bear acorns, a fruit peculiar to them. Oaks are divided into two groups. The "white oak" group, including the white, swamp white, bur and chinquapin, bear acorns that mature that same fall and the mature leaves have rounded tips. The inside of the cup over the acorn is smooth; the bark of the mature tree is scaly. The "black oak" group, including the black, red, Hill's black, pin and shingle oaks, bear acorns maturing the next spring and their mature leaves have sharp tips. The inside of the acorn cup is silky-hairy; the bark is dark, tight, and furrowed on the older trunks but not scaly.

Acorns are valuable food for hogs and all-important as winter food for squirrels. Those of the white oak group are sweet and edible, especially the chinquapin. During the Civil war, acorns served many a family as a substitute for flour and, when roasted with chicory, for coffee.

The name "oak" has come to stand for great strength and durability. Very slow-growing, they are the longest-lived and most valuable of our hardwood trees. They have many uses for furniture, structural timbers, agricultural implements, railroad ties, fence posts and barrels.

Count the annual growth rings on the next big oak stump you see. Don't be surprised if you find it to be 300 years old.

To return to the Nature Bulletins Click Here!
Hosted by NEWTON

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Sponsered by Argonne National Labs