The red oak is one of the largest and most important timber trees. It can grow 2 feet per year, and attain a height and width of 60 to 75 feet. It is used in residential landscapes, on city streets, in parks and on golf courses. The acorns ripen biennially in fall and drop early, providing a food source for grouse, nuthatch, blue jays, wild turkeys, squirrels, bears, deer, and raccoons. Fall color is inconsistent and varies from red to reddish-brown or sometimes yellow. The leaves of this oak are broad and sharply toothed. There are more than 150 northern red oaks in the Chicago Botanic Garden's collection.

The genus Quercus includes more than 600 species of the oak tree, of which 90 are native to North America; the Chicago Botanic Garden's collection contains more than 60 varieties and over 1,000 individual trees. Twenty oak species are native to Illinois.

Oaks are slow growing, long lived, hard wood trees that produce fruit we all know as acorns. Within the white oak group, acorns mature annually; in the red oak group, acorns take two years to mature (biennial). Oaks are often imposing shade trees at maturity and provide habitat and food for a variety of wildlife.