Illinois Official State Tree (IL)

White Oak

(Fagaceae Quercus alba)
Adopted in 1907; 1973.


As noted below, the law that originally made the oak the state tree did not specify which one. Approximately 20 native species of oak occur in Illinois. The law was amended in 1973 to designate the white oak, Fagaceae Quercus alba, as the official state tree.



The white oak can be very large. Individual trees commonly reach a height of 30 meters (100 ft.). When growing in the open, they often have widely spreading branches. These characteristics make white oaks excellent shade trees.


In 1907, Mrs. James C. Fessler of Rochelle suggested to state officials that Illinois schoolchildren vote for a State Tree and State Flower. They selected the Oak as State Tree.


Sen. Andrew J. Jackson of Rockford introduced a bill making it official in 1908. In 1973, a special poll of some 900,000 children changed the Official State Tree from the "Native" Oak to the White Oak, and the amended bill was signed into law that year.

White oak (Quercus alba) is an outstanding tree among all trees and is widespread across eastern North America. The most important lumber tree of the white oak group, growth is good on all but the driest shallow soils. Its high-grade wood is useful for many things, an important one being staves for barrels, hence the name stave oak. The acorns are an important food for many kinds of wildlife.

  • Leaf: Alternate, simple, oblong to ovate in shape, pinnately veined with an evenly lobed margin, 4 to 7 inches long. The apex is rounded and the base is wedge-shaped. Leaves are hairless, bright green above and whitish below.
  • Flower: Male flowers are green, borne in naked catkins, 2 to 4 inches long. Female flowers are reddish and appear as single spikes. Appearing with the leaves.
  • Fruit: Ovoid, but may be oblong, with a warty cap that covers 1/4 of the fruit. The cap always detaches at maturity. Matures in one year, ripens 120 days after pollination (July to September).
  • Twig: Red-brown to somewhat gray, hairless, with red-brown multiple terminal buds that are small, rounded and hairless. Twigs are often shiny or somewhat glaucous.
  • Bark: Whitish or ashy gray, varying from scaly to irregularly platy or blocky. On older trees smooth patches are not uncommon.
  • Form: A large tree; when open grown, white oaks have rugged, irregular crowns that are wide spreading, with a stocky bole. In the forest crowns are upright and oval.


Taxonomic Hierarchy
Kingdom Plantae -- Plants
Subkingdom Tracheobionta -- Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Hamamelidae –
Order Fagales –
Family Fagaceae – Beech family
Genus Quercus L. – oak
Species Quercus alba L. – white oak


Dendrology at Virginia Tech
U.S. Department of Agriculture