The bur oak is also known as burr oak and the mossycup oak. It is found in all of Ohio except for the southeastern part of the state. It is more frequent in the western part of Ohio.
This type of oak is mostly found in the Midwestern and Great Plains states. It extends into south-central Canada to the north, and Texas to the south.
The older trees can be quite massive as shown in the pictures on this page. The best place to see massive versions of this oak is at Goll Woods State Preserve in Fulton County.
The trees in this preserve are the largest you will see anywhere in the state. Some are over 400 years old.
This oak is frequent in Northwest Ohio. They grow on the sandy ridges and loamy soil as well as flood plains and swampy areas.
To the untrained eye it is sometimes difficult to distinguish this oak tree from other oaks by only looking at the bark. While the older trees can be distinguished by the deep furrowed ridges in the bark, the younger trees don't have the real deep grooves.
It is much easier to identify the tree by the leaves and acorns. The acorns can get quite large, from 3/4" to 2" and are fuzzy looking in the spring and early summer.
This type of oak has large, bold-textured, leathery leaves that are alternate, and usually dark green. The leaf shape is highly variable in these trees, but consists of about five to nine lobes of greatly different size.
The lower lobes are very small, the central lobes average, and the upper lobes very large with crenate margins. The sinuses in the central portion of the leaf may be shallow, but are usually very deep (sometimes to the mid-rib), giving this leaf the approximate shape of a base fiddle.
-- Click on the images for larger pictures --
Information Source: Ohio DNR