The majestic oak can live more than 200 years and is considered a slow-growing deciduous tree --- that is, one that sheds its leaves in autumn. With more than 400 different known varieties, oak is one of the most prevalent hardwoods on the planet. Prized for its gorgeous grain marks when quartersawn, oak is considered one of the finest building materials available.
Gather the leaves of your suspected oak tree. With more than 400 varieties, you will find some slight variations in the leaf shape and size, but all oak have five to eight unique lobes or sections to the leaf. The top side should be smooth and shinier than the bottom, where the fine veins go up into the lobes. In autumn, oak leaves turn different colors, depending on the variety.
Inspect the branches of the tree. Oak trees have twisted, knotted twigs that grow out in every direction. They tend to be knobby with a callused-like appearance and new buds on the ends.
Feel the bark on the trunk for more of that same knobby, knotted feeling. The bark should be gray and pitted.
Note the size of your tree. Oaks make excellent shade trees and can grow to 100 feet tall with a circumference of six feet. Oaks usually are upright trees with a branch span twice its size. In mature trees, branches are usually well out of reach of human hands.
Check for acorns. These small nuts are an excellent food supply for many animals. Considered a "fruit," acorns are ripe in late summer to fall and grow exclusively on oak varieties. A tree's acorn growth will depend on the amount of water the tree has taken in during the earlier months, and only one in every 10,000 acorns will result in a new oak tree.