Around the world, it is hard to find a more important group of trees than the oaks (Quercus species). They are native to the northern temperate regions as well as Asia. Oaks have alternate, simple leaves and produce generally large, coarse textured trees.

Oaks native to America include:

Some of the most common oaks grown in woodlots or landscapes in the United States include:

1. English Oak - Q. robur
2. Daimyo Oak - Q. dentata
3. Mossycup Oak - Q. macrocarpa
4. Red Oak - Q. borealis
5. Pin Oak - Q. palustris

Insect Pests: Oak is a preferred host of the gypsy moth caterpillars which may defoliate the tree in about 2 weeks. Canker worms in the spring and orange-striped oak worm in late summer are important leaf eaters. Many, many insects cause conspicuous growths such as oak-apple, wool sewer and oak bullet gall on the leaves. Gouty oak gall wasps, form rough, lumpy galls on the twigs and branches Small twigs with leaves on the ground in midsummer may have been infested by the oak twig pruner, which tunnels in the twig causing it to break, especially from wind.

Diseases: Oak wilt is a serious disease of black and red oaks especially in the Midwest. The deadly disease is spread by root grafts and insects. Anthracnose, a fungal disease, curls the leaves of white oak inward and forms spots on the leaves of black and red oak along margins and veins. Shoe string root rot often causes the death of weakened oak trees. The inside of loose bark is covered with black string-like threads. It commonly lives on dead stumps and roots in the woods.