Oak lumber is hard, tough, durable, the porous wood stains well, and its uses are too extensive to enumerate. Several species of oaks are used as ornamentals. Identification of Oaks In naming oaks, utilize twigs with leaves from the exposed part of the crown when possible. Avoid heavily shaded leaves, twigs that have elongated a second time during the growing season, young trees, saplings, and rootsprouts. Determining whether a tree is a white oak or a red oak can be helpful.
Identification is complicated by the occurrence of hybrids, which often have quite variable leaves.
All species are inclined to hybridize except that white oaks do not hybridize with red oaks . Since many hybrids lack fruit, it is a good idea to turn to nearby trees with fruit. When these fertile trees have been named it is often possible to recognize a hybrid in respect to the two parents that are involved. Within each type the species are arranged for easier recognition according to similarities and differences in leaf shape and not necessarily according to natural relationships. Characters for positive identification of all variants in a species are sometimes numerous and are not included in a description.