The Bur Oak, is a species of white oak. Native to North America in the eastern and midwestern U.S. and south-central Canada. It is a large deciduous tree growing up to 100 feet in height, and is one of the most massive oaks with a trunk diameter of up to 10 ft. It is also one of fastest-growing oaks, with rates of 2 - 3 feet per year when young. It commonly lives to be 200 to 300 years old, and may become significantly older. The bark is a medium gray and somewhat rugged. The leaves are 3-6 in. long and 2-5 in. broad, variable in shape, with a lobed margin. The flowers are greenish-yellow catkins, produced in the spring. This variety produces very large acorns. Bur Oak typically grows in the open, away from forest canopy. For this reason, it is an important tree on prairies, where it is often found near waterways in more forested areas, where there is a break in the canopy. It is also a fire-resistant tree, and possesses significant drought resistance by virtue of a long taproot. New trees may, after two to three years of growth, possess a 3 - 6 foot taproot. Heavy nut crops are borne only every few years. Bur Oak makes an outstanding ornamental tree.