Quercus phellos, the willow oak, is a North American species of a deciduous tree in the red oak group of oaks. It is native to the south-central and eastern United States.
Description
It is a medium-sized tree growing to 20–30 meters (65–100 feet) tall (exceptionally to 39 m, 128 ft), with a trunk up to 1–1.5 m (3+1⁄2–5 ft) in diameter (exceptionally 2 m or 6+1⁄2 ft). It is distinguished from most other oaks by its leaves, which are shaped like willow leaves, 5–12 centimeters (2–4+3⁄4 inches) long and 1–2.5 cm (3⁄8–1 in) broad with an entire (untoothed and unlobed) margin; they are bright green above, paler beneath, usually hairless but sometimes downy beneath. The fruit is an acorn, 8–12 millimeters (5⁄16–15⁄32 in) long, and almost as wide as long, with a shallow cup; it is one of the most prolific producers of acorns.[2] The tree starts acorn production around 15 years of age, earlier than many oak species.[3]
Willow oaks can grow moderately fast (height growth up to 60 cm or 2 ft a year), and tend to be conic to oblong when young, rounding out and gaining girth at maturity (i.e. more than 50 years).