typically grows to between 50 and 75 feet in height, with a trunk diameter
of 1 to 3 feet. It has an oblong or rounded crown that becomes more irregularly
open with age. The lower branches droop and are slowly lost, leaving pin-like,
grows in moist, usually rich soils of bottomlands (palustris refers
to marshes) in almost every county in Illinois. It is common in floodplains
along streams and at the edges of swamps and ponds. Throughout the rest
of its range from Massachusetts, west to southeastern Iowa and south to
Oklahoma east to northern Virginia, it occurs in moist, clay soils.
Overall, it commonly grows on sites that flood occasionally, but not during the growing season. It grows on sites with a 'claypan' such as Illinois flatwoods, which tend to be very wet, with standing water at the surface in the winter and spring.
Pin oak is very similar to Hill's or northern pin oak. It is distinguished from Hill's oak by its acorns, which are shorter and covered by a shallower cup than those of Hill's oak which are about twice as long and taper. The trees also differ in their habitat preferences. Whereas pin oak grows in moist, bottomland soils, Hill's oak prefers drier upland soils. Pin oak leaves turn red or brown in the fall and persist on the tree during the winter. Hill's oak leaves turn color and are shed in the autumn. The winter-persistent leaves and the pin-like stubs (which remain after the lower branches of pin oak are lost as the tree matures) are the most distinctive characteristics of the tree.
Pin oak is a member of the red oak group. Its bark is lighter gray or reddish brown when young, becoming or darker gray brown when mature. It is smooth when young, developing shallow furrows as it ages.
are slender and reddish brown to gray brown and shiny.
are approximately 1/8 inch long, reddish brown and are sharp pointed.
The leaves are alternate and simple, with 5-7 deeply incised, bristle-tipped lobes. They are up to 7 inches long and up to 4 inches broad, with a slender leaf stalk up to 2 inches long. They are dark green and shiny on the upper surface and paler with tufts of hair along the veins on the underside. Dead leaves tend to remain on the tree in the winter.
is monoecious; both male (staminate) and female (pistillate) flowers are
borne on the same tree. The male flowers appear as catkins and the female
flowers in groups of 1-3 just as the leaves begin to unfold.
are 1/2 inch long and up to 1/2 inch across, and are borne singly or in
groups of up to four. They can occur with or without stalks, and are nearly
hemispherical in shape, the cup being thin and saucer-shaped. The nuts
are often striate, and the cups are reddish brown and finely hairy or hairless.
wood is hard and heavy. It is used for fence posts, fuel, and general construction.
Because it is fast growing and tolerant of urban stresses, it is commonly
planted as an ornamental.