Quercus stellata: Post Oak

Common Name:

Post Oak

Identification:

Recognized by first-year twigs densely covered with minute grayish to tawny hairs that hide the cuticle in at least the tip tenth of the twigs; by leaves 5-10 cm wide, lobed, the lobe tips lacking a bristle, underside grayish-green to brownish. During summer these hairs become matted and often form a "crust" which may become cracked and fall off in small sections, thus exposing a portion of the cuticle. Characteristically, tiny almost black granules are scattered in the matted hairs, a feature apparently lacking in other oaks. Trees grow to around 27 meters tall. They are slow growing. The trunk is grey to light reddish-brown, normally fissured, the ridges are rounded and scaly. Leaves usually with 5 primary lobes, the two nearest the terminal lobe quite broad; undersurface with abundant to scattered clusters of 4-9 hairs, rarely a few clusters with hairs fused at base. Acorn cups sessile, 12-27 mm broad, covering about 1/3 of the acorn; scales small, finely hairy, closely appressed, with tips sometimes free. The flower structure is incomplete; they have no petals.

Geography:

Found on dry rocky outcrops, ridges, and upper slopes with southerly and westerly exposures. Also found on the droughty flats of higher stream terraces. Natural community is upland forest, flatwoods, savanna, and primary. The range is the southern 2/3 of Eastern Deciduous Forest. Found in sites of gravelly to sandy, and/or acidic soil.

General Information:

Post oak is an indicator of the poorest sites, occuring in mixture with other oaks and pines. In deep sands, it is often merely a shrub, mixed with other scrub oaks, including turkey oak, blackjack oak and many similar oaks. On slightly better sites, it occurs as a scattered to abundant tree along with white, scarlet and chestnut oaks, upland hickories and pines. Also found in thickets on abandoned land, especially around the edges of oldfield prairies. Post oak is both intolerant and very slow growing.

Post oak flowers at the time of leaf-out in spring. Flowers are wind pollinated, and acorns mature the fall of the same year. The small acorns are cached by squirrels, bluejays other birds and small mammals. Post oak, though intolerant, grows slowly, and may live to 500 years. However, it usually succumbs to chestnut blight or fire long before that. Large are typically 50'x2'.

Post oak are ectomycorrhizal; wind pollinated. Post oak is susceptible to chestnut blight fungus, Cryphonectris parasitica, which infects the base of the stem. It shortens the life of the tree but is not an immediate threat.

Its uses were formerly for fence posts, hence the common name. It has no ornamental uses.

Written for your pleasure by:

David Peterson, Antonio Sanders, Valyncia Smith, Diane Sullivan, Brian Wages, & Shateiara Williams

References: