Post Oak

Post oak, sometimes called iron oak, is a medium-sized tree abundant throughout the Southeastern and South Central United States where it forms pure stands in the prairie transition area. This slow-growing oak typically occupies rocky or sandy ridges and dry woodlands with a variety of soils and is considered drought resistant. Post oak is susceptible to chestnut blight, which has caused heavy losses. Post oak gets its name from the traditional use of the wood for fence posts

Leaf: Alternate, simple, oblong, 6 to 10 inches long, with 5 lobes, the two middle lobes are distinctly square, resulting in an overall cruciform appearance, thickened texture; green above with scattered stellate pubescence, pubescent and paler below.

Flower: Species is monoecious; male flowers are yellow-green, borne in naked, hanging catkins, 2 to 4 inches long; female flowers are reddish and appear as single, short spikes from leaf axils, appearing with the leaves.

Fruit: Acorns are 1/2 to 2/3 inches long and ovoid; cap is bowl-shaped and warty/scaly, covering 1/3 to 1/2 of the nut; Individual scales are more apparent than white oak; maturing in one year and ripening in the fall. The acorns mature in one growing season and drop soon after ripening, from September through November. In common with many other oaks, post oak begins to bear acorns when it is about 25 years old.

Twig: Gray or tawny-tomentose and dotted with numerous lenticels; multiple terminal buds are short, blunt, orange-brown, somewhat pubescent, short, thread-like stipules may be present.

Bark: on mature trees thick and distinctive with ashy gray and initially quite scaly, later becoming more blocky and ridged, very similar to white oak

Form: A small to Medium sized tree up to 65 feet tall with a crown that has gnarled and twisted branches.

Range: the range of post oak extends from southeastern Massachusetts, Rhode Island, southern Connecticut and extreme southeastern New York (including Long Island); west to southeastern Pennsylvania and West Virginia, central Ohio, southern Indiana, central Illinois, southeastern Iowa and Missouri; south to eastern Kansas, western Oklahoma, northwestern and central Texas; and east to central Florida.

It is a large and abundant tree in the southern Coastal Plain, the Piedmont, and the lower slopes of the Appalachians. It is common in the southwest and grows in pure stands in the prairie transition region of central Oklahoma and Texas known as the "Cross Timbers".

Growing Conditions: Post Oak grows on a variety of sites and soils. Its range coincides mostly with that of the Utisols but also includes some Alfisols in the western portion of its distribution. Typically, it grows on dry sites. Rocky outcrops, ridges, and upper slopes with southerly or westerly exposures are common.

Wildlife value: Post oak is a valuable contributor to wildlife food and cover. Acorns provide high energy food during fall and winter and are considered important in the diet of wild turkey, white-tailed deer, squirrels, and many other rodents. When acorns are available animals fatten quickly, go through the winter in good condition, and are most likely to produce healthy young. Leaves are used for nest building by birds, squirrels, and raccoons. Cavities provide nests and dens for various birds and mammals.

Timber Value: Considered a beautiful shade tree for parks, post oak is often used in urban forestry. It is also planted for soil stabilization on dry, sloping, stony sites where few other trees will grow. It develops an attractive crown with strong horizontal branches. Large trees are difficult to transplant and do not tolerate compaction or removal of soil in developments.

The wood of post oak, commercially called white oak, is classified as moderately to very resistant to decay. It is used for railroad ties, lathing, siding, planks, construction timbers, mine timbers, trim molding, stair risers and treads, flooring (its highest volume finished products), fence posts, pulp, veneer, particle boards, and fuel. The bark provides tannin, decorative and protective mulch in landscaping, and fuel.

Damaging Agents- Post oak is susceptible to most insects, diseases, and pollutants that present a threat to other oaks. Regeneration efforts are hampered by acorns being destroyed by weevils. Insect defoliators, leafrollers, tent caterpillars, Gypsy moth, sawfly, leaf miners, and skeletonizers may cause growth losses, and when repeated, may cause mortality (14). The foliage also is susceptible to at tacks by aphids, lace bugs, various scales, gall wasps, and mites. The trunk, twigs, and roots may be damaged by carpenter worms, borers, beetles, twig pruners, white grubs, and cicadas (locusts). Some of these cause defects that render the wood unfit for many commercial purposes (1).

Lifespan: Post oak has an average lifespan of 250 years and Maximum lifespan of 450 years

Sources

John Stein and Denise Binion USDA Forest service January 2003. Field Guide to Native Oak Species of Eastern North America

Links:

http://plants.usda.gov/core/profile?symbol=QUST

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=77

http://aggie-horticulture.tamu.edu/ornamentals/natives/QUERCUSSTELLATA.HTM