Whit Gibbons

Whit Gibbons

Abundance and ubiquity do not guarantee the continued existence of any species. In the late 1800s passenger pigeons and Carolina parakeets were commonplace. No one thought they would disappear. Their demise at the hands of humans is a classic story of modern extinctions. We must not take plants or animals for granted simply because they are familiar and prevalent. Consider oak trees.

From 400 to 600 species of true oaks exist today, the number depending on which botanist you talk to. Oaks are a prominent feature of the South. Massive Southern live oaks draped with Spanish moss give many towns character, charm and sometimes their names – Oak Ridge, Tenn.; Live Oak, Fla.– or nicknames, like the Druid City for Tuscaloosa, Ala. Noteworthy individual trees have even been given names, like the iconic Angel Oak near Kiawah Island, and the Evangeline Oak in Saint Martinville, La. Oaks have had a discernible influence on Southern lives and culture. Oak furniture, the shade of an oak-lined boulevard, the reds, yellows and oranges of autumn oak leaves are part of everyday life. 

Oaks are in the beech family, and representatives are native to all warm continents except Australia. More than 150 kinds are known from Mexico. The United States has 90 species. In volume and number of trees, more oaks are found here than anywhere else. Aiken has an unusual collection of U.S. oaks. A different kind was planted every 75 feet along 2 miles of city street, probably the densest concentration of oak species in the country.

In the cooler regions of the Appalachian woodlands one finds large and impressive canopy trees, including the white and chestnut oaks. Among common large oaks of the Deep South are the grand old live oaks, as well as willow and water oaks. On a smaller scale, but no less conspicuous, are turkey and blackjack oaks of the sandhills region. Even botanists have difficulty identifying oaks because of their high level of natural hybridization. If anyone asks you to identify an oak, tell them you think it’s a hybrid. They’ll think you’re a botanist.

Much is known about oak tree biology. Once maturity is reached, often after many years, each tree produces both male and female flowers. The pollen-bearing male flowers, called catkins, are commonly observed dangling from the trees in late spring. The pollen is frequently indicted as the cause of allergic reactions. The oak fruit, commonly known as an acorn, develops from the female flower in late summer or autumn. Although a 200-year-old tree may have produced more than a million acorns, only a handful, or maybe none, will have developed into trees. Why? Because acorns are a food source for various kinds of wildlife, from insects to large mammals. Native Americans used them to make flour.

Oaks are incontestably long lived. Scientific counts of annual growth rings have confirmed trees over 300 years old. Reports of 500- to 1,000-year-old trees are unverified and suspect, though some may be true. Most of our big trees have been timbered, and the process continues. Nonetheless some enormous oaks still survive. Many are more than 10 feet in diameter. The Live Oak Society lists the Seven Sisters Oak in Lewisburg, La., with a diameter more than 12 feet, as the largest in the country. The second largest is the Middleton Oak near Charleston, about 11 feet in diameter. Imagine entire forests of such enormous trees. What must early explorers like William Bartram have thought as they traveled through those Southern forests in the 1700s. We’ll have to wait a couple of centuries and change our tree-cutting practices to see the return of forests with massive oaks.

Though oaks are still plentiful, remember the fate of Carolina parakeets and passenger pigeons – abundant, then extinct. Let’s not take oak trees for granted. Next time you stand in the shade of an oak tree or walk through a hardwood forest, appreciate what we have.

​Whit Gibbons is an ecologist and environmental educator with the University of Georgia’s Savannah River Ecology Laboratory. Send environmental questions to ecoviews@gmail.com.