Large sandhills located on the northeast margins of several Georgia rivers have an interesting geological origin. During the Wisconsinian Ice Age, climate cycles of alternating glacial expansion and retreat occurred. Severe drought conditions in southeastern North America correlated with climatic phases of glacial expansion when much of earth’s water became locked in ice. Some rivers, such as the Ohoopee, for the most part dried up, while larger rivers suffered reduced flow and were clogged with sandbars. The dry climate and large herds of megafauna congregating around shrinking waterholes created a denuded landscape with sparse vegetation. Strong and frequent Ice Age winds blew the exposed riverine sand across the landscape into eolian sand dunes. All of these sandhills are located to the northeast margins of rivers–evidence the predominant winds of the Ice Age came from a west-southwesterly direction.
This is a crude diagram I made of the 3 giant sandhills along the Ohoopee River. Other sand dunes can be found to the northeast edge of the Ogeechee River and the Canoochee River. These date to ~30,000 BP and ~45,000 BP. The Ohoopee sandhills date to ~20,000. The majority of geologists also think the windy dry conditions contributed to Carolina Bay formation as well.
Today, scrub oak and pine hold down the sand dunes. This is part of the Mcleod Bridge Tract.
The Nature Conservancy and the Georgia State government manage these areas. Predictably, the sign restricting vehicles past this point is pockmarked with bullet holes and is ignored.
Tire tracks go well past the sign. Rednecks use the sand dunes as a trash dump. Shards of glass, spent shotgun shells, and rusted tools litter the preserve. It reminds me of a used ashtray.
Almost looks like a desert. The tallest trees are 30 feet high. Some of the small scrub oaks may be 100 years old but never get big because the soil is so poor here.
Turkey oak is a common tree here.
So is sand post oak.
Scrub oak and pine makes for a drab landscape. I was rather unimpressed.
I had the opportunity to visit the Ohoopee Sand Dunes last week on my way to the Moody Forest Natural Area. To be honest, I was underwhelmed. The vegetation consists of scrub oak and loblolly pine. I didn’t see nor hear a single bird, though I did see deer and turkey tracks. This scrub habitat seems dull and lifeless. Perhaps one reason I was unimpressed was because an extensive stand of scrub forest occurs about a 3 minute drive from my home, and it took 90 minutes to drive to a landscape that looks similar to one so close to my house. However, there are distinctly unique species living on the sandhill. The scrub forest near my house is probably just second growth, although sandy soils are predominant there. The sandy soils in south Richmond County originated from Eocene age beaches, not Ice Age riverine sand deposits.
If I had the trip to do over again, I’d double the time I spent at Moody Forest and I’d skip the Ohoopee Sand Dunes. The latter may have an interesting origin, but they’re not worth the time spent off the beaten path. (They’re located 5 minutes southwest of Swainsboro.) I drove by the U.S. 80 tract and didn’t even bother stopping the car to get a closer examination. It consisted of nothing but closed canopy pine woods and dense oak scrub.