At first glance, the 800-acre Big Hammock Natural Area in Tattnall County seems like any other South Georgia forest, thick with oaks, pines, hickories and an assortment of understory shrubs and other plants.

But this is no ordinary wild place. In 1976, the National Park Service designated the state-owned preserve in the Altamaha River floodplain as a “national natural landmark” because of its variety of natural habitats supporting several rare and endangered species.

The natural landmarks initiative is the only nationwide program that recognizes the best examples of biological and geological features.

Most notably, the Big Hammock preserve harbors one of the state’s rarest wild plants, the Georgia plume, a small, showy, white-flowered tree that occurs nowhere else in the world except in a few South Georgia counties. The largest population occurs in the Big Hammock preserve. (A hammock is a rise in elevation of an otherwise flat landscape.)

The natural area’s remarkable diversity drew several of us Georgia Botanical Society members there last weekend. Bobby Hattaway, the society’s current president, led us along a 1.3-mile trail through the array of habitats with their huge mix of plant species. (We found the Georgia plume just coming into full bloom.) Hattaway, a botanist who taught at Georgia Southern University, is thoroughly familiar with the flora and geology of Big Hammock, which is managed by the Georgia Department of Natural Resources.

Our trek took us up and over an ancient river sand dune that gently rises 100 feet above sea level and now supports the different types of habitats depending on soil moisture. Ascending the dune, we saw stunted hardwoods and lichens that made an interesting sight. The driest part of the dune ridge had deep, white sands with scattered turkey oak, longleaf pine and sand spike-moss. At the foot of the ridge lay a lush pine wiregrass woodland and cypress-tupelo swamp.

All of this supports an abundant and rich variety of wildlife. “Truly a national natural landmark,” Hattaway noted.

IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be first quarter on Thursday. Venus and Mars are low in the west just after dark. Jupiter and Saturn rise in the east just after midnight.

Charles Seabrook can be reached at charles.seabrook@yahoo.com.