NATL has nearly a third of its area devoted to each of these three upland ecosystems. In addition there are smaller areas devoted to these aquatic or transitional ecosystems. Understory vegetation may be quite sparse. Hammocks occur on rolling terrain. The soils vary from somewhat poorly to well drained, are high in nutrients, and contain more organic material and litter than drier sites.
Hammocks occur commonly in north central Florida and sparingly elsewhere in Florida.
The largest historic hammock areas are near Brooksville, Ocala, and Gainesville. Some of the most common plants in this community are black cherry, flowering dogwood, laurel oak, live oak, pignut hickory, American beautyberry, sparkleberry, common greenbriar, wild grape, and blackberry. Animal species include spring peeper, broadhead skink, Florida box turtle, pileated woodpecker, tufted titmouse, cardinal, carolina wren, and gray squirrel. By suppressing naturally occurring fires, humans have caused many natural upland pine communities to be succeeded by hammock-like communities. Normally, hammock plants that invade adjacent upland pine are killed by fire.