While the vast majority of trees in the Unicoi Mountains are second-growth, the range is home to one of the few remaining stands of old growth forest in the eastern United States. The Joyce Kilmer Memorial Forest along Little Santeetlah Creek is home to a substantial stand of virgin cove hardwood forest, and contains some of the oldest and tallest trees in the Unicoi Range. The largest trees in Joyce Kilmer are over tall and have circumferences of just over . The oldest trees in the forest are over 400 years old. Other stands of old growth forest include a patch around Falls Branch Falls and a remote section of the Citico Creek Wilderness near Glenn Gap.