October 3, 2014. I depart at daybreak on a walk from the South Cedar Creek Landing to Old Dead River. The flickers are starting to move into the swamp for the winter, and I hear a few calling along the Kingsnake Trail. Their numbers will continue to build up over the fall. By the time of the Christmas Bird Count in later December, Congaree will rank at or near the top in the nation for yellow-shafted flicker numbers: in 2013, it was in fourth place with 201; in 2012, second place with 316; and in 2006, in first place with 366. It is noteworthy to see a bird like the flicker shift from one habitat type during the nesting season – upland, open country with scattered trees and short grass – to an entirely different one in winter, in this case, heavily forested floodplain. Robins do the same thing, preferring lawns, parks, orchards, golf courses, and other “short grass” environments during the breeding period before moving into the swamp for their winter quarters. In the process the robin goes from a diet heavy in earthworms, insects, and other protein to one consisting mostly of berries and fruits.
I continue south towards the river beyond where Kingsnake makes a sharp turn to the west. This is an old, grown-up logging road but is still passable. Thickets of switch cane have taken over in places but are easy to walk through or around. Just before Running Gut, another old road splits off to the east. It’s easy to miss if you don’t know where to look. This road was constructed around 1974, when they were logging this part of the swamp. It crossed Dead River Gut, bridged with a culvert and earthen fill, (which has since been removed), near the east side of Dead River, and ended on Butler or Tabor Island, part of which was selectively logged.
I find my first deer scrape of the fall in the middle of the old road bed, a fresh one that looks like it was made last night. Scrapes are bare spots on the ground, carved out by bucks with their hooves, and herald the fall rut. They are signposts where various bucks and does communicate through olfactory senses. Scrapes are typically made under a small overhanging limb which the buck chews on and deposits his saliva scent; he also attacks the limb with his horns and forehead and in the process leaves scent from his forehead gland. Bucks also urinate in the scrapes, depositing more scent.
I walk along the north and west side of Dead River, a shallow oxbow lake that would have been the main channel of the Congaree River 250 years ago. There are many trees and bushes along the bank and it is difficult to get a decent view of the lake. Other than hearing the squeal of a wood duck taking off and seeing a few turtles basking on logs, the lake appears empty.
There is a natural “levee” forest on this side of Dead River of beautiful, tall sweetgums growing on very flat terrain with an understory of pawpaws. It’s an even-aged forest since the gums are all about the same size and growing fairly close together. Most are running about 32-34 inches in diameter, with a range of approximately 24-40 inches. It indicates to me that this area was some sort of clearing, field, or pasturage, probably prior to the Civil War. That would place the ages of these gums at about 150 years, assuming the clearing was abandoned and reverted to forest either during or shortly after the War.
This gum stand fits at least one definition of Eastern old-growth forest, which is that the trees are 120-150 years of age or greater. But it is not old, old-growth. There is a noticeable lack of large logs and limbs on the ground, and no tip-up mounds created from the massive root systems of fallen giants. Ironically, it is also the lack of smaller and medium-size trees, so characteristic of an all-aged, old-growth hardwood forest with its abundance of different-sized trees.
One of the most significant attributes of Congaree’s old-growth forest for me is that we can observe the various tree species achieve their maximum growth potential before dying of disease or falling over from wind throw. I’m confident, for example, that a Congaree sweetgum cannot grow much beyond a circumference of eighteen feet before it gets so heavy that its shallow root system can no longer support it, or insect damage and decay kill the tree. Likewise for persimmons, whose maximum growth in the swamp seems to be about eight feet in circumference; for sugarberries, twelve-to-thirteen feet in circumference; swamp chestnut oaks, twenty feet or so in circumference; and cherrybark oaks, twenty-four-to-twenty-six feet in circumference, to name a few. For those species that often have swollen trunk bases (buttresses), such as American elm, overcup oak, laurel oak, bald cypress, water tupelo, and swamp tupelo, freakish individuals with oversized buttresses can distort the pattern. For these species, height may be a better measure of maximum potential growth.