Bottomland Hardwood Forest
A valuable, productive, and diverse ecosystem
As I write this article, the pungent aroma of simmering mayhaws fills my house on the edge of the D’Arbonne Swamp. Mayhaw trees produce small crabapple-like fruits in the nearby bottomland hardwood forest in early May. I call mayhaw jelly “essence of the swamp.” Adorning a buttered biscuit, its tart, sweet taste always reminds me of the importance and benefits of the swamp where the mayhaws grow.
In my volunteer work as a naturalist and environmental educator, I realize that many people don’t know much about the natural environment near their homes. (As I will explain later, a swamp rabbit is now helping me change this situation.) Everyone in Louisiana lives within a few miles of a bottomland hardwood forest, yet few understand and appreciate its diversity and value.
A bottomland hardwood forest, a type of swamp, is a rich and productive wetland nourished by minerals and nutrients left behind during seasonal floods and by the rapid decay resulting from our warm, moist climate. Some are also called “overflow swamps” because they are inundated by flood waters during the wet seasons. This forest type is located on the floodplains of streams, bayous, and rivers in the Southeast, from east Texas across the southern states and up the eastern seaboard to Virginia.
All the living components of this swamp interact with its nonliving parts—water, soil, and air—to make a dynamic ecosystem. The wet/dry cycles of this environment, for instance, create a climate of constant flux for the resident organisms, which have developed adaptations to cope with these conditions, including physical structures or behavioral traits that allow them to survive in their changing environment. In this way, every living thing found in the swamp has adaptations, refined over generations, that help it exist there, linking it inextricably to the swamp.
The fertile alluvial soils of the bottomland hardwood forest nourish huge baldcypresses, water tupelos, oaks, and a variety of other trees, woody vines, and shrubs that can tolerate “wet feet” during the seasonal flood cycles. Oak trees are a dominant tree species in these forests, with each species adapted to specific elevations, water regimes, and soil types. In this context, oaks provide good examples of plant adaptation, showcasing a diversity related to the subtle changes in elevation found throughout the bottomland hardwood forest: overcup oaks grow on some of the lowest sites; higher elevations (in some cases only a few inches higher) yield good habitats for willow oaks and nuttall oaks; climbing a bit more, water oaks and cherrybark oaks thrive.
Botanical diversity includes giant baldcypress trees that may live to be a thousand years old. With their enigmatic “knees” and cave-like hollows, they harbor many forms of life including the curious Spanish moss. Spanish moss, the quintessence of southern swamps, is not a true moss at all but, rather, a flowering plant that grows on the stems and branches of other plants. It is not parasitic, but makes its own food by photosynthesis and collects moisture from the air. Tiny, bright yellow-green flowers bloom in the spring, and the wispy seeds drift off to land in another tangle of Spanish moss. This is how the “moss” grows longer and longer.
With this great assortment of green plants comes a wealth of other life forms that constitutes the forest’s biodiversity. Catching a glimpse of or hearing any wild animal in the bottomlands is a privilege. A few of the larger animals that reside here are the black bear, wild turkey, American alligator, white-tailed deer, swamp rabbit, otter, fox squirrel, and red fox. The pileated woodpecker sings a laughing song that echoes through the treetops.
The longer, warm days of spring awaken the swamp; and the fragile, new leaves create a green haze. Wood ducks squeal to their mates across the sloughs, and long swags of the fragrant flowering vine called yellow jessamine hang across the upper branches of the trees. Mayhaws bloom along the bayous in the lowlands. Oak trees fill the air with pollen, and the winter pools of backwater begin to disappear. These times of transition are magical moments in the swamp, and I never tire of watching and hearing the swamp return to life.
Mistaking swamps for boggy wastelands, humans have cleared and drained most of these valuable wetlands. According to one source, seven million acres of bottomland hardwood forests have been cleared and converted to agriculture in the lower Mississippi Alluvial Valley during the last century. The ivory-billed woodpecker, a beautiful, large bird, lost much of its habitat because of intense logging in these forests. The ivory-bills could not adapt to the sudden environmental changes and have disappeared from the landscape.
These forests still provide important habitat to migratory songbirds called “neotropical migrants” and to a variety of waterfowl. Here, these birds can feed, rest, and nest. Any birdwatcher or bayou fisherman knows he or she can find many colorful vocalists—like the prothonotary warbler—in these diverse forests. Cavities in the big trees provide homes to wood ducks, screech owls, flying squirrels, and bats. Black bears den in hollow trees. The acorns from oak trees are an important source of nourishment for squirrels, deer, and many other animals. Swamp rabbits eat the native cane and are an important link in the food web for predators like foxes, bobcats, and great horned owls. Backwater sloughs are important breeding grounds and refuges for frogs, fish, and crawfish.
Studies have revealed that bottomland hardwood forests hold tremendous value not only to wildlife, but to humans as well. The swamps act like giant sponges to soak up floodwaters, protecting downstream areas from flooding and filtering and purifying the water as it moves through the wetland plants and soil. Cleaner water then enters our streams, bayous, and rivers.
Conserving the remaining bottomland hardwood forests will result in greater production of many renewable resources like timber, furbearers, and fish that we all need and enjoy. Not to mention the benefits of a leisurely hike through a stand of bottomland oaks or a kayak paddle among giant baldcypress trees to restore the spirit and calm the nerves.
As for the swamp rabbit, he first appeared one morning as I was leading a group of students on a field trip at Black Bayou Lake National Wildlife Refuge. As we watched him munch clover at the edge of a briar patch, the curious children asked many questions about him and his habitat. It occurred to me then that this creature, whom I named Swamper, would be an ideal ambassador to teach people about bottomland hardwood forests. He shares his knowledge currently in my book, Swamper, Letters from a Louisiana Swamp Rabbit. As Swamper writes, “Nature waits for you,” And as I am reminded by the odors wafting from my kitchen, mayhaw jelly waits for me.