By Jeff West
Down in McCreary County, Kentucky, in the compact hills of the Cumberland Plateau near the Tennessee border sits a grove of oak trees. They’re perched on a small promontory overlooking a ravine where 200 feet below, a pair of seasonal creeks come together in a tidy Y. The oaks are tall and full, the mix of species divided between scarlet oaks and whites, with deep trenches in their bark and layers of high branches carving out a gothic tracery against the sky. Grey, shaggy mosses hang around the trunks of the oaks in small, irregular patches. Softer, greener mosses grow near the ground in the arched clefts where the trees’ trunks begin spreading into thick roots. Low-rising viburnum and wild blueberry bushes pepper the sandy soil in between the trees.
It’s a beautiful location, one that gets sheltered, protected, and nourished by all those oak trees. But across the Appalachians and the whole of the eastern United States, the number of oak trees is in decline. The continued presence of these trees in many upland areas is threatened by an influx of species such as maple, birch, and tulip poplar that have not historically occupied such spots in the forest. So, in March of 2011, fire managers of the Daniel Boone National Forest and their partners from conservation organizations like The Nature Conservancy set fire to this patch of woods. Their hope was that such prescribed burns, much like a physician’s regimen of treatment for a sick patient, could return conditions in this grove to a state that will allow its oaks to thrive once more.
“A lot of people consider oaks to be a keystone species, a species on which the ecosystem largely depends,” Danna Baxley, director of conservation for the Kentucky chapter of The Nature Conservancy, said during a July interview. Speaking via Zoom from the warm, natural wood of her home office, she explained the importance of oaks. On top of sequestering carbon and providing lumber for furniture and bourbon barrels, “oaks support more forms of life than any other tree in Appalachia,” she said. Acorns from oak trees provide calories for Appalachia’s menagerie of deer, bears, possums, raccoons, turkeys, foxes, and other wildlife. In addition, over 500 types of butterflies, moths, and other insects feed on oak leaves and hide themselves in oak tree bark. These invertebrates subsequently become food for innumerable songbirds, woodpeckers, and other bug-eating creatures.
Oaks create favorable conditions for plant life as well. On the forest floor, the sunlight filtering in between an oak tree’s high, widely spread branches allows for the development of what Baxley calls an “incredible herbaceous understory” of bushes, shrubs, and grasses. Other species of trees grow well in the neighborhood of oaks, too. Throughout Appalachia big oaks shelter varieties of pine, hickory, and many more.
The diversity of plant and animal life that oaks support makes these trees an anchor in the forests of Appalachia. Huge and unassuming, they’re like the old bass fiddle in a bluegrass band, holding a song together while the fiddle, banjo, guitar, and mandolin color the tune with all their different shades. Such diversity is crucial for forests as they navigate the always uncertain future. It makes for serendipitous beauty in periods of plenty and is a source of underappreciated possibilities when times turn gray.
Young oaks are notoriously difficult growers, however. They don’t use sunlight as efficiently as many small trees and brushy plants, so oak seedlings often are overrun in open fields and on mountain balds. Oak seedlings also expend much of their early energy supplies growing down instead of up, developing firm roots before pushing out stems and branches. While this preference for building roots can give oaks a strong foundation, it also allows maple and other species to get a head start in deeply shaded areas. These faster growing trees then capture almost all of the available sunlight, preventing young oaks from getting the photosynthetic energy they need to push for the sky.
Fortunately for oaks, Mother Nature rarely leaves a forest undisturbed. Wind storms, ice, mudslides, drought, bug infestations, and disease all break off branches and fell trees, creating conditions of mixed sunlight and shade that oaks adore. Wildfires also provide a useful assist, burning through thin-barked maples in the forest midstory and offering surviving oaks the chance to reach into the canopy before new maple growth can catch up.
Human beings have long opened helpful holes in the forests, too. As U.S. Forest Service researcher Daniel Dey noted in a 2014 review article for the journal Forest Science,
Quercus (the genus to which all species of oak belong) has been a dominant and widely distributed genus throughout eastern North America for thousands of years, and it rose substantially in prominence through anthropogenic fire with the advent of human colonization of the region.
Early peoples in eastern North America burned areas for hunting, cleared patches for farming, and built villages using nearby timber. Later, European settlers carved out homesteads throughout the eastern forests, annually setting fires to improve foraging conditions for their livestock. After the Civil War, mining, lumbering, and railroad construction in Appalachia drew labor away from mountain farms allowing forests to reclaim less productive agricultural lands. All of these activities created the kind of partially open environments that favored the growth and spread of oak trees.
Additionally, Dey pointed out that,
The origin of many of today’s mature oak forests throughout the region is from forest disturbances…in the latter 19th and early 20th centuries.
These disturbances resulted mostly from a timber boom that occurred between the 1880s and the 1920s. This boom reduced much of Appalachia’s forests to small, secondary growth trees. Under such conditions, the strong root development of young oak trees and their ability to energetically resprout after being burned, cut, or grazed multiple times gave these trees an advantage when the boom eventually petered out. In the 1930s, as the forests began to regrow, oak took the lead, establishing the foundation for the forest ecosystems that predominate Appalachia today.
In the last century, modern tools have reshaped the possibilities of our lives and the speed with which we act. At the same time, the ecological world often responds gradually to change, creating consequences for our trials that are not always clear in a single career or lifetime.
In 1935, the U.S. Forest Service established a goal of extinguishing as quickly as possible any wildfire on public lands. Made possible by advances in motor vehicles, pumping technology, fire suppression chemicals, and evolving ideas of what a government agency can and should accomplish, this policy sought to preserve important timber resources, temper the erosion of fragile mountainsides in the wake of the timber boom clear cuts, and protect private property in and around public lands.
Initially, this experiment in land management benefited the burgeoning young oak trees of Appalachia, giving them protection against the damage that severe wildfires can cause. But as forest lands remained lightly disturbed for decades, and the number of spaces opened by wildfire faded away, the regeneration of oaks failed. While established trees continued to grow, fewer young oaks found the conditions they required to survive. As those older oaks now begin to die, there are not enough young ones available to fill the voids left behind.
The use of prescribed fire in a forest represents an adjustment to the continuing wildfire suppression experiment. Fire ecology research has shown that in exchange for a short-term decline in air and water quality, prescribed burns can help control insect populations, limit the growth of invasive species, return nutrients more quickly to the soil, and initiate the seed germination processes for certain trees. Prescribed burns also reduce the amount of dead material available for wildfires to use as fuel, potentially lowering the destructive intensity of blazes like those in California, Oregon, and Montana this past summer, and the ones that swept through Gatlinburg, Tennessee, in 2016.
Many foresters also hope that such burns can open up forest canopies in ways that will support the growth of young oaks. However, the exact formula of when, how hot, and how often to burn remains a matter of trial and exploration. To this end, fire managers in the Daniel Boone National Forest have established numerous monitoring sites to measure and track the impact of their prescribed burning efforts.
The oak grove in McCreary County is one of these monitoring sites. In early August of this year, with the Forest Service’s permission, I gathered up the baseline data taken prior to the 2011 burn and took my kids down to check out how the land had changed.
After driving down the interstate, a U.S. highway, a state highway, a county lane, and a Forest Service fire road, then covering two more miles on foot, we found the spot. From the point above the creeks’ Y, we could see a ravine tailing off toward the south, a wrinkle in the deep, green carpet of trees. A recent rain meant there was water down below. We could hear the faint sound of it burbling over stones and under fallen trees. In the grove, ashes and black scorches from a more recent prescribed burn marked some of the trees. Within minutes of our arrival my son found a long-horned beetle inching its way up the trunk of a white oak. Soon afterward my daughter discovered a bristletail hidden in the bark of another. Later she photographed an ant jumping down through the moss on one of the scarlet oaks. The spot was as beautiful, serene, and alive as we imagined it might be.
A long-horned beetle, left, and a bristletail, center, are seen on the bark of white oaks in McCreary County, Kentucky. A black ant, right, makes its way through the moss on another white oak | Photos by Helen Rose and Peter Jefferson
And as we counted and compared the trees we saw with those noted on the lists in our hands, we found a sign that made us smile: There were more oaks and fewer maples in the grove than were recorded there ten years ago. It was exactly the kind of result we’d hoped to find.
Jeff West is a writer living in Lexington, Kentucky. He is working on a novel set within the first U.S. satellite program. In his free time, he organizes prescribed fire data for the Kentucky chapter of The Nature Conservancy.