CULLOWHEE – The origin of heath balds, peculiar treeless areas located high in the southern Appalachian Mountains, has long been a mystery to scientists, but research being conducted by Western Carolina University students and faculty is beginning to shed some light on that subject.
Western faculty member Rob Young and his students are trying to determine the ages of select heath balds located in Great Smoky Mountains National Park. By figuring out if the balds developed at the same time, or over a span of time, possible causes for their formation can be eliminated, Young said.
Over the years, scientists have speculated that the heath balds existing today may have developed as a result of activities by Native Americans or European settlers, grazing by cattle or native animals, fire, or changes in the mountain climate.
If all the heath balds in Western’s study turn out to be the same age, it probably means climate change is what caused them to form, Young said. In that case, the study “will be adding the geologic piece to climate change research, and other researchers looking into climate change can then begin to use our data as a benchmark,” he said.
Balds are the most famous botanical unknown of the southern Appalachian Mountains. Although there is no natural “treeline” in the southern Appalachians, numerous treeless areas are scattered throughout the mountains at elevations ranging from 4,000 to 6,500 feet. Some of those areas, called “grassy balds,” are dominated by low-growing plants and are known for their 360-degree views.
Heath balds, on the other hand, are closed-in and shaded by the dark green leaves of rhododendron, mountain laurel, and other members of the heath family of plants. Because of their greater accessibility, grassy balds have been the subject of much more research than heath balds, Young said.
Last spring, Young, associate professor in Western’s department of geosciences and natural resources management, and his students began a study of the soils that lie underneath heath balds in the Smokies. The park contains an estimated 300 heath balds covering about 7,300 acres.
The Western study got a boost from soil mapping at heath bald sites that already had been carried out by the U.S. Department of Agriculture, and from background information provided by the National Park Service, Young said. The Park Service is funding Western’s study.
The Western Carolina researchers began collecting soil samples in March, and the samples are being sent off for radiocarbon dating. Results from the first sample site, a heath bald below Alum Cave Bluff on the slopes of Mount LeConte, show that the bottom layer of soil under that bald is 3,000 years old. That indicates the bald is pre-European, eliminating logging or cattle grazing as the cause, Young said.
The group plans to collect soil samples, and obtain radiocarbon dates, from a total of 10 to 15 balds by the end of the fall semester, Young said.
The layer of soil that lies underneath heath balds, an extremely acidic layer of peat ranging in thickness from just over one meter to about 50 centimeters, “can reveal all kinds of interesting information about climates and past environments,” Young said.
In particular, the remains of beetle exoskeletons extracted from the soil indicate past conditions, Young said. Beetles rapidly colonize newly established habitats, and prehistoric environmental conditions can be determined by identifying the habitat favored by living members of the species collected from the soil.
Young said the study of heath balds “goes hand in hand” with another study he has been leading for several years of the wetlands areas in the Smokies. Both efforts are part of an integrated effort in Western’s geosciences and natural resources management to fill in the blanks in the climate change story of the southern Appalachians, he said.
One of the students involved in the heath bald study, Lucas Conkle of Stoneville, will be using his own research results as the basis for his master’s degree thesis project. Both Conkle, a second-year student in Western’s biology program, and Young have been invited to make presentations about their work at an October meeting of the Geological Society of America.