Fire plays an essential role in the maintenance of yellow pine (Pinus pungens, P. rigida, P. virginiana) communities in the southeastern United States. Adaptations of yellow pine species to fire include medium-thick bark, the need for a thin duff layer to germinate, and serotinous cones. Fire suppression in Great Smoky Mountains National Park has been detrimental to yellow pine communities on several levels. First, the current stem density of mature yellow pines is thought to be greater than in pre-settlement, making them more susceptible to the southern pine beetle (Dendroctonus frontalis). Second, these communities are being invaded by fire-intolerant species like red maple (Acer rubrum) and white pine (Pinus strobus). The resulting change in nutrient composition, increased shading and increase in hardwood litter has reduced pine seedling germination and survivorship. This increased density of underbrush has also made these pine communities less hospitable to the endangered red-cockaded woodpecker (Picoides borealis) that once inhabited the Smokies.

In unburned yellow pine communities, our data show an exponential decrease in the density of yellow pine species with decreasing age class and an exponential increase in red maple density with decreasing age class. In burned areas, we observed a decrease in the density of fire-intolerant saplings (2.5 – 15 cm DBH) and an increase in pine seedling density. Given the current massive southern pine beetle outbreak in Great Smoky Mountains National Park, yellow pine communities may be lost if fire is not returned to the landscape.