Southern Appalachian forests are some of the most biologically diverse forests on the planet. Western North Carolina alone contains all the major forest types you would see driving from Georgia to Maine, concentrated in one region and distributed by elevation. The incredible diversity of forest types makes active forest management in the region exciting, complex and challenging! Across our diverse Southern Appalachian forests, we observe the same trend, an unnaturally high level of closed canopy, middle-aged forests and a lack of appropriate levels of young, open and old forest structure. The lack of structural diversity across the regions’ forest types is the primary driver of ruffed grouse decline.
Starting at around 1,000-feet, the lower elevations and foothills of the mountains are dominated by shortleaf pine-oak forests. As the name suggests, shortleaf pine (Pinus echinata) is a dominant tree species, with a codominance of southern red oak and pitch pine. These forests are “fire-adapted,” meaning they need frequent fire to perpetuate and maintain the open woodland structural conditions that historically were dominant. Historic fire was frequent (every 3-5 years) and primarily caused by Native Americans and early European settlers. Ruffed grouse could historically be found in these forests, but their current range has generally shifted to higher elevations, and they are sparse in the lower elevations today.
From about 1,200 – 5,500 feet, mountain oak forests are a dominant forest type on the landscape. Oak forests have several types, including pine-oak heath, dry oak, dry-mesic oak and mesic oak. These forests are distinguished by the dominance and codominance of several different species of oak trees (Quercus,) including white oak, southern red oak, northern red oak, black oak, chestnut oak and scarlet oak. The differences in oak forest types are driven mainly by aspect, slope position and soil moisture. For example, dry ridge tops are often dominated by dry oak or oak-pine heath, whereas mesic slopes and flats are typically dominated by dry-mesic oak or mesic oak. Oak is also more drought tolerant than other Appalachian hardwood trees, making it more competitive on south-facing aspects that receive more sunlight and are drier sites. High-elevation red oak forests dominate at the higher end of oak’s elevation range (3,500 – 5,500 feet).
Fire was historically a vital disturbance feature in mountain oak forests. The frequency and intensity of historic fire likely varied across oak forests, with fire being more significant on drier sites than mesic sites. Ruffed grouse are associated with mountain oak forests and are typically more abundant today in the more mesic, higher-elevation sites. Oak acorns are a preferred hard mast for ruffed grouse in the Southern Appalachians and make up a significant part of their diet.
Mountain cove forests are found from about 2,000 – 4,500 feet and can broadly be grouped into acidic coves and rich coves. Cove forests occur in mesic concave slopes and are distinct from mountain oak forests by the dominance of more moisture-loving trees such as tulip poplar, black birch, yellow buckeye and Fraser’s magnolia. Where oak is present, northern red oak and chestnut oak are common, typically on the relatively drier, upland cove locations. The historical and current role of fire in cove forests is less significant than oak forest types. Fire was, and is, less common in cove forests due to the more mesic, wetter conditions associated with cove sites. Naturally, wind and ice storms frequently create variably sized smaller canopy gaps (1/8- to 1/4-acre) and occasionally large, 20-acre wind-blown gaps. Ruffed grouse are often associated with young forests in coves, as these sites have high stem density for cover and a diversity and abundance of vegetative species that grouse eat.
At the highest elevations in the Southern Appalachians, northern hardwood and spruce-fir forests dominate. Northern hardwood forests range from 4,000 – 5,500 feet and are dominated by yellow birch, sugar maple, yellow buckeye, beech, white ash and scattered northern red oak. Interestingly, these forests contain the same tree species as northern hardwood forests in Northern states. Lastly, spruce-fir forests can be found at our highest elevations – above 4,800 feet. Spruce-fir forest types are dominated by red spruce and Fraser fir. These high-elevation forests support several rare wildlife species, including the Carolina northern flying squirrel, which is federally listed under the Endangered Species Act. Ruffed grouse are also relatively abundant in these higher-elevation sites, especially in places with more young forests from stand-replacing natural events and timber harvests.
The scale of disturbances, both historically and currently, varies across forest types in the Southern Appalachians. However, all forest types can benefit from active forest management that restores age-class and structural diversity. Achieving a natural range of variation across forest types in the region will support healthy forests and abundant wildlife, including viable populations of our beloved ruffed grouse. All of our forests have departed from healthy conditions, and it’s up to us to restore a balanced distribution of age classes and structure for the diverse wildlife species that depend on those conditions before it’s too late. Table 1: Natural ranges of historic forest structure before Euro-American settlement on the Nantahala and Pisgah National Forest in North Carolina. Historic conditions provide a useful framework for making forest management decisions and establishing goals for individual projects (Source: Nantahala-Pisgah National Forests Draft Forest Plan).