Woody plants of Big South Fork National River and recreation area, Tennessee and Kentucky and floristic comparison of selected southern Appalachian woody floras

Castanea, Jun 2003 by Shaw, Joey, Wofford, B E

ABSTRACT

A survey of the woody plants was conducted at the Big South Fork National River and Recreation Area, a 49,776 ha (123,000 acre) natural area on the Cumberland Plateau in Tennessee and Kentucky. The annotated catalogue consists of 216 (186 native) species and lesser taxa in 114 (102 native) genera and 55 (52 native) families. One hundred thirty-three taxa are county records. Magnolia fraseri and Ilex ambigua var. ambigua, collected in Scott County, are physiographic records for the Cumberland Plateau in Tennessee. Twelve listed taxa of conservation concern were documented including two Federally Threatened species (Conradina verticillata and Spiraea virginiana). The Big South Fork National River and Recreation Area was compared to 12 other natural areas including the Obed Wild and Scenic River, Land Between the Lakes, Prentice Cooper State Forest and Wildlife Management Area, and the Great Smoky Mountain National Park. Results show that the Big South Fork National River and Recreation Area is among the most floristically rich natural areas in the Southern Appalachians.

INTRODUCTION

Established in 1974, the Big South Fork National River and Recreation Area (BSF) is an impressive tract of land with incredible vistas, lush vegetation, remarkable rock formations, and countless whitewater phenomena including several falls. It is part of a large government land holding containing approximately 331,842 ha (820,000 acres) including itself, Scott State Forest, Pickett State Park, and Daniel Boone National Forest. Some of the land within the BSF is privately owned and under acquisition, after which, the BSF will contain 49,776 ha (123,000 acres). It is shared by Tennessee and Kentucky and is on the Cumberland Plateau physiographic province between 36[degrees]19'30'' and 36[degrees]47'48''N and 84[degrees]30'10'' and 84[degrees]50'45''W. Most of the project area is within Scott County, Tennessee and McCreary County, Kentucky and lesser portions are inside Fentress, Morgan, and Pickett counties, Tennessee.

The Cumberland Plateau physiographic province is vegetationally unique (Braun 1950, Clark 1966, Schmalzer 1978, Wofford et al. 1979). Few other temperate regions in the world rival its floristic richness (Braun 1950, Hinkle et al. 1993). Although the Cumberland Plateau has long been considered extraordinary, there have been many negative impacts on the environment (Patrick 1979). These were outlined by DeSelm and Clark (1975) and include: (1) suburban development and industrialization, (2) home establishment, (3) strip mining, (4) pine monoculture, (5) flooding of flood plain habitat, (6) channelization, and (7) digging of plants of special concern by nurseries and individuals. Considering the threats to the biota of the Cumberland Plateau, the BSF and adjoining protected lands serve as a relatively large Southern Appalachian refugium.

Floristic studies are important for regional biological inventories, impact assessment, research, management decisions, and policy formulation (Palmer et al. 1995). A floristic investigation should be prior to other investigations due to the ecological significance of dominant plant life. In an area as large as the BSF, a study limited to the woody plants is a useful tool for gross interpretation of floristic richness and ecology because woody plants are (1) an artificial group with representatives from many plant families, (2) fairly conspicuous and with a few exceptions readily identified, (3) relatively few in number, therefore a group convenient for study, and (4) an important group economically (Little 1970). In addition, upper canopy vegetation is an efficient predictor of the understory vegetation and results from woody plant floristics may apply to other plants with similar distribution patterns (Braun 1950, Little 1970).

The objectives of this study of the BSF were to (1) compile an annotated list of the woody plants (trees, shrubs, and woody vines); (2) locate and document state and federally listed woody plants of conservation concern known from the northern Cumberland Plateau in Tennessee (Comptonia peregrina, Thuja occidentalis, Spiraea virginiana, and Polygonella americana (Fisch, and C.A. Mey) Small; and (3) to compare the woody flora of the BSF with the floras of nearby natural areas of other physiographic provinces.

STUDY SITE

The BSF is an important part of the Cumberland River drainage. It directly encompasses the South Fork of the Cumberland River and its two major tributaries, the Clear Fork River and the New River. The South Fork of the Cumberland River is the third largest tributary of the Cumberland River, having a total drainage area of 358,000 ha (1382 sq. mi.). Surface run-off is due to the impermeability of exposed rocks, steepness of the slopes, and thinness of the soils; this causes great variability of stream flow. The river system extends 124 km (77 mi.) northward through McCreary County, Kentucky to Lake Cumberland. Beginning at the confluence of the Clear Fork River and New River, the South Fork of the Cumberland River is at the bottom of a narrow gorge cut into the plateau. The gorge slowly widens northward to reveal river benches, flood plains, and broadening bottomland, most of which are now artificially flooded. Many streams drop suddenly from the plateau surface into deeply entrenched valleys (Braun 1950). The gorge bottoms range from flat, sandy, and almost beach-like to extremely large boulder beds that create much whitewater. This riverine habitat supports a particularly unique flora.