Six field research locations distributed throughout the Ohio-Tennessee river watersheds were established during the winter and early spring of 1998. The establishment of these sites was done with the cooperation of the U.S. Forest Servicešs Fernow experimental forest in West Virginia (FEF), the U.S. Park Service at Big South Fork National Recreation Area in Tennessee (BSFNRA), Indiana University and the Morgan Monroe State Forest in Indiana (MMSF), and with the Tennessee Valley Authority and U.S. Park Service at the Great Smoky Mountains National Park (GSMNP). An upland oak stand (WB oak) and pine stand (WB-pine) were also located on the U.S. Department of Energyšs Walker Branch Watershed near Oak Ridge, Tennessee.
The sites were chosen as representative closed-canopy forest common to the eastern deciduous forest. Four of the sites (WB-oak, FEF, MMSF, and BSFNRA) are dominated by a mixture of oaks and maples with each being located in a distinctly different climate zone. A site having a significant pine component (WB-pine) and a site dominated by yellow poplar (GSMNP) were also added to get a more complete picture of the water use by other common closed canopy forests of the region.
A. Vegetation and soil characterization
A complete vegetation inventory for each site was conducted using nested circular plots to facilitate the selection of representative trees for sapflow measurements. Data for allometric equations relating cross-sectional sapwood area to bole diameter were collected from additional trees of the selected species for each site. The plot survey data and information on mean sapwood thickness for each species were used to calculate total and sapwood basal area per plot. Sapwood area of each species expressed on a ground area basis is the key stand variable required to scale observations of tree water use to the forest landscape.
Six 0.2 m2 litter collection baskets were placed at random locations within the plot for fall leaf litter sampling.
Graph of the basal area (solid bars) and sapwood area of each site (select graph).
B. Photographs of each site:
