Table 1: Mean and range of site index, soil, and topographic variables by species for stands sampled in the Southern Appalachian Mountains of North Carolina, USA.

ModelRed oak ( )Yellow-poplar (
variablesMeanRangeMeanRange

Site index (m)25.518–303225–38
A-horizon thickness (cm) 8–36 8–41
Solum thickness (cm) 36–152 43–140
Elevation (m) 442–1329 646–1165
Aspect (deg) 45–330 10–355
Gradient (percent) 10–60 2–38
Landform index 0.01–0.27 0.08–0.38

a Indicates no significant difference ( ) between the two species.
bIndicates significant difference ( ) between the two species.