Old-Growth Forests at the Sugarloaf Mountains-Midland Peak Natural Area, Arkansas.

The Sugarloaf Mountains-Midland Peak Natural Area (SMMPNA) is a new 1191 acre natural area established by the Arkansas Natural Heritage Commission. A previous survey indicated that the SMMPNA includes uncut old-growth forests, with vegetation types classified as oak-hickory, shortleaf pine (Pinus echinata), cedar glade, and Cross Timbers. Selective increment core sampling of mature and old trees, aerial photograph interpretation, and field inspection were used to test the hypothesis that the natural area includes areas of uncut old-growth forest. Cores were extracted from 148 individuals of five target species based on external characteristics associated with longevity in trees such as heavy limbs, canopy dieback, and longitudinally twisted stems. The minimum age of the sample trees was determined with dendrochronology. The oldest sampled individuals were, at least, a 325-year-old eastern red cedar (Juniperus virginiana), a 280-year-old post oak (Quercus stellata), a 250-year-old Pinus echinata, a 119-year-old red oak (Quercus rubra), and an 83-year-old maple-leaf oak (Quercus acerifolia). The steep, dry, infertile soils of the natural area result in slow growth rates and strong ring width sensitivity to growing season climate. The presence of mature to old individuals near the longevity maximum for each species, the xeric noncommercial nature of the forest, the absence of roads, stumps, and other evidence for human disturbance all indicate that the vegetation cover in the study area on East Midland Peak is largely dominated by old-growth forests. [ABSTRACT FROM AUTHOR]