Crop trees and quality in bottomland hardwoods ten years after an early thinning in a young sprout-origin stand in south carolinaThis article is part of a larger document. View the larger document here.
A 23-year-old, mostly sprout-origin stand in the Congaree river bottom near Columbia, SC, was commercially thinned in 1994 using three methods of thinning: (1) the "Leave tree", (2) “Trainer tree”, and (3) “Corridor” methods. The stand was created in 1971 by KG-blade shearing a 90-year-old, heavily cutover bottomland hardwood stand. Before thinning, the stand had 260 to 300 trees averaging 8 to 9 inches d.b.h. and 28 to 31 cords per acre. There were 80 to 100 potential crop trees per acre (30 to 40 percent commercial oaks) of different bottomland species (oaks, sycamore, sweetgum, green ash and red maple). After-thinning, stocking levels were targeted to meet 80 to 100 crop trees per acre. In early 2000 and 2005, the effects of thinnings on residual stand quality were determined by measuring the diameter and number of stems per acre, epicormic sprouts in the first log, logging damage, and residual vine encumbrance, respectively, of residual crop trees. In 2000, the stand had 50 crop trees per acre, averaging 12.4 inches d.b.h. and 2.35 logs merchantable height. In 2005, the stand averaged 45 crop trees per acre, 15.7 inches d.b.h., and 1.8 logs merchantable height. The leave tree thinning resulted in a minor increase in epicormic sprouts, 1.3 in the first log per tree versus 0.33 for the control. All thinnings reduced vine encumbrance of crop trees from 40 to 24 percent, an enhancement in quality. Logging damage was lowest in the trainer tree thinning but is not now appreciable in any of the thinnings. The control has 53 crop trees per acre, the leave tree 46, the trainer tree 41, and the corridor 40, respectively. Diameter is greatest in the leave tree, 16.2 inches, having increased by 3.8 inches since the 2000 measurements.