First-Year Response on an Upland Hardwood Forest to Five Levels of Overstory Tree RetentionThis article is part of a larger document. View the larger document here.
Response of a north Alabama upland oak-hickory forest to five levels of overstory tree retention was compared following treatment. Fifty-acre experimental blocks were established on the mid-Cumberland Plateau, which included the highly dissected margins and sides of the southern subregion. Blocks were replicated three times. Each of the five retention treatments (corresponding to 100-, 75-, 50-, 25-, and 0-percent basal area retention) was randomly assigned within 10-acre units of each block. Leave trees within treatments were marked based on species and crown position, and the harvest was implemented by chain saw felling and grapple skidding. The 75-percent retention treatment was accomplished using stem-injected herbicide, and most injected stems were midstory canopy trees. An average of 381 stems per acre were treated with herbicide, and the average diameter of treated trees was 2.9 inches diameter at breast height. Following treatment, canopy tree basal area was not significantly different between the control and the 75-percent retention treatments, but these two treatments retained significantly greater basal area than the other three. The residual basal area between the 25-percent retention (28 percent retained) and the 50-percent retention (38 percent retained) treatments was not significantly different but did differ significantly from the clearcut, control, and 75-percent retention treatments. The treatments created a gradient in light levels and percent canopy cover. One year after harvest, the number of sugar maple and oak seedlings < 1 foot tall has decreased, the number of oak seedlings > 1 foot increased, and yellow poplar seedlings of all sizes increased.