A mid-rotation bottomland red oak stand three years after thinning and fertilization

Abstract

To determine the effects of intermediate silvicultural treatments on bottomland hardwoods, two types of thinning (crown thinning and low thinning) and one level of fertilizer (200 lb/ac N + 50 lb/ac P) were applied to a predominantly red oak stand in southeastern Texas. Treatments were applied in a 3 × 2 factorial arrangement as a randomized complete block design of 12 ac in size. Crop trees were selected prior to the treatments, and diameter at breast height measurements were taken pre-treatment and for three proceeding years to assess diameter growth response of all trees. Epicormic branching measurements were also taken for three years post-treatment to evaluate epicormic branching response of all crop trees to crown thinning, low thinning and fertilization. Furthermore, reproduction plots were established pre-treatment to evaluate reproduction height growth response to all intermediate treatments. First-year results showed no significant difference in current annual increment (CAI) of crop-tree diameter growth response; however, second-year results of CAI diameter growth showed that crop trees in thinned plots achieved significantly more growth than in unthinned plots. With third-year results of CAI diameter growth, crop trees in crow-thinned plots grew significantly better than in both low-thinned and unthinned plots, all regardless of fertilization. Epicormic branching was generally greater in crown-thinned and fertilized plots immediately following treatment, and reproduction height growth was generally greater in crown-thinned, and in some cases, fertilized plots.