First rotation Eucalyptus macarthurii cut stump control in KwaZulu-Natal, South Africa

Abstract

Many cold tolerant eucalypts, E. macarthurii in particular, coppice vigorously following harvesting, and in contrast to E. grandis are proving difficult to kill by existing cut stump control methods. Based on past research, selected cut stump treatments were tested on single stem E. macarthurii trees, that had not been coppiced, in Paulpieterburg, KwaZulu-Natal. These included the application of the herbicide triclopyr (amine salt, 360 g l^-1), alone, or in combination with glyphosate (isopropylamine salt, 360 g l^-1), either to the cut-surface, or to a basal frill. Due to the uncertainty as to the efficacy of these treatments for killing stumps of species other than E. grandis, the above treatments were integrated with current harvest residue management operations (burning; the piling of harvest residues on top of stumps; removal of the harvest residues away from the stumps) to determine if any of these further reduced the level of coppicing. Compared to the removal of slash away from the stumps, the burning, or piling of slash on top of the stumps resulted in a significant but small reduction in coppice regrowth. At the rates tested both herbicides killed 83-90 % of the stumps, irrespective of how they were applied (basal frill or cut surface). This result has important commercial implications as it will allow the forest companies the flexibility to choose the herbicides, and (or) manner in which they are to be applied.

Keywords: coppice, sprouts, stool, cut surface, basal frill, herbicides

Southern African Forestry Journal Vol. 207 2006: 15-20