Control ofEucalyptus grandiscut-stumps of single-stem origin

Abstract

SYNOPSIS Four methods to control coppice re-growth on single-stem cut-stump Eucalyptus grandis stools were tested in the Zululand region of KwaZulu-Natal. The methods used were the burning of the plantation residue as opposed to a no-burn control, the application of triclopyr (amine salt and butoxy ethyl ester) and glyphosate (trimesium) as a cut surface treatment within 30 minutes after felling, and the application of triclopyr (ester) and metsulfuron-methyl as a foliar treatment to the coppice regrowth when 1,5 m tall. The efficacy of the various treatments were compared in terms of the kill achieved, as well as the number of times the coppice regrowth had to be manually cut back after the imposition of the initial treatment. There was little to be gained in terms of killing stools by burning the plantation residue on the site. Although the foliar application of the two herbicides tested reduced the number of follow-up operations required, it would still require a delay in the planting of the trees until the coppice regrowth has grown sufficiently so that it can be treated. It would appear that the use of cut surface chemicals (such as triclopyr in an ester or amine formulation) are the most effective for the killing of single-stem Eucalyptus grandis stools, with little or no follow-up control required.