Indigenous scrubweed conversion methods for Westland plantation establishment: past, present, and future

Authors: J. M. Balneaves, P. G. Milne, B. J. Cosslett
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1983, Issue N.Z.J.For. 28(2) 1983, pp 194-202, Aug 1983
Publisher: New Zealand Institute of Forestry

Abstract: A review of available information dealing with the conversion of indigenous scrubweed areas to exotic forests in Westland (and elsewhere) is given. Current site preparation regimes involve felling of residual scrubweeds, a cure spray when necessary, and then burning. After planting with radiata pine (Pinus radiata D. Don) a release spray with 1.08 kg 2,4,5-T is essential where scrubweed regrowth is a problem. Where bracken (Pteridium aquilinum var. esculentum) and other fern regrowth occurs, asulam is used as a release spray, though greater emphasis is being placed on the use of hexazinone.

In areas where a successful burn of felled material has been achieved, scrubweed regrowth is not apparent until 3 years from planting. By age 7 years, of the radiata pine crop, indigenous scrubweed offers a dense understorey and makes any silvicultural operations extremely difficult and expensive. In some areas regrowth can be so vigorous that the radiata pine crop may fail completely. Alternative land preparation options have been tested with the most successful regime tested involving felling, burning, and oversowing with maku lotus (Lotus pedunculatus cv. 'Grasslands maku') and Yorkshire fog (Holcus lanatus) before or immediately after planting.