Grass control for radiata pine establishment on droughty sites.

Authors: J. M. Balneaves
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1982, Issue N.Z.J.For. 27(2) 1982, pp 259-276, Aug 1982
Publisher: New Zealand Institute of Forestry

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Abstract: Survival and growth of radiata pine (Pinus radiata D. Don) seedlings in the warm dry-summer climate of Canterbury are markedly influenced by competition jrom grasses and other herbaceous weeds. Weed control not only produced an immediate increase in growth but also had a positive effect on tree growth for the following eight years.

Site improvement by either ripping or weed control had a marked effect on tree growth. A combination of the two further increased survival, height growth, and total basal area. With the option of either ripping or weed control, the results suggested that post-planting weed control would give better value for money,

Further work on the effects of fertiliser application in the presence or absence of weed competition indicated that failure to achieve good weed control will result in an increase in weed competition and may reduce the survival and growth of radiata pine seedlings.

Broadcast vegetation control resulted in better survival and growth of tree seedlings. If, however, spot application is desired because of costs, then the "Spot Gun" applicator may be used with hexazinone. Best results can be achieved with the flat fan nozzle. Costs for such an operation on hill country are around $45/ha.

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