Review of weed control practices in radiata pine plantations in Australia.  P. C. Fagg and D. W. Flinn.  November 1984.  15 pp. (unpubl.)

SUMMARY

This report describes the major weed problems encountered in radiata pine (Pinus radiata D. Don) plantations in Australia, and briefly reviews the common techniques used, and associated costs, in their control.

From the results of a questionnaire, it was estimated that more than $4.8 million was spent on weight control in about 39 700 ha of these plantations during 1983. Some 62% of this expenditure was for the control of woody weeds (e.g. eucalypts, wattles), using either non-chemical methods open preferences (e.g. slashing) or herbicides (e.g. hexazinone, 2,4,5-T or 3,6-dichloropicolinic acid); 20% was for control of herbaceous weeds, using mainly mixtures of atrazine and amitrole, or atrazine and hexazinone; 14% for the control of noxious weeds; and 4% for the control of natural regeneration of radiata pine. The latter will become an increasing problem as larger areas of mature plantations are clearfelled. Control techniques varied widely between States, reflecting differences in factors such as weed populations, topography and site conditions of the treated plantations, and differences in constraints on the use of specific herbicides.

As expenditure on weight control is a significant component of the costs of establishing and tending most radiata pine plantations, further attention needs to be given to identifying and developing control procedures that are most cost-effective. Thus, plantation blocks should be carefully evaluated, taking into account topography, soils, climate, environmental factors, and the size, extent and density of the weed population, before identifying appropriate control procedures to meet management objectives. In addition, the range of options available for treating specific weed problems needs to be increased, through advances in weed control technology, to provide forest managers with more flexibility in implementing weed control programs.

Also published:

Flinn, D.W. and Fagg, P.C. (1984)  Review of weed control practices in radiata pine plantations in Australia.  Proc. 7^th Aust. Weeds Conf., Weed Soc. W. Aust., Perth, 17-21 Sept. 1984, pp. 220-32.