Effects of injecting varying rates of glyphosate on mature eucalypts in LEMS forests, East Gippsland.  G. Dooley, D. Terrell and M. T. Lutze.  May 2000.  14pp. (unpubl.)

SUMMARY

The management of non-merchantable trees is a common requirement on regeneration coupes in East Gippsland. The objective of this experiment was to determine the effect of injecting different rates of the herbicide glyphosate in different seasons on four eucalypt species: Eucalyptus sieberi, E. globoidea, E. baxteri and E. botryoides. These trees varied in DBHOB between 25 and 152 cm. The technique involved using an inoculating gun to inject liquid herbicide into holes drilled around the circumference of the trees. Percent live crown and percent mortality were evaluated at 3-5 and 10 months after treatment.

It was found that spring treatment of the four eucalypt species at a rate of 40g of glyphosate per m² basal area gave the highest rates of mortality. Autumn treatment gave acceptable, but delayed results, and summer treatment produced unacceptable results in terms of mortality and percent live crown.

Treatment at the rate of 20g M^-2 basal area was reasonably effective on E. sieberi in one year, but could not be recommended until further research is carried out.