Evaluation of a hand-held burner for the control of woody weeds by flaming

A hand-held burner (Atarus Ranger) was evaluated as a method for controlling woody weeds by flaming in sensitive or riparian areas where traditional methods, such as chemical or mechanical control, have limited usefulness. The equipment was trialled on 3 North Queensland weed species: bellyache bush (Jatropha gossypiifolia), parkinsonia (Parkinsonia aculeata) and rubber vine (Cryptostegia grandiflora), at 5 different heat durations (0, 10, 30, 60 and 120 s) and on 3 plant size classes based on basal diameter (15-25, >25-50 and >50 mm). No significant difference in percentage mortality was recorded between a 10 s treatment and longer heat treatments for bellyache bush and parkinsonia plants, or between a 60 s treatment and longer heat treatments for rubber vine. A 10 s treatment killed 92% of the treated bellyache bush plants and 83% of the parkinsonia plants, while a 60 s treatment killed 76% of the treated rubber vine plants (values are the means of all size classes combined). Flaming was least effective on rubber vine, which had the thickest bark, but was highly effective on bellyache bush, which had the highest bark moisture content. Weeds with a low capacity for root suckering, thin bark, high bark moisture content and low bark density appear the best candidates for flaming. Flaming is an effective technique for the control of woody weeds with efficacy varying among species. Individual plants are targeted, and the technique is accepted by organic farming groups.