Issue 8, December 1998 - January 1999


Rubbervine fire trials reap killer results

Trial using fire to control rubbervine

Burning rubbervine at Wrotham Park in November produced a 100 per cent kill rate. Photo: Faiz Bebawi

A blazing, white-hot fire that turns rubbervine to ashen "snow" is beating infestations of the destructive pest plant in the far north of Queensland.

Researchers at the Queensland Department of Natural Resources recently trialled large-scale burns as a means of managing the invasive weed on the cattle station Wrotham Park, 70 kilometres west of Chillagoe. The trials have been some of the most successful undertaken for controlling rubbervine. Although prescribed burns took place at Wrotham Park two years before the trials were started (in 1997), researchers believe the trials have proved burning is a viable option for large areas.

Within the experimental plots, the first burn produced a rubbervine kill of 80 per cent. However, if that first burn was followed up with a second burn 12 months later, 99 per cent of the weed was killed.

"The trials have shown the follow-up burn is essential. If a follow-up isn't done, the 20 per cent of the weed that is not killed will regenerate from the base," project leader Dr Faiz Bebawi said. Wrotham Park manager Henry Burke agreed the results of the trials were outstanding. "Fire is proving to be the most successful and econo-mical way of controlling rubbervine," he said. "From this experience we'll continue to use this strategy to control the rubbervine."

It is believed rubbervine was introduced into Australia as an ornamental shrub in the late 1800s. The weed, which is declared in Queensland, first invades waterways where seeds germinate in moist silt layers after rain. The plant smothers riparian vegetation and forms a dense thicket. This degrades the native vegetation and prevents access to both stock and native animals.

Infestations expand outward from waterways, colonising hillsides and pastures, which results in loss of land for grazing and difficulty in mustering stock. Dr Shane Campbell, who also worked on the trials, explained fire trials were carried out on rubbervine that had previously been infected with rubbervine rust disease.

This disease was first released in Queensland in 1995. It causes heavy infection in the weed resulting in defoliation and reducing seed production. However, it does not kill established plants.

"The presence of the rust disease appears to have contributed to the success of the fire, and the amount of rubbervine killed," said Dr Campbell. "Rust reduces the vigour of the plants, making the plants more susceptible to fire as well as enabling more pasture growth and therefore an increased fuel load."

The prescribed burns took place over two years—the first in October 1997 over an area of 16 square kilometres. Some areas were left unburnt to allow for comparisons. "The purpose of the trials is to gauge the success of fire as a weed management strategy to control rubbervine infestations that spread over a large area," Dr Bebawi said.

He added that fire was the most economic means of control for land-holders with large tracts of rubbervine infestations, a point supported by Mr Burke. He said Wrotham Park would continue to do follow-up burns on the larger infestations. The trials also had the added benefit of flushing out 500 head of cattle hiding in the thick rubbervine near streams!

Contacts

Dr Faiz Bebawi
Natural Resource Management Project Officer
Dept Natural Resources & Mines
Tel: 07 4787 0616

Fax: 07 4787 3969

PO Box 187
CHARTERS TOWERS, QLD 4820


Dr Shane Campbell
Dept Natural Resources & Mines
Tel: 07 4787 0605

Fax: 07 4787 3969

PO Box 187
CHARTERS TOWERS, QLD 4820