Wednesday 22 December, 2004

The northern cypress pine, the native Christmas tree of northern Australia, is being wiped out by bushfires that have swept through half of Northern Territory ’s Top End in the past few months.

The northern cypress pine (Callitrus intratropica) is particularly vulnerable to hot fires, according to Mark Gardener, a researcher with the Tropical Savannas Cooperative Research Centre (CRC).

“This tree, unlike local Eucalyptus species, will die when subject to fires that burn 100 % of their leaves,” he said. “The Cypress pines take at least 10 years to mature and produce seeds, meaning they could easily be wiped out by frequent fires before they reach maturity.

“Eucalyptus trees can sprout new shoots to survive fires, but these fire-sensitive plants like the Cypress pine don’t have ways for surviving hot fires,” he said. “This could be changing our landscape forever.”

Old-timers who used to log cypress pine in the Top End tell stories of dense forests of cypress pine once being found across the landscape.

“Now you can only find these pines in isolated areas,” Dr Gardener said. “We don’t yet know the long-term impacts on biodiversity of losing such plant species in the landscape, but it is sure to be impacting on the animals that live in the area.”

Dr Gardener said that many of the native plants in northern Australia are likely to be suffering the same fate. For the Arnhem plateau, one of Australia’s biodiversity ‘hot-spots’, this is of particular concern.  There are at least 85 fire-sensitive trees and shrubs that are only found in this area in Australia.  Almost the entire 35,000 km² Arnhem plateau was burnt this year by wildfires.

The unusual weather conditions experienced in the Top End this year have meant even more hot fires during the late dry season, October–November. Late-season fires are hotter and harder to control.

“There have been nearly 300,000 km² burnt in tropical Northern Territory this year,” said Brian Lynch, also with the Tropical Savannas CRC. “This is because the fuel available to be burnt has built up over two good wet seasons followed by the late wet season we experienced in June this year.”

Similarly, in the Gulf region of Northern Territory , fires have burnt nearly everything this year. These fires are impacting on grazing and Aboriginal land influencing the livelihood of these people

“The one good thing about these fires is that it is bringing pastoralists, Aboriginal communities and National Park managers together to look at how to prevent such fires in the future,” Mr Lynch said.

The Natural Heritage Trust recently provided $1.9 million to the Tropical Savannas CRC to develop guidelines for managing fire across northern Australia , which will be accessible to all land managers via the Internet. The project is developing the capacity of Aboriginal, pastoral and conservation land managers to achieve this.