More than 50 per cent of Gondwana rainforests have been burnt in the past 12 months, according to an analysis of the data on fire cover in the Blue Mountains.
Scientists have found that approximately 80% of Gondwana forests have been burned in the last year, with 50% being burned in the Blue Mountains.
The analysis found that on average, up to 5% of the national park forest cover burned during a two-week fire period. Overall, 89% of the land burnt was covered by forest.
Dr Kath Whitney from the Australian National University (ANU) led the investigation, which examined the extent of fire cover in 191 national parks across Australia, and looked at fire stats from four years of weather data between 2000 and 2011.
Previous data shows up to 50% of Blue Mountains forests burned between 2001 and 2005, while between 47% and 50% of the ranges were affected between 2006 and 2010.
According to the scientists, the Blue Mountains are particularly susceptible to bushfires due to severe drought conditions between 2002 and 2011, which affected 80% of the region and killed an estimated 8,000 bushbirds. That environment didn’t have a long recovery period, making the effects on the trees even more severe.
High levels of run-off from droughts also caused soil erosion, shifting the fire front and causing some forests to be moved or destroyed.
While all national parks were affected by fires, there were varying degrees of disruption for forest communities across the country.
Garters and other hardwood forests were most prone to high to extreme rates of fire cover, while hardwood forested hillsides were also affected more, but not quite to the same extent as their forest neighbors.
In Queensland’s Great Barrier Reef, 40% of the environment was burnt during the 2001–2007 fire season, while a minimum of 27% was burned in the five years between 2010 and 2012.
Whitney warned of the impact the scale of the fires could have on climate change. “The longer this burning goes on in any ecosystem, the more vulnerable that ecosystem is,” she said.
“When we’re starting to see 10% of a rainforest being burned out as a weekly event, is it going to accelerate or not? The more time that we take to re-plant, the less likely it is that we’re going to have that beautiful fire as a consequence of these large fires.”
Dr Tom Daube, a former Australian of the year and a climate change researcher, said bushfires are usually associated with drought but climate change was making extreme temperatures increase in proportion to increased dryness.
The scientists also reported that there were eight large fire events in the Blue Mountains between 2002 and 2010, whereas in the past 40 years there have been 11 incidents of large fires.
A spokeswoman for the Blue Mountains National Park said the nature of the study “contained a number of errors”, including errors about the expected fire season, while additional technical research into the impact of climate change had been initiated.
“As per normal practice, other research and community input are considered as we develop management and response plans to cope with bushfire threats to our national park,” she said.
The Blue Mountains blaze was one of about 74,000 fires Australia has seen since 2000, and an estimated $200m in damage has been caused. A separate analysis published last week has found about 25% of Australia’s firefighting budget is going to responding to bushfires.