As Australia gears up for another risky bushfire season this summer, some of its most iconic and valuable forests are at risk.
Giant eucalpytus trees rely on fire to regenerate, but an increase in major bush fires due to climate change could stunt their growth, a Tasmanian ecologist has warned.
The Unviersity of Tasmania’s Professor David Bowman says giant gum trees – which can act as valuable carbon stores – may become a thing of the past.
Giant gum trees can grow up to 100 metres, and are hundreds of years old.
“They are a globally unique rainforest tree that recovers from bushfires with explosive growth to out-compete the other rainforest trees,” Bowman said.
“With climate change, we see the trend in increasing fire weather, and if the trees get burned in quick succession you can actually lose them because they don’t have any seeds.”
And while the trees may act as valuable carbon sinks now, Bowman says insulating them from fire in the long-term is impossible.
“If we wanted to use them as carbon sponges, the real challenge would be to keep fire out of these landscape for a long time – hundreds of years.”
“We’re not certain how we’re going to do that if we’re up against a drying, warming trend with increased fire weather.”
There is concern this summer will bring increased risks of bushfire activity.
“Every summer is dangerous,” Bowman said, “But drawing from what we’ve seen around the world, the US has just been through one of the most extreme fire season in their history. There has been unprecedented fire activity, just mind-boggling in the scale and dimensions of it.”
“We have had droughts and then we have had La Niña so we’ve got a lot of fuel. There is a lot of grass out there, it just depends on the rain.”
And if Australia does face many more catastrophic fires, it could spell the end of some of the oldest trees in the world – and the biggest.
“Some of the work we’ve done here in the lab shows an older middle-aged giant eucalypt in Tasmania will be 500 years old,” Bowman said. “To get them back to what they were, well, 500 years is a long time to wait.”