31/05/2020

(AU) Bushfire Report Warns Climate Change Will Cause More Intense And More Frequent Blazes

The Australian

Climate change will increase the duration of the fire season, a report has warned. Picture: Getty Images

Climate change will increase forest fires, making many areas drier and hotter, extending the duration of the fire season and increasing the area and intensity of unplanned forest blazes, a government report has warned.

The Australian Bureau of Agricultural and Resource Economics and Sciences study of ­forest fires, released on Wednesday, says the changes will reduce the interval between fires and the ­opportunity for using planned fires to contain the hazard.

ABARES principal forest scientist Steve Read said while ­climate change would have an impact on most forests one way or another, the ­bureau had identified “a distinct north-south divide” in the pattern of forest fires.

“Unplanned fires in forests in northern Australia are more frequent and occur over greater areas,” Dr Read said.

“Unplanned fires in forests in southern Australia are less frequent than in northern Australia, but they can be much more intense when they do occur and in some years, such as 2019-20, cover large areas.”

The ABARES study has found that between 2011 and 2016, 55 million hectares, or 41 per cent of Australia’s total 134 million ha of forest, burned one or more times.

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Of the cumulative forest fires over the five years, 96 per cent covered northern Australia, including large areas burnt in multiple years. Of all the fires, 69 per cent were unplanned and 31 per cent were planned.

“The difference between northern and southern Australia is the biggest point to communicate,” Dr Read told The Australian. “The biggest difference is that there is a huge amount of fire every year in the savannah forest right across northern Australia.”

This reflected the regular annual pattern of a wet season when grasses, including more invasive species, grew, followed by a dry season when they burned.

“Fires in northern Australia are driven by fuel load,” Dr Read said. “Climate change in the north will work through, giving you more fuel seasonally every year because of potentially better growing seasons in the wet season when the grass grows.”

In the south, Dr Read said, extensive forest fires were usually produced after a set of dry years.

“The real driver for the fires in 2019-20 was that we had a hot drought — a series of dry years and some heat — and climate change is expected to give you more heat and drier conditions in southern Australia,” he said.

The report says most Australian forests are adapted to fire and can regenerate.

“Fire is an important ecological driver in most Australian forests, whether the tall moist forests of southeastern and southwestern Australia or the woodlands of northern Australia. It influences the nature of entire forest ecosystems,” the report says.

Some tree species specifically require fire to regenerate or establish, it says, such as mountain ash which forms tall forests in Victoria and Tasmania.

In southern Australia, nearly 80 per cent of the fires occurred on nature conservation reserves or multiple-use public forests.

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