Managing a summer scorcher

Thursday 20 March, 2014

Bushfires during the long hot summer are an expected part of land management in Australia. This summer, on Carnarvon Station Reserve in Queensland, wildfires burnt for several weeks. Changing climatic conditions are making fire planning and preparation, to handle such events, more important than ever.

Prescribed burning on Carnarvon Station Reserve, Qld. Photograph by Emma BurgessPrescribed burning on Carnarvon Station Reserve, Qld. Photograph by Emma Burgess

When dry storms and lightning strikes led to wildfire on Carnarvon Station Reserve, Manager Chris Wilson sprang into action, joining colleagues, members of the Rural Fire Brigade, neighbours and teams from adjacent National Parks to deal with it. The fire started in grasslands, and was soon crowning (burning up into tree canopies) to the south of the reserve.

Working around the clock they carried out back burns and upgraded firebreaks to contain the spreading flames.

Low intensity patchy fire scars on Carnarvon hills. Photo by Emma BurgesLow intensity, patchy fire scars on Carnarvon ridgeline. Photo by Emma Burges

“As the weather conditions are so intense, back burns have to start at midnight with teams working through until the early hours,” says Executive Manager North, Rob Murphy, who fills us in while Chris has a much‑deserved rest.“Those are the coolest times and therefore the safest and most effective times to burn.”

Carnarvon Station abuts Queensland’s spectacular Carnarvon National Park. The reserve’s sandstone hills, narrow valley floors and high escarpments create a dramatic setting that’s home to hundreds of animal and plant species. Some, such as the northern quoll, are nationally threatened and sensitive to fires that could remove their shelter of low shrubs and fallen logs, as well as interrupt their food supply.

A Dingo pup hunts crickets after a controlled burn. Photograph by Emma BurgessA dingo pup hunts crickets after a controlled burn. Photograph by Emma Burgess

Planning for wildfires

So far the intensity of the main blaze has been reduced by patches of land with recent burn histories – including some burnt in a similar 2013 wildfire – which wouldn’t easily burn again. As Ecologist Murray Haseler explains, evaluations of the 2013 fire confirmed that our best defence is a mosaic of controlled burns conducted over many years.

“These strategically reduce fuel in priority areas, and greatly reduce the impact of unplanned fires,” he says. Like any reserve, Carnarvon has a diversity of vegetation types, which all respond differently to fire and climatic conditions. Careful planning goes into recording rainfall and temperature, monitoring vegetation growth and mapping the fire history of the area to feed into controlled burn planning.

“Fire sensitive vegetation, such as brigalow, vine scrub, belah and lancewood, mostly occurs in small patches, often within natural fire barriers, such as rocky areas,” explains Murray. “Their dense canopies provide some protection by naturally preventing the growth of ground-level fuel.”

Cycad burning. Photo by Emma BurgessLow intensity fires promote regeneration and help reduce the spread and intensity of hot fires later in the fire season. Photo by Emma Burgess

“It’s the open grasslands and grassy woodlands that need to be most intensely managed by controlled burns,” he says. “They also have the highest density and diversity of small mammals that respond to changes in rainfall, temperature and vegetation. Controlled burning removes cover and biomass (grass), meaning the animals must move to find food and shelter. However, cool burns also promote growth so they return following increases in edible biomass.”

“We burn when there’s good soil moisture, low temperatures and higher humidity,” says Rob. “This enables us to create a mosaic effect with various burn histories and reduced fuel loads that can help to slow and decrease the intensity of any wildfire that does alight through there again.

The cooler months are also a time for preparing and maintaining firebreaks and access roads, and ensuring equipment and safety plans are up-to-date in preparation for what can be long episodes working with wildfires over summer.

A 2013 report by the recently formed Climate Council (formerly the Climate Commission) titled Be Prepared: Climate Change and the Australian Bushfire Threat, outlines some of the factors working against land managers. It reports that climate change is making hot days hotter and heatwaves longer and more frequent, reducing the opportunity for controlled burns.

The report suggests that Australia will experience an increase in the number of days with extreme fire ratings and that prescribed burning activities in some areas will need to increase two- to three-fold to counteract increased fire activity.

The threatened northern quoll is sensitive to fires. Photog by Jean-Paul FerreroThe threatened northern quoll is sensitive to fires. Photograph by Jean-Paul Ferrero

“At Carnarvon we’ve had fires on every pointof the compass – north, south, east, west – over the past month,” says Rob. “There have been more lightning strikes since the first, and fires are burning in the neighbouring properties and the National Park, so we’re helping out with those too.”

“Carnarvon is quite amazing country”, he adds. “It’s very rugged and broken, which means it’s fairly inaccessible. When fire gets up into the high country it can kick around for weeks on end."

At the time of writing some significant recent rains had fallen and it looks like we’ve avoided any significant damage to the ecology on the reserve.

“There are no guarantees with any fire. You need a bit of luck as well as careful planning,” says Rob. “But these wildfire events have become more frequent and intense over the past ten years, so we really need to make sure we’re as well prepared and resourced as we can be.”

Carnarvon Station Reserve was acquired in 2001 with the assistance of the Australian Government’s National Reserve System program.

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