Fighting fire in the dry

A recent wildfire on Yourka Reserve has revealed the benefits of best practice controlled burning in tropical north Queensland.

Fires start quickly and often in the top end of the continent. Extreme wet and dry cycles determine how the landscape burns, but also how it recovers. On Yourka Reserve, Jirrbal and Warrungu Country, far-north Queensland, Bush Heritage Reserve Manager Paul Hales witnessed a massive fire burn for weeks in 2019. After six months, the scars had disappeared.

“You wouldn’t know it had burnt unless you knew what the country looked like beforehand,” he said.  

Due to high levels of rainfall in the wet season, Paul says, “you can almost stand there and watch it starting to respond.”

For over a decade, Paul had been tirelessly working to create fire breaks and manage the 43,500-hectare reserve through controlled burning. But despite these efforts, 43% of the reserve still burnt that summer. Paul is sure the fire would have been significantly worse without the work that preceded it. The need for hands-on fire management is a no-brainer for Paul. 

In November last year, after a long dry season, another fire ignited on the neighbouring block, threatening a significant patch of land on Yourka and once again testing Paul’s hard-won fire breaks.  

“This fire was a lot smaller than 2019,” he said, “but had we not had those breaks and scars in place, it might've been a little bit different.”

Paul could see his strategy working in real time, and when you’re dealing with a reserve of Yourka’s size, that’s impressive.  

The reserve's fire management involves 'the art of burning in the rain', through which Paul creates an intricate system of mosaic burns between early wet-season storms, a method which bears similarities to how Traditional Owners use right-way fire to manage the landscape. In 2019, and in last November’s wildfire, these techniques helped to safe-guard areas of habitat frequented by Mareeba Rock Wallabies.

In recent years, Bush Heritage National Fire Program Manager, Rhys Swain has been able to help Paul plan and execute his controlled burns, utilising his expertise in fire management in the Kimberley.  

“For the last 15 years, Paul has been doing it without much on ground support. So, we've really focused on being able to provide that support for reserve managers,” Rhys says. “Just an extra set of hands and an extra fire unit can help get more work completed when it needs to.”  

Rhys, as well Bush Heritage’s National Fire Program Officer, Alistair Hartley, provide much of their assistance remotely, but if there’s a significant wildfire, they are on the next plane. When Alistair arrived onto Yourka last November to assist with firefighting, he was surprised by what he saw.  

“On my way into the reserve, I counted five or six different fires on the horizon and as I got closer,” he said, “I drove past one fire and a big eucalypt had fallen. In a normal burn you wouldn't even worry about them. But because it was dry season, there is very little soil moisture, and therefore no sap flow in big trees meaning they are more likely to burn. Even Queensland Blue Gums were burning down.” 

From an ecological perspective, fire is typically at its most unpredictable and threatening in November in Tropical north Queensland. The long, dry season tends to put fuel loads at an increased risk of combustion, and there is less moisture in the soil. Rhys Swain looks for an array of signs and signals to determine the risk of wildfire and the landscape’s suitability for prescribed burning.  

“Bush Heritage takes a very holistic approach. So we put in fire breaks, we look at all the science in terms of when is the best interval for different veg types…we're looking for things like soil moisture and other environmental triggers when we’re assessing risk or reward.”

Thankfully, the fire breaks were effective, and the block that burnt within the mosaic structure had been effectively isolated. Subsequently for Paul and the team, it was about monitoring, safety and protecting neighbouring blocks. Thermal imaging technology (pictured) allowed them to do so with extreme accuracy, without getting too close to the fire line.

The result reinforced the effectiveness of their strategy. What has happened at Yourka is a good indicator of what’s possible with appropriate fire management.  

As for the preparing for the next fire season, according to Rhys, “We've had above average rainfall across much of the country over the last few months, grasses and fine fuels are flourishing. Once the fuels dry out, the bushfire potential increases and at some point, there'll be big fires across the country. Yourka shows just how useful managing those fuel loads can be when the reality strikes.”