Burning question tackled

By David Kavanagh | posted on August 8, 2019

A NEW research project examining the effect prescribed burning has on the flammability of the tingle forests between Denmark and Walpole was launched at the Denmark Environment Centre last weekend.

Fire behaviour specialist and research fellow at the University of Wollongong Philip Zylstra was in town on Sunday to share his research with the community and to kick-start the project alongside local ecologists Melissa Howe and Nathan McQuoid.

Mr Zylstra has been working in fire management since 2002 and has long challenged the notion prescribed burning, which targets the build up of “fuel loads” such as dead leaves on forest floors, reduces flammability.

His studies have instead found that landscapes become more flammable after burning “largely due to regrowth that the fire causes”.

“The fire germinates plants or it damages forest canopies … but then as the forest ages those shrubs thin out and the landscape becomes much less flammable,” he explained.

“Mature forests, from what we’ve seen in the areas we’ve examined so far, are much less flammable.”

According to Mr Zylstra, the Red Tingle Forest Flammability and Vegetation Research Project would initially run for around six months and “get some hard numbers” about the effect of prescribed burning on the region’s tingle forests.

“There’s a lot of prescribed burning happening through southwest Australia and in areas like the Walpole wilderness there are a lot of fire sensitive plants,” he said.

“There’s also largely anecdotal evidence talking about the loss of old growth tingle tree due to burns.

“Potentially burning is actually increasing the flammability there if the pattern is the same as has been measured in other forests.”

Mr Zylstra cited recent studies that suggest frequent burning has adverse effects both on biodiversity and on human health.

He said that a week of prescribed burning in the eastern states in May 2016 resulted in more estimated deaths from smoke inhalation than has occurred from all wildfires in Sydney’s history.

As part of the research project, Ms Howe and Mr McQuoid will work to survey the forest at different ages, using a set technique to measure the dominant plant species and the size and spacing between those plants.

Mr Zylstra will then apply the peer-reviewed fire behaviour model he developed to the information the pair provides him.

“We’ll publish a journal paper for it outlining what’s happening, whether it’s becoming more flammable as it ages or if it’s a more complex picture,” he said.

“The fire authorities will be able to make much more informed planning decisions around it [and will be able to work out] whether it should be burned or if fire should be excluded or if certain areas should be focused on.”

My Zylstra spoke at the Prescribed Burning Conference 2019 in Perth a few days prior to his visit to Denmark.

Among other topics, his lecture referenced the difficulties of changing pre-existing ideas about prescribed burning.

“The idea we need to reduce fuel loads comes from a leaflet from the 1960s which has no scientific basis to it and there’s been a lot of research since then that has shown a far better understanding of things,” he said.

“It’s very hard to change a culture when you have it well established. There are people who have worked their lives build- ing certain systems and thinking a certain way and it feels disempowering to those people to tell them there’s a better way.

“A huge industry builds around it. The longer it takes, the harder it is to change from old ways.”