Ancient trees reveal Australia's bushfire history

Published: Tuesday 12th April 2016

Trekking through the remains of an ancient forest in Tasmania, hiking up a mountain and camping for the first time are all achievements NSW School of Arts Geography Honours student Raquel Russo can now cross off her bucket list.

Raquel has just spent a week in Tasmania in the name of research for her Honours project – a study looking at the tree rings of the Athrotaxis species and what they can show us about the history of bushfires in Australia and their impact.

Raquel’s study has particular relevance given that parts of north-western Tasmania have recently experienced devastating bushfires.

“I wanted to specifically look at dendrochronology and the impacts of natural hazards on trees,” Raquel says. Dendrochronology is the dating of a tree based on the pattern of the rings inside it.

“I was advised by my co-supervisors Duncan Cook (ACU School of Arts, NSW) and Kathy Allen (University of Melbourne) that I should focus my thesis on the Athrotaxis tree species as they responded quite well to Australia's climate and are able to date back to 1000’s of years ago.”

With the remains of an ancient Athrotaxis forest still accessible in Tasmania’s north-west, Raquel and her supervisors packed their hiking gear and tents and set off for some field work.

“Duncan, Kathy and myself camped at Lake Gaye for two nights, collecting tree ring samples from a forest of dead Athrotaxis trees. After this I went back to the University of Tasmania with Kathy to conduct lab work; mounting the samples on planks of wood, sanding them down and using different software to analyse the tree rings and to identify the birth and death dates of the samples as well as the impact of bushfires on these trees.

“I expect to find some good correlations between ring width and Australia's climate e.g. temperature and precipitation, as it will help me identify years that were experiencing periods of drought and whether any rotting or fire scars are present in the samples. This would then link back to how bushfires have and are impacting on these species,” Raquel explains.

Having developed her keen interest in physical geography as a Bachelor of Teaching/Bachelor of Arts student, Raquel thought a Bachelor of Honours was the next logical step in her studies and is relishing the challenge that field work provides.

“When I started my honours program I knew I had to do some fieldwork but probably not to the extent of camping, as I have never been camping before.

“It was a bit of challenge for me to face, but because I was pretty adamant and passionate about this topic, I realised that if I wanted to achieve great results from my thesis then I would have to endure climbing a 900m mountain, the ‘bush bashing’ and crawling on logs to cross one side of the lake to the next topic.

“But in the end I knew it was going to be beneficial to not only my thesis but also have the experience of working in the field with professionals who have discovered the first centennial-length tree-ring chronology in Australia and quite possibly the world.“