“Charcoal has accumulated at the foot of a dune after a fire and been gradually buried by layers of sand, creating a time-capsule effect,” Dr Patton says. “These sediments can be dated using radiocarbon dating, providing an accurate record of past fires in the area.”
Most environmental records of fires have typically been found in places that are very wet, such as bogs and small lakes. “As a result, many areas with high fire risk, such as parts of Australia, California and the Mediterranean, have poorly understood natural fire regimes.”
Professor Shulmeister says the new research, published this week in the journal Quaternary Research, is critical because the Black Summer bushfires of 2019-2020 in Australia highlighted that fires are possible on much larger scales and greater intensities than had previously been imagined.
“Here in New Zealand, recent dangerous wildfires at Lake Ohau and in Northland have demonstrated that our bush is also more susceptible to uncontrolled burning. Understanding how, why and when these fires might occur is important for the future management of wildfire risk, particularly in areas such as Central Otago that have a dry climate and a high potential fire risk.”
Dr Patton says the work is ground-breaking in demonstrating that sand dunes can act as archives for fire history. “We believe our approach could be applied to dunes in arid and semi-arid regions and could revolutionise our understanding of past fires, modern fire risk and future fire management.”
The study is a collaboration between researchers at Lincoln University, the University of Queensland, the Australian Nuclear Science and Technology Organisation and Utah State University in the United States.
