Culturally significant trees on Minjerribah (North Stradbroke Island) have been found to be up to 531 years old, showcasing the enduring value of traditional Aboriginal land management practices.

Radiocarbon dating conducted by ANSTO's Centre for Accelerator Science provided the evidence, supporting the role of cultural burning in protecting these ecosystems.

Quandamooka man, Darren Burns, an Elder and Joint Management Coordinator with the Quandamooka Yoolooburrabee Aboriginal Corporation (QYAC), emphasised the vulnerability of Bugari (Cypress pine) trees.

"Bugari are killed by canopy-scorching bushfires but survive low-intensity ground-layer fires," he said.

Mr Burns said large old trees hold deep cultural and ecological significance for Indigenous communities, however are often overlooked in modern conservation approaches.

The study, published in Ecological Management and Restoration, was led by the Queensland Department of Environment, Tourism, Science and Innovation in collaboration with QYAC, Griffith University, and other partners.

Researchers analysed trees ranging in age from 63 to 531 years old, with the oldest being a smooth-barked apple tree.

Other species included forest red gum, pink bloodwood, and scribbly gum.

Principal Conservation Officer and lead author of the study, Dr Michael Ngugi, highlighted the role of Aboriginal practices in maintaining these trees.

"The presence of large old Bugari trees suggested a long history of cultural burning using mild fires, and the importance of continuing these practices to protect these trees," Dr Ngugi said.

Radiocarbon dating on live trees posed challenges, explained ANSTO scientist Dr Quan Hua, due to irregular growth rings, hollow cavities, and potential contamination.

"Using a single recent sample for dating often yields imprecise results," Dr Hua said.

"However, sampling at several depths along the core provides a more precise chronological constraint and better estimates of the tree's age."

The findings also revised previous age estimates that had been based on less precise methods.

For instance, a Bugari tree was determined to be between 225 and 508 years old, while a forest red gum was dated to between 372 and 516 years.

The research underscores the importance of integrating traditional knowledge and scientific methods to safeguard ancient ecosystems and preserve cultural heritage for future generations.