As South Australia’s urban landscape suffers through a second consecutive dry year, a team of scientists from Flinders University has turned to an unconventional method to help save the region’s trees — measuring their “personality.”
Here’s the lowdown from AusBiz
To better understand how trees may respond to drought differently, the researchers used a new approach to assess a plant’s resilience to take up water from the soil – in a sense measuring their ‘personality’.
Trees exhibit different behaviours under stress. Some are better at soaking up water when it’s present, while others are more conservative — and more likely to survive extended drought.
With Australian cities growing hotter and drier due to climate change, it’s crucial to understand how trees respond to water stress for urban planning and long-term livability.
Meet a pro who can shed more light
Flinders co-authors Professor Guan, PhD candidate Zhechen Zhang and Professor Okke Batelaan, from the National Centre for Groundwater Research and Training at Flinders University, worked with colleagues from the University of WA and Colorado School of Mines in the US on the new article.
“Some trees take up water from soil more efficiently than others when soil water is abundant, but become less safe in drought – just like humans with different personalities respond to different stressors,” says Professor of Hydrology Huade (Walter) Guan, explaining a new article in Hydrology and Earth System Sciences.
“With this in mind, the tree ‘personality’ test to measure how the tree is responding during drought can help to determine whether it’s likely to recover when the soil moisture returns – and whether irrigation or watering is recommended, or too late to apply,” says Professor Guan, from the College of Science and Engineering.
Measuring personality
Current measurements of plant water properties are labour intensive, as well as destructive and difficult to scale. This limits the comprehensive characterisation of the whole plant and surrounding land-surface water properties.
To carry out this work, the team studied the Allocasuarina verticillata, a native Australian species commonly found in South Australia. They attached two small, non-invasive devices to the tree stems — one to measure sap flow and the other to monitor water potential, essentially the tree’s internal water pressure.
The setup is similar to a Holter monitor used to check a human heart’s rhythm, only in this case it tracks the tree’s response to changing moisture conditions.
The results are promising. By observing how each tree balances water uptake with drought resistance, the team can determine which are likely to bounce back after a dry spell and which may not.
A smart investment for greener cities
This new ability to measure tree resilience comes at a critical time. As urban councils and developers across Australia invest more heavily in green infrastructure to combat heat and improve quality of life, keeping those trees alive through extreme weather becomes both an environmental and financial concern.
The tree personality test offers a smarter way for councils to manage their urban forests. After understanding which trees need more support — such as targeted irrigation or better soil water retention — resources can be directed more efficiently. In some cases, it might even help councils decide whether watering a particular tree during drought is worth the effort, or too little, too late.
Real-world impact
This ‘personality’ research is now being trialled in the real world as part of the ‘Drywells and Trees’ project, funded by Hort Innovation’s Green Cities Program, with aims to investigate how roof water harvesting for garden soils may improve tree health in the dry season and enhance canopy cooling in summer.
A consortium of local councils — including the Cities of Marion, Mitcham, Unley, Port Adelaide Enfield, and Onkaparinga — are participating, alongside a broad network of urban design and climate resilience partners such as TreeNet, Resilient South, and the University of South Australia.
The business of climate adaptation
Flinders University experts have also recently published a complementary study on vegetation response to climate variability. The aim was to examine better use of water levels and improved plant evapotranspiration (water moving to the atmosphere) to protect urban and other plants in future hotter and drier conditions.
A second study from Flinders University, recently published in the Journal of Hydrology, compliments the personality testing. Led by Dr Nastaran Chitsaz, the study focuses on improving water use models by factoring in how vegetation naturally responds to climate variability.
Understanding evapotranspiration — how plants release water — allows for more accurate predictions of runoff and water demand in a changing climate. As climate change intensifies, innovative studies like these are becoming essential for saving Australia’s urban green spaces.
Cities can make smarter, more resilient investments in the living infrastructure that keeps communities green and healthy by understanding how individual trees respond to drought.
The latest article, ‘Revealing seasonal plasticity of whole-plant hydraulic properties using sap-flow and stem water-potential monitoring’ (2025) by Zhechen Zhang, Huade Guan, Erik Veneklaas, Kamini Singha and Okke Batelaan has been published in Hydrology and Earth System Sciences ‘.
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