Western Australia’s jarrah forests were not uniformly affected by the record‑breaking 2023–24 heatwave and drought, with new research showing that subsurface conditions — not just extreme temperatures — determined which areas declined and which remained resilient.
The study, led by PhD researcher Huanhuan Wang from The University of Western Australia’s Centre for Water and Spatial Science and School of Environmental Engineering, has been published in Environmental Research Letters. It is the first to combine satellite observations with groundwater, soil and geophysical data to map how forests across the South West responded to last summer’s extreme climate stress.
Wang said the findings revealed that forests growing on shallow soils, rocky terrain, and areas with limited groundwater access were far more vulnerable to heat and moisture stress: “We found these areas showed much stronger declines in forest health than areas with deeper soils and better subsurface water availability,” she said. “The results suggest forest vulnerability depends not only on extreme climate conditions, but also on what lies beneath the surface.”
By integrating multiple data sources, the researchers uncovered spatial patterns of vulnerability that would have been invisible from climate data alone — insights that could reshape how land managers prepare for a hotter, drier future.
Co-author Professor Sally Thompson, also from UWA’s Centre for Water and Spatial Science, said the study provided real‑world evidence for a recently published framework describing how ecosystems adapt to drying climates. “The jarrah forest study showed how the framework can be applied in practice, helping forest managers decide where to act — such as by thinning — and where to prioritise protection of areas that cope better with heat and drought,” Professor Thompson said.
The research also highlights the growing value of pairing remote sensing with hydrological science to understand how forests respond to climate extremes: “By integrating satellite data with subsurface process knowledge, the study improves our ability to understand ecosystem vulnerability and support more targeted forest management strategies,” Wang said.
The findings come as Western Australia faces intensifying climate pressures, with scientists warning that rising temperatures and declining rainfall will continue to challenge the resilience of native forests.
