Taking the temperature of human-modified tropical forest landscapes using airborne laser scanning

Dr Tommaso Jucker1

1CSIRO, Floreat, Australia

Microclimatic conditions in forest understoreys play a key role in shaping the composition and function of these ecosystems. Consequently, understanding what drives variation in microclimate is critical to forecasting ecosystem responses to global change, particularly in the tropics where many species already operate close to their thermal limits. To address this knowledge gap, we explored the potential of airborne laser scanning (ALS) as a way to indirectly map microclimate across human-modified tropical landscapes. To do so, we established a network of microclimate sensors across the world’s largest forest degradation experiment in Borneo. We then used structural equation modelling to combine these observations with ALS data to characterise how topography and canopy structure shape microclimate. We found that topography and vegetation structure were strong predictors of local microclimate, with elevation and terrain curvature primarily influencing daily mean temperatures and vapour pressure deficit (VPD), whereas canopy height had a clear dampening effect on microclimate extremes. This effect tended to saturate once canopy height exceeded 20 m – suggesting that despite intensive logging, secondary forests remain largely thermally buffered. Nonetheless, at a landscape-scale microclimate was highly heterogeneous, with maximum temperatures ranging between 24.2–37.2°C. Based on this, we estimate that 15% of the landscape is currently sub-optimal for forest regeneration, a figure that we project could rise to 34% by 2100 due to regional warming alone. Together, our results emphasise how emerging remote sensing technologies such as ALS can redefine how we model habitat suitability at scales relevant for conservation.


I’m a Research Scientist at CSIRO and an adjunct Research Fellow at the University of Western Australia. My research is broadly focused on understanding what determines the composition, structure and function of forest ecosystems in an effort to predict how these will respond to rapid environmental change and how this in turn will impact society.

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