Australian cities are among many through the world to implement large scale tree planting in the belief it will combat climate-related urban heating.
But new research confirms that if not managed properly, trees aren’t as effective in combatting heat during heatwaves as may be thought, and could even be increasing temperature and adding to pollution.
A UNSW study published in Sustainable Cities and Society shows that conventional climate models overestimate the ability of trees to cool during heat waves by 60 per cent.
This is related to a process known as transpiration, where trees release water vapour through their leaves, absorbing heat and reducing the surrounding air temperature.
While this is fine in normal summer conditions, where trees can lower temperatures by up to 2C during the day, once the mercury hits 34C trees begin to protect themselves by reducing their sap circulation, which in turn reduces transpiration.
Friday, August 23, 2024
Cooling ability of trees during heatwaves overestimated
Saturday, August 10, 2024
Trees may not cool cities during heat waves as much as we thought
A new study suggests that the cooling potential of greenery is reduced in sweltering conditions.
Many cities have undertaken initiatives to plant more trees to help combat climate-driven urban overheating. However, those bold planting efforts may not be as effective in tackling the issue as we once thought.
A study by UNSW Sydney researchers Kai Gao, Dr Jei Feng and Scientia Professor Mattheos (Mat) Santamouris found that the heat mitigation benefit of trees is significantly hampered in extremely hot conditions. The findings, published in Sustainable Cities and Society, opens in a new window, show that conventional climate models overestimated the ability of trees to cool during heat waves by 60 per cent.
“Adding green infrastructure, especially planting trees, is a commonly employed measure to mitigate against urban heat,” says Prof. Santamouris, co-author of the study and the Anita Lawrence Chair in High-Performance Architecture at UNSW Arts, Design & Architecture. “But as our research shows,
Many cities have undertaken initiatives to plant more trees to help combat climate-driven urban overheating. However, those bold planting efforts may not be as effective in tackling the issue as we once thought.
A study by UNSW Sydney researchers Kai Gao, Dr Jei Feng and Scientia Professor Mattheos (Mat) Santamouris found that the heat mitigation benefit of trees is significantly hampered in extremely hot conditions. The findings, published in Sustainable Cities and Society, opens in a new window, show that conventional climate models overestimated the ability of trees to cool during heat waves by 60 per cent.
“Adding green infrastructure, especially planting trees, is a commonly employed measure to mitigate against urban heat,” says Prof. Santamouris, co-author of the study and the Anita Lawrence Chair in High-Performance Architecture at UNSW Arts, Design & Architecture. “But as our research shows,
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