Thermal Imaging Research Shows Trees Lower Temperatures

Melbourne, Australia (February 18, 2013) – New thermal imaging research out of Australia is showing how street trees, parks, green roofs, and other green infrastructure are lowering city temperatures compared to the built, gray environment. Results show that leafy, green streets and irrigated open space areas were much cooler than built up urban areas without green infrastructure.

Urban treesCities are covered in heat absorbing, hard surfaces such as concrete absorb, and store heat, making urban areas warmer than the surrounding areas. Trees and vegetation lower surface and air temperatures by providing shade and through evapotranspiration. Tree planting is one of the most cost-effective means of mitigating urban heat islands.

The team of University of Melbourne and Monash University researchers are hoping to establish how street trees and green infrastructure can interact with urban design to reduce temperatures in cities.

Researchers used thermal imaging and mobile weather stations during summer extreme heat events to identify some of Melbourne’s ‘hot spots’ and compare these with temperatures from areas with abundant green infrastructure such as Royal Park.

This information will now be used to produce a guide with collaborators at RMIT, to demonstrate which types of green infrastructure should be installed on streets with different orientations, widths and building heights to best reduce surface temperatures.

“Plants are attractive, natural air conditioners so we should be using them more to cool cities. As well as providing shade, plants also cool cities by evaporating water through their leaves into the atmosphere,” said Dr Williams, from the Melbourne School of Land and Environment at the University of Melbourne.

According to Monash University’s Dr Andrew Coutts, “By using airborne thermal mapping and combining it with on-ground measurements, we can produce a good spatial picture of surface temperatures across the urban landscape. This will allow us to assess which areas are cooler than others and how vegetation might be helping.”

Source: “Plants Help Lower Temperatures,” Science Alert (February 18, 2013)

Related Resources
ACTrees “Benefits of Trees and Urban Forests: A Research List”