UW study links planting native trees, greenery with lower day-time temperatures

A person in the process of planting a small tree outside. Stock photo.

Looking for ways to beat the heat? A new study from the University of Waterloo suggests planting could help.

Native trees, shrubs and greenery can help reduce day-time temperatures by over four degrees within a decade.

According to a release from the university, researchers came to this conclusion from gathering thermal images of backyards before and after native plants were re-introduced. 

“We found a decrease of 4.5 C in summer daytime temperatures over 12 years and we found that this change was dependent on biodiversity,” said Jonas Hamberg in the release, PhD candidate at Waterloo’s School of Environment, Resources and Sustainability and lead researcher on the study.

Hamberg says native plants are adapted to the local environment and are better equipped for cooling their surroundings.

"For example, native tall-grass species have deeper roots and can pull up water to cool, much like a water-cooled AC, long after non-native grasses have gone yellow and dry." said Hamberg in the release.

Recently, Hamberg presented his findings to local governments, speaking with them about the benefits of planting native greenery.

“I’ve advised local governments that restoring natural areas with diverse native plants and trees is a very effective way for us to adapt to a hotter summer climate on a local level," said Hamberg.

He adds residents should also consider planting native trees, shrubs and other plants in efforts to keep their homes cool during the rising seasonal temperatures. 

The images for this research were captured using a thermal camera on the International Space Station called ECOSTRESS. The release says Hamberg and his team are the first group of researchers to use this camera since it was attached to the ISS in 2019.

Dr. Christine Lee, applications lead for ECOSTRESS at NASA's Jet Propulsion Laboratory, says ECOSTRESS aims to increase people's knowledge of how terrestrial ecosystems respond to changing environmental conditions, like water availability, and how this data can be used for practical purposes.

“Jonas’ study utilizes ECOSTRESS surface temperature products to examine how different plant communities cool their surroundings and assess restoration outcomes,” said Lee in the release, "We look forward to seeing continued research and work in these areas."

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