How can trees provide relief from extreme heat in urban climates? This is what a recent study published in Environmental Research Climate hopes to address as a team of researchers investigated using urban street trees to provide shade relief from extreme temperatures, which continue to increase due to climate change. This study has the potential to help researchers, climate scientists, legislators, city planners, and the public better understand the benefits of trees for cooling urban spaces in the face of the increasing threat of climate change.
For the study, the researchers used a series of computer models between July and August 2022 to simulate how street tree planting in Las Vegas could provide relief from extreme heat and heat exposure. The goal of the study was to ascertain the overall effectiveness of planting non-native trees in an urban setting while estimating the amount of water they would need to survive and provide shade relief from extreme heat. In the end, the researchers found that desert environments are too hot for trees to adequately provide shade relief, primarily due to the trees’ water conservation efforts.
“Urban trees are not a silver bullet for cooling our cities, particularly for desert cities like Las Vegas,” said Dr. Juan Henao, who is a postdoctoral researcher at the Desert Research Institute and lead author of the study. “But they provide significant shade and of course other benefits. I know that I prefer to see trees, and they can help store carbon. We just need to remember that in order to cool the air, they need to release water vapor, and we need to give them enough water to do that. Any hot, dry city will need to consider these tradeoffs and really do their research to identify the right species for planting efforts.”
