A rainwater tree trench on Richards St. in Vancouver, planted to help cool the local environment.
Credit: City of Vancouver Engineering.
Climate researchers and the City of Vancouver are working to better protect people in BC’s largest city as heatwaves become more frequent and extreme.
A new project funded by the Pacific Institute for Climate Solution (PICS) is helping to get one tool into and off the ground – trees.
Cooling with Trees: Urban Tree Solutions for Tempering Climate Extremes will demonstrate how urban planners can use trees to bring down the temperature in neighbourhoods. The project will receive $180,000 over three years.
Over that time, researchers at the University of Victoria and the University of Calgary will work with the City of Vancouver to experiment with various types of soil and tree planting practices to find the ideal combination to boost trees’ benefits to the local climate and to society.
Concrete, asphalt and vehicle emissions combine to create urban heat islands. But trees have been shown to reduce the urban surface temperature through shading, evapotranspiration (water being transferred from the land to the atmosphere) and the channeling of air currents.
It’s been shown that a single tree can actually modify the local microclimate, making the vicinity noticeably cooler,” says Caterina Valeo, the project’s principal investigator and professor in Mechanical Engineering at the University of Victoria.
“Our overarching goal is to reduce the heat island effect and reduce the extreme temperatures that we’re seeing in Vancouver,” she says.
But the path forward is not without barriers, says Sylvie Spraakman, senior water resources engineer with the City of Vancouver, and project partner.
“One big challenge that we run into is that the City of Vancouver is already very developed and it’s difficult to find the space to plant new trees,” Spraakman says. “Trees are seen as the ‘nice to have’ and not the ‘absolutely necessary’.”
“The issue is transforming the narrative to one which stresses that urban forests are essential for adapting to climate change.”
The City of Vancouver will use the project’s results to develop guidelines and policies for designing, monitoring, operating and maintaining a type of tree planting, called tree trenches, to grow the city's urban forest. The city will also use the project’s findings to create other strategies to reduce urban heat islands both now and in the future.
