Throwing shade on streets without trees

Hey there, time traveller!
This article was published 09/07/2021 (1265 days ago), so information in it may no longer be current.

AS a heat dome descended on Western Canada and the temperatures skyrocketed this month, architect Brent Bellamy decided to test a theory.

He set out to demonstrate how a city’s tree canopy can provide relief from sweltering heat, both in the air and on the ground. He based it on claims from the Environmental Protection Agency in the U.S.

“I wanted to see it for myself, so I bought a meat thermometer, and I went down to Edmonton Street,” said Bellamy. “It was a stunning difference in the temperature of the street and the temperature of the air between the two blocks — one having trees and one not.”

On one block of Edmonton Street, close to Assiniboine Avenue, the ash and elm canopy has been preserved. Two blocks away, the trees were cleared to make the street wider.

The difference in temperature was stark: under the tree canopy, the surface temperature reached 33.7 C, while the tree-less block was 48.7 C. Air temperatures differed too, from 32.7 C on the shadier part of the street to 40.5 C on the unprotected city block.

As extreme heat waves become more common, Bellamy stressed urban tree coverage — both existing canopies and newly planted trees — are essential in keeping the city at safe temperatures.

“We seek out shade on hot days because its cooler than it is in direct sunlight, and that definitely compounds when you take into account these very dark surfaces like concrete that absorb and radiate heat long term,” said Martine Balcaen, program director with Trees Winnipeg, a non-profit dedicated to protecting the urban forest.

On top of cooling, Balcaen said trees improve the quality of life, health outcomes and property values.

As temperatures rise and diseases attack Winnipeg’s two main tree species — the American elm and ash — the city has been working on its million-tree planting challenge, operated in collaboration with Trees Winnipeg, with the goal of planting one million trees by the time the city reaches a population of one million.

This year, 3,660 elm trees and 1,760 ash trees have been removed because of Dutch elm disease and the ash borer beetle. The city has replanted 1,300 trees as part of its reforestation program, the city’s public works department said.

“The Winnipeg urban forest strategy will include a strategy for planting, and canopy cover targets, for the entire city including the downtown,” a spokesperson said.

The city is expected to plant trees on public land such as boulevards. Trees Winnipeg aims to support people in planting and maintaining trees on private land. So far, more than 11,000 new trees have been listed as planted, including in all quadrants of the city.

Bellamy noted mature trees are the “real workhorses” for present-day cooling, and stressed both provincial and municipal funding should be dedicated to preserving as many trees as possible.

“It’s critical that we save the mature trees as long as possible until the replanted trees can begin to take some impact,” said Bellamy. “Climate change is going to be a distant rear-view mirror problem by the time those trees are mature.”

Balcaen said Trees Winnipeg encourages both residents and the city to plant diverse types of trees.

“People always ask what’s the best tree to plant, and the answer is whatever isn’t on your block,” said Balcaen. “If we increase our diversity, we increase the resiliency of our canopy.”

julia-simone.rutgers@freepress.mb.ca

Twitter: @jsrutgers