In August, the average temperature in Phoenix was 105 degrees fahrenheit. This type of extreme heat is not unprecedented. It’s caused by the heat island effect, where heat is trapped in the city through the sides of buildings and the concrete sidewalks and roads.
One solution to this problem is trees. This is exactly what the Urban Heat Island/Trees and Shade Subcommittee and the Environmental Quality and Sustainability Commission met to discuss on Sept. 13.
Dr. David Hondula, director of the Office of Heat Response and Mitigation for Phoenix, was the first speaker to address the council. He proposed trees as the solution for Phoenix’s heat island effect. Hondula referenced the “American Forest Tree Equity Map” to demonstrate how Phoenix is lacking in their implementation of more trees.
“The average neighborhood in Phoenix has a score of 80 on a 0 to 100 scale, and the goal, at least in the American Forests’s eyes, is to get every neighborhood to 100,” Hondula said.
He set the target, based on his own office’s calculations in collaboration with American Forests, to be 460,000 trees. This goal would bring below average neighborhoods in Phoenix up to the average number of trees.
The three annual plans that Hondula’s office has set in place cost more than $2.1 million annually, and are projected to only result in just over 4,000 trees planted. That is less than one percent of the total goal.
And as Hondula explains, this does not even account for the amount of trees being lost each year:
“We don’t have terrific accounting on tree losses in the city. While the number of trees planted is of great interest, of even greater interest is the number of net trees planted per year,” he said.
So even though the plans for more trees are in place, there are still major hurdles that Hondula and the Office of Heat Response and Mitigation need to get through to achieve their goal.
Trees fall under the umbrella term of “low-impact development,” or LID. This includes things like gardens, rain barrels and other things that help to curb heat, lower pollution and manage stormwater.
The Urban Heat Island/Trees and Shade Subcommittee brought up another potential roadblock that could halt the development of these urban trees and gardens: variances.
“Very recently I learned that to incorporate low-impact development on your projects, you have to get a variance for it. So that seems difficult,” committee member Tiffany Halparin said.
Committee member Nicole Rodriguez agreed.
“It is a little backwards, I think we over require variances and permits,” she said.
The committee members were unsure of how exactly these variance requirements could influence their plans.
To commit to more green infrastructure, such as trees, rain gardens and water run-off filtration systems, the Urban Heat Island/Trees and Shade Subcommittee, along with Dr. David Hondula and the Office of Heat Response and Mitigation, may run into the problem of finding permits for all of their ambitious projects.
Contact the reporter at dgrowney@asu.edu
