As dry weather continues in Calgary, some local arborists are concerned about the health of the city’s trees, especially with strict outdoor watering restrictions coming into effect at the end of the month.

According to the Canadian Drought Monitor, Calgary is experiencing “abnormally dry” conditions. According to Alberta’s drought map, the Bow River Basin, which includes Calgary, is at level 3, which is also where water levels are monitored.

Matthew Davis, owner of Adair Tree Care, said that trees in places where people don’t normally water them, such as local parks, “really start to show the signs of a number of years of less than ideal moisture conditions.”

Those signs may include yellowing leaves or the loss of entire branches, Davis said, adding that dry soil conditions on the surface could mean “it’s probably dry further down.”

Arborist Matt Davis is urging Calgary residents to water the soil beneath their trees to prevent drought-related stress. (Colleen Underwood/CBC)

Davis pointed to poplars, which the city says form the “backbone” of Calgary’s urban forests, and said they “seem to be having problems all over the city.”

When trees suffer from drought conditions, they become more vulnerable to insects and diseases, Davis says.

Kevin Lee, a longtime arborist and owner of KRL Tree Service, said he is always concerned about Calgary’s trees because the city is not in a forest zone.

In addition, Lee said Calgary is “in the fourth year of a pretty serious drought cycle in a naturally dry area,” which is exacerbating the current problem.

Lee believes the city’s trees will only thrive if people understand the challenges and provide plenty of extra water. “So, yes, I’m very concerned about the trees in Calgary,” he said.

“A tree has an incredibly high water requirement and simply cannot live and function without sufficient water. That’s where it starts.”

Strict restrictions on outdoor water loom

The City of Calgary plans to implement Stage 4 of outdoor water restrictions on August 26. Under these rules, the use of water outdoors is not permitted. Residents and businesses across Calgary are also being asked to use water sparingly.

Lee said that while Calgary has seen cooler days recently, he strongly recommends people water their trees before restrictions go into effect.

Davis offered the same advice, saying people should take advantage of the current more lenient outdoor water restrictions to prepare as best as possible.

He said it was “not ideal” for the strict restrictions to be reinstated as “most of us would recommend watering trees well into the autumn before they or the ground freezes.”

Arborist Kevin Lee says he’s always concerned about Calgary’s trees because the city is not in a forest zone. With strict water restrictions looming, he recommends people water their trees now. (Dan McGarvey/CBC)

In a statement to CBC News, the City of Calgary said: “One method to protect trees during drought periods is to water the trees and surrounding soil in a timely manner and to ensure the root zone is covered with mulch.”

“When cooler temperatures and shorter days set in, the soul becomes less dehydrated than at the beginning of summer,” the statement continued.

Davis said when watering trees, make sure the water penetrates as deeply into the soil as possible so the roots grow deeper.

This will make the tree more resilient to future droughts because the roots will be able to absorb deeper water that evaporates more slowly, he added.

City officials have said Level 4 restrictions are expected to last until the end of September.