How people and cities can prepare for the effects of climate change

Philip Van Wassenaer crouches down to pound nails into the base of a 25-metre-tall tree in Scarborough, Ont.

He isn't tapping for sap — the nails around the base of this tree will help him diagnose its health.

Once the sonic tomograph sensors are attached to the nails, Van Wassenaer gently taps each one, sending sound waves through the trunk. The device measures how quickly the sound travels, and a small screen shows different colours for different speeds, essentially showing what the tree looks like on the inside and exposing any rot.

"It may be attributable to climate change, but we are getting asked more often to do a deeper look at the risk of urban trees," said Van Wassenaer, a consulting arborist for 30 years.

WATCH | Arborist Philip Van Wassenaer uses a sonic tomograph to look inside a tree:

"We see climate change happening. It's not somewhere else, it's here. But that doesn't necessarily mean that all our trees have all of a sudden become a problem."

Van Wassenaer says there needs to be a more balanced approach: trees need to be saved whenever possible because they absorb greenhouse gases, which helps mitigate climate change and prevent soil erosion, which contributes to mudslides.

"Some trees absolutely should be removed, many trees can be made smaller. They could be cabled. There are so many conservation techniques."

The devastating effects of climate change and extreme weather are no longer theoretical, and experts say tree maintenance is just one of several preventative measures people and municipalities should take to prepare for more intense and frequent storms.

Cheryl Evans, director of flood and wildfire resilience at the University of Waterloo's Intact Centre on Climate Adaptation, said "every location in the country has slightly different risks that are present now and that will continue to increase."

Residents should regularly inspect trees around their properties and do preventive maintenance, like pruning, when needed.

"As the winters warm, we're gonna get a lot more freezing rain as opposed to snow, so we're gonna see a lot more burden on trees — so check how close the trees are to your hydro lines."

Other regions will have hotter summers and drier conditions, which contributed to the wildfires that destroyed the hamlet of Lytton, B.C., this past June. Meanwhile, in the fall, atmospheric rivers deluged British Columbia's Interior, causing flooding and mudslides in place like Princeton, Agassiz and Merritt.

"For most people, floods, high heat and freezing rain — those are going to be some of the key impacts," said Evans.