Spotlight: Winnipeg’s tree-pruning cycle a never-ending game of catch-up

A devastating storm in October 2019 damaged roughly 30,000 public trees in Winnipeg (City of Winnipeg)

Trees in Winnipeg are pruned once every 27 years — a far cry from the industry standard of once every seven; city alone can’t handle the amount of work to be done

By Joshua Frey-Sam

Fraser Paterson’s workday consists of removing dead and diseased trees, building habitable ground for new saplings, and pruning Winnipeg’s canopy.

In his two-years work as a grounds crew member, Paterson has gained a wealth of knowledge for trees and adores their beauty — specifically the ones belonging to the city.

“One thing I really like about living in Winnipeg is we have a crazy canopy,” he says.

Paterson’s expertise means he’s also grown a keen eye for issues plaguing the city’s forest, including the lack of maintenance, which had left many trees in desperate need of a touch up and the canopy far from thriving.

Trees in Winnipeg are pruned once every 27 years — a far cry from the industry standard of once every seven years. Longer cycles, like Winnipeg’s, can present a laundry list of public safety issues while being detrimental to the overall health of the canopy.

Regular pruning leads to clear roads and sidewalks, better visibility of road signs and traffic lights, and an aesthetically pleasing urban forest.

Paterson has lived in the Wolseley area for three years. He says there isn’t a lot of variance among trees species in his neighbourhood, though he’s grateful for the American Elms that arch his street.

But after an inevitable rainstorm, he sees branches from damaged trees litter his street while poorly pruned Elms are left in rough shape. He says the city is often slow to clean up after a storm, leaving a big problem for residents to deal with.

He’s also noticed the threat unmaintained Manitoba Maple trees present in many areas of the city.

“[Manitoba Maples] grow like weeds,” he says. “You’ll commonly see them sprawled out under power lines, and if they aren’t pruned, that can present quite the hazard.”

Paterson says he mostly notices problems with trees on private property. Though, the city doesn’t manage those trees, they are adding to the canopy’s biggest threat: diseases and pests.

“The injured trees that are susceptible to diseases are going to make other trees around them susceptible to diseases,” he says.

Invading insects threaten life and limb

Most prominently, Dutch Elm disease (DED) has wiped close to 100,000 Elm trees from the canopy since 1975. The fungal is spread through Elm bark beetles while they feed.

American Elms make up roughly 10 per cent of the city’s urban forest, rendering DED a significant threat.

Emerald ash borer (EAB) and cottony ash psyllids (CAP) — known as jumping tree lice — are equally harmful to city’s canopy. Both are dangerous insects that target the forest’s Ash tree population, which account for more than 17 per cent of Winnipeg’s total leaf area.

City of Winnipeg Forester Martha Barwinsky says the city alone can’t handle the maintenance of the more than 290,000 trees spanning its canopy. Pruning is augmented by local contractors, like Paterson’s company, but is still an issue due to a lack of equipment and manpower.

In order to meet the standard seven-year pruning cycle, Barwinsky says the city would need to maintain over 41,000 trees each year. She says the city needs time to build a capacity of arborists who can help reduce the cycle’s timeframe.

The resources available to the city are often occupied playing catch-up on the rampant diseases and pests. Rather than pruning trees proactively to prevent diseases from spreading, arborists are removing trees that are already past a salvageable point.

“Particularly in the case of EAB, responding to threats from invasive pests and diseases can take priority over pruning due to possible imminent mortality of thousands of trees in a short period of time and increased risks to public safety if not addressed in a timely manner,” Barwinsky says.

The city is also subject to a province-wide ban on pruning American Elm trees. No work can be done on the tree species from Apr. 1 to Jul. 31, as pruning, ironically, could be fatal to the tree.

Barwinsky says it’s difficult to determine how long and how much it will take for the city to get back to industry standard, but that all factors will be discussed in the city’s Urban Forest Strategy — a long-term vision for the urban forest established by the City of Winnipeg.

Barwinsky acknowledged the severity of the pruning-cycle issue but believes it’s trending in the right direction. From 2006 to 2014, the cycle sat at an acceptable once every 13 years before eventually shooting up to once every 31 years in 2020 after the city implemented a 36 per cent budget cut to the forestry department.

After additional budget was approved by city council in 2021, the pruning timeframe dropped to its current state and should continue to drop, as the forestry department saw a budget top up of $2 million for 2022.

Paterson is hopeful the city will continue diversifying the tree types in its canopy, as it will increase the forest’s resiliency toward invasive species.

For much of the urban forest’s existence, foresters thought a street uniformed with American Elms was the ideal look for Winnipeg. While it’s made for scenic neighbourhoods, it’s also cultivated an ideal environment for threats like Dutch Elm disease to quickly maim nearby Elms by the thousands.

The city has worked since 2007 to change what its vision of a tree-lined street looks like, Barwinsky says.

“It’s a matter of getting as much diversity as we can in hearty material and selecting the proper location to plant those different species,” Barwinsky says.

Twitter: @jfreysam

Further reading: 

Red tape blamed for hindering tree-planting efforts on city property (Winnipeg Free Press)

Throwing shade on streets without trees (Winnipeg Free Press)

Urban Forest Solutions (Trees Winnipeg)

Local tree loss data and tools (Trees Please Winnipeg)

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