Explained: Winnipeg’s urban forest reaps benefits; needs protection

street view of winnipeg hoarfrost
Photo by Lloyd Gwilliam on Pexels.com

By Joshua Frey-Sam

“Imagine Winnipeg without our trees,” is how Martha Barwinsky, forester for the City of Winnipeg, describes the importance of the urban forest.

“It would be a very bleak city.”

Winnipeg is home to one of the great urban forests in North America, with more than three million trees spanning its canopy and holding a compensatory value (cost to replace each tree) of $3.31 billion.

Its trees offer benefits we often forget about: shade and reducing cooling costs in the summer months, controlling water runoff during rainstorms, shelter for wildlife, increasing property value, mitigating climate change, and providing microclimates that boost peoples’ quality of life.

But Winnipeg is reaching an important juncture for the state of its urban forest and voters need to be conscious of its future when casting their ballots this fall.

The city saw just a one per cent fall-off in its canopy’s population from 2005-2018, suggesting a secure outlook. But the tree loss was because of several infectious diseases and pests, which are here to stay, leaving a potentially frightening scene on the horizon.

“We are losing thousands of trees every year to Dutch Elm disease (DED), cottony ash psyllids (CAP), and emerald ash borer (EAB),” Barwinsky says.

DED is fungus that targets the city’s American Elm trees, which make up roughly 10 per cent of the canopy. The disease has claimed close to 100,000 Elm trees since 1975.

CAP, also known as jumping tree lice, and EAB are harmful insects that affect the canopy’s Ash trees, which make up more than 17 per cent of the canopy’s total leaf area. Some experts suggest the Ash tree population is doomed because of the pests.

So what’s the solution?

The city can’t stop the diseases from spreading and it doesn’t help that the trees weren’t planted with these threats in mind.

A challenge that Winnipeg’s urban forest management team must navigate is, well, being in Winnipeg. There aren’t many tree species that can withstand the city’s vast temperature fluctuation. Along with other natural threats like ice storms, droughts and severe rainfall, it makes for selective nursery stock.

But when the city’s forestry team began creating an urban forest in the 1890s, they planted the small group of suitable tree species in bunches around the city, allowing the harmful pests and diseases we see today to spread with relative ease.

Since 2007, the city has changed its vision of what a tree-lined street looks like and has worked to create a more resilient canopy by planting more species.

“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.

An issue future councils will face is how the city is behind on its replacement tree planting and canopy maintenance.

“The maintenance of our canopy certainly isn’t at the state it should be,” Barwinsky says.

The city’s current pruning cycle is one in 30 years – the industry standard is one in seven years.

Barwinsky says it will take years, and millions of dollars, to get Winnipeg’s cycle back up to par.

Tree pruning and disease control will account for more than 80 per cent of the city’s expected $12.3 million budget, by 2023, to get its cycle back on track.

The good news is after city hall implemented a 36 per cent budget cut to its urban forest spending in 2019, it re-upped its funding heading into 2022 to lower the pruning cycle and get more trees planted.

Barwinsky is hopeful the city can double the number of trees it planted in 2021, this year. The city holds a five-year average of 2,000 trees planted on boulevards and in parks.

Public awareness is key, expert says

Winnipeg has also created a comprehensive urban forest strategy for the next 20 years that gives the public an in-depth look at how the city will need to address the issue.

“The public needs to know about that,” says Dr. Richard Westwood, a biology professor at the University of Winnipeg.

Another solution is current Mayor Brian Bowman’s initiative, the Million Tree Challenge, a call to action for the public to plant one million trees by the time the city reaches one million people in population.

The challenge is ambitious, given the city’s rapid growth and reliance on the public to plant —experts believe it will cost about $43 million and 50,000 trees planted each year to reach the goal.

The plan, originally introduced in 2019, encourages people to not only look at public spaces but also their private property.

“The city has no jurisdiction over private properties but a lot of the urban forest resides there,” Westwood says.

Westwood emphasized the threat climate change presents to the urban forest and that it will need to be a major consideration as the city moves forward with its strategy.

“Some of our tree species may have trouble adapting,” he says. “That’s why now is that time to build that resilience into the urban forest.”

Barwinsky says a goal that the public can expect the city to reach over the next four years is greater protection of trees on public and private property through more species being planted.

Twitter: @jfreysam

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