‘Ecological emergency’: Saskatoon confirms record number of Dutch elm disease cases

WATCH: A record number of Dutch elm disease cases is prompting the City of Saskatoon to declare an ecological emergency.

A record number of Dutch elm disease cases is prompting the City of Saskatoon to declare an ecological emergency.

On Friday, the city confirmed 12 cases of the tree-killing disease so far this season, more than the record of 11 confirmed cases last year.

“With each tree removal being about $2,000 on average, it’s a very expensive problem,” said Thai Hoang, director of parks. “But it’s only going to get more difficult and expensive to manage if it continues to spread.”

The city says cases are widespread and are not concentrated in any particular neighbourhood.

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Tree inspectors have found an additional seven elms displaying symptoms of the easily-spread blight that are being removed as a precaution.

In total, Hoang said a total of 37 trees will be removed, accounting for nearly $500,000 in value.

“One of the things that we want to get across to people is that storage of elm wood, [and] transportation of elm wood, are the two primary vectors through which the disease spreads,” he said.

When a case is identified, samples are collected from symptomatic trees within one kilometre of an infected tree, and staff sweep a one-kilometre radius for any stored wood once a case is confirmed.

Despite continued efforts reminding people not to store elm wood, city crews have already destroyed nearly 10,000 kilograms of seized wood this summer.

“I don’t know if we could be more clear on this, but do not store elm wood,” Hoang said. “Do not transport it. It becomes a huge issue for us to be able to manage.”

Dutch Elm Disease is described as an aggressive fungal infection threatening elm trees worldwide.

It spreads rapidly and often kills mature trees in a single season with irreversible effect. Hoang said roughly 25 per cent of Saskatoon’s urban canopy is made up of elm trees, which he estimates is anywhere from 25,000 to 30,000 trees at risk of being destroyed.

“To eradicate the disease would be very difficult,” Hoang said.

“But if we manage to spread and continue to plant additional trees, the hope is that we can slow it enough that it doesn’t impact us.

The provincial ban on pruning elm trees will be lifted on Monday. But given the hot weather over the last two weeks in Saskatoon, Hoang and his team say the elm bark beetle, which spreads the fungus, is still very active.

He’s asking residents to hold off on pruning their elm trees for another couple of weeks until cooler conditions settle in.

Numerous cases have been reported since Dutch elm disease arrived in Saskatoon in 2015.

In 2024, there were 11 cases, there were four cases in both 2023 and 2022, with an additional case reported in 2021 and 2020.

Regina has had trouble managing Dutch elm disease in recent years.

Last year, the city reported its highest on record, 85 cases. Twenty-four were recorded the year prior with 18, 14, and 12 cases reported each year dating back to 2020.