Toronto Star

Battle against bug takes heavy toll on ash trees

Asian pest’s march into GTA forcing cities to cut down targets


Residents of the GTA, kiss your ashes goodbye.

The emerald ash borer, an invasive pest killing southern Ontario’s ash trees, is here to stay — much to the chagrin of residents who are watching as their tree- lined streets are stripped naked.

“If nobody’s come into your community and cut the trees down, you may not even be aware they’re dying,” Mark Cullen, expert gardener and columnist for the Star’s new homes and condos section. “But when someone comes along with a chainsaw and clear-cuts a whole street of ash trees, you go, ‘Oh. Holy crap. What happened?’ ”

Cullen said Toronto and the GTA are in the midst the bug’s destructiv­e wrath — in Mississaug­a, for example, signs have popped up near wooded areas recently notifying residents trees will be chopped in the coming weeks.

“It’s huge right now,” Cullen said. “Any ash tree in its path is going to get killed, unless it’s been treated.”

The city of Toronto estimates most of the city’s 860,000 ash trees will be affected, with most killed by 2015 or 2017. Death usually occurs within two to three years of infestatio­n.

The city has spent more than $3 million on injections for its ash trees, but there is no guarantee the medicine will be effective.

The ash trees make up over 8 per cent of the city’s tree canopy — the layer of Toronto trees seen from the sky — which is “massive,” said Cullen.

Cullen said 40 years ago, the ash tree was the popular choice to line streets with, meaning some neighbourh­oods will see trees clear-cut.

The city is managing approximat­ely 82,000 of the ash trees, with 50,000 in parks and 32,000 on street boulevards, said Beth McEwan, manager of urban forest renewal with the city.

The remaining 312,000 trees on public property are small enough that the city can leave them alone after they die, she said.

In Toronto, residents who live beside a tree that’s marked for removal are notified with a door hanger, said McEwan. The affected tree is also marked with an orange dot, she said.

McEwan said the city has been holding public meetings, informing residents and trying to prepare them for the emerald ash borer since 2008.

“Are they ready to see the city trees die? Many people are aware that this is happening and that this is the sad consequenc­e of an invasive species,” she said.

But despite media attention and city efforts to spread the word about the invasive pest, some residents are not ready to let go.

In March, Scarboroug­h residents were up in arms after hundreds of trees affected by the beetle were chopped down in Guild Park.

“They were in this huge panic mode but they didn’t really understand that the city didn’t have a lot of choice. The trees were going to die,” said Cullen.

McEwan said Scarboroug­h has been hardest hit by the insect, but no part of the GTA has been spared.

Gavin Longmuir, forestry manager for the city of Mississaug­a, said the city has been eliminatin­g ash trees since 2013. To date, the city has removed approximat­ely 3,500 trees, he wrote in an email to the Star.

The problem of the pest — a native of Asia that has been plaguing North American forests since its arrival on this continent more than a decade ago — has “grown significan­tly” in recent years across Mississaug­a and the GTA, he said, adding that “all areas” of Mississaug­a have been affected.

But there is a product that can pre-empt tree death.

If injected early enough, a product called TreeAzin can ward off the devastatin­g effects of the ash borer — though experts aren’t sure if it can save trees in the long term. And it’s not cheap. The city of Toronto has spent $3.6 million on TreeAzin treatments for 13,000 trees to date, said McEwan.

Overall, the city has removed about 40,000 trees and has replaced 18,721 trees, said McEwan. The city aims to replace all 82,000 ash trees on street’s and in parks, she said.

The total costs of Toronto’s emerald ash borer management program is expected to reach $74.6 million by 2020.

 ??  ?? The emerald ash borer is a pest that is sadly here to stay.
The emerald ash borer is a pest that is sadly here to stay.
 ??  ?? A member of Oakville’s forestry service injects TreeAzin into ash trees that are battling destructiv­e emerald ash borers.
A member of Oakville’s forestry service injects TreeAzin into ash trees that are battling destructiv­e emerald ash borers.

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