2011 Villain: The Emerald Ash Borers
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2011 Villain: The Emerald Ash Borers

Nominated for: nibbling their way through our tree canopy.

Torontoist is ending the year by naming our Heroes and Villains—the very best and very worst people, places, things, and ideas that have had an influence on the city over the past twelve months. From December 12–23, the candidates for Mightiest and Meanest—and new this year, a reader’s write-in option! From December 26–29 you’ll be able to vote for Toronto’s Superhero and Supervillain of the year, and we’ll reveal the results December 30.

If you pass an ash tree [PDF] on the way home—and there’s a good chance you will—you might want to take a picture and give it a consoling hug; it might not be there next time you come back.

It’s hard to imagine something so cute and little could be so damned evil, but sadly Toronto is facing just such a villain. The emerald ash borer is sweeping across the GTA, basically doing exactly what its name says: donning a dashing shade of green and boring holes into ash trees.

In 2003, no one had heard of these little Asian beetles (they didn’t even have an English name), but over the next few years the little buggers will kill most, if not every single ash tree in the GTA (not to mention southern Ontario, Michigan, and many other places). That’s 860,000 trees in the City of Toronto alone that will simply be gone by 2017.

As we speak, there are eggheads figuring out how to stop these small but mighty foes, but so far mitigation and counting them is about the best anyone can do: if you happen to spot an infested tree you might just be able to save it with a bit of expensive pesticide but it’s a mug’s game. What’s worse is that with every year that goes by, the ash borers are being found further and further afield. As the Borg might say, resistance is futile.

The borers were first spotted in Toronto four years ago, near Highway 404 and Sheppard Avenue, and now the whole eastern half of the city and numerous patches of trees elsewhere are infested [PDF]. If you’re reading this, you’re likely too young to remember when Dutch elm disease wiped out most of the elm trees on the continent. Well, this is will be much worse.

Toronto takes pride in its tree canopy but these little civic malcontents will wreak havoc with it. About 20 per cent of the city is now leafy—a percentage of tree cover the city would like to double over the next 30 years or so. The borers will make that difficult as they eat away at about 8 per cent of what’s there now. (Green ash is the city’s fourth most-common tree; the most popular non-maple.)

In addition to the trees in local parks and other wooded areas, ash trees are (or rather, were) commonly planted by municipalities along streets. That means some neighbourhoods are full of them and the trees will have to be taken out (at a cost) and replaced (at a cost). Toronto figured on spending more than $1 million this year [PDF], for starters. But this isn’t just a government issue: most of the affected trees are on private land, meaning there’s a big role for Joe Backyard to play in keeping the foliage flourishing.

In neighbouring York Region [PDF], where they still have bona fide forests, they expect to spend more than $10 million over the next decade. Its three southern municipalities, Markham, Vaughan, and Richmond Hill, will likely each spend about the same as they move to remove thousands of trees. In total, York Region has 2.8 million ash trees walking the proverbial Green Mile.

Go away, agrilus planipennis! We’ve got enough trouble without you!