Oakville refuses to cave to emerald menace – Toronto Star
The emerald ash borer, an invasive species, has been munching its way through the province's native ash trees over the past decade.
Alyshah Hasham Staff Reporter
The Emerald ash borer, the “ebola virus” of its species, will kill most of the 860,000 ash trees of Toronto by 2017.
But in Oakville, hope springs eternal.
One in 10 of the town’s trees are ash — roughly 180,000. This year the town council approved a multi-layered plan to use pesticides to treat about 7,000 trees on public property.
But the town isn’t stopping there. Part of its forestry services action plan is a “Canopy Club” that encourages residents to work at saving ash trees on private property, using Facebook, Twitter and community events. There’s even an emerald ash borer mascot.
The town has created two detailed videos explaining how the beautiful green beetles systematically destroy a tree. John McNeil, manager of forestry services, graphically describes the borer larvae eating through the tree’s nutrient delivery system as the equivalent of cutting through human veins and arteries.
The videos also explain the treatment process — injecting the tree biannually with TreeAzin, a pesticide developed by BioForest Technologies and the Canadian Forest Service. The treatment doesn’t cure an infected tree, but if repeated every two years, it can stave off death.
A series of interactive maps on the town’s website make it easy to find the 80 per cent of salvageable trees growing on private property.
The town mapped its ash trees through hyperspectral analysis — a process that involved flying over Oakville with a specialized camera capable of detecting ash trees. The maps make it easy for residents to see whether they live in an area with ash trees. Trees are tagged with a GIS system so residents can see whether their favourite ash tree is being treated, as well as the height and diameter of the tree.
It’s not a cheap investment, said McNeil. The hyperspectral mapping cost around $175,000. A report to Oakville Town Council estimates the cost to save the ash trees will be about $2.8 million a year for the next six years, with ongoing expenses to last for 10 to 15 years.
Treatment is an approach McNeil took from Milwaukee, which he says is being scientific and innovative in its approach to dealing with the pest. The Wisconsin city is treating 100 per cent of its 28,000 trees.
He is also taking a leaf from Milwaukee’s communication strategy, which uses social media, advertising and radio broadcasts.
“The simple answer is that this is a priority for our council,” he said. “Our community has a long-standing commitment to the urban forest. Any threat to the canopy is taken seriously.”
This may come in handy again. Another budding tree trouble is the Asian longhorned beetle, which affects Acer trees, better known as maples, which make up 40 per cent of the town’s canopy. If that beetle becomes a threat later, the town will be ready.
Meanwhile, McNeil says, the town is becoming a model for other municipalities. “Oakville is doing a phenomenal job,” said Allison Barr of the Canadian Food Inspection Agency. “Awareness and education is everything.”
It can be hard to care until you picture your favourite park — or golf course, as Barr told one councillor — devoid of trees. On the other hand, there is no need to press the panic button when a tree becomes infected. With treatment, the tree could survive another 10 years.
Toronto announced in June that its policy would focus on tree removal and replacement rather than treatment, meaning the city would lose about 860,000 ash trees. Some 450 “high-value” trees are being treated with TreeAzin at about $140 per dose.
Ash trees were planted to replace the elms that succumbed to Dutch elm disease in the 1960s. Now that they, too, are dying, it’s clear that biodiversity is key to replacing diseased trees, said Barr.
The borer is No. 9 on Time Magazine’s “Top 10 evil animals” list and has destroyed 60 million trees in the United States.
One approach being tried south of the border is launching exotic predatory wasps that are the beetle’s natural predators in its original territory in Asia. Canada is not using this method, but is researching the use of native wasps as bio-surveillance, to more accurately detect the presence of an ash borer infection.
It’s all part of the systematic approach McNeil believes can save Oakville’s urban forest. He pushed to get the town involved in a University of Toronto research project in 2009 that looked at branch sampling as a way to detect the beetle’s spread.
The town has placed more than 100 neon-green traps in trees to track the spread of the insect plague — another factor residents can monitor online. If a cure for the emerald borer does arrive, Oakville will be in the best possible position to adopt it.
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