The emerald ash borer threat
EMERALD ASH BORER
Canadian Food Inspection Agency photo
The emerald ash borer.
A tiny green bug is destroying Brantford's ash trees.
Sometime during the 1990s, the emerald ash borer burrowed into wooden pallets and snuck aboard a Chinese ship containing cargo eventually bound for Detroit. The ash borer later travelled across the border into Windsor and over the last decade has laid waste to thousands of acres of ash forest in Ontario, Quebec and the northeast United States.
Today, the rapacious insect threatens approximately 90,000 ash trees growing in the City of Brantford.
Emerald ash borer larvae kill trees from the inside out by tunnelling behind bark and cutting off nutrients. By the time damage is spotted some three to five years later in the form of splitting bark and green shoots emerging from the tree's lower trunk and roots, it is too late to save the tree.
The loss of Brantford's ash trees is a given, but the city hopes a costly treatment and removal program can prolong the inevitable, said Brian Hughes, acting director of parks operations.
“You could call it a crisis,” Hughes said of an infestation that targets some of the city's oldest and tallest trees. “Entering into 2013, we're on a severe slope now where the infestation is here and we're going to start seeing dramatic loss of trees.”
In response, the city is evaluating the 4,000 ash trees located in municipal parks and on public land.
Last year, some 400 diseased ash trees rated in poor condition were cut down and replaced with non-ash saplings. Parks staff injected 200 trees graded good or excellent, mostly in the heritage downtown core, with the insecticide TreeAzin in an attempt to grant the towering trees a stay of execution.
However, the city is fighting a losing battle, admitted arborist Scott Porter, Brantford's urban forestry coordinator.
Porter said branch sampling has revealed that the rate of ash borer infestation shot up tenfold from 2011 to 2012.
“It's going through town quite rapidly," Porter said. "We'll see a significant increase in 2013.”
Ash groves can be found in woodlots in the industrial north and abutting homes on Dufferin Avenue, but the loss of tree canopy will be felt citywide.
It costs the city between $155 and $200 to remove a tree, versus $200 to $400 per TreeAzin treatment.
“It's cheaper to take the trees down, but it would be devastating across the city to just remove them,” Hughes said.
“Some of the trees look healthy, but they are fully infested with the ash borer and it's just a matter of time before they die,” Porter added.
Residents with ash trees on their property should check for cracking bark, green shoots breaking through the lower trunk and roots and tiny D-shaped holes where the ash borer makes its entrance. Woodpecker holes are also a giveaway, as the bird pecks at the larvae under the bark.
There are an estimated 86,000 ash trees on private land. Trees deemed unsafe must be removed at the owner's expense.
With no natural predators in North America, the only solution is to hope the ash borer dies out after the ash trees do, Porter said.
The parks department is looking to double its budget to inject or remove ash trees in 2013. Council must decide whether to approve $320,000 for the project, which is currently classified as an “unmet need” in the city's ongoing budget deliberations.
Coun. Marguerite Ceschi-Smith recently brought the municipal perspective on the emerald ash borer issue to the federal government's standing committee on the environment and sustainable development.
Speaking in Ottawa on behalf of the Federation of Canadian Municipalities, Ceschi-Smith argued for increased federal funding to help municipalities fight invasive species and a national plan to protect urban forests from a problem that crosses municipal and provincial borders.
“Urban forests contribute environmental, economic and recreational value to communities, all of which enhances quality of life,” Ceschi-Smith said.
The loss of trees impacts air quality, wildlife habitat and stormwater collection, she said.
Coun. Dave Wrobel piloted a resolution through council calling for Ottawa and Queen's Park to help Brantford cover the “significant costs” associated with the emerald ash borer, which are projected to be in the millions.
How much the city can afford to spend on saving its ash trees remains unknown. What is certain is that Brantford's streets and parks will soon miss the shade and beauty the trees provide. Property values are expected to drop as the trees vanish, to say nothing of the odds that the city can achieve its stated goal of 40 per cent tree cover.
“When you're replacing large trees with smaller trees, obviously the canopy is going to decline,” Hughes said.