Beetle battle all but lost

StCatherinesStandard.ca
Aug. 7, 2014
Rob Houle

Unlike the band that started the British Invasion of the 1960s, these beetles were not welcomed to North America.

While the Beatles changed the musical landscape, the emerald ash borer is just plain changing the landscape. It's estimated by experts that within the next five years, the Asian import will have killed the majority of Niagara's ash trees — approximately 15,000 on City of St. Catharines property alone.

The white flag of defeat has been raised by the City of St. Catharines and the Niagara Peninsula Conservation Authority. The city is set to start cutting the ash trees in its parks and adjacent to its boulevards, while the NPCA, in addition to removing the trees from its properties, is advising woodlot owners to cut healthy ash trees while they still have value for lumber.

Concerned with the optics of cutting what may seem to be healthy trees in the city's 114 parks, the city held a media event in Burgoyne Woods Thursday morning to announce it's intentions beginning Aug. 18. The dead ash trees in 78-hectare Burgoyne Woods will be the first to be felled, followed by those that pose the biggest liability issues alongside the city's boulevards, parks operations foreman John Bellehumeur and forestry foreman Gavin Pally said. Bellehumeur noted some of the standing dead trees that pose no danger to the public within Burgoyne Woods will be left standing to provide animal habitats.

Pally said it's expected the majority of the ash trees in St. Catharines will be dead by the end of 2015.

"The way the tree is compromised by the insects in the process of killing it, it compromises the tree at the base, and so after a year of it being dead, we see the tree snapping off at the base, so we're basically scurrying trying to keep up with that as much as possible," Pally said.

Pally noted some 500 city ash trees were injected with an insecticide to protect them from the ash borer, but the cost to do so was prohibitive on a large scale.

He said homeowners who have an ash tree on city property in front of their home will be advised 14 days in advance of its removal via a door-handle notice left at the house. He said once a tree is removed, the homeowner can choose from a list of 10 other species of tree the city will have available for replanting.

There are an estimated 3,000 to 3,500 ash trees along city streets.

Trees taken down in parks will be run through a chipper that can handle limbs and trunks up to 18 inches in diameter and the chips will be used by the city as mulch. The bigger stuff will be carted to landfill. The trees felled along boulevards will be chipped as well, but opportunity will be given to residents, Pally said, to take the remnants as firewood.

The Canadian Food Inspection Agency said the emerald ash borer was first noticed in Niagara, in Welland, in 2009. It is believed the beetle originally made its way to North America by hitching a ride in untreated wood pallets transported in cargo ships. They have since spread as far north in Ontario as Manitoulin Island.

"Once they get infected, within three years, they're toast," NPCA forester Dan Drennan said of ash trees.

Drennan said by the time an ash tree shows the signs of infestation, it's too late to save it with an injection of insecticides. He said early signs of infestation are leaves dying at the top of the tree and "you start seeing lower branches popping out where they shouldn't be, that means the tree is in stress."

The infestation begins, he said, when an adult ash borer lays eggs under the bark of the tree and the larvae subsequently create "S" like channels in the wood.

"When it does that it creates galleries and what that does is it interrupts the flow of nutrients and water up and down the tree," Drennan said.

Once the beetle reaches maturity, it exits the tree via holes it burrows through the bark.

He said while the ash borer is kept in check in Asia by predatory insects such as wasps indigenous there, there are no natural enemies to it in North America. He said the NPCA is advising woodlot owners to harvest their healthy ash trees while they still can derive lumber from them.

He said ash trees will not become extinct in Niagara since the ash borer does not attack saplings and it's expected that once all the mature trees are dead, the borer will have perpetuated its own demise and those saplings will mature to replenish the region's forests.