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Ash borer continues to dig into city’s pocketbook

Hundreds of trees in the City of Oshawa, including these ones recently cut down on the south end of General Motors’ Oshawa Assembly, have been affected by the emerald ash borer, an insect that destroys them from the inside. City council will soon vote on spending $170,000 to help protect Oshawa’s trees from the pest.

By Joel Wittnebel/The Oshawa Express

The war against the emerald ash borer continues to have a hefty impact on the city’s coffers as council gets set to shell out thousands of dollars in further effort to protect its remaining trees.

The most recent expense could see council approve the sole sourcing of $170,000 for TreeAzin, a product used to protect trees from the invasive species.

The insect thrives by laying its eggs in the bark of healthy ash trees, and when they hatch the larvae bore into the tree and feed under the bark. This disrupts the movement of nutrients and water through the tree and eventually kills it. It’s estimated that over 90 per cent of the city’s trees will be impacted from the first wave of EAB, which came in 2011.  In 2012, it was estimated the city had 3,500 ash trees along city streets and around 1,500 in city parks.

The chemical, once injected into the trees, kills the larvae that attempt to feed there and has an approximate success rate of 70 per cent. The treatment will be used on anywhere from 700 to 1,770 trees.

“It is important to note that the city does not treat ash trees in open space areas, as witnessed by the damage to Second Marsh and the airport woodlots,” the report reads.

The reason for the sole sourcing is due to the fact that only one other company makes this similar type of product. However, according to staff, the competitor, a product known as Confidor, is more costly as it requires specific equipment for the injections and has also been found to be detrimental to bees and certain aquatic animals.

“Our mission is to try and keep the trees alive so that hopefully we can protect them enough that they stay alive,” says Dru Chillingworth, the manager of parks maintenance services.

In the most recent meeting of the community services committee, several councillors raised concerns about the beetle and the city’s processes for dealing with the dead trees. The city has had to close several trails in the city due to the danger of fallen trees killed by the emerald ash borer.

And while staff note it is significantly cheaper to treat the trees while they’re alive than it is to cut them down, chip them and remove the stumps, Councillor John Neal was concerned about spreading the larvae further when the trees are chopped up

“The larvae is still there in the wood chips and then blowing away in the wind,” Neal said.

However, staff replied that most of the larvae would be destroyed in the chipping process and with the widespread nature of the EAB infestation, the best option is to push ahead with the treatment, something that has shown real success in the past.

“This is about vaccinating trees,” said Mayor John Henry, pointing to the success of this treatment that saved many of the large trees in Lakeview Park.

“Being proactive is a lot better than being reactive,” he says.

With that said, according to a 2012 report on the EAB, the city is still set to incur hefty costs due to the removal and replacement of trees.

That report estimates that 600 trees will need replacement this coming year at a cost of $600,000. That number will jump to 800 in 2018 at a cost of $800,000 and increase to $1 million and 1,000 trees in 2019.

In total, between 2012 and 2021, tree replacements due to the EAB is expected to cost over $5 million.

Across Canada, the economic impact of the EAB is expected to be anywhere between $500 million and $1 billion over the 30-year period.