Aurora’s ash trees might make it after all

April 9, 2013 · 0 Comments

By Brock Weir

The invasive Emerald Ash Borer beetle was expected to wipe out almost every ash tree in Aurora over the next decade or two, but there might be some hope for them after all.

Aurora is set to change course this week on their previous plan to let the beetle run do its damage on municipally-owned trees in parks and along streets following changes in the world of chemical treatments.

Council previously approved a plan, based on cost, to let the bug run its course but, in the meantime raise replacement trees within a Town-leased tree nursery, removing and replacing the dead trees on an as-needed basis.

At the time, it was estimated this would cost the Town nearly $2.3 million over a 10 year plan. For residents wanting to save the street trees in their respective neighbourhoods, the option was also there for homeowners to pay for chemical treatments to give the municipal trees they enjoy a fighting chance. As the Town laid the groundwork for the option for homeowners to pay for their trees, it was found market costs for the treatment, TreeAzin, had come down markedly over the past year, according to Al Downey, Aurora’s Director of Parks and Recreation.

“It became immediately apparent that the costs associated with treating ash trees was lower than previously anticipated in the May 1, 2012 report,” he said in a report before committee this week. “It now appears that treating Aurora ash trees will be more cost efficient than removing and replacing trees and this is due primarily to a reduction in the costs of TreeAzin and the associated application.”

Cost estimates have also come down for the removal and replacement of trees. According to the report around this time last year, the removal and replacement of the 1,989 trees in question would cost nearly $2.3 million while treatment would come in at $3.7 million. Now, removal and replacement clocks in at $1.3 million and treatment at $1.1 million.

“Since May, staff have determined that Newmarket and Richmond Hill have both elected to treat selected ash trees in their EAB management plans,” said Mr. Downey. “In view of this, staff expect that it is reasonable to assume there will be an expectation on the part of homeowners and residents that the Town will do likewise and provide similar treatment programs for the ash street tree in front of their residence.”

Councillors approved going out to tender for a round of TreeAzin to potentially treat 1,989 trees around Town. Mr. Downey said the movement of the borer appears to be heading in a westerly direction through King, although the first example of the beetle found in Aurora was caught in a pheromone trap near Bayview Avenue and Stone Road. Going to tender, he added, would help Aurora get a better handle on just how much it will cost to treat unaffected trees in Town.

The chemical acts almost as a vaccine in that if successfully treated, one injection will keep the beetles from destroying the tree for what is believed to be the rest of the tree’s life. The treatment is useless if the tree is already harbouring the bug.

“We have difficulty determining what those actual costs are without going to tender to capture those actual costs,” said Mr. Downey at last week’s Committee Meeting. “It’s the only chemical we know that could have positive results. It is not 100 per cent successful, but we know it has a pretty high success rate and many municipalities are using it and having good results.

“We feel that much of the failure rate has to do with the fact they are treating trees that have already been infested. The issue is to prohibit that infestation.”

This question caused some hesitation around the Council table in determining the best way forward.

“There is no guarantee,” said Councillor Wendy Gaertner. “We could spend this money and there would be no guarantee this chemical is going to work on a significant number of trees.”

Whether or not chemical treatment will be a practical – but cost-effective – solution for Aurora will be decided this week by Council and, if approved, could provide a change in direction on another decision made last year to establish a tree nursery to raise their own stock of the trees expected to be killed.

Mr. Downey said last week the Town was not successful in its first bid for a tract of land to establish a tree nursery, but are looking at three other sites to get this going this spring “as quickly as possible.” These are likely, he added, to be on plots of land already owned by the Town.