City staff will cut down 10 per cent of Hamilton's public ash trees each year for the next 10 years — including some that are still healthy — to cope with the spread of the emerald ash borer.

The general issues committee voted Thursday to adopt a $26.2-million action plan that will gradually chop down the city's 22,738 ash trees along streets and in public parks and cemeteries. Staff will come back to the committee each year with an update.

Councillors had trouble stomaching the notion of chopping down healthy trees. But many accepted the plan as necessary, and the plan passed unanimously.

"I think it's important we recognize we need to get ahead of this and be responsible," said Coun. Sam Merulla.

The emerald ash borer is an invasive pest native to Asia that was first spotted in Ontario in 2002. It kills nearly every ash tree in its wake within 10 years of the first sighting. It was first spotted in Hamilton in 2009.

The Hamilton plan will cost $26.2 million over 10 years and will include planting a new borer-resistant tree every time an ash tree is removed.

The city will also write to the federal government asking for money to help pay for it. Currently, the city must foot the bill itself, which represents a tax increase of about 0.4 per cent, said Roberto Rossini, the city's manager of finance and corporate services.

The proactive plan — cutting still-healthy ash trees and replacing them — allows the cost to be spread evenly over 10 years, said Craig Murdoch, director of environmental services.

It will also allow the city to plant new trees sooner so ash-heavy neighbourhoods will have an emerging tree canopy as the ash trees die.

'Concrete jungle'

 "(This option) is the only way to address areas that are heavily hit when we have streets and neighbourhoods that won't have any trees left," Murdoch said. "You see pictures in magazines where trees are knitted across the road. It's one of the most beautiful images you can see."

The ash borer will create a "concrete jungle" in some areas, he said, and "it takes a long time to get it back."

The city will need a strong communications plan, Murdoch said. Otherwise there will be an outcry.

Coun. Lloyd Ferguson of Ancaster didn't like the idea of cutting down healthy trees. He wanted to remove trees only after they were sick or dying, and do replanting within the city's existing budget. That would have cost $18.3 million over 10 years.

There will be public outcry if the city cuts down still-healthy trees, Ferguson said. And people won't pay attention to the issue until crews turn up to chop down a tree in front of their home.

"I just hope we're not overreacting to this," he said.

Some trees saved

Eight hundred trees will be saved via biannual inoculation with a pesticide that protects still-healthy trees from the borer. Staff will work with councillors to identify important trees in their wards, such as downtown's ash-heavy Gore Park.

Homeowners who want to pay to inoculate a tree near their home can do that.

Still, the trees will be a loss, said Maria Pearson, who represents urban Stoney Creek. Her ward is the most heavily affected. Nearly 20 per cent of its trees are ash.

"There are whole streets where tree canopy touches and they're all ash," she said.

About eight per cent of city-owned trees are ash. Homeowners will have to foot the bill to remove their own ash trees.