One by one ash trees are being cut down across the City of Barrie and some people are disappointed it's come to this.

The reason for this massive tree removal is a tiny bug called the Emerald Ash Borer. The bugs are small, but they do a lot of damage to ash trees.

“This tree right here shows signs of what's called copus growth. Branches growing down on the trunk, popping out which is not normal. It’s a sign of infestation,” says Kevin Rankin, urban forester for the city.

Small holes and unusual patterns under the bark are the telltale signs.

“The bug chews in under the bark. It eats off the cambium layer and kills, stops the transport of water and nutrients up and down the tree and then the tree dies off from the top down,” he says.

That makes the trees dangerous.  The bugs have been spreading across the province for the past decade and are now showing up in Barrie.

They are usually transferred by people moving infected fire wood and in an effort to learn more about the ash borer, the city has 25 traps set up.

Crews are even trying to save some of the trees with a different approach. They are injecting some trees with extracts from other trees that seem to fight the bug off.

“It's costly. You have to do it every other year or every year and that treatment itself can save some of the trees.”

The trees they are trying to save are mainly located along the city's waterfront, but all of the trees that line residential streets will have to come down.

“It's sad. I mean these trees have life of their own and they look beautiful on this street,” says Barb Favvro, a Barrie resident.

All of the trees cut down in residential areas will be replaced with more than a dozen different species of trees. It’s going to cost about $170,000 a year.

In all, 5,000 trees will be cut down in Barrie, which will take several years to complete.