Corp Comm Connects

Oakville to cut down thousands of insect-ravaged Ash trees

Dead and dying trees are safety hazard, forestry official says
June 15, 2015
By Bob Mitchell

Oakville’s woodlands will look different by next spring as thousands of dead or dying ash trees are about to be cut down as part of a massive re-forestation program.

The trees are infested by the deadly Emerald Ash Borer (EAB). It’s an invasive insect that has been fatally feasting on the trees since at least 2002.

About 22 properties, including private properties, will be involved in Year 1 of a 10- to 15-year renewal program for all of the Town’s 280 woodland parks, said John McNeil, Oakville’s manager of forestry services.

“We’re looking at 100 hectares with literally thousands of ash trees,” McNeil said Monday, during a tour of Shannon Creek Trail, one of the sites where professional foresters will be knocking down trees beginning in August. More than 50 per cent of the trees in these properties are ash trees.

Most, if not all, of the town’s 43,000 woodland ash trees are now dead or dying. The first 22 woodland areas were chosen for the start of the program because the insects were first detected there, town officials said.

The trees must be removed for safety reasons, McNeil said.

“With the impact of the insect killing the trees, they become structurally unsound and unsafe and can break apart in a severe wind storm or ice storms, such as Oakville experienced a few years ago,” McNeil said.

“These trees are dead and dying and potentially a safety issue if left standing. There is a potential for them to fall on a public trail or pathway or on somebody’s property.

So they will be taken down in a controlled manner and a restoration program will follow.”

The Emerald Ash Borer is native to Asia, but it’s believed it was introduced into Canada in wood pallets shipped in ocean freighters, McNeil said.

“It’s a borer insect. It drills into the trees in the winter and destroys the circulation system, rendering it unable to bring up water and other nutrients throughout the summer,” McNeil said. “It kills the tree within a few years. That’s why it’s called a primary tree-killer.

“There is also no natural predator for this insect.”

The restoration, which will begin in the spring of 2016, will occur in three phases.

Natural regeneration will take place with existing vegetation sprouting up in the woodlands from natural seed sources. Then, intensive planting will include two different sizes, ranging from two- to three-year seedlings to seven- to eight-year-old saplings. The hardwood trees will include oak and maple, as well as various fruit-bearing trees.

By years three, four and five, weeds will be pulled by hand from the native hardwood trees.

While the Town of Oakville will establish intensive planting sites in select areas, natural regeneration will account for most of the regrowth in the woodlands. Following tree removals, the logs, branches and wood debris left on the forest floor will eventually break down, nourishing the soil, and aid in the natural regrowth of shrubs and trees.

“We won’t be re-planting any ash trees because we don’t want to re-establish its foot source,” McNeil said.

All of the ash trees will be completely removed.

Trees affected generally die from the top down, which is why the trees are bare at the top, McNeil said. “By then the whole tree is infested.”

“They (EAB) burrow around for two to three years,” McNeil said.

Some of the trees that need to be cut down have been standing for as long as 80 years, McNeil said.

In Canada, most of the affected ash trees are located in Ontario and Qu├ębec although Manitoba is on the lookout for EAB. In its adult stage, the insect looks like a green-winged bug. After the eggs hatch, legless grubs emerge in the late fall and bore into trees.

Citing Iroquois Shoreline Woods as an example of how forests can regrow, McNeil said he is confident the ash program will also rejuvenate the woodlands.

“In 2003, we had a similar scenario at Iroquois Shoreline Woods,” he said. “Nearly 4,000 oak trees were dead and dying due to a combination of oak decline and an invasive pest called the two-lined chestnut borer.

“The town developed a long-term forest management plan to restore the forest through plantings and natural regeneration. Today, anyone would be surprised to learn that only a decade ago, the forest lost 80 per cent of its oak trees. Where once you would have seen cut trees and branches on the forest floor, now we see it has come back to life.”

In keeping with best forest management practices, the Town will also remove trees other than ash, if they’re identified as structurally unsound or are overcrowding the forest and causing stagnation, Town officials said.

A map of the properties in this year’s woodlands program is available on the Town’s website at Portions of select woodlands will be temporarily closed over periods throughout the year while trees are removed.

Residents are invited to a community open house at Sixteen Mile Sports Complex on June 17 at 6:30 p.m. to learn more about how EAB is affecting the woodlands and plans for the future restoration of the woodlands.