Beetle infestation forces tree cull
Conservation authority to cut down up to 14,000 ash trees in next decade to remove hazard to people
WATERLOO REGION — The Grand River Conservation Authority may have to cut down up to 14,000 ash trees over the next decade because of damage to the trees from the emerald ash borer.
The pest beetle, first discovered in North America in 2002, kills virtually every ash tree it infests. Its presence was confirmed in Waterloo Region in 2010. It multiplies quickly and was introduced to the U.S. from Asia via wood cargo crates.
The conservation authority manages 115 square kilometres of forest (30,000 acres). Although only about six per cent of all trees on its lands are ash, that still adds up to as many as 500,000 ash trees on its lands, says Lisa Stocco, manager of communications at the conservation authority.
In some areas, forested stands can be 50 or 60 per cent ash. Hard-hit areas include the Elora Gorge.
In forests where there’s no human activity, the ash trees will simply be allowed to die. But the dead and dying trees can pose a hazard, because infestation rots the roots and trunks of ash trees. So the authority has budgeted $400,000 a year for 10 years to deal with infested trees.
Most of that money will be spent cutting down trees that could pose a risk to people or property. The authority has identified more than 14,000 such trees, along trails and tracts owned by the authority, as well as in camping and picnic areas, or near roads and buildings, said Stocco. “It is very likely that most of these ash trees will need to be removed over the next five to 10 years.”
In some areas with lots of ash, the infestation could change the look and feel of the forest, she said. Some sections along
the Doreen Thomas Trail, which skirts the Laurel Creek reservoir in Waterloo, are littered with the felled trunks of infested ash trees. Those trees were likely cut a year ago, but more ash trees in the area will need to come down, Stocco said.
In most cases, the trunks of the felled trees are left on site, because the dead trees can provide habitat for wildlife, and the decomposing logs add nutrients to the forest soil. But the sight of crews cutting down trees, or of logs piled up on the forest floor, often prompts calls from the public, Stocco said.
The $4 million earmarked for dealing with emerald ash borer includes some money for replanting, and to inject about 200 trees with a bio-insecticide to protect them against the beetle’s depredations. “The treatment itself is expensive,” Stocco noted — about $15,000 each year over the 10 years — but the authority hopes to save some ash trees as a source of future seed supply and for education. Trees chosen for injection were healthy and in visible areas such as near beaches and campgrounds.
For more, go to the authority’s website at grandriver.ca.