Ash borer hits Bruce national park

Nov. 4, 2016
OwenSoundTimes.com

Hundreds of ash trees have been infested by the emerald ash borer and will eventually have to be culled from forests in Bruce Peninsula National Park, a park official said Wednesday.

So far, the pest is confirmed in the sporadic stands of ash in the popular Cyprus Lake campground and at a number of other locations in the park, said Jeff Truscott, the park's manager of resource conservation.

This fall, some dead trees and others that would present a hazard to campers were removed.

“They will eventually all have to all be cleared out, in and around our campgrounds, for example, because they'll eventually turn into hazard trees. So that will change aspects of the landscape, there's no doubt about that.”

To date “hundreds” of trees have been identified as “hazard” trees. Monitoring for the bug is taking place several times a year to track its expansion.

“So really we're hemmed in now. So it's a matter of time, I think, before there will be full spread,” Truscott said. He understands 99 per cent of infested trees die. All three ash species in the park - black, white and green - are affected.

If there's good news, it's that only about 20 per cent of the land of the park is suitable for ash to grow, Truscott said. “We don't have a lot of forest where ash is sort of the really in dense, it's not the main species there.”

Ash in forests across Ontario are falling to the emerald ash borer, whose larvae tunnel under the tree's bark, killing it by disrupting the flow of water and nutrients. It was discovered in Windsor in 2002 and has been spreading rapidly across southwestern Ontario and into Quebec.

Some areas of the park at the top of the Bruce Peninsula are more dense with ash. Those areas where there are hiking trails and places with infrastructure for visitors are the focus of an ongoing inventory of trees which present a hazard now or will in time, he said.

The invasive species was first found in the park in 2014, at Little Cove, a visitor access point to trails and the shoreline, about four kilometres southeast of Tobermory. That's near a golf course where the bugs were found the year before.

Traps were set in areas of the park where the ash trees are thickest to monitor for the beetle, which is native to Asia.

Thirty-two trees were selected for inoculation with the TreeAzin insecticide and began treatment in 2014 and 2015. The treatment must be repeated every couple of years for some years to come. But given the vastness of the park, inoculating all ash is “impractical,” at $1,000 per tree, Truscott said.

More than 4.5 kilograms (10 pounds) of ash tree seeds from the park have been collected and sent to The Gosling Research Institute for Plant Preservation at the University of Guelph and to National Resource Canada's National Tree Seed Centre in New Brunswick to preserve the genetic diversity of the trees.

Arrangements with members of the local Saugeen Ojibway Nation will provide them with some wood this fall from infected black ash trees for traditional basket-making. They'll process the wood in the park to ensure no infested wood is transported to places where the bug hasn't reached, Truscott said.

Since about 2013, the park implemented a firewood ban and exchange program to discourage people from bringing firewood potentially infected with the emerald ash borer and to swap any wood people brought into the park for wood free of the bug.