Residents are reminded not to carry firewood across provincial borders this summer.
Gordon White, urban forester for the Town of Okotoks, presented an amendment to the Integrated Pest Management Plan at council’s Jan. 27 meeting, citing a new potential threat to trees in town – the emerald ash borer.
“That insect, small beetle, came to North America in the ‘90s and into Ontario in 2002 and it’s spread to five provinces since then,” said White.
The metallic green-coloured beetle bores into ash trees, where it feeds on tissues beneath the bark and ultimately kills infected trees, he said.
Most recently, an incident of the emerald ash borer was reported in Winnipeg, and though that seems far away White said it’s closer than people think.
Though the borer’s travel is limited by flight and prevailing winds, they get a little help from people taking leftover logs home from their campsites, he said.
“Before it hit Manitoba it was in Thunder Bay, Ont.,” said White. “It’s quite a distance there, but what people do is they transport firewood, and this is one of the main reasons invasive insects get spread long distances.”
He said the Society to Prevent Dutch Elm Disease (STOPDED) has erected signs at most borders and has also included, in some higher-traffic areas, firewood drop-off stations for people to unload wood that isn’t local.
The emerald ash borer can spread quickly once it takes root in a forest. It has already killed millions of ash trees in North America, he said
In Okotoks, there are approximately 4,000 ash trees in the urban forest and an unknown number on private property. All 4,000-plus trees could be lost within a decade should the borer make it to town, he said.
“By year seven it’s peaking and if you have any ash trees left at that time you’d be lucky,” said White.
The Town of Okotoks has chosen to prepare for the emerald ash bore the same way it addresses Dutch elm disease, he said. As of council’s Jan. 27, it has been added to the Integrated Pest Management plan.
Prevention includes constant monitoring of trees for signs of infection and placing sticky traps, which will be inspected to see whether any borers are caught, he said.
When crews are out doing regular maintenance they’ll also take a closer look at ash trees, he said.
“When we prune branches we’ll peel the bark back and look for galleries, which indicate the insect’s presence,” said White.
Should the emerald ash borer be identified, he said there are some chemical injection programs that have been used in other areas where the insect was established that may work. There is also a fungus that may infect the borer, he said.
Coun. Ray Watrin said he was supportive of addressing the emeralds ash borer before it potentially worked its way into Okotoks’ trees.
“I think it’s really important we keep on top of these things,” he said.
He wondered whether more could be done to also wipe out black knot from trees around town, which can be eliminated by cutting out infected branches.
“It’s kind of an unsightly disease and it’s carried by birds that are going around,” said Watrin.
White said while the disease looks ugly, it’s not fatal to its hosts. In 12 years with the Town he said only a handful of public trees were removed due to excessive black knot.
It’s difficult to make people to cut out the infected branches, he said.
“It’s not a regulated pest, so we don’t have any legislative authority to force people to prune black not,” said White.
Instead, when concerns are brought to the Town, a fact sheet explaining black knot is delivered to the homeowners with the infected tree, he said.
On Town land, about 450 trees are susceptible to black knot and it is pruned out as it is identified, he said.
