Pine beetles prepare to launch more attacks

Pine beetles that killed large swaths of Okanagan forest five years ago may be down, but they’re not out.

The pest has infested hundreds of trees made vulnerable by the Trepanier Creek fire near Peachland in 2012. Crews felled about 400 pines along the four-kilometre greenway this spring.
“The fire essentially brought the beetle in, and trees that didn’t die from the fire have since died from the beetle,” said Cathy MacKenzie, parks natural-resource technician for the regional district.
The beetle has attacked trees in Kalamoir and Glen Canyon parks as well as pockets elsewhere in the Central Okanagan. Still, the damage is nowhere near the destruction seen from 2005 to 2012.
The mountain pine beetle was on a tear in those days, ravaging more than 14 million hectares of the province’s lodgepole pine. The city of Kamloops lost 95 per cent of its pine trees in 2006 alone. Okanagan communities braced for the beetle’s inevitable migration to the south.
“We thought we were going to be devastated,” said Blair Stewart, Kelowna’s urban forestry supervisor. “We’re just lucky we have more diversity with our trees than other areas.”
Kelowna may have withstood the onslaught, but the city removed thousands of infested trees to prevent new generations from spreading to fresh stands. Crews took out as many as 500 trees a year from Knox Mountain Park over five years, Blair said.
Last year, they extracted 25 or 30 pines. This year they may not haul out any.
“It’s scattered. When we do (see beetle damage), we have them removed, but for the most part we haven’t had to do nearly the amount of work we have in the past,” said Blair.
Small outbreaks have occurred in the McKinley area of North Glenmore and Carr’s Landing north of Winfield.
A large beetle population is growing in the Boundary region, and pockets of pines are turning red in the southeast Okanagan near Beaverdell.
The early spring has enhanced the pest’s activity. The heat has had little impact on forests north of Kamloops
because mature pines are so far apart, it takes too much energy for the insect to search for them.
South of Kamloops, however, plenty of pine forest is still standing. Beetle populations are endemic to the region and could build enough to start more outbreaks, said Lorraine McLauchlan, a government expert on forest insects.
“The last one was a doozy. We’re going to have another outbreak. It’s just that it’ll probably pale size-wise,” she said.
One reason the Central Okanagan sustained the damage it did was the Western pine beetle, which kills only ponderosa pine, was already entrenched here when its mountain cousins arrived. Their populations collided, making local parks and forests ripe for the taking.
Homeowners should be more wary of the western beetle because it produces two generations in a summer instead of one, McLauchlan said.
The risk of localized outbreaks could rise if the Okanagan sees long heat waves this summer as forecast. Foresters remain vigilant.
“You can’t be complacent. It’s like all forest-health issues. You’ve got to watch them,” said MacKenzie.