Keeping an eye on pests to protect forests
By Chad Ingram
July 26, 2016
The Ministry of Natural Resources and Forestry expects the forest tent caterpillar to affect a million hectares of trees this year.
Vanessa Chaimbrone, a terrestrial monitoring and forestry health technician with the MNRF, was one of several speakers during a lake and forest health summit held by the Municipality of Highlands East at the Lloyd Watson Memorial Centre in Wilberforce on July 23.
Chaimbrone said there tends to be an outbreak of the forest tent caterpillar, a native species, every 10 years or so.
“2015, 2016, we were due for an outbreak in Ontario,” Chaimbrone said. In 2015, forest tent caterpillars, whose larvae feed on the foliage of hardwood tree species, affected more than 680,000 hectares of forest in the province. Chaimbrone said this year, it’s expected that number could exceed one million hectares. Outbreaks typically last three to five years.
Despite their name, forest tent caterpillars do not actually weave tents. It’s the eastern tent caterpillar, the species recognizable by the tell-tale white stripe down its back, that weave the light-coloured tents that can be found on trees in Haliburton County.
The jack pine budworm is another pest native to North America tracked by the MNRF. For 2015, aerial mapping showed some 21,000 hectares with moderate to severe defoliation.
“Jack pine is one of our key commercial species, especially in the north,” Chaimbrone said.
The spruce budworm, another pest native to Ontario, was responsible for nearly 150,000 hectares of defoliation in 2015.
“The insects start out at the chute . . . and then feed on the new leaves,” Chaimbrone said, adding that since spruce budworms are particularly messy eaters, they are easy to survey.
There is a high concentration of spruce budworm around North Bay, which is home to one of last stands of red spruce in the province.
In cases of outbreaks of native species, Chaimbrone said it’s basically a case of nature running its course. She recommended to attendees that anyone observing damage to trees on their properties report the sightings to the ministry. She advised staying away from any pesticide-type treatments and contacting a professional tree service.
Tim Reece, a forester with the MNRF’s Bancroft district, talked about beech bark disease, which is killing beech trees in Haliburton County.
Beech bark disease can be difficult to detect, trees appearing healthy on the outside, but rotting from the inside out. Eventually, infected trees will start to display a sort of fuzz on their bark. The disease is spread through an invasive, scaling insect from Europe.
Diseased trees are prone to sudden snapping – known as “beech snap” and so also pose a safety risk.
Beech trees regenerate mainly through root spreading, so diseased trees will continue to regenerate, resulting in gnarled beech thickets.
“It’s an endless cycle of these beech thickets,” Reece said.
The thickets can prevent other types of trees from growing and Reece recommended that property owners cut and thin them out.
Beech trees are key in the diet of black bears and so the disappearance of the trees in the county is having an effect on them, and sending them elsewhere for food.
“Beech is a very important species for black bears,” Reece said. “They really rely, in a lot of cases, very heavily on the beech seed for fat and protein.”
Beech bark disease has swept through the American eastern seaboard during the past 130 years, killing most of the beech forests there.
Forests in states such a New Hampshire are “aftermath forests,” all of their beech trees dead, only thickets remaining.