It’s actually jumped the Rockies and has spread across Alberta to Saskatchewan. That’s in the far north, it’s interior. It’s typically very, very cold, and in the past too cold for the beetle to survive there, but now it’s warm enough. Diana Six, entomologist at the University of Montana
Yale Climate Connections reported this news when they recently shared this post on social media.
Canada’s vast conifer forests are being destroyed by tiny beetles that are on the move. Mountain pine beetles are native to western North America, but as the climate warms, the beetle’s range is expanding.
Diana Six is an entomologist at the University of Montana. She says that, as the beetles spread to these new locations, they are starting to kill a new type of tree: jack pine, which is a dominant species across much of Canada.
Six: “Jack pine is what we call a naive host. It means it’s one that the beetle hasn’t co-evolved with and so that tree has never had to evolve defenses against the beetle.”
Six worries that the pine beetle, which she describes as being the size of a mouse turd, “could destroy vast areas of jack pine forests across Canada, and eventually even move into eastern pine forests”.
Mother Jones in 2015, reported on Diana Six and her research on the mountain pine beetle. It is a fascinating read. They note that these winged beetles have been a part of culling sick trees for a very long time.
But due to climate change enhanced droughts and shorter winters, the insect has been able to kill billions of trees, and they are migrating eastward.
MJ describes this growing infestation as the “largest forest insect outbreak ever recorded, about 10 times the size of past eruptions. “A doubling would have been remarkable,” Six says. “Ten times screams that something is really going wrong.”
Mountain pine, spruce, piñon ips, and other kinds of bark beetles have chomped 46 million of the country’s 850 million acres of forested land, from the Yukon down the spine of the Rocky Mountains all the way to Mexico. Yellowstone’s grizzly bears have run out of pinecones to eat because of the beetles. Skiers and backpackers have watched their brushy green playgrounds fade as trees fall down, sometimes at a rate of 100,000 trunks a day. Real estate agents have seen home prices plummet from “viewshed contamination” in areas ransacked by the bugs. And the devastation isn’t likely to let up anytime soon. As climate change warms the North American woods, we can expect these bugs to continue to proliferate and thrive in higher elevations—meaning more beetles in the coming century, preying on bigger chunks of the country.
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A healthy tree can usually beat back invading beetles by deploying chemical defenses and flooding them out with sticky resin. But just as dehydration makes humans weaker, heat and drought impede a tree’s ability to fight back—less water means less resin. In some areas of the Rocky Mountain West, the mid-2000s was the driest, hottest stretch in 800 years. From 2000 to 2012, bark beetles killed enough trees to cover the entire state of Colorado. “Insects reflect their environment,” explains renowned entomologist Ken Raffa—they serve as a barometer of vast changes taking place in an ecosystem.
Typically, beetle swells subside when they either run out of trees or when long, cold winters freeze them off (though some larvae typically survive, since they produce antifreeze that can keep them safe down to 30 below). But in warm weather the bugs thrive. In 2008, a team of biologists at the University of Colorado observed pine beetles flying and attacking trees in June, a month earlier than previously recorded. With warmer springs, the beetle flight season had doubled, meaning they could mature and lay eggs—and then their babies could mature and lay eggs—all within one summer.
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That’s not the only big change. Even as the mountain pine beetles run out of lodgepole pines to devour in the United States, in 2011 the insects made their first jump into a new species of tree, the jack pine, in Alberta. “Those trees don’t have evolved defenses,” Six says, “and they’re not fighting back.” The ability to invade a new species means the insects could begin a trek east across Canada’s boreal forest, then head south into the jack, red, and white pines of Minnesota and the Great Lakes region, and on to the woods of the East Coast. Similarly, last year, the reddish-black spruce beetle infested five times as many acres in Colorado as it did in 2009. And in the last decade, scientists spotted the southern pine beetle north of the Mason-Dixon Line for the first time on record, in New Jersey and later on Long Island. As investigative journalist Andrew Nikiforuk put it in his 2011 book on the outbreaks, we now belong to the “empire of the beetle.”