One strategy to control the spread of mountain pine beetles in Banff National Park sometimes does the opposite, a study by a University of British Columbia researcher shows.
While pheromone baiting followed by tree removal — purposefully attracting the pests to a tree, which is then cut down in winter when the larvae are trapped inside — can be successful where there is a dense population of beetles, the strategy can increase the number of beetles in some areas of the Canadian Rockies, according to mathematical modeling led by Rebecca Tyson, an associate professor of mathematics at UBC’s Okanagan campus.
“What our study found is that where the beetle population is low, the pheromone is actually attracting more beetles and thus helping the beetle population increase,” said Ms. Tyson, whose research was recently published in ScienceDirect.
In these areas, the beetles have a hard time finding each other, she said. Additional pheromone, placed by humans, can help attract enough beetles to attack the baited tree.
“With pheromone baiting, this means that humans have put strong signals in the forest that help the beetles find each other. They can then collect in sufficient numbers to attack a tree,” she said. “In these situations, baiting is making things worse for the trees.”
Ms. Tyson described the mountain pine beetle as an endemic pest capable of killing entire stands of mature pine. While the beetle has a short lifespan, climate change and warmer winters have helped the population increase during an epidemic that began in the late 1990s.
The two-year simulation compared four strategies: no management (monitoring only), pheromone baiting, tree removal, and pheromone baiting combined with tree removal. Other management methods are prescribed burning and clearcutting, which Ms. Tyson said cause severe changes to the landscape and have not been proven to stop the spread of the beetle.
The study found that removal of beetle-attacked trees in the absence of baiting is the most successful strategy if managers are able to locate areas with significant pine beetle activity.
According to Ms. Tyson, an adult beetle emerges from a tree each summer and looks for a new one where it will nest. Once selected, the beetle emits a pheromone to attract other beetles to the same tree. Other beetles then arrive, release more pheromone, and the tree is attacked as adult beetles drill into the bark and make tunnels where they lay eggs. By the following summer, the larvae have hatched and turned into adults, and that tree is dead, with the needles turning red. The cycle continues as the beetles move to a neighboring tree.
Under normal population control circumstances, when a tree is baited with pheromone, it is cut down in winter when the larvae are trapped inside, Ms. Tyson said. Crews also search for other trees near the baited one, and all trees identified to contain beetles are removed.
“If all goes well,” said Ms. Tyson, “the beetle population is so severely reduced that it dies out.”
However, her models indicate that pheromone baiting is not working as expected.
“From the field work done in Banff, we know that baiting didn't stop the beetle epidemic,” she said. “Baiting may have slowed it down, but it did not stop it.”
Tyson was aided in her research by then-Ph.D. candidate Shaun Strohm and University of Calgary professor Mary Reid.
Comments
Thats were you are wrong. Following the path of AGW hysteria will cause us to lose much.
In the past, yet their "model" says it did happen in the past. The events didn't change, just the study. And this still doesn't address the question regarding differing elevations being attacked at the same time.
EC, if you could point out where in their study they say it happened in the past that'd be helpful. What I see is the authors stating that, "During the latter half of the last century, there has been a substantial shift in climatically benign habitats for mountain pine beetle northward, and toward higher elevations."
More so:
As for different elevations being attacked at the same time, I don't think their paper was intended to answer that question. But still, if there are large stands of mature lodgepole down low for the beetles to feast on, and similar stands up high where the beetle population is expanding into, why wouldn't that be possible if not even logical?
Kurt, they cited a 2001 study that said there was no apparent impact from climate change. They then applied their model to the same time frame that the 2001 study covered.
EC, and you don't think it's possible that using a new analysis could produce a different outcome? Obviously, as the bulk of their report states, they have reached a different conclusion.
Yep multiple studies, multiple different conclusions. But the science is settled. Riiiight. Just shows if you want to reach a conclusion looking backward you can always build a model to get there. Its the model looking forward that counts. And so far, those predictions have been horribly worng.
Even with these "different conclusions", I don't see any explaination of simultaneous attacks in dramatically different nearby elevations.
I am no scientist, but attacks at different elevation would always happen. The but the higher elevation would only happen if it is warm enough for the insect to survive and procreate. Also it is important to note that elevation is relative to how far north or south you are. For example...the elevation for tree line is different in Rocky Mountain N.P. than it is in Glacier N.P and even lower in Banff....and varies by how far you are from the coast. The spread of the beatle could be impeded by rivers, rock ridges, wind direction, maybe even roadways. It is also possible that the beatle could mutate and be more adaptable to colder or warmer enviroments than in the past...unless you do not believe in Darwin... LOL
I'm not talking about different latitudes. One example was Yosemite Park where Sugar Maples withint 5-10 miles of each other are being attacked at the same time despite 4,000 of elevation difference. The second as here in Summit County where we see the same phenomenon. And Yosemie is substantially warmer than Summit County but is being attacked years after Summit County. And since the beetles have now left here, does that mean our climate is cooling?