Jan 08, 2014 12:18 PM EST
Emerald Ash Borer A Positive Casualty Of 'Polar Vortex' 2014
*This story has been edited to reflect a change.
Besides cancelling school, the previous week's "polar vortex" may have created some other favorable results, this one in the field of entomology, or the study of insects. Scientists in the Midwestern regions where the emerald ash borer (EAB) is frequent hope at least some portion of the larvae of the invasive species died from the freezing temperatures, Minnesota's Winona Post reported.
Temperatures approaching an un-wind chilled negative 20 degrees in parts of Minnesota might have been enough to significantly damage the breed of insects responsible for gnawing the region's ash trees. A frustrating characteristic of invasive species, however, is their resilience; more than likely; some survived. The added protection of bark, which adds some warmth, also aided their survival.
"The bark of trees are pretty good insulators, and that's where the bugs are," Lee Frelich, director of the Center for Forest Ecology at the University of Minnesota, told the Winona Post. "It ranges usually anywhere from three to seven degrees warmer under the bark of a tree."
Though a negative 20 degree swing is capable of killing off 80 percent of the population, the freeze would have to last long enough (longer, presumably, than a few days) to counteract the bark.
"At -20 degrees, 79 percent of the EAB population would be expected to die," Frelich said. "But this would have to last quite a while because bark is a good insulator."
Still, a sizeable portion will likely submit to the cold, even if it isn't the 80 percent number in "ideal" conditions, according to Frelich. At below thirty, 98 percent of the population would perish, according to WUWM, a Milwaukee public radio website. (To a lesser degree, the insects have also infested Wisconsin.)
Perhaps ordinary Minnesotans wouldn't accept the type of conditions that have persisted over the last few days, but concerened entomologists like Frelich probably would, so bad is the EAB infestation. Ash trees are currently under quarantine in four Minnesota counties, including Winona's.
How greatly the "polar vortex" of early 2014 affected EAB populations will only be known in the spring, according to the Winona Post.
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