All our shivering hasn’t been for nothing.
Deep inside as many as 1 billion trees in Minnesota, a destructive pest, the emerald ash borer, is riding out the winter by producing chemicals in its body that act as antifreeze. However, as the Minnesota Department of Agriculture reminded bundled-up Minnesotans in a statement last week, when temperatures drop to 30-below zero, 98% of the borer’s larvae die. At minus-10, 34% perish, the state agency found by monitoring infested logs.
So, let it be cold.
"These temperatures are not going to wipe out the population, but would set it back and buy a few years of additional life for ash trees," as Lee Frelich, director of the University of Minnesota Center for Forest Ecology, told the News Tribune two Februarys ago when temperatures also plummeted for a prolonged period. "The extreme cold in the interior of northern Minnesota, like negative-50 at Kabetogama and negative-56 at Cotton, with negative-40 occurring every few years, is probably cold enough to keep the pest at bay.”
The emerald ash borer is a big concern in Minnesota because we have so many ash trees, and they have little or no resistance to the imported pest. We have the largest concentration in the country. An estimated one in five trees in Minnesota’s woods are ash trees. In addition to out in the woods, thousands of ash trees line Duluth’s boulevards. Many urban areas lined streets with ash trees as a replacement for Dutch elms, which were decimated by Dutch elm disease in the 1980s.
The ash tree-killing beetles originated in China, hit the U.S. in the early 2000s, and arrived in the Twin Ports by way of Superior in 2013, the News Tribune has reported. They moved onto Park Point in late 2015 and emerged near Hartley Park in the fall of 2016. The city has placed ribbons on ash trees along streets in Congdon, Morley Heights, Hunters Park, Woodland, and other neighborhoods to call attention to the presence of the pest ahead of those trees being removed or treated.
Last year, Duluth was one of 25 Minnesota communities given a grant from the Minnesota Department of Natural Resources to combat emerald ash borer. The money was for tree inventories and ash removal. Duluth received $92,400.
This year, Duluth is joining lobbying efforts for additional funding to help local governments remove and replace infested trees and to develop markets for products resulting from wood waste.
Since firewood moved into our region from elsewhere is the likeliest way the emerald ash borer got here and then spread here, “We need to be vigilant,” the Department of Agriculture warned last week. “It is best to buy wood right where you are, and avoid transporting firewood to another part of the state.”
Also, for the trees, it doesn’t hurt to keep cheering for super-cold weather. While we shiver, we can take solace in knowing that a pest of a problem is being frozen out.