Remember how cold it was this past winter? You know, the freeze that felt like it was never going to end.
Our deeply frozen state had so much snow pack that it contributed to historic flooding when the thaw finally came.
One silver lining, some national news outlets reported, was that the widespread bitter cold was helping to kill of the invasive emerald ash borer (EAB). The ash tree-killing pest was first discovered in Nebraska in July, 2017.
So, did that happen? Are our trees safe?
Unfortunately, the answer is “no,” according to the Nebraska Forest Service (NFS).
“Most insects have ways of staying alive during the winter, and EAB is no exception. They burrow deeper into the tree for the winter months and also produce anti-freezing compounds in their bodies that help them survive, the NFS reports.
So, while extreme cold can kill off some of the bugs, we’d have to go through more than one tough winter to really see results.
“We’d have to be in a much more prolonged period of extremely cold weather to see it make an impact with EAB,” said Mike Norris, a utility forester with Omaha Public Power District.
Norris is on the Nebraska EAB Task Force and has been working to educate property owners about the threat posed by EAB.
“They’re responsible for either treating their ash trees to try and prevent an infestation, or removing them entirely,” Norris said.
Ash trees are extremely popular in Nebraska. They were heavily planted to replace trees lost to Dutch elm disease some 40 years ago. As a result, there are thousands of ash trees in proximity of power lines within OPPD’s 13-county service territory. When ash trees succumb to EAB, they can collapse onto those power lines or anything else in their path.
“Diseased trees are a threat to not only electric service reliability, but even more importantly, to safety,” Norris said.
Unfortunately, our bitterly cold winter won’t be much help in preventing the spread of EAB, which has been known to destroy 70 percent of ash trees within four years of its first appearance in an area.
“The majority will have survived and will reproduce as normal this season. This trend was also observed in 2014 with the polar vortex that hit the East. Even though temperatures were in theory cold enough to kill EAB, it did little to slow them down.”
The best thing we can do is treat or remove ash trees, and plant a variety of trees to replace those lost, Norris said.
“With a larger variety of trees, our area will not be as vulnerable to canopy loss as we have been in case a particular species succumbs to bugs or disease.”
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