Science & Nature
Exploding Trees: Legit Cold-Weather Danger or Overblown Hype?
(Volha Zhukava / iStock)
Exploding trees have taken the country by storm.
With huge swaths of the U.S. under winter weather warnings of one form or another, it seems everyone’s suddenly worried about the potential for stressed trees to spontaneously combust. And it’s not just TikTok influencers fanning the flames of hyperbole, even CNN has reported on the phenomenon.
WTTW News spoke with Sharon Yielsa, a plant knowledge specialist at the Morton Arboretum, to separate fact from fiction.
So are “exploding” trees a real thing?
Yes and no, Yielsa said.
It is indeed possible for trees to split apart in extreme conditions and to do so quite noisily, she said, typically when there’s a big swing in temperatures. In these instances, sap rapidly freezes when the mercury plummets and the tree expands, its trunk or limbs busting open like the buttons on a too-tight shirt after Thanksgiving dinner.
But in her 40 years as a horticulturalist, Yielsa has never seen this happen. Not during recent polar vortexes, and not even on the day some years ago when the temperature fell 50 degrees in a 24-hour period.
“This has been blown out of proportion,” Yielsa said of the hysteria, no pun intended.
What’s more likely to happen is something called “frost cracking,” which is a fairly common occurrence in the Chicago region, she said.
Frost cracks, she explained, are vertical strips — almost like a zipper — that open in trees when the bark expands, say on a day when it’s warmed by the sun, and then contracts quickly. The bark cracks under the strain of attempting to tighten over a core that also expanded but is cooling more slowly.
There aren’t really any preventative steps people can take. Trees are pretty resilient and will heal these cracks, Yielsa said. But keep an eye on slits that don’t close, she added, as these can create openings for pests or diseases.
Young fruit trees and young maples, which have thinner bark, are among the most susceptible to frost cracks.
In terms of winter weather damage, ice storms are a far greater concern, weighing down branches until they snap. And if you really want to see a tree reduced to flying shrapnel, well a lightning strike might do the trick, Yielsa said.
Overall, Yielsa said she considers the sudden obsessions with exploding trees — misinformation and all — a healthy distraction. Minimally, she said, it’s gotten people talking about nature.
“There’s a lot of cool stuff going on outside,” she said.
Contact Patty Wetli: [email protected]
