Next time you’re out for a hike in the woods, if you’re brave enough to step out into these frigid temperatures, you might here some loud pops and cracks. And no, you’re not imagining it. The concept of exploding trees has been circulating as temperatures around the region have reached windchills of minus 25. But can trees actually explode when temperatures get to be this extreme? Exploding is a little bit of a dramatic description, according to Graeme Davis, a forester with the County of Simcoe. The bark can certainly pop and crack though. The way it works is living trees have sap that move up and down the trees and when the region gets a fast, cold freeze, sap can freeze in some cases, Davis explained. When that freezing happens, that can cause the cracking and splitting of bark. “They can be quite loud cracks – there’s no question about that,” Davis said. He said native tree species, trees that grow naturally in this area, are well acclimated to the conditions and have evolved to withstand relatively cold winter conditions. But trees that tend to have thinner bark like ash trees and Norway maple trees are not as well suited to the extreme cold conditions and there could be splitting in these cases, Davis explained. People may even recognize the sound from their own backyard. “If you have a new deck, there can be moisture in the lumber which will then crack,” Davis said. That crack would make a popping sound, just like the sound a tree could make. According to Davis, the moisture in the lumber is freezing and then expanding, so there must be some give and that’s when people would hear a popping sound. He explained it’s often going from one extreme to the other where the likelihood of the sound would happen. “If we had a night that plummeted to minus 30 in early December, you would have more frost cracking, but by mid January that would not be the case,” Davis said. He said, however, it is entirely possible some trees could have bark splitting from frigid weather. The sap could freeze and expand adding some pops and cracks to the soundtrack of a winter hike.
