9 February 2025

On a walk in Hays Woods on 2 February, Linda Roth and fellow hikers found a few severely damaged trees with long vertical cracks in their bark and trunks. What made the trees split like this?

One of the most common reasons for cracks and splits on tree trunks is cold temperature. Frost cracks are caused when the inner and outer wood in the tree’s trunk expands and contracts at different rates when temperatures change. This happens when winter temperatures plummet below zero especially after a sunny day when a tree’s trunk has been warmed by the sun. The different expansion rates between the inner and outer wood can cause such a strain on the trunk that a crack develops.

— Missouri Botanical Garden: WHat causes cracks and splits in tree trunks

January’s weather was extreme enough to cause the damage. It was 43°F on the 18th, then plummeted below zero a few days later.

Frost cracks occur suddenly, can be several feet long, and are often accompanied by a loud rifle shot sound. They often originate at a point where the trunk has been physically injured in the past. Maples and sycamores are the most prone to frost cracks. Apples, ornamental crabapple, ash, beech, horse chestnut and tulip tree are also susceptible. Isolated trees and trees growing on poorly drained soils are particularly prone to frost cracks.

— Missouri Botanical Garden: WHat causes cracks and splits in tree trunks

You know it’s cold when the trees crack and explode. According to Wikipedia, the Sioux and Cree called the first full moon of January “The moon of cold-exploding trees.”

But no one was out in Hays Woods on those extremely cold nights so no one heard the sound of exploding trees.