MADISON — As a deep freeze heads our way, headlines and social posts about “exploding trees” are everywhere, and although it can technically happen, the less exciting headline of “cracking trees” is usually more appropriate.
According to the Wisconsin DNR, when it gets cold enough, the liquid sap inside trees can freeze. When this happens, the sap expands and puts intense pressure on the inside of the tree. If the tree can’t handle that much pressure, it physically cracks.
As you can probably imagine, cracking open a tree takes a lot of force. A loud cracking or popping noise often occurs when the physical crack forms. While these cracks can certainly be startling, a true “explosion” would be rare.
A large crack seldom kills the tree, but it can be an entry point for insects, bacteria and fungi that can contribute to eventual tree decline.
Property owners seeing a large crack in a yard tree are urged to consult an arborist to determine if there is a risk of the tree falling or dropping large branches.
