Rare pressure pops in ring porous trees can occur during extreme temperature swings.
With winter weather swinging dramatically in parts of the Midwest, some residents have begun asking about a seasonal oddity known as “exploding tree season.” While it may sound like folklore, experts say there is a scientific basis behind the idea—though true explosions are highly unusual.
According to Julie Crick, natural resources educator with Michigan State University Extension, sudden and severe drops in temperature can create enough internal pressure inside a tree to cause loud cracks or pops. “It is possible for trees to ‘explode,’ but it is rare,” Crick says. “To explode, a tree experiences a wild temperature swing from near freezing to bitterly cold very quickly.”
Crick notes that Michigan recently saw a temperature drop of nearly 30 degrees in a short period. However, because the days leading up to it were already well below freezing, trees were less vulnerable to a flash freeze that could cause extreme pressure-induced cracking.
Why Some Trees Are More Susceptible Than Others
The reason certain trees make loud popping sounds in extreme cold comes down to their internal structure.
“Trees can be characterized as either ring porous or diffuse porous; the difference lies in the size of the cells that transport water as the tree is actively growing,” Crick explains. “Ring-porous species can be oaks, hickories, elms, and catalpas.”
Ring porous species contain larger water carrying vessels, making them more prone to internal pressure when sap freezes rapidly.
“Ring porous species are more likely to pop in the bitter cold weather due to the large size of the vessels,” she says. “While this may cause cracks or breaks in the wood vessels, it generally does not cause a tree to explode.”
In most cases, the result is a sharp crack, not an explosion—often startling, but rarely dangerous, and usually something the tree can recover from.
How Exploding Trees Happen (and Why It’s Rare)
For a true “explosion” to occur, the following conditions must line up:
- The tree is near the freezing point (with sap still unfrozen).
- A sudden plunge into bitter cold happens within a very short time.
- There is water or sap trapped inside the wood.
- The expansion of freezing water creates enough internal pressure to split the trunk.
Because these conditions rarely exist simultaneously—especially for already frozen trees—the phenomenon is more myth than yearly event.
Can It Be Prevented?
Crick says prevention is extremely limited.“Bottom line is that while trees can explode, it is rare and occurs under the right weather conditions,” she says. “Ring porous species will create a startling pop, but they will recover. There isn’t much that can be done to prevent this from happening.”
For landowners, the best approach is simply understanding the science behind the winter pops—and knowing that their trees are likely to be just fine afterward.
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