Much has been in the news lately about “exploding trees,” caused by the extreme cold temperatures. But is this something to be worried about?

Can trees explode?

The short answer is, yes, but it’s very rare. More likely is a loud popping noise caused when trees crack due to the expansion of water in the tree. This expansion can put pressure on the bark which eventually cracks, creating a loud pop.

Existing cracks can also become worse due to “frost shrinkage,” where the tree’s cell walls contract due to water loss. It is thought that trees that have had some past damage (such as from a mower or animal browse) could be more prone to cracking because of the already weakened tissues.

Trees suffering from “wetwood,” a bacterial disease also can be prone to frost cracks due to excess water in the affected areas.

What’s next?

Fortunately, as the temperature increases, the crack should shrink and eventually, the tree will be able to seal the crack, much like how it seals over pruning cuts. While the split will still exist inside of the trunk, new cambium layers will grow over it.

If you look at a cross-section of a tree that had a frost crack at some time in its life, you will still see the crack in the growth rings, but subsequent growth rings may be thicker – the tree’s attempt to prevent future issues.

What can you do?

Honestly, not much. Preventing other kinds of damage, such as mulch rings to keep mower and string trimmers away from the trunk and generally keeping trees healthy is the best way to prevent this kind of damage. Proper mulching (keeping mulch away from the trunk, i.e. not “volcano mulching”) also can help the tree better regulate moisture levels and soil temperature.

Wrapping trees is not recommended because of the issues that can cause. For more information on tree care, check out the University of Illinois Extension’s website. Also, check out the University of Illinois Extension Horticulture YouTube Channel for videos on tree care and other horticulture topics.

• Jamie Viebach is the University of Illinois Extension horticulture educator serving DuPage, Kane and Kendall counties. Viebach’s primary areas of expertise are native plants, landscaping, pollinators, and rain gardens.