A: With vertical cracks in the bark along the trunk like that, I suspect those are frost cracks. These commonly happen in maples, which are thin-barked trees.

Missouri Botanical Garden explains how they happen better than I could. “[Frost cracks] occur when daytime sun heats the bark and underlying wood, causing tissue expansion. Then with a sudden, sharp temperature drop, the outer bark layer contracts , more rapidly than the inner layers. The difference in contraction is particularly severe where there is an injured area."

Frost cracks most often appear on the southern or western side of the tree, since that’s the side exposed to more full sun.

So what can be done? Naturally, as the weather warms in spring, the tree will try to callus over these vertical cracks. But in the meantime, the tree is prone to disease or insect attacks. Stay vigilant about monitoring for these stressors. Do not make an attempt to inject any product into these cracks.

©2025 Cox Media Group