Quick winter temperature changes can damage trees

Frost cracks are vertical cracks in the stems of trees. On sunny winter days bark will warm up, causing cells to expand in the bark and wood directly below the bark. As the sun sets, temperatures drop quickly, causing the bark to cool and contract. The wood under the bark does not cool as quickly, causing the bark to split.

Frost cracks may first appear on very young trees that have not developed a thick layer of bark. The south and southwestern side of trees are most susceptible to frost cracks. Once damaged, the injured area can split back open on very cold, winter days.


The south and southwestern side of
trees are most susceptible to frost cracks.