If the crack is long, deep, and narrow, running up and down the tree trunk, the tree has a 'frost crack'. Frost cracks usually appear on the south side of the tree trunk but it can occur on any side. Young trees or trees with smooth bark are usually most likely to develop these cracks. Once a crack occurs, not much can be done. Adding fertilizer may help the tree grow faster and thus close the crack more quickly.

Warm winter sun is the cause of frost cracks. The sun warms the trunk and the tissues expand, sudden cloudy or colder weather, or even sunset, cools the tissue and the tissue shrinks or contracts. The difference in contraction rates causes the outer trunk to crack from the inside out. The best prevention method is using tree paper wrap. Wrap the tree, starting at ground level, all the way up to first main branches. Along with preventing frost cracks, the wrap is good for helping to keep critters and lawn mowers from damaging the bark. Fruit trees can be painted with white, latex paint, which reflects the sunlight and prevents the trunks from cracking.