We now know how to care for evergreens in the winter to prevent needle kill. What about trees that lose their leaves? If there are winter thaws during January and February, this can cause frost cracks going down the trunk especially on newly planted trees and thin bark trees like red maples.
Frost cracks are caused by the sap beneath the bark to thaw and rapidly freeze again went the night temps fall. The moisture in the sap will explode causing a vertical crack going down the trunk. If you are close at the right time, you can hear the exploding crack. In the spring when the tree leaves out, this crack can cause a problem with the health of the tree.
Prevention is the main step in preventing this condition. Start by placing a mulch down after the ground freezes to prevent the soil from warming up in mid-winter. By not mulching until the ground freezes also prevents rodents seeking out the mulch as a home.
As the trees get mature and the bark thickens and the branches grow and start to shade the trunk, frost cracking becomes less of a problem. Especially for young trees like fruit trees and maples, wrap the trunk with paper or plastic spiral wrap (this is reusable year after year).