Smooth-barked trees, especially young ones, are sensitive to winter temperature extremes. Winter sunscald is caused by warming of the bark tissue during sunny winter days, followed by rapid freezing of the tissue at night. Frost cracks are caused by a similar temperature fluctuation problem that causes long, vertical fissures in the bark. Wrapping trunks of susceptible trees for the winter will help prevent these problems while also discouraging mice and rabbits from chewing on the bark.
Start at the base of the tree trunk. Go around the trunk 1 1/2 times and pin the wrap only (not the tree) with a nail (as you would a straight pin through the fabric) or use electrical tape to secure. Mound soil around the base of the trunk or push the tree wrap 1” down into the soil to help prevent rodent damage (see Figure 1). Continue wrapping up the trunk at a slight diagonal, overlapping 1/2” as you go (Figure 2) until you are up to the main branches (at least 4’-5’ above ground). Wrap snuggly, but not so tight that you don’t allow for some air circulation between the bark and the wrap. Lower side branches can be bypassed as you go above them (Figure 3). Pin with a nail or use electrical tape at the top as you did at the base.
If you have a serious problem with animals gnawing on the bark, add a hardware cloth cage around the trunk (not tight fitting) and/or use chemical animal repellents.
Unwrap the trees and remove all nails or electrical tape and protective cages in early to mid-April depending on when temperatures stabilize in the spring. Leaving tree wrap, cages, and/or fastening materials on the tree longer may promote other types of problems for your tree.
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