Well, in the area you live in trees get wrapped to prevent them from cracking (and killing the underlying cambium layer) in the early spring as things warm up. It is called sunscald but the way it was explained to me was the predominantly west side of the tree gets warmed up first and the sap will start flowing again after winter dormancy. A freeze comes along and freezes the sap expanding and killing the cambium leaving the bark split and dead underneath (and susceptible to pests/disease).

Painting the tree white has the same effect---keeping the sun from heating up one side of the tree too early.

Here is a link that might be useful: search coop exts wrap tree trunk