Splitting trunk on weeping cherry
Answer
Fruit trees are very susceptible to frost cracks or bark splitting due to the fact that they have thin bark. These are caused by drastic temperature fluctuations, especially in the winter, or by warm sun on the tree in the winter time. This past winter was a devastating one, especially in your area. The good news is that these splits tend not to be fatal to the tree. But management is crucial to prevent an invasion of insect or disease damage. Some sources suggest using a paper wrap to wrap the lower part of the tree, thus giving the trunk some extra winter protection. But here is a link to a fact sheet from Cornell which provides good information about bark splitting, as well as providing a more specific and authoritative procedure which will promote healing.
http://plantclinic.cornell.edu/factsheets/barksplitting.pdf
Good luck.