Splitting bark is due to death of the underlying cambium layer, often due to mid-winter cold damage one to several years ago.  Splitting opens the tree to infection by wood rotting fungi.  Sorry to say there is no effective remedy to this condition.  
Cold damage tends to be more of a problem if trees continue to grow into the late fall.   This is more common on rich and/or well fertilized soil.  Painting trunks with white latex paint when young helps to avoid trunk heat build-up on sunny winter days, which leads to abrupt temperature drop at sunset and subsequent bark cracking.