Hi Tom, thanks for the question.

This is a common occurrence on thin barked tree.  This is known as "Southwest" injury since it is most often found on the southwest side of the trunk. This is due to quick temperature fluctuations, usually in late winter.  White trunk guards are frequently used to help prevent the problem by reflecting the light and heating that leads to the cracking.  Cleaning up the wound, and bark tracing can help the tree heal properly.  Fertilizing the tree to stimulate growth can help.  Fertilizing past mid-summer should be prevented since late season growth can lead to more cracking.  Check out the following links for additional information and detail:

Frost Cracks and Sunscald on Trees | Home and Garden Education Center (uconn.edu)

Preparations to Prevent Southwest Injury (purduelandscapereport.org)

barksplitting.pdf (cornell.edu)

I hope this is helpful.