Hello

Thanks for contacting us.  The cracks in your trees' bark are frost cracks.  They typically occur in maples which are thin barked.  It especially occurs on the south facing trunk and is caused from the bark freezing in the winter and then, during sunny days, that bark tissue heats up and expands, thus causing the bark to crack.

Unfortunately, there is nothing you can do to 'fix' this bark now.  If you have newly planted trees, you can wrap them to help prevent this.  You do have to remove the wrap each year.  Or, in the case of apple trees, their trunks are often painted with a white latex paint to help reflect the sun's winter rays.

Here is an MSU Extension article that explains more about frost cracks:  https://www.canr.msu.edu/news/frost_cracks_in_trees