Bark splitting on trees and shrubs is commonly caused by alternating cold freezing temperatures and warmer thawing temperatures during the winter. In Colorado much of this damaged is caused during the winter when our intense sun causes the tree or shrub bark to expand during the day. These cracks are usually on the south or south west side of the trunk. The trunk will try to heal over these splits. It might cause permanent damage if the split interferes with nutrients and water traveling up and down the trunk. However many trees recover well from trunk splits.

Alternating dry and wet conditions can also cause or exacerbate stem splits.

You might try to prevent further damage by using tree wrap on the trunks from late October removing it in the spring. Do not leave tree wrap on the trunk during spring and summer. Also be consistent in watering the trees during the summer and during periods of low moisture during the winter when the ground is not frozen and the temperature are above 40 degrees. Here are some fact sheets to review: https://cmg.extension.colostate.edu/Gardennotes/653.pdf

https://extension.colostate.edu/docs/pubs/garden/07211.pdf