Longitudinal splitting of bark along the trunk of young trees is a common problem during winter. The problem is more severe on the south and west side of saplings and is caused by the sun-beams striking the tender bark. It sets up a huge temperature difference between internal sapwood under the bark (hot) and the external environment (cold).
The big change causes the sapwood to desiccate, shrink and die. The outer bark eventually cracks along the fault line of the dead sapwood. As the picture shows, the best way to prevent winter bark splitting or sun-scald is to place light-colored tubing around the trunk of the trees. The white tubing will prevent the heat build-up by reflecting the rays of the sun away from the tree. You can also use white latex paint as an alternative prevention.
