Hello As you know, frost cracks are vertical cracks in the wood of trees. They may arise from a previous injury on the tree, such as a nick from a weed wacker or where an animal gnawed on it. I’m attaching an article from Michigan State Extension that describes the process and how to treat it. https://www.canr.msu.edu/news/frost_cracks_in_trees As you can see the treatment is best cultural practices. If you have more questions about how to deal with the trees, I suggest that you contact a certified arborist at http://www.treesaregood.org, the website of the International Society of Arboriculture to find one in your area.