Good Morning, 

Thank you for contacting the U of M Extension Service. 

No photos was included, so I am guessing here. If the crack faces the south or southwest, it may be a crack from the snow reflecting on the trunk of the tree in winter. Please click on the following link from the U of M Extension Yard and Garden website: https://extension.umn.edu/planting-and-growing-guides/protecting-trees-and-shrubs-winter#sunscald-1263860

If the crack is only in one spot on the trunk, it will probably survive. You might consider protecting the tree as the information states, for the winter. 

Here is another link about tree care: ttps://extension.umn.edu/how/planting-and-transplanting-trees-and-shrubs#mulching-1401311

You might consider adding a layer of wood mulch a few inches away from the trunk of the tree, in a circle a few feet out from the trunk. This mulch will protect the tree and keep the soil moist and cool. 

Good Luck!