Bark peeling away on Japanese cherry (Amanogawa)
Last summer (2018) was hot for very many weeks and sap started to come out on the west side of my Amanogawa - this attracted ants, who began to gnaw on the bark (I saw bark dust on the ground). Once I got rid of the ants and temperatures cooled down, the tree bark didn't look too bad - see the photo. Over the winter and now into spring (2019), I had hoped the bark would heal, but it seems to be splitting open and getting worse - see the next two photos. I have seen no insect activity and there has not been any damage by tools, etc. The last two photos perhaps look worse than they really are because the tree was wet from rain today. I can provide more photos if permitted. The leaves are nice and green and the branches look fine. Help! I do not want to lose this beautiful tree.
Washington ornamental cherry
It's not unusual for the bark of young cherry trees to split when exposed to extreme heat, and the fact that it's on the west side of the tree would point to an environmental factor. The split isn't a problem by itself. The wound is vulnerable to infection. I can't tell if your tree has bacterial canker by looking at it. Look at the articles I've sent you below. If you are still unsure of how to proceed, you can call your county's extension service, and they can help you to send in a sample for a free diagnosis at our WSU Plant Pathology lab. Another option is to call a certified arborist. You can look for one in your area here: https://pnwisa.org/hire-an-arborist/isa-certified-arborist-directory/
This article is about what to do about bark splitting: http://plantclinic.cornell.edu/factsheets/barksplitting.pdf
And the other is about bacterial canker on ornamental cherry trees http://hortsense.cahnrs.wsu.edu/Public/FactsheetWebPrint.aspx?ProblemId=481