Hi, 

We're not sure exactly what caused this. Does the canopy look healthy? Do you notice any other signs of stress to the tree? Feel free to send in additional photos of the canopy in a reply email.

We can see a gridling root at the base that is wrapping around the trunk. It could be that the tree is dying on that side and the bark is cracking as it is drying out, but the moisture that is trapped under the bark is causing adventitious roots to grow. 

Another possibility is that it could have cracked from a repeated freeze/thaw pattern which can happen to the bark on many trees. The opening and cracking is causing roots to grow. The roots will dry as they are exposed to the air though- we have seen this happen on cherry trunks before, oddly enough. 

In our region and in urban/suburban settings, flowering cherry trees tend to have a lifespan of about 25-30 years so it could be reaching its pinnacle. 

You could consult with an arborist or licensed tree expert to see if there is anything that can be done (unlikely though). They may suggest root pruning where the girdling root is, if it is not too late, but it may not add much more longevity to the tree. 

You can search for a professional to assess the situation and feel free to consult with us again based on their recommendations. 

ISA Certified Arborist: https://www.treesaregood.org/findanarborist

MD Licensed Tree Expert: https://dnrweb.dnr.state.md.us/forests/tree_expert_search.asp

If the tree doesn't have a sentimental value and the end up giving you a quote that is above you're budget, we would recommend enjoying the tree for as long as you can and have it removed if it becomes a safety concern. 

You can review our Ornamental Cherry Diagnostic Page to watch out for other symptoms or issues that may arise due to the cracked bark. 

Emily