Hello, I have a mature Japanese maple tree with a trunk width of 15+ inches. Over the past 6-8 months the bark around the base of the trunk is splitting apart. I've inspected (as best I can) and wasn't able to see any sings of disease or insects. The leaves and canopy seem otherwise healthy. Do you recommend any treatment to the splits/cracks to stop further damage and proved protection to heal the current splits?
Your tree might have a bacterial or fungal disease. Slime flux (yeast) and bacterial wetwood are two possible problems that might be occurring in the trunk. There isn't really anything you can do to treat it. There is no "cure." We do recommend removing the mulch from the base of the tree so that it doesn't touch the trunk. Mulch right up on the trunk can create an ideal environment for crown rot. Keep the tree well watered during hot, dry weather. That's really all you can do.