Q: My Kwanzan cherry tree has splitting bark then the limb dies. No visible pests. What is your opinion?

A: I see two smoking guns. In the first picture there is a hole that looks like it was formed from a stub being left when a limb was pruned from the tree. The tree could not heal over the stub, so when it finally rotted and fell away a hole was left…a perfect entrance for rainwater. The water introduced rot and now the whole limb is rotten and dying.

The second picture shows where a large limb was removed. No stub was left but the wound was simply too large to heal over. Water has already begun rotting the center of the wound. This big limb will die eventually.

There is no good way to fix the holes. Sealants are never 100% effective. They usually allow water to seep in around the edges, which continues the rotting process.

You could try making a rain-proof shield above the damage to keep the area dry…..but I don’t hold out much hope.

Enjoy the tree while you can. I don’t expect it to live much longer.