Why did the bark split?

[capetrees]

Kwanzan Cherry, about 8" caliper, been planted for at least 10 years maybe a few more, seems health, just about to bud out, never seen any bugs, no abnormal watering or fertilizing. Don't even know when it happened but it's in the last year for sure. Heartwood looks dry, split edges seem healed.

Any ideas why it split?

 

[DR. P. Proteus]

I believe its some kind of fungal infection which causes the splitting and cankers.