A tree disease caused by the fungus Hypoxylon Atropunctatum.
Hypoxylon canker is a fungal disease that appears as a dead lesion on limbs, branches, and trunks of affected trees. The disease develops just under the bark and in advanced stages, causes a white rot decay of the tree bark. Because the disease decays certain parts of the tree, the structural integrity of the entire tree becomes compromised. Timber!
Sources: