bottom of oak turning black
We have a tall oak tree that I am worried about. While the leaves and such look ok, the bottom of the tree is turning black. Butterflies are landing on it I assume sucking up the sap and such and hornets seem to be making homes inside cavities in the bark. Some of the bark is loosening up and I fear the tree is dying. Any advise if great appreciated as I am very concerned. (I can take pictures if that would be helpful).