A certified arborist should assess the decay. If the decay is severe, the tree should be removed. If not, keep watch on it and reassess every three to five years. Branches break off because of poor branch structure and weak angles. Or thin out branches to that distance.
Wider angles make stronger branches.
Lightning struck the tree and blew off bark. If more than one-third of the leaves die, remove the tree,'' says MacNair. Don't use tree paint and don't fertilize. Watering a large area around the tree may help. For majestic, valuable trees, consider lightning protection such as a framework of aerial rods and wires connected to a grounding rod placed near the tree.