I have a fun entry to the exception to the topping rule. I have a diseased sycamore that was really struggling. The disease was primarily at the top of the tree. We were going to cut it down to prevent neighboring trees from being infected or the tree from falling. The cutting company had a “hold my beer” style suggestion that topping it would bring the tree back. Boy did it. It’s flourishing with new branches from the cut and beautiful coverage. The fungus hasn’t come back and I’m not worried about it dying and falling on my house. Everyone wins!