A reduction in the extension of shoots should be noted and is a reliable clue that the tree's health has changed.
Deformed growth, mushrooms, and conks on the trunk should also be noted.
A dying of the canopy or individual limbs should be recorded as well.
Get recommendations from professionals on appropriate treatment when a problem is developing, or leave it in the hands of the professionals. If you are ever uncertain as to what should be done, it is best for the tree that you clarify the proper treatment before you implement your plan. For additional information, you can report your findings to your local ISA Certified Arborist, professional tree service or State Service forester for advice on possible treatment.