Why is this topic important?

Is there a optimal time to look for serious problems? What do I look for?
bladder gall on maple
                                                    Bladder gall on maple, a disfiguring but minor disease

What serious problems can be seen? What inconsequential problems affect maples? Where can I get more information?

Miller, H. C., and S. B. Silverborg.  1973.  Maple Tree Problems.  Syracuse NY: SUNY ESF.  (To order, call 315-470-6644)  George Hudler, 1984.  Diseases of maples in eastern North America.   For other information, advice and help on this topic, call offices of your State Urban Forestry Coordinator or University Extension service, visit urban forestry web sites.