We have a sugar maple that is mature and appears to have something wrong this year. We first noticed cream colored mushrooms growing on the trunk and also noticed the leaves seems smaller this year and are turning and dropping at this point. In your opinion, is there any chance for this tree...do we need an arborist ASAP? Thanks.
Since this is the first you've ever seen or noticed the mushrooms on the trunk and smallish leaf size my inclination is that they are most likely both inconsequential indicators for the tree's general and long term health. This has been a very wet year and those are both symptoms typical of that climatic condition.
Its extremely doubtful that a mature sugar maple would be in mortal danger from anything short of mechanical damage (wind, limb breakage, impacts, etc) in such a short time span.
If you could provide a few pictures and describe the tree history, soil and setting in greater detail, we might be able to offer more assistance.