We have a very large Maple Tree in our front lawn aprox 10-20yrs old. Last Fall it seemed to drop all its leaves very early and now this spring/summer it has hardly leafed out. I hate for this tree to die! Can't find any form of fungus or anything growing on it. I do have many Hosta's planted around it as it did give us lots of shade. Not this year

You haven't given us anything to go on. Call an arborist.