Question
My Maple tree is distressed for the 2nd year.....it has tiny spikes embedded in the leaves and the follage is getting sparse.

Answer
Bruce:
From your description, these tiny spikes on the leaves are probably a type of plant gall caused by a mite or tiny wasp, it is called a "maple spindle gall".  These have little if no overall significant impact on tree health.  I suspect your stressed tree is from another cause and this is just incidental. If you live in the U.S., consider contact your local county Agricultural Extension office to talk about having a house call so someone could evaluate your tree in person. Another option is to contact your local garden center/nursery about this.

Steve