Shelf fungi appearing on the trunk of a tree are usually indicative of an interior rot. I would get an arborist skilled in pathogen diagnosis out to look at your tree. There is really nothing you can do and generally by the time you see the fungi appearing, the rot is too far advanced to save the tree. Be prepared to remove and replace it. But find out what is causing the problem first.......it may not be advisable to replant in the same area.

Bummer...thanks for your reply!