I'm not sure if thats a fungus at all -I obviously can't tell the size of it from that pic, but tinder fungus tends to not grow to a huge size.
There is a chance its a burl - which is like a knotty lump of wood growing on the side of the tree, at a place of damage to the tree. These are often covered in moss/algae and are hard. If its tinder fungus, you should be able to cut it off with a knife, and also cut into it - if its a burl, it will be harder than the underlying wood.