Fungus? No in the sense that it is a disease. Fungi? Yes in the form of lichens and mushrooms, of which there are many different types. First thing you should know is lichens do no harm to the tree. Here is a link to more on lichens: http://msue.anr.msu.edu/news/what_are_lichens_and_what_are_they_doing_on_my_tree

The large number of other fungi however suggest that the tree is not in good health and is not growing well. Internal rot would be a possibility but the tree should be examined by a professional, namely a certified arborist, one who specializes in everything woody. He/she will want to see the whole tree, along with where and how it is growing, looking for injury or other causal situations. Arborist evaluations are not expensive and are usually quite informative. You could then plan a course of action or inaction based on professional information.  You can find one or more certified arborists in your zip code at www.treesaregood.com    Click on find an arborist.

Large numbers of bark mushrooms are cause for concern. Some rots can kill the tree.  Here is more on bark mushrooms.
http://homeguides.sfgate.com/mushrooms-grow-tree-bark-28272.html

Otherwise, there isn't anything else that you can do.  Good luck!