Can you identify Gall or growth on oak tree(in photo)? Is it a concern and...
This is an oak or wool sower gall. It is formed as a reaction to a very tiny gall wasp (not one that will hurt you or the tree) who lays eggs on plant tissue. The gall forms to protect the wasps. No control is necessary. See the following information, http://www.ces.ncsu.edu/depts/ent/notes/O&T/trees/note05/note05.html