1 Iritis is uncommon, but can be due to trauma, infections, or autoimmune conditions. Symptoms include pain, red eye, and often, decreased vision.  Optic neuritis. The nerve travelling from the back of the eyeball into the brain can become inflamed.
Oak root fungus, or white rot, is a widespread disease that becomes visible just beneath the bark and on roots. What looks like layers of light brown to tan mushrooms form in clusters at the base of the trees.
Tree fungus is damaging to trees and typically a sign that a tree is under stress or has been wounded. Tree moss, on the other hand, is not always damaging to trees unless it becomes too thick or heavy. Managing both fungus and moss can be difficult. Fungus, in particular, is best managed with preventative measures such as proper tree care.