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.
These rhizomorphs (root-like structures) can grow for several feet through soil from stumps to nearby trees and from tree to tree. This is very unusual for a fungus since most fungi remain relatively dormant in soil unless a host plant is very near. The rhizomorph invades a tree at the buttress or upper part of the root system.