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.
Abnormal growth on twigs, branches or trunk. 6. Seepage of sap on bark-with or without an odor. 7. Insects on branches and leaves. Presence of a caterpillar type worm indicates insect infestation. 8. Mushroom type growths on lower base of tree trunk, or even in the ground, near the tree base.