I have a ten year old ginkgo tree that appears in good health; tall and straight with many healthy leaves. It is in full sun and is not crowded by other plants/trees. There are growths on the bark that look like lichens. I am in need of guidance on this one! Thanks Al
Morgan County West Virginia
Lichens are not harmful to the tree. They are not parasites. Here's some info on lichens: https://ohioline.osu.edu/factsheet/plpath-gen-12
Hope this helps.