Fungus on Camellia tree
i have 4 Camellia trees, growing together, (each a different color) approximately 12 -15 ft. tall, trunks vary from 3-5 inches thick. There are several grey fungus pathces on many of the trunks, and branches. They are dry when scratched. Overwhelming majority of the leaves have correct color and shape. What is this fungus, and how do I treat?
Clackamas County Oregon lichen