Maple tree bark fungus
We have a newly planted Maple tree. It has light green patches on the bark. They are easily scratched off. The patches have small round cells in it. They are about 1/32" round. What is this? Is it harmful? And how to treat it if it is harmful? Can you reply to Oakhaus3@hotmail.com
Certified GKH Gardening Expert
This could be something as simple a lichen forming on the trunk or more serious diseases.
These articles address these issue. You may need to do some further inspections of the tree; the trunk and leaves to help may a correct identification and then how to treat the issue.