Yes, it appears to me that what you have is some type of lichen. Lichens are not harmful to the trees. However, while lichen does not harm the host plant, its presence might be an indicator that the tree or shrub could be under some kind of stress.

Lichens are actually two organisms, a fungi and algae. There are thousands of types of lichens made up of various fungi and algae.

The following links may be of help to you:
https://www.canr.msu.edu/news/what_are_lichens_and_what_are_they_doing_on_my_tree

https://www.canr.msu.edu/news/what-s-that-growing-on-my-tree

https://pubs.nmsu.edu/_h/H167/

If you continue to be concerned, you may find it helpful to consult a Certified Arborist.
We suggest Certified Arborists because they must pass a test and must acquire continuing education. You can locate such individuals at http://www.treesaregood.org/findanarborist/findanarborist.aspx