@lauralorax For trying an answer, can you please tell more about your photo? Which region of the world? Are you sure that you photographed lichen, not moss? Is it a coniferous tree? Unfortunately, I can't zoom enough into the photo to decide it.
@NatureMC hi! This was in the Tahoe National Forest in the US. The tree is a conifer. I'm not great at identifying conifers but I'm fairly certain it wasn't a pine, although some of the other affected trees may have been, I don't remember. It was definitely a lichen and not a moss; it looked like wolf lichen to me. This growth pattern was present on multiple trees. I did notice that the bands of lichen seemed often to be present at the level of a branch. Here's another photo:
