Everything I've read says that lichen doesn't hurt the tree but only grows on unhealthy but that was the funny thing because it grows on bricks, my clothes line, stones. I'm glad to hear that it's not necessarily unhealthy trees because I have 3 of them. But never any blossoms. I've made sure to get ones that blossom at the same time. Someplace I read where it said two Northern Spy won't pollinate each other, whick is why we got a third kind that supposedly blossoms at the same time. This year I had beautiful blueberry and black berry bushes but y strawberry and raspberries kind of went to the wayside as my mother has been so ill since last August.Lichen is not an indicator of health-- nor do they harm the tree. The actually don't absorb nutrients at all from the surface they grow on. The are an indicator of good air quality-- though most of us don't live urban enough to worry about that too much, I think.
Lichens of this type indicate two things: The air is clean and that area is getting a lot of sunshine.
People think that lichens only attach to unhealthy trees-- not so. It attaches to all things, as you have observed. It only seems to grow in great abundance on live wood that either: gets a lot of sun (such as broad horizontal branches of large mature trees), or if the branch is already in decline, reducing the amount of foliage and therefore allowing the lichen to get more sun.
I know this does not necessarily help you but lichens are often misunderstood.
By the way, this looks like perhaps Wax Paper Lichen, or Hammered Shield Lichen.![]()