Lichen. It is a symptom of slow growth, not the cause of problem.

lichens are on every tree in my yard... and none of them are growing slow because of them ..

consider it a free show of ma nature.. and an indication that nature is in harmony with itself ... [they wouldnt be there if pollution was high. ... i think]

ken

Lichens and Spanish moss are on most of my trees. Many birds use both for their nests and the trees don't seem to suffer.

Rhonda

Thank You all for the insight.