Q&A – What is this growth on my magnolia? -Lichen

Question:
What is this growth on my sweet bay magnolia?  Is it harmful? 

Answer:
It is lichen. The lichen is not harming the tree. Lichen is a relationship between an algae or cyanobacteria and a fungus. Lichen grow on dead tissue, in this case, the bark. Lichen can be a symptom of a tree problem, but in this case, it looks like it is not.

Related Resources:
Tree-Dwelling Lichens
Lichens on Woody Shrubs and Trees
Lichens and Vines on Trees