Help me identify this green stuff on my trees

+40
Answered
This green mold/algae looking stuff is all over my Japanese maple. I've discovered it on the bark of some other trees as well. Does anyone know who I would take a piece of tree bark to in order to identify what it is?
q help me identify this green stuff on my trees, gardening
q help me identify this green stuff on my trees, gardening
  37 answers