tree fungus?

[kinger]

We live in western PA and have recently noticed a light green mold growing on the trunks of our trees. It seems to be affecting every tree: sunset maple, oak, weeping cherry, flowering crabapple, etc. The weeping cherry tree has a branch of yellow leaves (dying) and the leaves on the oak have some small holes in them.

What to do?!

 

[texasnative]

Is it mold or moss? It would help alot if you posted a picture.

 

[NYCHA FORESTER]

Lichens

http://www.earthlife.net/lichens/intro.html