What are these green patches that I see on trees? - Ask Extension
On my walks through my neighborhood I have noticed an increasing number of trees that have green patches on them. Are these patches lichen and do they...
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What are these green patches that I see on trees? #765393
Asked August 02, 2021, 9:20 PM EDT
On my walks through my neighborhood I have noticed an increasing number of trees that have green patches on them. Are these patches lichen and do they harm the tree.
Baltimore City County Maryland
Expert Response
We notice algae, moss, and lichen on the tree branches. Algae and mosses grow in any moist shady site. They live on the tree bark without harming it. Here are photos and more information. https://extension.umd.edu/resource/algae-and-mosses
Lichen are non-destructive living organisms composed of fungus and algae and typically appear as gray-green patches on trees and shrubs. They are harmless. https://extension.umd.edu/resource/lichens
Marian
