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Lichens on Trees: Harmless Indicators of Stress, Not Disease

Gray Patches and White Spots on Tree Bark? They're Likely Lichens

Lichens are symbiotic organisms (fungus + algae) that grow on bark of stressed or slow-growing trees. They don't cause decline—they're a symptom of it.

What to Do

Focus on improving tree vigor: water during drought, fertilize if needed, avoid trunk damage. Lichens will diminish as tree health improves. See this bulletin for more.

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