Green Fungus Killing Sweetgum Trees: Likely Lichen or Algae, Not Fatal

Mint-green coating on sweetgum trunks and branches that spreads tree-to-tree is likely lichen or algae—not a killer fungus. These grow on bark of stressed or slow-growing trees but don't cause death. Sweetgum decline is more often from root stress, borers, or cankers.

What to Do

• Check for tent caterpillars/webworms (common on sweetgum) and treat if defoliating.
• Improve tree vigor: water during drought, mulch, avoid trunk injury.
• Lichen/algae need no treatment; they indicate clean air and slow bark growth.

If trees are dying rapidly, consult an arborist for root/vascular assessment.