Stump the Forester: Christmas Lichen

QUESTION: What’s growing on my tree?

ANSWER: I’m lichen it! The red and green circular patches have a striking resemblance to a Christmas wreath, earning the name Christmas lichen, or Cryptothecia rubrocincta. The bright, festive colors can make any tree, at any season, a Christmas tree.

Lichens are formed from a complex, symbiotic relationship between a fungus and an algae. The fungus provides structure for the photosynthetic algae. The Christmas lichen is common throughout Florida and the Southeastern United States. It is frequently found on cypress, oaks, and Sabal palms. The lichen typically grows on the rough bark of trees in shaded and moist habitats.

The Christmas lichen is no Scrooge. Yule be happy to know lichens do not harm trees. They are not parasitic like mistletoe. Similar to orchids, ferns, and moss, the lichens are biologically harmless epiphytes. They use the bark surface to grab and grow. Their presence is merely cosmetic. If a tree is showing signs of stress, decline, or waning health, the lichen is not the culprit. Reach out to a consulting arborist or local tree care provider to have the tree’s health and site conditions properly assessed. The Christmas lichen’s vivid red and green pigments can be year-round and can be the spark of curiosity, making any walk in the woods a most wonderful time of year.

Answer provided by Joe Anderson – Utility Forester, ISA Certified Arborist, FUFC Board Member