Identifying Lichen vs. Disease on Maple Trunks and Managing Frost Cracks

Identifying Lichen vs. Disease on Maple Trunks and Managing Frost Cracks

Maple trees have white spots on trunk and splitting bark. Woodpecker damage also noted.

White Spots = Lichens

Lichens are harmless, epiphytic, and indicate good air quality. They don't harm the tree.

Bark Splits = Frost Cracks

• Maples have thin bark; rapid temperature swings (winter sun → night freeze) cause vertical cracks.
• Extreme heat can also cause splitting.
• Some varieties are more resistant.

Management

• Do not wrap or paint cracks.
• Protect young trees with white trunk wrap in winter.
• Maintain vigor (water, mulch, fertilize) to promote callusing.

Woodpeckers are after insects, not damaging the tree. Lichens are cosmetic.