Lichen on a tree trunk
Lichen on a tree trunk

Although a bit intimidating to look at, lichens are a symbiotic combination of a fungus and algae that appears mainly on older trees, but also occasionally younger trees. Lichens are also found growing on rocks, houses and tree stumps. The appearance of lichens may actually be a good thing, as it indicates the air quality is clean enough to support their growth. Over 20 years ago the air quality in Illinois and throughout the Midwest was so poor it was very difficult to find lichens growing anywhere. Recent actions to improve our air quality have helped lichens return.

Larger, older trees are more likely to have lichens growing on branches and the trunk and this is a natural occurrence. If a younger or smaller tree has a large amount of lichen growth, this may be an indicator of other problems. Lichens don’t cause the problem, but can signal other issues of concern. Large amount of lichen growth on a younger, smaller tree may indicate that the tree was planted too deeply, the roots are being strangled or the tree is suffering from a disease or insect infestation.

See lichens? The appearance of lichens is not usually a reason for alarm. If there is heavy lichen growth on a younger, smaller tree it may indicate other problems. Call Kramer Tree Specialists to have a certified arborist investigate the “root” cause.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.