Mysterious Bumpy Beech Bark

We have a mystery to solve–what causes bumpy bark on American beech trees? Most American beech trees have smooth, light gray bark. We’ve noticed stands and individual trees that have surface bumps on the lower part of the trunks. We don’t know the cause! It could be a pathogen, a stress response, or a genetic variant. For now, we’d like to understand how prevalent this is and the geographic range. There is a perception that it is not harmful to the tree, which we’d like to assess by looking at the fullness of the tree canopies after trees leaf out in spring. Don’t forget to tag your observations with “bumpy beech bark” if they have it!

How to identify American beech:
Bark: usually smooth and gray, often carved by humans in populated areas.
Leaves: bright green, elliptical in shape, and very soft underneath. Veins go to the leaf margin; extending into a small point that makes the margin look serrate. In winter, leaves turn tan and often stay on the tree–this is called marcescent.
Buds: Look for long, pointed buds to confirm your beech ID, especially in fall and winter (they are still developing in the spring and summer).
Fruits: small (1/2 inch), spiky husks on short stems split open when ripe and contain two small, shiny brown 3-sided seeds.