Both Ruth and Gail wrote to me about the spiral bark I saw on a tree in the woods. When Gail said it was a target canker, a “fungus that attacks red maple trees. The bark grows in circles as a defense, ” I had something to google.
When I did I found a blog called New Hampshire Garden Solutions that had more information. The writer of this blog got her information from Cornell University.
She wrote….“A fungus invades healthy bark, killing it. During the following growing season, the tree responds with a new layer of bark and undifferentiated wood (callus) to contain the pathogen. However, in the next dormant season the pathogen breaches that barrier and kills additional bark. Over the years, this seasonal alternation of pathogen invasion and host defense response leads to development of a ‘canker’ with concentric ridges of callus tissue—a ‘target canker.’”
She goes on to say that over time the fungus gives up and the tree will continue to grow. As the tree grows the circular pattern disappears into the regular bark.
Thanks for your help in figuring this out Gail and for your input Ruth.
