Cherry streaks

Q: I just purchased some cherry and it is full of small dark streaks. What are they and are they found in one area of the country more than another?

A: What you are seeing are called gum spots or streaks. These spots or streaks are typically about 1/16-inch wide and ½-inch long (or a bit longer). They are common and are associated with the activity of a peach bark borer and other insects or injuries that damage the cambium layer in the tree. Sometimes, dark streaks will extend several inches down from the gum spot. Almost all grading rules (lumber, veneer, plywood) allow a number of these spots without lowering the grade. Although one site may have more damage than another nearby site, I have not noticed or heard that one area of the country has more or less of these character marks.

Two items of concern: When a finish is applied, it may not be able to bridge over larger gum spots and streaks; thus the finish may appear to be defective. Once in a while the gum may exude from these larger spots or streaks after the finished product is put into use. The gum cannot be removed during manufacturing and cannot be "set" the way that pitch is set in softwoods.


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Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.