Q: We have some hickory lumber that has some darker colored splotches under the surface. We notice this color variation only after we plane the lumber. If we plane it several times, removing more wood, the splotches go away. It is not cost effective to make 1/2-inch thick pieces out of 4/4 lumber, however. What do we have?

A: Hickory is one of the species that develops variations in color during drying when the lumber is dried at different rates. These color variations seem to be most objectionable when the lumber comes from stored logs rather than fresh logs. Lumber exposed to rain also seems to have these stains more often than lumber that is protected from direct rainfall. Prompt drying at an acceptable drying rate immediately after sawing fresh logs (and no air drying) will eliminate the problem in the future.

Several people associate this defect with anti-sap stain treatments. I cannot confirm this relationship, but it might be wise to avoid them too!