Prevention of non-microbial sapwood discolorations in hardwood lumber: chemical and mechanical treatments
T L Amburgey, S Kitchens
Sapwood discolorations in hardwood lumber that are non-microbial in origin result from the formation of pigmented starch-like granules in ray parenchyma cells. These discolorations can be prevented by treating unseasoned lumber with an antioxidant (sodium bisulfite). Exposing unseasoned lumber to microwaves or treating logs with fumigants also will prevent these discolorations. Subjecting unseasoned lumber to mechanical stresses (compression and/or vibration) also prevents sapwood discolorations of non-microbial origin. A machine to mechanically stress lumber and thereby prevent these discolorations has been built and is being field-tested at cooperating sawmills.