Moisture content and discoloration of wood during dry and wet storage of Norway spruce (Picea abies (L.) Karst.) pulpwood

Changes in sapwood moisture content (MC wet-base), depth of brown discoloration in the outer rings, and the occurrence of bluestain in spruce pulpwood were studied during 12 weeks of storage. Three different treatments were evaluated: wet storage by two different sprinkling intensities and unprotected dry storage. The results show that the importance of the sprinkling intensity increases with storage time. Both sprinkling intensities were sufficient to keep the MC above the 50% level, while dry storage caused rapid drying-out. The results also imply that there might be a contradiction in the choice of relative sprinkling intensity. The high sprinkling was enough to prevent bluestain in the logs, while the low-sprinkled and dry-stored logs were affected by bluestain after about 8 weeks of storage. Yet the high sprinkling intensity caused significantly deeper brown discoloration than the other storage methods. The results also indicate that the high sprinkling intensity maintains a more homogenous distribution of the MC than the low sprinkling intensity and the dry storage.