After drying a load of 4/4 red oak lumber (mixed quartersawn and flatsawn) I realized that the quartersawn boards took much longer to dry. Is it the orientation of the growth rings that caused the slower drying in the quartersawn lumber? Do quartersawn boards from other species typically dry slower than flatsawn boards of the same thickness and species?
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
When drying flatsawn lumber, some of the moisture can move along the ray cells (which run radially in the tree and therefore run across the rings, from face to face in flatsawn lumber). These rays assist in drying. In q-sawn lumber, the rays are running from edge to edge and so provide little assistance in drying. The difference will be about 15% in hardwoods. In softwoods, with less ray volume (rays are smaller), the effect is much less.