Quarter sawn lumber is cut roughly parallel to the radius of the log. It shows growth rings with an angle of 60-90 degrees. These rings will appear vertical on the face of the board. In oak, you will also see light stripes—called flake—from the tree’s medullary rays, which carry nutrients from the center of a tree to its outer layer.
Rift sawn lumber is cut showing growth rings with an angle of 30-60 degrees. These rings will appear vertical on the face of the board. Because of the reduced angle, flake does not appear on the face.
Plain sawn lumber is cut parallel to a line through the center of the log. It shows growth rings with an angle of 30 degrees or less. On the face of the board, growth rings appear in a cathedral pattern.