Rift sawn lumber is typically narrow with a very straight grain pattern on the face of the board. Rift sawn lumber is usually used with oak to avoid the flecks that are common in the species. The annular rings or a rift sawn board are about 30-60 degrees to the face of the board, but 45 degrees is the most optimum. Similar to quarter sawn lumber, rift sawn lumber is also referred to as radial grain. The most stable boards, and also the most wasteful to produce, are rift sawn planks. Each of these boards is cut radially perpendicular to the growth rings of the tree. There are large triangles of waste left from between each board. As a result, rift sawn lumber is costly to produce and therefore, the most expensive type of planks available from a log.