Institute for Transportation

Traditionally mechanically graded lumber has been produced
from 2-inch-thick lumber from softwoods. However, there is increasing interest in using hardwood dimension lumber for structural applications, and procedures have been proposed for the mechanical grading of both softwood and hardwood structural timbers. Research has shown that mechanical grading offers improvements in grading efficiency over visual grading for hardwood dimension lumber and softwood and hardwood structural timbers. Two-inch thick lumber produced from hardwoods can be mechanically graded using the currently available equipment and procedures that are used to mechanically grade softwoods. It has also been demonstrated that there are no technical barriers to bar the development of standardized mechanical grading procedures for structural timbers. This article discusses extending the mechanical grading process to dimension lumber produced from hardwoods and the possibility of mechanically grading structural timbers of softwoods and hardwoods.