Relationship between log and lumber modulus of elasticity

Past nondestructive evaluation (NDE) research efforts have paved the way for the successful use of NDE for determining the quality of finished wood products. However, little effort has been expended on developing nonvisual NDE techniques for use in grading or sorting logs for internal soundness and structural quality. This paper describes the results of a study that addressed this problem. Longitudinal stress wave NDE techniques were used to evaluate the quality of 193 balsam fir and eastern spruce logs prior to processing into lumber. Longitudinal speed-of-stress wave transmission was used to determine the modulus of elasticity (MOE) for each log. The MOE of each piece of structural lumber cut from the logs was then determined using transverse vibration NDE techniques. A strong relationship was observed between the MOE of the logs and the lumber obtained from the logs.