Machine Stress Grading Revisited

With New Zealand’s adoption of the random location testing standard AS/NZS 4063:1992 and the move to shorter tree rotations and younger age at clear-felling, the effectiveness of current machine stress grading(MSG) procedures is questioned. A known and reliable relationship between strength and stiffness forms the basis of any MSG operation. This relationship has deteriorated making the prediction of strength implicit in an MSG operation often unreliable and inefficient in terms of grade recovery. Options for improving the effectiveness of MSG on young radiata pine are examined.