A Quick Summary of Timber Strength Grading
The future of timber grading
There is no reason, other than cost, that prevents new test data updating these grading assignments, or adding assignments for other UK grown timber, but with the new generation of portable and lower cost grading machines, it may well make more sense to use a machine assisted visual grading process, to improve yields and assignments. Slovenia has recently introduced a simple grading machine - “STIG” - based on a tablet computer and microphone, which measures the frequency a piece of timber makes when struck with a hammer. This is essentially all that acoustic machine grading involves, and since this is a kind of measurement of the timber’s stiffness, it is usually a more powerful grading predictor than knots, ring width and slope of grain.
Dr Daniel Ridley-Ellis (BEng, MRes, PhD) is Head of Centre for Wood Science and Technology at Edinburgh Napier University.