stress wave timer
(decay detection)
Instrument to measure the time taken for a shock wave, initiated with a hammer blow, to travel from one sensor to another attached to the outside of a tree stem, pole or piece of timber. The speed is affected (among other things) by internal defects. Stress wave timers (such as the Metriguard) have wide application in the quality control of sawn timber.
This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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