TY - JOUR T1 - Detection of Decay in Trees With the Metriguard Stress Wave Timer JF - Arboriculture & Urban Forestry (AUF) JO - JOA SP - 374 LP - 378 DO - 10.48044/jauf.1993.058 VL - 19 IS - 6 AU - Claus G. Mattheck AU - Klaus A. Bethge Y1 - 1993/11/01 UR - http://auf.isa-arbor.com/content/19/6/374.abstract N2 - The Metriguard Stress Wave Timer measures the time needed for a stress wave to pass from a hammer blow to a sensor on the opposite side of the stem. A calculated sound speed will indicate decayed or hollow spots within the stem. A table of velocities for healthy trees is given and also some examples showing cross-sections of trees containing defects together with the measured velocities. ER -