Measurement of heartwood moisture content of Sugi by the lateral impact vibration method: Comparison with data obtained from the moisture meter method and measurement of longitudinal distribution

Heartwood moisture contents of five kinds of Sugi (Cryptomeria japonica D. Don) were measured by lateral impact vibration, a non-destructive and convenient method. Moisture content values were also determined using a radio-frequency type moisture meter after cutting down the trees. The results are summarized as follows: 1) The relation between trunk diameter and the inverse of the frequency obtained from the lateral impact method yielded information on the existence and position of defects. 2) The moisture content values obtained by the lateral impact vibration method have mostly the same precision in comparison with the exact values obtained from the oven-drying method. 3) There are three different heartwood moisture content distributions in the radial direction and two different distributions in the longitudinal direction according to the oven-drying method. The longitudinal distributions were also obtained non-destructively by the lateral impact method.