Abstract
In order to investigate the influence of wood moisture content on Pilodyn driving depth, immersion testing was conducted using a small log of larch (Larix kaempferi) timber with a diameter of about 17-21 cm. Three states of wood moisture content―raw material, saturated and air-dried―were investigated, and the variation in the mean value (μ) and standard deviation (σ) was examined by measuring the driving depths at approximately the same location. As a result of fitting a histogram of the relative frequency of the driving depths with a probability density function, the measured values were found to be normally distributed for the three states. The value of μ increased by about 2.0 mm when the state changed from raw material to saturated, and decreased by about 4.8 mm when the state changed from saturated to air-dried. On the other hand, σ was 1.4-1.7 mm and no significant dependence on state was observed. Among the three states of moisture content, the variation in driving depth was not immediately noticeable, so when measuring driving depths on site, it is necessary to carefully evaluate the wood moisture content.
