Evaluation of Moisture Content of Sugi Logs Using Impedance Measurement

We developed a method for evaluating the moisture content of sugi logs using an impedance measurement to categorize the effective wood-drying process. The patterns of moisture content distribution in a trunk were found to affect the impedance frequency dependence. For example, in case of high moisture content of heartwood, we observed that the impedance values are constant with increasing frequencies and the phases are constant at about 0
^o
with increasing frequencies. In contrast, with the high moisture content of heartwood, the case of low moisture content of heartwood showed that the impedance values decreased with increasing frequencies and the phased are constant at about -90
^o
with increasing frequencies. We estimated the distribution of moisture content in a log using an electrical impedance measurement method. Classification of the wood according to its moisture content is important for improving the wood-drying process and for efficient conversion into timber. We suggest that the frequency behavior of impedance and the phase angle could be used to classify the moisture content distribution in a log using three models in a series connected to the two-parameter model based on parallel resistance and capacitance.