Density compensation for moisture measurements in wood

Abstract

A dielectric model for moisture measurement is described. It uses physical parameters that may be obtained through measurement or from published data, and one fitting parameter. For three species of timber, it demonstrates good agreement with published data. An alternative method for incorporating density compensation into TDR measurements of wood moisture content within the harsh and highly variable conditions of a drying kiln is described. For the purpose-built TDR-based measurement system, calibrating for gravimetric moisture content, an R-squared value of 0.96 was obtained from 147 data points, with a range of wood dry density from 0.4 to 0.5 g/cm3. For the density component alone, an R-squared value of 0.5 was obtained from 93 data points, with a range of wood dry density from 0.4 to 0.5 g/cm3.