The effect of the dielectric properties of adhesive and wood on heating selectivity of test pieces was analysed. The experiment was carried out in 2 phases. First the influence of temperature (22-80 °C) and frequency (79.4 kHz-25.1 MHz) on the dielectric properties of liquid PVA adhesive, and the influence of frequency on the dielectric properties of beech wood (Fagus sylvatica L.) were measured. The measurements were performed with the Agilent 4285A Precision LCR Meter and the according test fixtures. In the second phase test pieces were made and heated indirectly and directly (HF). The test pieces were heated in a press, and the growth and distribution of temperature in the boards were monitored. It was determined that by increasing the temperature the dielectric properties of the adhesive increase. Adhesives have considerably higher dielectric properties than wood, and therefore, heat faster. The differences in heating were more obvious in early stages of heating. No differences in speed of indirect and direct heating were found.