Two urea-formaldehyde adhesives, one resorcinol-based adhesive, and one with poly(vinyl acetate) were tested with spruce and beechwood. The least suitable was found to be the urea-formaldehyde adhesive containing 1.5 wt. pts. of ammonium chloride. The conductivity ratio, i.e. the ratio between the specific conductivity of the adhesive and wood multiplied by the thickness of the adhesive layer, expresses the suitability of a given wood adhesive system for dielectric heating; it depends upon the dielectric heating frequency. This method of heating is widely used in the wood-processing industry to accelerate adhesive setting. -- AATA