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Debarked samples from three wood species (Spruce, Douglas-fir and Pine) and Douglas-fir bark were treated with saturated steam at 220°C for 5min. The objective was to quantify physical and compositional properties of the treated biomass that would affect on the degree of carbonization (torrefaction) of softwood particles. The resulting data indicated that the calorific value increases as a result of steam treatment; the highest increase was 26.0% for Spruce, from 18.7MJ/kg to 23.6MJ/kg. The corresponding carbon content of the treated Spruce increased from 46.5% to 57.0%. The equilibrium moisture content of the treated wood, placed in a chamber at 90% relative humidity and 30°C air for 180min, dropped from around 0.103 (decimal dry basis) (before treatment) to about 0.045 (decimal dry basis) for Spruce treated particles. Bulk density of Spruce particles increased the most from 87kg/m³ to 129kg/m³ after …