The invention relates to a method for surface treating the surface of a metal. The surface treatment is performed in a surfacing chamber, using a surfacing material, which is formed of one or more compounds and possible additives, and in which the surfacing material is brought to a principally gaseous state, the surfacing material is led to the chamber, and the surfacing material is permitted to react with the metal surface being treated. The metal surface being treated is subjected in the chamber to a passing flow of the surfacing material, and in which the said surfacing material comprises compounds arising in dry distillation of deciduous-wood. The invention also relates to the equipment and surfacing material used in the method.