AbstractThe potential of sulfurous acid prehydrolysis followed by chemical pulping was examined at the laboratory scale using radiata pine. The residue obtained by sulfurous acid prehydrolysis with base addition was sufficiently delignified in a subsequent soda pulping stage, while the delignification of the residue was completely insufficient in subsequent kraft pulping. The residues prepared by prehydrolyses of hydrochloric and sulfuric acids were not delignified sufficiently regardless of the pulping method. The yield of hemicellulose-derived monosaccharides was about 90% on a theoretical basis in the optimal sulfurous acid prehydrolysis. In subsequent soda pulping under various conditions, pulps with kappa number 21 to 34, pulp yield 37 to 41%, and high cellulose content could be prepared from the residue obtained by sulfurous acid prehydrolysis with base addition. It was suggested from these results that sulfurous acid prehydrolysis with base addition in combination with subsequent soda pulping is an effective method for the utilization of wood hemicelluloses.