Mechanical woodpulp (4701) is produced solely by mechanical defibration — grinding or refining — with no significant chemical pre-treatment. Semichemical pulp (heading 4705) uses a combination of chemical softening and mechanical defibration. If a pulp is produced by a combined process, it belongs in 4705 rather than 4701.

Newsprint mills, directory and catalog paper producers, and tissue manufacturers are the main consumers. Mechanical pulp's high yield and bulk make it cost-effective for high-volume, short-life print grades, though its lignin content limits use in premium printing and writing papers.