Abstract. Biomass utilization for bio-energy, bio-fuels or bio-based products requires reductionof the material size within specific ranges depending on feedstock specie, handling and further processing / conversion processes. Biomass size reduction is a mechanical treatment process that refers to either cutting or comminuting processes that significantly change the particles size, shape and bulk density of organic material.The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASABE meeting paper. EXAMPLE: Author's Last Name, Initials.