Pretreatment of lignocellulosic biomass for cellulose ethanol production requires that material be reduced to small sizes, so that the cellulose molecules are more accessible for processing. The method of size reduction ("chopping or shredding") has been found to have some effect on cellulose accessibility and the quantity of energy input. This could also ultimately affect the cost of cellulose ethanol production.  Dennis Buckmaster, Associate Professor of Agricultural and Biological Engineering at Purdue University (United States) reports that shredding (rather than chopping) corn stover allows better access of cellulose and consumes 40% less energy. According to Buckmaster, "shredding corn stalks increases the surface area of the plant material. Since stalks can be shredded along the grain of the plants, like splitting a log with an axe, it takes less energy." The complete results of the study are published in the Transactions of the ASABE (American Society of Agricultural and Biological Engineers) (URL above)..