On Finnish Independence Day in December 2018, Finland’s first lady, Jenni Haukio, wore a dress made from birch trees. No, she wasn’t covered in bark and leaves. The garment was woven from fibers made using a process, called Ioncell, developed by Aalto University and the University of Helsinki. The process uses ionic liquids such as 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium acetate ([mTBDH][OAc]) to dissolve cellulose and extract it from wood pulp. The natural polymer is spun into fibers. Making fibers out of cellulose isn’t new. Viscose cellulose has been made since the 19th century in a cumbersome process requiring the harsh chemicals sodium hydroxide, carbon disulfide, and sulfuric acid. Ioncell, according to Herbert Sixta, a professor in Aalto’s Department of Bioproducts and Biosystems, is a simpler, closed-loop process with no chemical discharges. Aalto is building a pilot plant that will produce 10 kg of fiber per day when it opens