One strategy to enhance CO2 fixation is to increase the biological deposition of cellulose in woody plants, because cellulose which is the most abundant organic compound on the earth is made from CO2 through photosynthetic pathways in the walls of plant cells. Cellulose has a strong tendency to self-associate into fibrils which are not easily hydrolyzed, either chemically or biologically, and accumulate in the walls. Certainly, cellulose is a good biological sink for CO2 on the earth, but the mechanism of cellulose biosynthesis is still unknown (the cellulose synthase activity in vitro in higher plants has not been completely identified or defined by anyone yet, and its gene is unknown ). In addition, the cellulose biosynthesis has not only been identified and defined as chain polymerization but is also involved in a dynamism of cortical microtubule association during the developmental growth of woody plants. W e report here our lab update on cellulose biosynthesis in higher plants to improve woody plants by genetic engineering through studies on the biosynthetic mechanism.