The expensive, energy-intensive process of turning wood into paper costs the pulp and paper industries more than $6 billion a year. Much of that expense involves separating wood’s cellulose from lignin, the glue that binds a tree’s fibers, by using an alkali solution and high temperatures and pressures. Although the lignin so removed is reused as fuel, wood with less lignin and more cellulose would save the industry millions of dollars a year in processing and chemical costs. [...] By genetically modifying aspen trees, Dr. Vincent L. Chiang, professor of forest biotechnology, and his colleagues have reduced the trees’ lignin content by 45 to 50 percent - and accomplished the first successful dual-gene alteration in forestry science.