Scientists and architects across the globe are trying to adapt wood, one of the oldest building materials, for the demands of the modern city. Spurred by new ways to work with wood and concerns about the environmental toll of urban construction, they are trying to push the limits of height for wood construction and win wider acceptance for its use. Engineers have conceived designs for soaring wooden skyscrapers that, at up to 80 stories, would rival their steel-framed cousins. But wood's true potential for 21st century cities is likely to emerge in the lab, where scientists are conducting myriad torture tests on new designs for wooden walls, beams, ceilings, and floors. Their goal: to see whether wood can overcome concerns about fire safety and strength that, in the past, have consigned wood to low-rises and single family houses.