When forests are logged, managed or selectively trimmed so they'll be less susceptible to raging fires, there are usually huge piles of stumps, branches and other wood debris left laying on the ground. Now a group of researchers at the University of Washington in Seattle is developing a portable technology to turn these waste piles into treasure troves by converting them into biochar—charcoal made from plant material that can be burned for energy or applied to soils, where it helps plants grow.