Forests are a source of numerous benefits to society, including clean water, wood products, and a more recent consideration that was published this year in the journal Proceedings of the National Academy of Sciences—soil carbon sequestration. Forests currently offset about 10 percent of the nation’s greenhouse gas emissions, and reforestation is necessary for maintaining this offset. Replanting after disturbances such as wildfires is critical, but other opportunities for reforestation include allowing forests to retake marginal croplands. A team of researchers from the Northern Research Station and the University of Michigan has creatively used more than 15,000 previously collected soil measurements from several large databases to quantify the soil carbon benefits of reforestation and forecast its future. The study delivers the first empirically based, published estimate of the total amount of carbon currently accumulating in the topsoil of U.S. forests undergoing reforestation—about 10 percent of the entire U.S. forest carbon sink. The gradual soil carbon increase during reforestation adds up: from 13 to 21 million tons of carbon are added to reforesting U.S. soils annually in a trend likely to continue for decades. Soil and its capacity for storing carbon could help to slow climate change, increase soil productivity, and protect the Nation’s water supplies.