As the United States moves to a low-carbon economy in order to combat global warming - first at the state level and eventually through a national program - credits for reducing carbon dioxide emissions will increasingly become a commodity that is bought and sold on the open market. Farmers and other landowners can benefit from this new economy by conducting land management practices that help sequester carbon dioxide, creating credits they can sell to industry to "offset" industrial emissions of greenhouse gases. This guide is the first comprehensive technical publication providing direction to landowners for sequestering carbon, and information for traders and others who will need to verify the sequestration. It will provide invaluable direction to farmers, foresters, land managers, consultants, brokers, investors, regulators, and others interested in creating consistent, credible greenhouse gas offsets as a tradable commodity in the United States. The guide contains a non-technical section detailing methodologies for scoping of the costs and benefits of a proposed project, quantifying offsets of various sorts under a range of situations and conditions, and verifying and registering the offsets. The technical section provides specific information for quantifying, verifying, and regulating offsets from agricultural and forestry practices.