Forest Service, agency of the U.S. Department of Agriculture, established in 1905. The broad function of the service is to provide for the conservation and best use of the forest resources in the U.S. The service manages the national forests and national grasslands in 44 states, Puerto Rico, and the Virgin Islands. Responsibility for the more than 77 million hectares (about 191 million acres) in the National Forest System is divided among nine regional offices. The service conducts research in forestry, the use of forest products, and wild-land management, through eight regional forest and range experiment stations and the Forest Products Laboratory at Madison, Wisconsin. In addition, the service provides technical and financial assistance to state agencies and private landowners to promote scientific forest-management practices. Forest rangers are responsible for the management and protection of districts of national forests.