An experimental forest, or experimental range, as defined by the United States Forest Service, is "an area administered ... 'to provide for the research necessary for the management of the land.'"
According to the USFS, "Most Experimental Forests are large enough to contain significant stream systems and several dozen contain experimental watershed study sites with multiple paired basins." Individual experimental forests range from 0.47 to 225 km2 (120 to 55,600 acres) in area. Experimental forests are distinguished from research natural areas and intensive monitoring sites.
The present system of 80 experimental forests and ranges began in 1908. Many experimental forest are more than 50 years old. The system provides places for long-term science and management studies in major vegetation types of the 195,000,000 acres (790,000 km2) of public land administered by the Forest Service.