In February 1932, Perkins Coville of the United States Forest Service Department of Silvics estimated the tree's volume to contain of board lumber. In 1938, engineers of the Island Creek Coal Company estimated that the tree's trunk contained of board lumber. Following the tree's felling in 1938, it was estimated to weigh approximately . Various estimates place the tree's seeding sometime between 1354 and 1361 AD. Using borings from the tree, the Smithsonian Institution determined that the Mingo Oak was the oldest tree of its species. In September 1932, West Virginia state forester D. B. Griffin and Emmett Keadle, president of the Mingo County Fish and Game Protective Association in Williamson, used an increment borer to estimate the tree as having begun its growth around 1356, with a margin of error within 25 or 30 years. Blueprints and boring samples were given to the West Virginia State Museum in Charleston and to the Smithsonian Institution in Washington, D.C.  Ownership of the timber land around the tree was eventually acquired by the Cole and Crane Real Estate Trust, which leased the timbering rights to the North East Lumber Company. Under the lease agreement, the North East Lumber Company only paid for the lumber that it cleared from the land. The company found the Mingo Oak too large to cut down, and assessed that its removal was too costly to undertake. The Cole and Crane Real Estate Trust also leased out the land where the tree was located to the Island Creek Coal Company for mining. The land around the tree continued to be developed. A highway connecting Logan to Williamson, was built parallel to the Trace Fork of Pigeon Creek, opposite the Mingo Oak. While the tree had long been known for its size, the unique status of the Mingo Oak was not recognized until 1931, when John Keadle and Leonard Bradshaw of Williamson took measurements of the tree, and found it to be the largest living white oak in the world. Upon this finding by the two men, Cole and Crane Real Estate Trust and the Island Creek Coal Company agreed to make a joint deed conveying the property to the state of West Virginia. In late 1931, Emmett Keadle of the West Virginia Oil and Grease Company wrote a letter to Governor William G. Conley informing him of the tree's significance and the companies' willingness to lease the land to the state. Governor Conley responded to Keadle and suggested the companies convey the property to the West Virginia Game, Fish, and Forestry Commission.