by North Central Forest Experiment Station (Saint Paul, Minn.)

1991

by North Carolina State College. Agricultural Experiment Station

1894

by Minnesota Agricultural Experiment Station. North Central Experiment Station (Grand Rapids), A. J. McGuire

1919

by North Carolina Agricultural Experiment Station

1921

by North Carolina. Department of Conservation and Development

1928

by North Central Forest Experiment Station (Saint Paul, Minn.).

1966

by North Central Forest Experiment Station (Saint Paul, Minn.)