August Mentz (5 December 1867 – 5 November 1944) was a Danish botanist, peat extraction and moor reclamation expert and a pioneer in nature conservation.
Mentz studied botany at the University of Copenhagen under professor Eugen Warming. He was employed by the Danish Moor Reclamation Society ("Det danske Hedeselskab") from 1899 to 1923. In 1912 he defended his doctoral thesis on the “Current Vegetation of Danish Bogs and Swamps” (Mentz 1912). From 1923 to 1938, he was professor of botanyatRoyal Veterinary and Agricultural University. He edited two voluminous colour plate floras – ”Billeder af Nordens Flora” and “Vilde Planter i Norden”.
Mentz was chairman of the state advisory board on conservation (”Naturfredningsrådet”) 1925–1944. However, with his background in moor reclamation, he had a foot in both camps – utilitarianism and conservationism.