Homer LeRoy Shantz, American plant physiologist and ecologist, was awarded a Bachelor of Science (BS) degree in botany at Colorado College in 1901 and the PhD degree in botany at the University of Nebraska in 1905. From 1908 to 1926 he worked for the Bureau of Plant Industry, United States Department of Agriculture, in Washington DC. During this period he travelled widely in the American West, Latin America, Europe and Africa, making documentary photographs of the natural vegetation wherever he went. In 1911 he published 'Natural vegetation as an indicator of the capabilities of land for crop production in the Great Plains area' in the Bulletin of the Bureau of Plant Industry. Other publications by him dealt with soil moisture and the wilting coefficients of plants (1911, 1912, 1913, 1925), drought resistance (1927), the vegetation of various parts of the United States (1906, 1911, 1914, 1924, 1925), the water requirements of plants (1911, 1913, 1914), and related topics.
After two years as head of the Department of Botany at the University of Illinois Shantz became president of the University of Arizona in 1928. He resigned in 1936 to serve as chief of the Division of Wildlife Management of the United States Forest Service until his retirement in 1944. Later he was associated with the Geography Branch of the Office of Naval Research to re-photograph many of the sites he had documented earlier in his career.
During 1919-1920 Shantz toured through Africa collecting plants, photographing the vegetation, studying the natural plant resources, and assessing the agricultural potential of the continent. During the first half of 1924 he undertook an expedition to eastern Africa. He published his results in The vegetation and soils of Africa (with C.F. Marbut; New York, 1923; dealing with the soils of South Africa on pp. 142-154) and in 'The agricultural regions of Africa' (in nine parts) in Economic Geography (1940-1943).
In 1956, accompanied by Dr B.L. Turner of the University of Texas, he once more toured the continent, starting in Cape Town in August and reaching Tanzania in January 1957, on his way to the Sudan. He re-photographed the vegetation at the same sites as during his first visit, in order to document the changes that had occurred in the natural vegetation since 1919-1920. Both his first and second series of photographs were published in Photographic documentation of vegetational changes in Africa over a third of a century (with B.L. Turner; Tuscon, 1958).