Rees Alfred Davis, horticulturalist, was the son of William E. Davis of Ficksburg, South Africa, and his wife Emma Davis, born Butler. He was educated privately and subsequently spent many years in California, United States, where he helped to start the first Cooperative Fruit Growers' Association. In 1898 he came to the Cape Colony to manage fruit farms for the British imperialist C.J. Rhodes. Shortly after the end of the Anglo-Boer War (1899-1902), in October 1902, he was appointed government horticulturalist and head of the Horticultural Division in the Department of Agriculture of the Transvaal Colony, a post he held until the formation of the Union of South Africa in 1910. He then became government horticulturalist in the Union Department of Agriculture. Within months of his first appointment he started a small fruit nursery in Pretoria and later tested the suitablility of various fruit trees at different experimental stations. In 1906 he was a member of the South African Association for the Advancement of Science, but his membership had lapsed by 1910.
Davis gained an international reputation for his research into fruit trees and published extensively, particularly on citrus growing. From 1904 to 1906 he wrote a horticultural section in the Transvaal Agricultural Journal. During the next four years he published more than 30 short articles in the same journal, dealing with fruit trees, fruit handling and related topics. Ten more similar articles by him appeared in the Agricultural Journal of the Union of South Africa during 1911-1913. In addition he produced several pamphlets and books: Fruit growing in the Transvaal (Pretoria, 1910, 19p); Citrus growing in South Africa (Cape Town, 1915?, 62p),with expanded editions in 1919 and 1924 (309p); A South African fruit planters guide, being practical suggestions for the fruit grower (Johannesburg, 1917?, 23p); and Fruit growing in South Africa (Johannesburg, 1928, 532p). During World War I (1914-1918) he was co-author (with Mary Higham) of a pamphlet entitled A plea for war time economy in South Africa (Johannesburg, 1917, 10p), issued by the South African National Union.
Davis resided in Johannesburg during 1924-1927, but spent his last years in Cape Town and Naboomspruit (now Mookgophong). He was married to Reba W. Davis, with whom he had four surviving children.