Finnish botanist, forestry ecologist and politician who was three times Prime Minister of Finland. Aimo Kaarlo Cajander made important contributions to the flora of Finland and north east Russia as well as to forestry education in his country. The son of a natural history teacher at a country school he was interested in botany as a student and fell under the influence of Johan Petter Norrlin, whose teachings he remained faithful to throughout his life. By the time Cajander was 19 he had already explored the Finnish flora to the extent that he was able to submit a detailed study of the plants of south-west Finland to the Societas pro Fauna et Flora Fennica for publication. Two years later he published another report on the eastern botanical boundary of Fennoscandia, showing that it was much further east than previously thought.
Over the years that followed Cajander undertook three major expeditions in Russia and Fennoscandia, on the first of which (1898-1899) he travelled through Karelia and down the Onega River in Arkhangel'sk with J.I. Lindroth. The second (1901) took him all the way to eastern Russia, where he explored 2,000 kilometres of the banks of the River Lena and the surrounding Taiga forests, producing an account of his findings which served as his PhD thesis. Here he became particularly interested in the patterns of forest communities, a topic he would study in greater detail later in life. The third was to the Torni and Kemi river basins in northern Finland where he researched species competition and the influence of ground moisture and sediment on plant communities.
In 1904 Cajander was named docent of botany but was soon tasked with the organisation of the forestry education system for the national government, for which he first had to take a courses at the Evo Forestry Institute (where he later began to teach) as well as study abroad. From these trips and various studies in the field of forest communities and exploitation, he published Ueber Waldtypen (1909), and important contribution particularly for its economic application. In it he espoused his theory of forest types, one on which the country's entire forest economy has been based since the 1920s.
Cajander taught silviculture at Helsinki University in their Faculty of Agriculture and Forestry between 1911 and 1934 and to aid his students published a two-part text book on plant ecology and geography (1916) and dendrology (1917). Later he also took on the role of general director at the Finnish Forest Research Institute (1918-1943) and, as a member of parliament, he served as Minister of Defence as well as Prime Minister of Finland (1922, 1924 and 1937-1939).
As well as his floristic and ecological work, Cajander also produced some taxonomic papers and named several vascular plant taxa. His herbarium was housed in the University of Helsinki's Department of Silviculture until it closed in 2000 and the material was moved to the botanical museum of the same university (H).
Sources:
T. Ahti and M. Boychuk, 2006, The botanical journeys of A.K. Cajander and J.I. Lindroth to Karelia and Onega River in 1898 and 1899
R. Colander, 1965, The History of Botany in Finland.
