This special volume of Acta Forestalia Fennica is published in memory of professor A.K. Cajander (1879-1943), who was one of the founders of the Finnish Society of Forest Science. It contains a short biography, a complete list of his literary works and one of the papers on forest types he has written.
This article contains professor A.K. Cajander’s paper on the theory of forest types in English. The article can be found in Finnish in separate PDF (article id 7695).
The idea of forest types was developed by professor Cajander first in 1904-1909, when he was working as a student in the Evo Forestry Institute. The first publication in 1909 was followed by intensive research and the findings of the investigations were published in 1929 in Acta Forestalia Fennica 29 (Metsätyyppiteoria, The theory of forest types).
When classifying forest growing sites, the purpose is to combine those having the same or approximately same yield capacity, and to separate into different classes those whose yield capacity is widely different. The article states that site quality classification is a necessity in organized forest management as it gives a basis for all forest calculations concerning with yield and profit. The principles of site classification and its meaning in forest management is discussed.