The article discusses the different methods to classify forest sites and applies the methods to classify forests in Latvia. The three methods are: height-over-age classification, from standpoint of floristic (botanical- plant geographical standpoint), and forest types. A good classification method must: describe the main characters of a site illustratively, the classification units need to relate to each other, and the classification method is easy to use in practice. In contrast to other methods, by forest type classification the stand and the site are considered as whole and hence it is considered as the best of the three.
There is one classification system for the whole Latvia. The forests can be divided into permanent and transition types. In the permanent types the site factors stay rather unchanged and the site characters tally with the requirements of the dominant species. sites where the current tree species produces less than optimum growth are classified as transition types.
The forest types have changed over the time because of leaching of the nutrients from the soil.
The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.