Current issue: 53(4)
Under compilation: 54(1)
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.
The article contains tree lectures given in the meeting of the Geographical Society in Finland on February 25th 1921. The titles of the lectures are I Forest types in general, II Forest types as a basis for new growth and yield tables in Finland, and III Other research on forest types.
The first lecture is a follow-up of the Cajander’s 1909 published article on forest types. It deepens the theory on forest types. The classification into forest types represents primarily different plant communities of ground cover. The types are named after the characteristic plant species, indicator plants, however, many other species appear in different abundance.
The second lecture represents the research proceedings of mensuration of forest stands of different types to compile yield tables for pine. The forest types differ from each other distinctly on their growing preconditions, but inside one class the variation of the growing conditions is so small, that the classification can be used for yield tables, determining the basis of taxation and for classification of forest based on height over age.
The third lecture is a summary of other studies about forest type classification. They confirm the results presented in earlier lectures.
The data used to control the developed methods are presented in chapter two. The third chapter presents the statistical analysis conducted. The factor analysis shows that tree stand characteristics must be divided into three factors to able the information needed for site indexing to distinguish different site classes. The phases of model development are presented and the results of calculations with control data are shown.
The results indicate that for calculations of nature-normal forests the suitable amount of tree stand characters for creating the site indexing function, is three. These are: number of trees (N), basal area of the stand (G) and mean height (H).
The PDF contains a summary in Finnish.
The article is the first part of a wider project aiming to study the measurement practices of stand’s height-over-age based classifications and to develop new methods for actually measuring the side index.
The first part of the article presents the concepts of site indexing and discusses it with a mathematical model. The second part of the article examines the structure of site indexing system regarding the reliability of the method. Third part presents the factors affecting the method development and the fourth part discusses the possible site index classes and their characteristics.
The PDF contains a summary in Finnish.