Current issue: 52(4)
Under compilation: 52(5)
The article tries to develop the method for defining the requirements of fertilizers for soil. The chemical soil analysis is also seen as the requirement for exact site classification based on height over age. The study is based on 1500 soil samples, one half of them from forest soils, the other half from arable land soils.
The productivity of different forest types and the results of soil analyses are in line with each other. The most important growth factors are discerned. Some shortcomings of the method are discussed. Combining the soil analysis and the plant analyses of the sample plots seems to give the most accurate about the amount of nutrients that are available for the plants.
The article statistically studies the vegetation patterns in different forest types.
467 sample plots with area varying from one fourth of a hectare to one eighth, even one tenth of a hectare were collected. There are different amount of sample plots representing every forest type. The sample plots are located in 58 communes in southern parts of Finland, reaching from the Gulf of Finland up to Oulujärvi –see in northern Ostrobothnia. The vegetation was examined from rectangle shaped study plots in even structured and even-aged stands with one primary tree species.
The results are shown in tables for every forest type. The amount of species is at highest in the most nutritious forest types, and decreases with the shift to more infertile types. However, some species occur in all forest types, and some only or mostly on more barren types. The occurrence and abundance of most plant species does not seem to depend on the tree species of the stand, but there are some exceptions to this.
The possible shortcomings of the research method are discussed. The importance of systematic studying of the sample plots with a method of survey lines is emphasized.
The article presents definitions for central concepts that are commonly used in the research of plant topography. The discipline has close connections to defining and classifying forest types.
The concepts defined involve concrete and abstract concepts linked to vegetation conditions and to habitat.
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.