Current issue: 55(1)
Under compilation: 55(2)
The article is a summary of a presentation by W. Wittich, held in the University of Helsinki in 26.4.1958.
The significance of fertility of the site in tree growh was known already for over 100 years ago in Germany, but after the First World War the view was abandoned in forestry. According to the Dauerwald system of managing forests that was introduced at the time, the type of site was considered relatively insignificant in forest management. Therefore, similar practices were used in all kinds of sites. The opposition against the use of this method resulted in new research on the site factors.
Knowledge of the relation of the site types and vegetation makes it possible to improve productivity: in regional planning the production that is considered to be necessary is assigned to the sites that have best conditions for it. For instance, in Niedersachsen county about 6% of the forest lands are reserved for cultivation of oak.
Another line of soil science studies the root causes behind the hands-on experiences of forest management. The aim is to abandon rigid approaches in forestry. Studying the effects of forest management practices on soil has been targeted, for instance, on effects of clear cutting on decomposition and vegetation, how the soil affects choice of tree species, and decomposition of litter from different tree species. Knowledge of soil and the trees’s demand of nutrients helps to mend disturbancies, such as nutrient deficiensies. Consequently, fertilization has become a new tool to improve productivity in forestry.
The article includes a German summary.