Forest types of northern Sweden

Abstract

The northern part of Sweden, making up nearly two-thirds of the whole country, belongs to the coniferous, oakless forests of the boreal region, the taiga of the northern hemisphere, Fig. 1. The two main tree species are the Norway spruce,Picea abies (L.) Karst., and Scots pine,Pinus silvestris L., and occur either alone or mixed, generally also with some deciduous trees; the most common being the birchesBetula pendula, Roth andB. pubescens, Ehrh.

The forests are rarely too dense to exclude a low ground vegetation with a field layer of dwarf-shrubs, herbs, ferns and grasses and a bottom layer of lichens and mosses. The plant species of both layers provide a fairly good indication of the characteristics of the site. The plant communities are even more reliable indicators of soil type and suitability of the site for growing trees. From the plant sociological point of view, the communities correspond to unions or associations forming ecosystems equal to forest types. These are named after the two main factorial systems, moisture/water and nutrients, and are ordinated into a scheme, here called the North-Swedish forest types scheme. These forest types provide information on the management of the forest at different sites, including the choice of the most suitable and economically most profitable trees and methods of regeneration, both natural as well as artificial. On forest land without trees, such as in a clearing, the phase of the forest type becomes quite different from the normal phase stabilized within a mature forest In a natural stand, as well as in a forest established by sowing or planting, the density of the canopy has great influence on the ground vegetation-and thus on the forest type. The different paths of succession and dynamics of these phases must be known.

The forest types scheme presented here in an English version was widely used in Sweden in teaching and training in forestry from 1945 to the late 1970's and is still used for pilot descriptions. Some new approaches by recent scientists and new systems, especially for the purpose of classification of the sites into quality classes, are briefly mentioned.