Open access publications in the SLU publication database

Abstract

The use of the selection system has always been a marginal part of Swedish forestry, and so has research about the system under Swedish conditions. However, the interest in Sweden for uneven-aged forest management has increased because of a rising concern for the ecological and aesthetical consequences from use of the dominating rotation forests system, which creates even-aged forest and has clear-cutting as primary harvesting method.

In this thesis I have studied the possibilities and limitations of the selection system in Swedish boreal forests. Stand development, ingrowth and volume increment has been studied in both Norway spruce (Picea abies (L.) H. Karst.), and Scots pine (Pinus sylvestris L.) forests.

My studies of uneven-aged Norway spruce show that 1) these forests have the capacity to spontaneously create and maintain an uneven-aged stand structure, 2) there is a positive relation between standing volume and volume increment, and 3) there is no clear relation between the level of ingrowth and stand density.

My studies of multi-layered Scots pine forests show that 1) a multi-layered stand structure is more likely the result of size stratification and not of continuous ingrowth, 2) There is positive relation between standing volume and volume increment, and 3) that a low stand density is seems required for ingrowth to occur on a sustainable level.

The results imply that for boreal Norway spruce forests, a high standing volume would be recommended when the selection system is applied, whereas for boreal Scots pine forest, uneven-aged management should be motivated by other values than stem production, e.g. aesthetical or ecological.