Vitality Structure of the Middle-Aged Northern Taiga Pine Forest Stands

Abstract

On the example of the northern taiga pine (Pinus sylvestris L.) forests of the western Kola peninsula (67°30′–68°10′ N, 33°57′–34°21′ W) the vitality structure of the middle-aged forest stands was studied in the communities within the lichen, lichen-green moss and green moss groups of forest types (12 permanent sample plots). It has been established that the studied forest stands are characterized by a numerical predominance of moderately and severely weakened trees (total share of 55–70%), and of moderately weakened and healthy trees in terms of trunk volume (total share of 50–75%). The significant factors found to contribute into the formation of the middle-aged pine forest stands’ vitality structure are their density, the sum of the basal areas and the forest type. The density of the forest stand is the main contributor to the nature of the trees’ vitality differentiation. Three main types of pine vitality spectra were identified, differing in the value of the stand vitality index.