Growth characteristics of norway spruce in the Pokljuka mires and forests

Abstract

The spruce mires and forests on the Pokljuka plateau are characterised by very diverse ecological conditions, plant species diversity, and a high variability of spruce-tree growth. The ecological conditions are well indicated by the floristic composition and vegetation. Therefore, based on the similarity of the floristic composition, plant-species cover and vertical vegetation structure, the studied spruce mires and spruce forests were clustered into six eco-vegetation groups. The growth characteristics of the spruce trees were tested among different eco-vegetation groups. The differences in the mean age of the spruce trees among the eco-vegetation groups are not significant. However, significant differences in the spruce-tree growth regime between trees growing on the mires and in the forest have been confirmed. The significant differences in mean tree height, mean tree breast diameter and in mean tree-ring widths have been established. The slow growth of spruce trees on the mires can be explained by harsh ecological conditions, especially by high soil water content and high ground water level.