Structural diversity change and regeneration processes of the Norway spruce natural forest in Babia hora NNR in relation to altitude

Abstract

The research was focused on exploring the dynamics and forms of regeneration processes and structural diversity of the Norway spruce virgin forest in Babia hora NNR in relation to altitude. In each developmental stage 19 sample plots were established. The structural diversity was assessed by the indices proposed by CLARK and EVANS (1954), FÜLDNER (1995) and JAEHNE and DOHRENBUSCH (1997). Concerning the spatial distribution of the trees in the virgin forest no tendency to their clustering with the increasing altitude was found in the zones below 1,460 m. The influence of the altitude was confirmed in the zone above 1,461 m where the groups of "family spruces" are typical. Diameter differentiation was significantly higher in the growth stage. Evaluation of this attribute in terms of the altitude detected significant diameter differentiation at an altitude below 1,260 m in the growth stage. According to the FÜLDNER index the virgin forest has generally medium differentiated diameter structure. According to the complex index by JAEHNE and DOHRENBUSCH (1997) the differentiation of the virgin forest decreases with the ascending altitude up to 1,460 m, where the compact forest ends. Evaluation of the seedbed revealed that 46.2% of the naturally regenerated individuals were growing on mineral soil, 52.4% on dead wood and 1.4% on wind-thrown roots. Regarding the developmental stages 46% of the individuals were found in growth stage, 23% in optimum stage and 31% in breakdown stage.