Abstract
Knowledge of the structure and dynamics of near-natural mixed forests is a key factor for ecologically oriented management of forest ecosystems. The development of these model forests mostly takes place continually without any pronounced disturbances. Natural regeneration can be locally limited by ungulate browsing. The paper was focused on the structure and development of forest stands with emphasis on natural regeneration in relation to ungulates in Černý důl Nature Reserve and Trčkov National Nature Reserve situated in the Orlické hory Mts., Czech Republic. The case study was conducted in a spruce-beech-fir forest stand on four permanent research plots (PRP) of 0.25 ha in size. PRP are situated in the same stand and in comparable site and stand conditions, but two PRP has been protected against game by fencing since 1985-1989. The stand volume ranged from 478 to 565 m3 ha−1 in age 143 - 156 year. The results showed that the diversity of tree layer was higher by 19.8% (48.0% in species richness) in the stands protected by fence. In the phase of natural regeneration, the species composition, stand structure and number of recruits were poorer on unfenced PRP (7,990 recruits ha−1) compared to fenced PRP (13,160 recruits ha−1). Admixed silver fir and rowan were completely eliminated by browsing (to 94 - 100% of individuals). Growth analyses statistically confirmed that ungulates were a significant limiting factor for successful forest development (P < 0.001).