Due to anthropogenically altered tree species composition, lush ground vegetation and high densities of large herbivores, altimontane forests have difficulty rejuvenating. This makes them harder to manage, and natural regeneration is long lasting. In Pahernik's forests, we set up 6 experimental gaps the size of two tree heights and analyzed 252 plots with rejuvenation. Some of the plots were placed randomly, some in areas with seedlings and others on excavated areas. Our research consisted of examining selected ecological factors in experimental gaps and stands, the structure of natural regeneration and the influence of factors on rejuvenation. Three tree species regenerated: Norway spruce, European beech and rowan. The average density of seedlings was 6944 specimens per hectare and varied greatly depending on temperature and diffused light by positions in the gap. The seedling density was higher in gaps at lower altitudes, on micro-habitats under the canopy, at the edge of the gaps with less ground vegetation (especially the genus Calamagrostis sp.), and also on micro-habitats with more woody debris. Large herbivores presented a big factor due to feeding on vegetation, as rowan did not overgrow into height classes above 20 cm.
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