Comparative Understory Development in Fenced and Unfenced Beech Forest Stands in the Southern Alps

Abstract

This study examines the impact of ungulate browsing on the understory dynamics of the Cansiglio Forest, the only European beech high forest in the Southern Limestone Alps. Utilizing seven pairs of fenced versus unfenced forest stands established over two decades, we assessed how fencing affects understory structure and tree regeneration. Significant differences were found in cover, height and vascular species composition in both tree regeneration and shrub layers. Fenced areas showed a significantly higher number and greater average height of young trees, supporting the hypothesis that ungulate browsing negatively impacts tree regeneration. Despite previous studies attributing the lack of silver fir (Abies alba Mill.) regeneration primarily to red deer (Cervus elaphus Linnaeus, 1758) browsing, our findings did not show a significant association of this species with fenced conditions. While Rubus abundance was higher inside fenced areas, overall vascular species richness did not differ. Our results highlight the evident effects of ungulate browsing and suggest the need to consider other factors influencing forest regeneration and understory development. Future research should establish additional study replicates, balanced across diverse site and stand structure conditions, to further explore these dynamics.