Druhové zloženie a synchronizovanosť disturbancií v primárnych lesoch s dominanciou buka lesného (Fagus sylvatica L.) v strednej Európe

Abstract

Natural disturbances such as windthrows and bark beetle outbreaks are essential in the formation of natural forest ecosystem structures in Central Europe. Therefore, evaluating disturbances’ spatial and temporal extent and synchronicity is critical for understanding of forest dynamics. This study aimed to evaluate the long-term natural disturbance history of primary mixed-beech forests and investigate the species composition-temporal synchronisation relationship. We collected a unique dataset of > 6,000 tree cores across 14 forest stands on 174 study plots, and using dendroecological methods we reconstructed 200-year-long plot-level disturbance histories and evaluated synchronicity within the stands. Subsequently, we used GLMs to evaluate the tree species diversity-synchronicity relationship. The results showed substantial temporal variability of natural disturbances and a prevalence of low and moderate severity disturbances. Disturbance synchronisation was higher in the Western than in the Eastern Carpathian forests, which have a lower proportion of admixture tree species. Moreover, the GLMs showed a strong positive dependence of synchronicity on tree species richness. The results contradict the general assumption that mixed-species forests have higher resilience to disturbances than monospecific forests. The reason behind these findings can be attributed to the substantial admixture of Norway spruce, and its vulnerability to disturbances such as windthrow and bark beetle outbreaks.