Vital rates and their multidecadal trends in the fir-beech old-growth forest of Badínsky prales

Abstract

The study aimed to quantify annual mortality and recruitment rates on permanent research plots in the Badínsky prales old-growth forest. The data measured in four stands originate from six censuses, which together cover a 48-year period. The mean annual mortality rate reached 4.2% (DBH > 2 cm) or 2.3% (DBH > 8 cm). The mortality peaked in the first part of the observation period, probably indicating an intermediate disturbance activity, and the subsequent declining trend led to minimum annual mortality during the last 20 years. We found substantially higher fir mortality in comparison with beech, primarily during the first decades of the measurement period. Among three size categories, the stems with DBH 2-8 cm showed the highest mortality rate. We detected the minimum fir recruitment rate throughout the observation period; on the other hand, the beech recruitment rate was relatively high responding to the open canopy. Standing and lying deadwood volumes indicated similar trends like mortality did, and high values of fir standing deadwood observed during the first decades can signify that a relatively high proportion of mortality was related to the fir decline caused by air pollution.