The long-term dynamics of the old-growth structure in the National Nature Reserve Badínsky prales

The main goal of this paper was to evaluate structure dynamics in the fir-beech, old-growth forest Badínsky prales. Measurements were taken on four permanent research plots (0.5 ha each) between 1970 and 2018, typically in ten-year intervals. In order to assess long-term structure dynamics, this study used basic stand characteristics and selected structural indices – the relative density (RD), coefficient of homogeneity (H), and structural complexity index (SCI). Species composition was quantified by the relative importance value (RIV), and a detrended correspondence analysis was carried out for the visualisation of long-term changes. The long-term mean of the stand volume reached 634 ± 99 m3·ha−1, and the mean of the basal area was 36.6 ± 4.0 m2·ha–1. Calculated values of the coefficient of homogeneity (1.46–2.54) were similar to values in other old-growth forests with a comparable tree species composition. An increasing trend in beech RIV values was observed; on the other hand, fir RIV values fell by approximately 20%–25%. In 2018, maximal values of the basal area, stand volume and relative density were recorded. These high values may indicate better growth conditions due to climate change, as well as fewer disturbance events in the last few decades.