ZLV Online

Abstrakt

Between 2007 and 2010, in the area of the most preserved subalpine old-growth forests in the Czech Republic (Šumava National Park, Trojmezná Reserve), windstorm and subsequent bark beetle outbreak caused the death of parent stands (15% and 85% of trees, respectively). The aim of this study was to describe the changes in stand structure characteristics in interaction with altitude, and determine the changes in amount and qualitative characteristics of dead wood before and after the disturbance. We carried out two measurements on regularly distributed 18 permanent circle plots (0.2 ha), in a 10-year interval (2001 and 2011). Only small numbers of adult trees (DBH ≥ 7 cm) survived the disturbance (the mortality rate of original adult trees was 99.4%). The recruitment intensity of new trees (DBH > 7 cm) was 16 trees/ha. New trees were present mostly at lower altitudes/elevation, where the stand was more structurally heterogeneous. DBH had no influence on the decay rate of single trees. The amount of dead wood was 2.5 times higher in 2011 than in 2001, but there was almost no change in the percentages of lying logs and standing snags before (37.6% and 62.4% of the total volume for logs and snags, respectively) and after disturbance (37.2% and 62.8% of the total volume for logs and snags, respectively). The highest increase of lying logs occurred in decay stage II and III (i.e. low and medium level of decayed logs).