Stand-replacing disturbance does not directly alter the succession of Norway spruce regeneration on dead wood

Abstract

Density of regeneration in European subalpine Norway spruce (Picea abies) forests is typically low with regeneration primarily located on dead or decaying wood. The post-disturbance development of this regeneration is crucial for natural forest succession. The aim was to identify the influence of disturbance on regeneration on decaying logs immediately after a severe disturbance event. Study plots were established in two subalpine spruce forests: the first, an undisturbed site located in the Hrubý Jeseník Mts. and the second site in the Šumava Mts. that has experienced recent severe disturbance. Regeneration density increased between 2008 and 2011 by 7% (0.29 individuals per square meter of log) at the undisturbed site and by 33% (3.24 individuals per square meter of log) at the disturbed site. The increased regeneration density observed at the disturbed site was mostly associated with the smallest saplings. The highest increase in regeneration density was observed on logs with the largest diameters. Three years after severe disturbance caused 100% mortality of the parent stand in the Bohemian Forest, no significant effect was recorded on the growth rate and survival of established spruce saplings on dead wood.