Tree Species and Management Effect on Herb Layer Species Composition in Mountain Fir-Beech Forests of the Western Carpathians

Abstract

The effect of tree species on herbs in forest understory was studied in the Dobročský prales National Nature Reserve in the Western Carpathians, as well as neighboring secondary stands at the same site. Herb species occurrence and dendrometric values were recorded on belt transects and analyzed by direct gradient analysis (RDA). The results of a permutation test showed that herb frequencies were significantly affected by both beech and spruce, regardless of plot position inside or outside of the Reserve. In general, frequencies of herb species occurrence reacted negatively to the increasing tree competition, particularly the density of trees (over 7 cm DBH) in their surroundings. Frequency of the occurrence of most herb species had negative correlations with increasing beech competition (especially with stem density). Several herb species were significantly associated with spruce (especially Festuca altissima, Oxalis acetosella, Viola reichenbachiana). A subset comprised of natural fir-beech and secondary spruce stands was also compared. Dentaria enneaphyllos was found as the best indicator of natural stands, whereas Asarum europaeum, Luzula luzuloides, Moehringia trinervia, and Veronica officinalis were characteristic for secondary spruce forests of the studied site. Spruce forests had a more diverse and species-rich herb layer; however, several species of original fir-beech forests were suppressed or excluded there. The consequences of such diversity change are also discussed in the chapter.