Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

The administration of the Karkonosze National Park possesses the documentation of the the Karkonosze Mts. plant communities’ survey which was conducted at the turn of 1950s and 1960s. The authors conducted similar studies in the 90s within the higher mountain forest belt as well as in some plant communities of the sub- and alpine belt of the Karkonosze Mts. Currently, these studies have been resumed in order to cover retrospective analysis of vegetation changes in the following 20 years. In this paper we present some prelimi- nary results of the survey carried out in the Empetro-Vaccinietum community. About 40% of historical plots were precisely located in the patches of that community. Comparative analysis of the data on the parameters of the species diversity based on all plots surveyed in 1959–1960 and in 2015 gave almost identical results as those obtained from the set of data restricted only to the plots precisely located. In comparison with histori- cal data, current vegetation showed a significant decrease in the number of species per plot and the values of Shannon-Wiener index, but the evenness index has not changed.