Study sites
The study was carried out in forest stands growing on technosols
developing from three different types of substrates referred to as
Clays, Sands and Ashes. Samples of Clays were taken at the external
spoil heaps of the open-pit lignite mine Turów (number of sampling
sites, n = 12) and the open-pit sulphur mine near Piaseczno (n = 12).
Clays sampled at Turów and Piaseczno represented acid and alkaline
materials, respectively. Sands were sampled in the reclaimed areas of
the sand quarry Szczakowa (n = 17) and on the external spoil heap of the
open-pit lignite mine Bełchatów (n = 7) while Ashes were taken at the
combustion waste disposal site Lubień (n = 24). Geographic localization
and basic data on climate, parent material and initial fertilization of
the sampling sites are given in Table 1.