Floor vegetation and soil of acidified Norway spruce forests in the Giant Mountains (Central Europe)

In autochthonous montane Norway spruce forest of the Giant Mts exposed to the airborne acidification, four representative communities identified as Athyrio alpestris-Piceetum typicum, Calamagrostio villosae-Piceetum typicum, C.v.-P. fagetosum and Sphagno-Piceetum molinietosum were analysed that. Their plant cover, soil profiles and soil acidity were examined as a baseline study on six permanent plots, situated along the gradient of decreasing air deposition. Prevailing soil types were leptic, humic and gleyed podzols. In 1995, B2 horizons were found strongly acid (pHaq between 4.3 and 3.9), and FH horizons were strongly to very strongly acid (pHaq between 2.7 and 3.9). This soil acidity differed from that referred in the same region by Matuskiewiczs 35 years ago. In plants, three kinds of long-term responses were distinguished. (1) Abundance of species with most roots in the uppermost horizon was related to the opening of the tree canopy in declining forests (increase of Deschampsia flexuosa, retreat of bryophytes Polytrichum formosum, Sphagnum girgensohnii, Dicranum scoparium). (2) Acidophilous forbs (Homogyne alpina, Trientalis europea, Oxalis acetosella and Maianthemum bifolium) with most roots in the strongly acidified FH horizon became less frequent. (3) In keystone species with root system reaching down to B horizon their reaction was not related linearly to the forest damage and/or soil acidity (e.g., expansion of Calamagrostis villosa partly due to its facultative endomycotrophy and/or both dieback-and-increase of Vaccinium myrtillus).