Zastosowanie Siedliskowego Indeksu Glebowego dla terenów górskich (SIGg) w ocenie jakości siedlisk zamierających drzewostanów świerkowych

In recent years, we face a massive dieback of Norway spruce stands in Poland. The cause of this process may lay in the way of their monocultural silviculture. The correct assessment of the habitat conditions and soil properties in particular is the basis of the proper management of these forest areas. The aim of this study was to verify application of the trophic soil index for mountain areas (SIGg) in the assessment of site conditions for spruce stands with different health condition. Three types of spruce stands were distinguished: degenerated, weakened and stable. In total, 32 study plots were established in following forest districts in southern Poland: Ustroń, Wisła, Bielsko, Węgierska Górka, Jeleśnia, Ujsoły and Lądek Zdrój. The SIGg was calculated on the basis of <0.02 mm fraction content, the sum of exchangeable base cations, soil acidity and the total content of N and organic C in the humus−mineral horizon. These attributes are useful to determine the potential productivity of the soils did not differentiate visibly the analyzed stand variants. The soil in degenerated and weakened spruce stands showed higher degree of acidity and less the content of base cations compared to soils of stable spruce stands. Mountain trophic soil index can be applied in the assessment of the forest sites potential. Although it does not enable to monitor the disturbances in the nutrients circulation, the detailed analysis of its components allows for precise assessment of the forest sites status.