Wpływ odnowienia lasu zrębem zupełnym na trofizm gleb rdzawych na przykładzie Nadleśnictwa Spała

摘要

The paper describes the influence of clear-cutting on the fertility of rusty soils expressed by trophic soil index. Soils in the Spała Forest District (central Poland) were covered by coniferous or mixed coniferous forests. Clear-cutting in acidic and oligotrophic mixed coniferous forests decreased soil fertility and affected an increase of hydrolitic acidity, particularly in Oh and Bv horizons. This type of timber harvest influenced also decrease of organic carbon in the first year after cutting.%The aim of this study was to assess the impact of clear-cutting on the trophic soil index of rusty soils in the Spala Forest District (central Poland). Soils in the study area were covered by coniferous and mixed coniferous forests and were classified as Albic Brunic Arenosols, made of loose quartz sand. We compared soils form plots selected from the areas where the clear-cutting was made one or two (coniferous forest) and one or five (mixed coniferous forest) years before the sampling. The clear-cutting area was subjected to regeneration one year after the cutting. Soil profiles in undisturbed forests were chosen as the control. The properties of the soil were analysed to determine the soil trophic index (SIG). Clear-cutting in acidic and oligotrophic stands of mixed coniferous forests decreased soil fertility and affected an increase of hydrolitic acidity, particularly in Oh and Bv horizons. Sorption capacity of these soils was mainly dependent on the value of hydrolytic acidity. SIG on the plots where the cuts were made was highly correlated with the sorption capacity of the soils. This type of timber harvest influenced also the decrease in organic carbon in the first year after cutting. In subsequent years, the renewal processes conducive to restoring disrupted stand the level of soil organic matter in a forest ecosystem. The study confirms the need for renewal, as an important step in restoring the natural balance of the forest ecosystems modified by human activities.