Assessment of Intra-Biogeocenotic Variability of Forest Litters and Dwarf Shrub–Herbaceous Vegetation in Spruce Stands

The differences in the species composition of the ground cover in spruce forest in dependence on the position in tessera are identified. Tessera is perceived as a combination of near-trunk, under-crown, and inter-crown areas with different ecological conditions depending on the influence of spruce tree as an edifier. The diversity of ecological groups, the species abundance, and the participation of nutrient-demanding nemoral photophilous species increase from near-trunk areas to inter-crown open areas. The thickness and reserves of forest litters decrease from near-trunk areas to open areas. The location in tessera predetermines the composition of forest litter and the ratios between litter stocks in different subhorizons. Litters of near-trunk areas are characterized by minimum pH values and minimum reserves of ash elements in the L subhorizon, as well as in the easily decomposable falloff components. These facts are in agreement with the high percent of acidophilic species and species with low nutrient demands in the ground cover. Indices of the rate of organic matter decomposition (the share of easily decomposable components in the L horizon, the supply of ash elements in litter and its easily decomposable components, and the ratios between the thickness and reserves of the L, F, and H subhorizons) are directly related to the ratio between plant species with different requirements for nutrients in the ground cover as estimated by special ecological scales. Thus, spruce is an edificator is responsible for significant differences in the morphological and chemical properties of forest litter in different tessera components. These properties are adequately reflected in the species composition and ecological structure of the ground cover.