An analysis of biological diversity at the level of species, spatial and ecological composition was made for three developmental stages of spruce ecosystem within a framework of the Fageta abietino-quercina group of geobiocoene types at the research facility operated by the Institute of Forest Ecology, Mendel University of Agriculture and Forestry Rájec. Data have been collected by several authors since 1977 with some breaks until the present time. The stage of maturity was found in the initial phase (transitional from the advanced phase, stage of growth) in two parts: with the effect of thinning and without it. The stages of regeneration and growth were monitored on a parallel research plot. The stage of regeneration is represented by the phase of clearing in which four parts were distinguished: preparatory, initial, advanced and transitional. The stage of growth is represented by the initial phase which followed after the phase of clearing. Some vegetation characteristics such as relation to soil acidity and reserve of available nutrients, regimes of soil moisture, light, heat, response to opening, conditions of humification and reserve of available nitrogen were assessed by using the ecologically typified groups of species. The development of the synusia of terrestrial mosses was captured at the stage of growth, initial phase in individual research squares on the former clearing. This stage was characterized by a rapid increase and dominance of acidophilous and oligotrophic species with narrow valency along with an increase of species contributing to the formation of raw humus and practically with a disappearance of species from the nitrophilous series, which documents a severely impaired humification.