Data from long-term (30 yrs) monitoring of changes in the ecological conditions and species composition of all vegetation layers (tree stand, young growth, undergrowth, dwarf shrub-herb layer, moss layer) of a drained herb-sphagnum pine stand after a combination of treatments (removal of birch + mineral fertilization) are reported. Owing to improved light and nutrient supply, representatives of oligotrophic bogs and a majority of plants associated with mesotrophic and eutrophic mires almost disappeared from the dwarf shrub-herb layer, while the previously absent mesotrophic forest-dwelling species arrived. The progressively thick herb layer has substantially influenced the distribution of nutrients. The rapidly and fully decomposing herbaceous dieback promoted the activity of microbiological processes, and biological recycling of nutrients from fertilizers provided for a long-lasting increase in the stand productivity. The moss layer lost the edifier species of oligotrophic bogs at the same time with increased representation of the forest flora and arrival of new species (Polytrichum commune, Rhytideadelphus triquetrus). Overall, the species composition of the ground cover settled down 8–10 years after the experiment had begun. Improved moisture and air conditions and nutrition have led to plentiful and rapid growth of spruce saplings. At the same time, the development of a dense ground cover, undergrowth and young birch growth has negatively affected the emergence of pine saplings, their further growth and development. There is no young growth of this species in the site now, and the number of pine trees and its contribution to the main stand are declining. The shares of spruce and birch in the stand are growing proportionately. An especially pronounced increase lately has been in the role of spruce in the stand. Generally speaking, the combination of treatments has transformed the herb-dwarf shrub and moss layers, and notably altered the growth conditions for and composition of young woody growth, facilitating the formation of a highly productive and commercially valuable stand.