Šerá B., Falta V., Cudlin P., Chmeliková E.: Contribution to knowledge of natural growth and development of mountain Norway spruce seedlings. Ekológia (Bratislava), Vol. 19, No. 4, 420-434, 2000. Influence of the climatic and pollution stress, soil substrates, mosses and dominant herb species on the Norway spruce (Picea abies L. K a r s t.) seedling development and their cohort growth was investigated in six permanent research plots in the Krkonoše Mts from 1995 to 1997. The results showed dependence of seedling development on the synergic influence of the multiple stress. The highest number of seedling cohorts was observed in the least damaged plots (the Modrý důl and the Sluneěne̊ údoli plots), where climatic conditions are not so severe, the canopy cover is high and consequently litter coverage is high, too. On the contrary, no seedlings were found in the heavily damaged Mumlavská hora plot and only a few seedlings were observed in the Alžbětinka plot (the north exposition and also relatively high polluted plot). One of the important secondary stress factors is an expansive growth of some dominant plants species. The majority of seedlings was germinating and growing in patches covered by litter. The seedling development in other substrates (as mosses and some herb layer communities) was much less frequent.