The paper concerns the direct and indirect impact of air pollution on the growth of Norway spruce in mature stands. Some population-ecological characteristics of dieback phenomena of spruce related to the character and intensity of air pollution stress were studied. Growth behaviour of250 spruce trees from the pre-Alpine, Alpine and pre-Dinaric regions of Slovenia in the course of the last 50 years was dendrochronologically analysed. The long and short-term growth changes in terms of the health condition of trees were examined and climatic factors were also taken into account. In the narrow emission area the trends of relative growing efficiency of trees were correlated with the trends of pollution caused by the thermal power plant of Šoštanj. General silvicultural strategies of tending and regeneration of severely endangered spruce stands were suggested.
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