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The hypothesis that trees have grown more rapidly in recent years as a consequence of climate warming and the reduced pollution was tested in Scots pine (Pinus sylvestris L.) forests in Lithuania. A hundred of the largest, dominant pine trees, with a diameter at breast height exceeding 50 cm, were selected in three experimental, over-mature stands located in different parts of the country (north-eastern, western and sea coast). Results confirmed that the annual increment of the trees analyzed has increased since 1980. The causes of such faster growth were higher air temperatures during the winter and, to a lesser extent, higher temperatures from May through August. The effect of precipitation was negligible. Using data on acidifying pollutants collected in last 30 years, a significant effect of the reduced SO2 concentration and sulphur deposition, as well as of the increased ammonia deposition, on the enhanced annual increment in the tree basal area was detected. Multiple regression analysis revealed that meteorological parameters can explain up to 50% of the observed variation in the increase of growth rate for Scots pine in Lithuania, while the variation in the concentration of acidifying pollutants accounted for an additional 30%. However, the pollution data set did not cover a timespan long enough (20-30 years) to clearly distinguish between the effect of the reduced pollution in recent years and the increased temperatures due to global warming as the driving factor of the enhanced growth observed for dominant pine trees in Lithanian forests. [ABSTRACT FROM AUTHOR]