Climatic signal in annual growth variation of Norway spruce (Picea abies) along a transect from central Finland to the Arctic timberline

Regional and temporal growth patterns of Norway spruce (Picea abies (L.) Ka rst.) were evaluated in 40 stands along a transect of over 500 km running f rom central Finland to the Arctic spruce timberline. Standard deviation of the ring-width series increased from south to north, but the geographical d ifferences in mean sensitivity and first-order autocorrelation were small. The high degree of similarity in growth variation between stands indicated similar growth responses of trees to weather variation despite different en vironmental conditions along the transect. The most pronounced differences in the regional increment chronologies were found between the southernmost and northernmost stands. Growth variation was most strongly correlated with current June mean temperature, and correlation between growth and July tem perature increased from south to north. In addition, negative correlation w as observed between winter temperatures, particularly February temperature, and growth variation. Growth was more weakly correlated with precipitation than with temperature.