Response of tree-ring width and density of Pinus sylvestris to climate beyond the continuous northern forest line in Finland

The influence of minimum, maximum and mean monthly temperatures and precipitation on the radial growth of Scots pine (Pinus sylvestris L.) was studied beyond the continuous forest line in northern Finland. Latewood density, annual ring width and earlywood width respond more strongly to climate than latewood width or earlywood density. Earlywood width is controlled by precipitation in June and temperatures in mid winter (December/January) and March. Low mean temperature in April, adequate precipitation in May and a warm July results in wide rings. A long and warm vegetation period results in high latewood density, the strongest correlations occurring with July and August temperature and precipitation.