%0 Articles %T The effect of temperature on height growth of Scots pine in northern Finland %A Salminen, Hannu %D 2009 %J Dissertationes Forestales %V 2009 %N 96 %R doi:10.14214/df.96 %U http://dissertationesforestales.fi/article/1879 %X The effect of temperature on height growth of Scots pine in the northern boreal zone in Lapland was studied in two different time scales. Intra-annual growth was monitored in four stands in up to four growing seasons using an approximately biweekly measurement interval. Inter-annual growth was studied using growth records representing seven stands and five geographical locations. All the stands were growing on a dry to semi-dry heath that is a typical site type for pine stands in Finland. The applied methodology is based on applied time-series analysis and multilevel modelling. Intra-annual elongation of the leader shoot correlated with temperature sum accumulation. Height growth ceased when, on average, 41% of the relative temperature sum of the site was achieved. The relative temperature sum was calculated by dividing the actual temperature sum by the long-term mean of the total annual temperature sum for the site. The positive effect of the mean July temperature of the previous year on annual height increment proved to be very strong at high latitudes. The effect of mean monthly precipitation on annual height growth was statistically insignificant. There was a non-linear dependence between length and needle density of annual shoots. Exceptionally low height growth results in high needle-density, but the effect is weaker in years of average or good height growth. Radial growth and next year’s height growth are both largely controlled by current July temperature. Their growth variation in terms of minimum and maximum is not necessarily strongly correlated partly because height growth is more sensitive to changes in temperature. In addition, the actual effective temperature period is not exactly the same for these two growth components. Yet, there is a long-term balance that was also statistically distinguishable; radial growth correlated significantly with height growth with a lag of –2 years.