Duration of shoot elongation in Scots pine

The within-season timing of shoot growth in trees has often been considered independently of shoot growth rate. Schiestl-Aalto et al. study lateral shoot growth in Scots pine (Pinus sylvestris) over 7 years and find that daily maximum growth rate correlates positively with growth duration, expressed as thermal time. Higher July–August temperature of the previous summer also prolongs the growth period. The results suggest that the thermal-time requirement for completion of lateral shoot extension in Scots pine may interact with resource availability to the shoot, both from year to year and among shoots in a crown each year. If growing season temperatures rise in the future, this will affect not only the rate of shoot growth but also its duration.