Two-yr-old Scots pine (Pinus sylvestris) seedlings were grown in sand culture for 1 yr with a generous supply of
a balanced nutrient solution. Trees were repotted into clean sand in February 1998 and given either a reduced or
adequate nutrient supply containing enriched 15N, 41K and 26Mg to label nutrient uptake during spring 1998.
Trees doubled their biomass during the experiment. Whole-tree net photosynthesis was reduced by 43% after 95
d in trees that received the lower nutrient supply (P < 0.001), although differences in biomass between the two
treatments were less pronounced. Remobilization contributed 83, 82 and 52% of the N, K and Mg, respectively,
used to support growth of new tissues in trees that received reduced nutrient supply. Those receiving the higher
nutrient supply still obtained 44–59% of nutrients used for spring growth of new tissues from remobilization.
Current nutrient supply had no significant effect on the amount of N or Mg remobilized to new tissues but K
remobilization was less in trees that received the lower nutrient supply (P = 0.025). The importance of
remobilization in young trees and problems associated with quantifying internal cycling of nutrients are discussed.