Fig. 3

N and TNC concentrations (means and standard errors in % DW) as a function of treatment and harvest date for a, d the whole trees, b, e the current-year organs, i.e. the flowers, fruits, leaves and current-year stems, and c, f the perennial structures, i.e. the roots and old axes. Harvests 1 and 2 are represented by dark and pale grey bars, respectively. Starch and ¹⁴N are shown by hatched areas, and the remainder, ¹⁵N and soluble sugars by non-hatched areas. The effect of treatment and harvest date was tested by randomisation tests based on the generation of 2500 random orders. It was significant (5 % level) if coded with different letters