Fig 2.

Means of relative ¹³C contents (%, ±SE; n = 4 for spring, summer, and autumn, n = 1–3 for spring+1 yr, see Table 1) recovered from bulk fine-roots of (A) new fine roots, (B) fine roots of class ≤0.5 mm, and (C) fine roots of class >0.5–1.0 mm for different seasons of ¹³CO₂ pulse-labelling (spring, summer, autumn) and for different harvesting seasons. Relative ¹³C contents are expressed in percentage of the maximum needle signals. Significant differences between control and clipped trees are given with * (P<0.05) and ** (P<0.01).