Figure 2.

Coefficient of variation (CV, gray) and the phenotypic plasticity index (PI, gray hatched) for fine root traits of four North-American temperate forest species (NF dataset). Different letters indicate significant differences between traits (capital letters for CV, capital letters on white inset for PI and small letters for PI:CV). Traits include specific root length (SRL_c), branching intensity (BI_c) and fine root diameter (D_c) and were measured on roots <2 mm (subscript ‘c’). Trait effects for CV and PI:CV were computed using the asymptotic interference test (Miller and Feltz, 1997). Trait effects for PI were computed on resampled populations and consecutive ANOVA models.