ROOT MORPHOLOGY AND CHEMISTRY IN MANCHURIAN ASH (FRAXINUS MANDSHURICA) AND LARCH (LARIX GMELINII RUPR.) ARE DEPENDENT ON SPECIES, ROOT ORDER AND COMPETITION

Interspecific variation in fine-root morphology and function is well documented. However, very less information is available regarding variation among monoculture and mixed-species plantations in temperate species. Thus, the present study used such plantations to investigate how belowground inter- and intraspecific competition influence major fine-root traits of larch (Larix gmelinii)and Manchurian ash (Fraxinus mandshurica). Overall root morphology, anatomy, and chemistry differed between species and root order (1–5). Specific root length, nitrogen concentration, and cortex: stele ratio was significantly higher in Manchurian ash, whereas root tissue density, stele diameter, and C/N ratio were significantly higher in larch. Additionally, when comparing the two species in a mixed plantation, root C concentration differed significantly between larch and Manchurian ash, but only for the second root order. However, root traits were largely similar across species within a given root order. In conclusion, critical root traits did not exhibit major intra- and interspecific differences, despite the ostensible presence of competition among tested plantations. Therefore, competition-induced root modification may not be a universal phenomenon in temperate trees.