Fine-root chemical traits rather than morphological traits of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations vary along an altitudinal gradient in Eastern China

Aim of study: To explore the different patterns of fine-root traits by elucidating changes in their chemistries and morphologies in Chinese fir plantations along an altitudinal gradient. Area of study: National Mazongling Nature Reserve (Anhui Province). Material and methods: Soil and fine roots (≤ 2 mm) samples were extracted from three soil layers (0-10 cm, 10-20 cm, and 20-30 cm) at four altitudes (750 m, 850 m, 1000 m, and 1150m), after which their nutrient concentrations and morphological traits, respectively, were quantified. We employed mixed model ANOVA to test the effects of altitude, soil layer, and their interactions on the characteristics of soil and fine roots. The relationships between the functional traits of fine roots and climate, soil and stand structures were evaluated by the standard major axis regression and the structural equation model. Main results: The chemical traits of fine roots were higher at medium altitudes (which decreased significantly with the soil layer). In contrast the morphological traits of fine roots  did not change significantly. In chemical traits, both altitude, organic matter components, and soil total phosphorus (TP) exerted dominant effects on fine-root N, and both altitude and soil TP exerted dominant effects on fine-root P. However, in morphological traits, we found that altitude and soil C:N were crucial impact factors. Research highlights: Fine roots might preferentially adjust their chemical traits rather than morphological traits to facilitate higher root efficiencies in response to variable environmental conditions.