"The data correspond to average root traits at the community level, and parameters describing the root diameter distribution at the community level. Soil parameters are also indicated. All measurements were conducted along a successional gradient on roadsides in the Mediterranean region (Montpellier, France, 43°6´N, 3°8´E). These data were used in the article entitled ""Dissecting fine root diameter distribution at the community level captures root morpological diversity"" from Erktan, A., Roumet, C., Munoz, F (in press) in Oikos (2022)." "All the information regarding to the dataset collection are provided in the associated manuscript entitled ""Dissecting fine root diameter distribution at the community level captures root morpological diversity"" from Erktan, A., Roumet, C., Munoz, F (in press) in Oikos (2022), and in Erktan, A. et al. 2018. Two dimensions define the variation of fine root traits across plant communities under the joint influence of ecological succession and annual mowing. – J. Ecol. 106: 2031–2042." Significance of the variables: "age: age of the plant community; NM: not mown; M: mown; Mx: average root diameter of the mode x (root diameter distribution at the community level); SDx: average standard deviation of the mode x (root diameter distribution at the community level); Px: average relative proportion of the mode x (root diameter distribution at the community level); SoilC: concentration in soil organic carbon (g/kg); SoilN: concentration in total nitrogen (g/kg); CEC : cation exchange capacity (meq/kg); SoilP: available Phosphorus (mg/kg); SRL: specific root length (m/g); MRD: mean root diameter (mm); Root_N: concentration in root nitrogen (mg/g); Root_C: concentration in root carbon (mg/g); RDMC: root dry matter content (mg/g); variance: variance of the root diameter distribution at the community level; graminoid: proportion of graminoids in the plant community in %; herb: proportion of herbs in the plant community in %; shrub: proportion of shrubs in the plant community in %; tree: proportion of trees in the plant community in %; Woodiness: proportion of woody species in the plant community (%); Cmean: average proportion of plants with a competitive strategy; Smean: average proportion of plants with a stress-tolerant strategy; Rmean: average proportion of plants with a ruderal strategy. Fric: Functional plant richness at the community level; simpson: Simpson diversity of the plant communities."