The biomass, carbon and nitrogen storage in the single tree components (foliage, branch, crown, bark, stem and total aboveground) of the grey poplar (Populus x canescens) in its distribution in Eastern Anatolia (Van, Turkey) were determined and modelled. The biomass, carbon and nitrogen storages were not estimated at a stand level but were based on single trees. Regression models based on the tree diameter at breast height (DBH) and total tree height (H) were developed to estimate the biomass, carbon (C) storage and nitrogen (N) storage of the different tree components of a total of 28 grey poplar trees. The two main regression models in the power function were developed based only on the DBH (Model 1) and the combination of the DBH and height ((DH)-H-2) (Model 2). All regression models, except for those of the foliage components, developed to estimate the biomass and C and N storages of the tree components were found to be statistically significant (p < 0.001). The partitioning of the total aboveground biomass in the bark, foliage, branches and stems was 0.7, 9, 17 and 73%, respectively. The average C concentrations of the tree components ranged from 48 (foliage) to 50% (bark, branch and stem), while the N concentrations ranged from 0.35 (stem) to 1.32% (foliage). Higher biomass and lower nitrogen concentrations of foliage compared with cultivated poplars were likely related to the natural site conditions, low soil nitrogen and/or characteristics of single tree growth.