This paper shows the numerical parameters of diameter and height structure of plantations of Eastern cottonwood (Populus deltoides Bartr.) clones 457, 618 and S_6-36 at two spacings (planting densities) on the sandy form of fluvisol after 24 years of plantation development. There is a significant difference in the main elements of plantation structure among the clones, i.e. the clones 457 and 618 are grouped in one group, while the clone S_6-36 shows significant advantages. Planting density of 625 trees per hectare (4 x 4 m) was a limiting factor for the development of tree diameters and height, which caused the decrease of tree numbers after 24 years of plantation development.