As forests in neotropical regions, particularly in developing countries, are devastated, interventions to restore biodiversity and its ecological functions are needed. Rural producers have thus been encouraged to grow trees for wood production as an economic activity. The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil. Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density. Three trees each of a species from the pioneer, early and late secondary successional stages and of the dominant species in the climax community. The radial profiles indicated increasing density from the pith to bark of trunks, except for some variations due to wood defects and growth. Average density was 0.576 g cm⁻³, 0.655 g cm⁻³, 0.706 g cm⁻³ and 0.775 g cm⁻³, respectively, for Peltophorum dubium, Schinus terebinthifolius, Cariniana estrellensis and Hymenaea courbaril. Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species. X-ray densitometry generated parameters such as minimum, average and maximum densities, and radial density variations. These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.