Resumo. The method “line-intercept sampling method of canopy trees” was applied to map the silvigenic mosaic of a patch of 5.12 ha in a cerradão at Estação Ecológica de Assis, in São Paulo state, aiming to verify its applicability in estimating the conservation status and to show the regeneration processes in this type of forest with open canopy. We also analyzed the distribution of shade tolerant or intolerant species among the categories of eco-unities. The mosaic comprised five tree fall gaps (eco-unities in reorganization) and 1,296 individuals, 845 of which in eco-unities in equilibrium, 241 in development, and 210 degrading. The predominance of eco-units in equilibrium 2B (tall trees with low pole) is coherent with the open canopy. The shade intolerant species Vochysiatucanorum, Xylopiaaromatica and Plenckiapopulneapresented occurred preferably in starting eco-units of silvigenesis. But most of the species, especially the shade tolerant ones, did not present any correlation with eco-unit categories. The method revealed the maturity and the good architectural conservation status of the studied cerradão. We noticed that there may be overlapping of ecounities in development and degrading when this latter one is delimited by dead standing trees that allow the growth of young individuals around them.