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The Aspidosperma quebracho-blanco is an important sclerophyllous evergreen species of the Argentine Chaco. There is scarce information about demographic patterns of A. quebracho blanco in the Arid Chaco. This paper focused on describing consequences of the process of degradation of the vegetation on the regeneration and size structure of A. quebracho-blanco population, compared to the contrasting scenarios of traditional management (cutting, grazing and fire) and a long undisturbed situation. Seedling and sapling establishment of A. quebracho-blanco has seldom been observed, in Cordoba’s Arid Chaco. A. quebracho blanco did not have significant seedling and sapling recruitment in any of the stands submitted to the effects of traditional management (extensive grazing and uncontrolled cutting). It had substantial seedling and sapling recruitment in the Chancani Forest Reserve, which was different to the other sites. In protected areas, the adult plant densities were higher than in areas of low grazing and cutting. Disturbed habitats will be often considered to be suboptimal, whereas more stable undisturbed habitats have higher success of regeneration. Though, the general patterns of size distributions are similar, the disturbing effect promotes changes in their distribution parameters. (C) 1999 Elsevier Science B.V. All rights reserved.