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Abstract: The paper is based on the researches carried out in a former bauxite quarry from Zece Hotare, Bihor County. The bauxite exploitation ended in 1998 and in 2004 complex works took place in order to set up experiments. In 2005, 2006, 2007 and 2008 determinations were made as to what concerns the settling of herbs vegetation. The three soil profiles located in the levelled area and the slope area were compared to the profile of the soil from the limitrophe beech tree (Fagus silvatica) forest. In the profiles from the former bauxite quarry, the colloidal clay content increased significantly compared to the soil from the limitrophe beech tree (Fagus silvatica) forest. The bulk density, the total porosity and the hydraulic conductivity had lower favourable values and the pH values were lower. The humus content was determined only on a 0 - 30 cm depth and on a 0 - 17 cm in soil profile from the hillside. Phosphorous and potassium had low values. The enzymatical activity - the actual dehydrogenase activity, the acid phosphatase activity, the catalase activity, the urease activity - was reduced in the soil profiles from the former bauxite quarry than in the beech tree (Fagus silvatica) forest. The process of vegetation settlement (Robinia pseudocaccia) was severely influenced by fertilization, and the herbs vegetation was influenced by its location in the quarry, the number plants grew from one year to another. Thus we can strongly affirm that the reconstruction process is underway.

Keyword: bauxite quarry, physical, chemical and enzymatical properties, vegetation, ecological reconstruction