Résumé
In the National Park of Tlemcen, tests of reforestation in Aleppo pine, pinion pine, Atlas cedar and cork oak had been realised in 2005 and it is possible three years later to try to clear the reasons of the successes and the failures of these works The vegetation has been observed on transect of 50 meters where the stratification of the vegetation was marked in order to see in which atmosphere of vegetation the regeneration has survived or not in each of compartment In each of the plots were pointed, topography, the rate of the recovering of the vegetation, the dominant kinds and the altitude As the number of the pointed out is weak, it is indispensable to use statistical tests, the observations have been done by non-inferential statistical methods It appears quickly that the complete failure of the regeneration of Atlas cedar to the success of the regeneration of Aleppo pine, pinion pine and cork oak in these heterogeneous plots depends of the vegetations and the present local ecology condition in each plots