Evolution of the leaching process in Salix babylonica,Populus nigra,Platanus acerifolia,Acer monspessulanum and Taxus baccata (Middle atlas region,Morocco) [Evolution du processus de lessivage chez Salix babylonica,Populus nigra,Platanus acerifolia,Acer monspessulanum et Taxus baccata (Région Moyen Atlas-Maroc)]

Leaching is to dissolve the soluble components of the litter,and it represents the first step in the degradation of the physical allochthonous organic matter. the obtained results for this work show that the weight loss of leaves and dead needles grows with the duration of leaching,the initial concentration and the type of treatment,fresh or dried. weight loss during leaching is a one linear phase. the speed of this process depends on the structure of the used leaves,so the soluble substances are slowly leached for needles litter,but faster for the particularly tender leaves as in the case of salix and acer.