related to the duration of the soil waterlogging. These observations are used as a basis for the definition of limitation classes, in view of the transformation of the soil map of Southern Belgium into specific maps of forest land practicability. - (L'A.).
The study of beechwood sites in the Belgian Ardennes, permits to select different soil factors related to the forest productivity. From mull to dysmoder humus form, the production of wood diminishes from 7.4 to 4.4 m/ha/year. Among the soil factors