MODELING OF TROPHIC LEVELS IN FOREST SOILS USING PHYTOSOCIOLOGY

The initial problem regarding the regeneration of forest stands faced by forestry experts is the choice of species to privilege or to be brought in. Now, the criteria are well known, but the task of evaluating site capacity remains. Soil pH is one of the best components to characterize trophic levels, but it is very difficult to map. Vegetation may solve the problem. Two methods were used. The first employed results of experiments carried out by Noirfalise (1984) in Belgium (tables II, III and IV), and the second consisted of resurvey of the pH measurements at La Fagne in Chimay (tables V, VI and VII). Both methods showed a logical pH gradation related to the trophic levels expected for the phytosiological groups (fig 2). Field measurements showed a low pH variation between trophic types. Variation coefficients remained inferior or equal to 5%, which was significant. We suggest that phytosociology may be used to replace high intensify systematic sampling by low intensity stratified sampling.