Résumé : Modification of some soil mechanical properties (penetration resistance and consolidation pressure) induced by vehicle compaction during mechanized forest exploitation was studied in an acid and loamy leached forest soil of the loessic belt of central Belgium. In situ penetration tests and laboratory Bishop-Wesley cell tests were undertaken for the two main soil horizons of a beech high-forest, i.e. the eluvial E horizon (5-30 cm depth) and the underlying clay-enriched Bt horizon (30-60 cm depth). Both undisturbed and wheel-rutted soil areas were studied (E and Bt horizons vs. Eg and Btg horizons). Results show that: The experimental overconsolidation pressure of the eluvial reference horizon (E) is about 50 kPa higher than the value calculated from soil overburden pressure; this probably results from suction action during dry periods. The clay-enriched reference horizon (Bt) shows the same trends. In wheel-rutted areas, seven years after logging operations, the Eg horizon memorizes only 14.5% of the wheel induced stress due to forest machinery. In the compacted Btg horizon, the experimental overconsolidation pressure represents 96% of the exerted theoretical stresses due to harvesting actions. The good recording of the exerted stresses, after seven years, can be explained by: (1) The Btg depth which keeps it from seasonal variations i.e. from desiccation-moistening or freeze-thaw cycling; (2) amorphous and free iron accumulation inducing a "glue" effect of the Btg soil matrix, which could stabilize the soil structure and prevent recovery to initial conditions. These results provide clear evidence that on loessic materials, soil compaction due to logging operations leads to modifications in both physical (bulk density, total porosity) and mechanical (penetration resistance and consolidation pressure) soil properties. © 2003 ISTVS. Published by Elsevier Ltd. All rights reserved.