German researchers confirm that silvicultural practices exert an influence on soil biology comparable to that of abiotic factors (subsoil pH, texture). Among the components of silvicultural management intensity studied, the proportion of native broadleaved species proves to be the most determining lever: it acts directly and indirectly — through humus form and the pH of the upper mineral horizon — on microbial biomass, the C/N ratio, and enzymatic activities. The volume of harvested timber constitutes the second most important factor, notably through its acidifying effect on the uppermost soil layers and its impact on enzymatic activities.
Humus form is confirmed as a robust field indicator: it reliably predicts pH, the C/N ratio, and several microbial characteristics of the upper mineral soil. Effects vary considerably, however, depending on regional site conditions, which underscores the importance of local pedological context in the interpretation of results.