Residual forest biomass: effects of removal on soil quality

Abstract

Residual forest biomass from forest cleaning operations can be enhanced through their use to produce energy. Their removal in a continuous manner may affect the quality of forest soils concerning the nutrients availability for plants.

The amount of nutrients both in the organic and mineral soil layer were evaluated in areas in the Centre of Portugal. The plots were selected based on lithology, slope classes and forest stands. In the study area, the schist-greywacke complex as well as the mild acid rocks is predominated. The most class slopes are 0‑10% and 11‑20% and the stands of hardwood and coniferous forest occupied most of the area. Organic layers biomass and nutrients, and texture, pH and concentration of C, N, P, K, Ca and Mg in the soil mineral layers were evaluated.

The effect on soil quality, of the removal of forest residues, and consequently of the depletion of the organic layer, should be higher in soils, where the mineral layer is poorer as a substantial proportion of nutrients is allocated in the organic layer.