Assessment of forest logging influence on soil environment

Mechanized ground-based logging methods are widely used today since they generally provide a safe work environment and high labor productivity. However, forest soils, so often characterized by humus rich soft and biologically active top horizons are particularly prone to compaction during logging operations and, as a consequence, other forms of degradation. This work evaluated the logging effect on soil, dealing with both its physical and biological properties. Two areas were investigated in Central Italy. In the first one, a stand of Umbrella pine growing on sandy soils, impact due to heavy machineries in clear cuts carried out in 2006 or 2011 were compared. In the second area, a conifer mixed stand growing on clay loam soils, wheeled and tracked tractors impact on soil were compared during thinning carried out in 2013. In both the study sites and both in trafficked and control areas, soil samples were collected to determine bulk density and porosity; in the field, we measured the resistance of soil to penetration and shear strength. Other soil samples were studied in terms of specific and quantitative composition of soil microbial communities by molecular approaches. The results showed significant differences in soil physical and biological characteristics between the trafficked areas and the control, which underline the necessity to carefully plan and check such logging operations.