Soil aeration and soil water tension in skidding trails during three years after trafficking

CO2 measurement, monitoring of soil water tension, and redox indication with iron rods showed that driving with harvester and forwarder not only affected the wheel tracks but also the unpassed middle lane of the skidding trails. Decrease of CO2-concentration in the soil air indicated an initial regeneration of air diffusivity in the first 6 cm of the impacted soil within the first three years after trafficking. Iron rods had significantly different frequencies of reducing conditions in the order wheel tracks > middle lane between wheel tracks > undisturbed soil. Iron rods indicated no recovery of soil aeration in depth 12-24 cm during the three years of observation. The soil water tension reflected the transpirational water extraction by trees in the undisturbed soil in the course of the vegetation period (from spring to summer/autumn). In the skid trail the water tension indicated a more water filled porosity than in the undisturbed soil. The generally weaker water tension in the skid trails indicated, that also the middle lane between the wheel tracks was separated from the transpirational flow of soil water to the trees. CO2-concentration in soil air at 6 cm depth in summer was more related to soil water tension than to soil temperature.