Seven-Year Changes in Bulk Density Following Forest Harvesting and Machine Trafficking in Alberta, Canada

Processes responsible for natural recovery of compacted forest soils are poorly understood, making estimating their problematic. Bulk density was measured over 7 years at nine boreal sites in Alberta, Canada, where harvest-only and three skidding treatments were installed (~10,000 samples). Air soil temperatures, moisture redox potential, snow depth also on the adjacent seven-cycle skid trail. Significant increases bulk occurred when water potential wetter than ?25 kPa. After 1 year, an additional significant increase 0.03 Mg m?3 across all treatments, depths, sites. The is attributed to mechanics process rebound disruption biological processes. By year 7, secondary had recovered trafficked soil, but not area. Some freezing no effect density, which moderated by snowpack. array physical processes, texture, supply, weather required make effective decompacting agent did occur. shrink–swell relevant because remained wet. As a result, failed recover after 20 cm. freeze–thaw as decompaction far more complex commonly assumed, its effectiveness cannot be assumed temperatures below 0 °C measured.