Physical effects of site disturbance on peatlands. Can. J. Soil Sci. 78: 45–50. Forest harvesting on peatland sites
during the frost-free season often creates water-filled ruts and transfers more humified layers of peat to the surface. Foresters have generally assumed that such disturbance has negative consequences related to proliferation of graminoid vegetation, disruption of surface drainage leading to raised water tables and, possibly, reduced site productivity. An experiment was established during 1996 near Cochrane, Ontario to examine the physical impacts of site disturbance on peatlands. Summer traffic by forest harvesting equipment was imposed at three intensities on a Black Spruce–Speckled Alder site type. The fractional area of surface disturbance increased with the amount of traffic, but disturbance effects on the thickness of the aerated zone, depth to the water table, and microtopography were not significant. However, the consistency of the effects produced by the most intense disturbance treatment suggests that it reduced average elevations and aerobic layer thicknesses, and increased water levels, by 2 to 6 cm. The hydrological effect of site disturbance in this study was small compared with the typical effect of forest canopy removal on water levels.

Forest harvesting; peat; peatlands; site disturbance; hydrology