Harvest caused soil disturbance decreased suckering capacity of quaking aspen (Populus tremuloides Michx.) following growing season harvests in Minnesota, USA

The effect of soil disturbance on quaking aspen (Populus tremuloides Michx.) sucker density and height growth was measured in mixed aspen and hardwood stands in east central Minnesota, USA. Loggers harvested stands during the growing season resulting in a range of soil disturbance conditions. Soil disturbance and parent stand aspen density accounted for a significant amount of the variation in suckering two full growing seasons after the harvest. Mineral soil exposure did not significantly affect total sucker density, but decreased sucker height growth as measured by the cumulative height of all suckers in a plot (sucker length) and density of suckers more than 1.2 m tall. Both shallow (<5 cm) and deep (5-15 cm and >15 cm) soil disturbance caused by machine traffic reduced sucker density and sucker length. Results indicated an effect of machine traffic on suckers in trafficked areas, but not adjacent areas. The long-term effects of reduced height growth in disturbed areas and severely reduced density in trafficked areas are not well understood. Loss in early height growth is likely to have long-term effects on productivity, and it is unlikely that aspen will recolonize rutted areas in time to recover full aspen productivity in trafficked areas in one rotation.