Forest floor protection during drilling pad construction promotes resprouting of aspen

- Current practices for constructing drilling pads require the stripping of topsoil.
- Protecting the original forest floor during winter drilling with subsoil could be an alternative.
- Leaving the forest floor in place increased aspen forest recovery 10-fold compared to stripping.
- It is critical that machine operators can delineate the subsoil from forest floor during clean-up.

Drilling pads that are used to explore petroleum reserves in the boreal forest are often only used for a short time. We studied the vegetative regeneration potential of aspen (Populus tremuloides) through root suckers as a means to rapidly recover forest vegetation in these disturbed sites. We compared protecting the original forest floor under a layer of subsoil during the leveling of drilling pads, with the current practice of stripping off the forest floor and topsoil and placing it back on the site (Rollback) in the re-contouring of the reclamation phase. We also tested three techniques of delineating the forest floor so that it can be effectively uncovered during the reclamation phase. After re-contouring and top soil placement on the sites, we assessed the extent of surface disturbance, soil temperature, soil bulk density, and the density and height of aspen regeneration. Aspen suckers were tallest, had the highest density and had better survival when the forest floor was protected compared to the standard Rollback treatment. When protecting the forest floor, delineating the original forest floor from the subsoil cover resulted only in small differences in the aspen regeneration among delineation treatments with little impact on soil compaction and only moderate effects on soil surface disturbance. The study indicates that protection and the careful uncovering of the forest floor with or without using a delineation layer should be a preferred strategy for temporary drilling pad construction and their subsequent reclamation in aspen-dominated boreal forests.