Incidental Effects of Cut-to-Length Harvest Systems and Residue Management on Populus tremuloides (Michx.) Regeneration and Yield
In Great Lakes aspen forests, clearcutting and whole-tree skidding (WTS) has been the usual practice. Soil disturbances from WTS sometimes lead to regeneration declines in areas of high equipment traffic. Advances in harvesting mechanization have resulted in increased utilization of cut-to-length (CTL) processing equipment, which can reduce site impact through placing harvest residues in operational corridors to spread surface load posed by equipment. While these practices may mitigate soil disturbance, heavy residue loads can decrease aspen regeneration. We sampled soil conditions and regeneration systematically, in transects perpendicular to CTL trails, and compiled metrics of residue loads, regeneration density and height, and soil characteristics to examine potential interactions. Our results indicate that residues are notably greater directly on the equipment trail when compared to adjacent areas, and that these trends correspond with a significant loss in regeneration height and density. Further, we observed a 186% increase in the stand area affected by CTL operations compared to those reported for WTS methods elsewhere. We projected these trends with growth and yield simulations, which suggest a reduction in timber yields at rotation age as compared to stands without explicit CTL equipment trails. These patterns may have unintended influences on effective stand regeneration and threaten short-term productivity and future yields. The impact of harvesting equipment and residues on edaphic conditions and recovering vegetation is likely site and cover type specific.
Premer, M. I., and R. E. Froese. 2018. Incidental effects of cut-to-length harvest systems and residue management on Populus tremuloides (Michx.) regeneration and yield. Forest Science 64:442–451.