In the summer of 2015, FPInnovations completed a silviculture study as part of a larger project in the Rocky Mountain Foothills of Alberta. The project included concurrent FPInnovations trials that evaluated the fuel efficiency of ground-based harvesting and forestry equipment working on steep slopes.
Chinook winds in this region cause up to 30% tree seedling mortality from winter desiccation on exposed south-facing slopes. Slash was returned to the cutover to provide the planted seedlings protection from exposure. The cost and effectiveness of the slash return techniques, and the impact of slash return on site preparation treatment in terms of achieving a desired density of plantable spots, were evaluated in five different treatments. Generally, returning slash to the cutover is a cost-effective treatment, especially if it increases seedling survival and reduces future fill-planting costs.
The cost of a “hot logging” harvesting treatment that used two processors working together with one skidder was lower than a standard separate-phase harvesting treatment, as long as there were no lengthy unplanned breakdowns or delays. Post-treatment measurements showed that all five treatments provided at least twice the density of slash” microsites required to meet minimum stand density objectives. Future research is needed to determine which slash microsites become occupied (natural or planted) and which slash microsites are effective at protecting seedlings from winter desiccation.
For more information, please contact Grant Nishio, Silvicultural Operations.