Commercial thinning in white spruce stands

This report details a commercial thinning study conducted in white spruce stands near Calling Lake, Alberta, in 2002, with the aim to understand its impact on forest growth, yield, and overall development. The study investigated three different removal levels (30%, 50%, and 70% of basal area), along with an uncut control. Key aspects examined were the productivity and cost-effectiveness of harvesting and forwarding operations using a Timberjack harvester and forwarder, the extent of damage to residual trees, and the influence of non-merchantable brush on harvester efficiency. The findings indicate that higher removal levels generally led to increased productivity for both machines, and that pre-harvest brushing significantly improved harvester efficiency by enhancing visibility and reducing wasted cuts.