• Ebeling, Robert A.
  University of Maine Graduate School
  

An investigation was conducted to determine the potential value of a combined mechanical-motormanual density control system in dense young spruce-fir stands. A hydro-AX 520 prime mover equipped with a rotary swath cutter was used in association with manual brushsaw workers. Both methods were evaluated using time studies on three sites on Scott Paper Company timberlands in west-central Maine. Conclusions pertaining to density control costs per acre are drawn based upon sensitivity analysis results. Under the study conditions, a precommercial thinning system employing some mechanization is cheaper than motormanual treatment alone. Total system costs are sensitive to the percentage of mechanical treatment only at high machine utilization rates or high labor costs. The level of mechanical treatment is limited more by silvicultural constraints than economic factors.