Simulation of thinning with a single-grip harvester

A simulation model of a single-grip harvester was constructed to evaluate different silvicultural treatments and to compare different machine concepts with a minimum of confounding factors. The model simulates machine movement, boom movement, felling, delimbing, and cross-cutting in stands where both size and position of each tree are known. To validate the model, model output was compared with data from recent time studies. Effects on harvester productivity of three harvesting intensities (extraction of 30, 40, and 50% of the basal area when thinning from below) and four distances between machine positions were studied. Productivity increased when harvesting intensity and with distance between machine positions.