Comparing selection system and diameter-limit cutting in uneven-aged northern hardwoods using computer simulation

Comparisons of selection system and diameter-limit cutting based on trials in specific settings have often yielded conflicting results. We used a simulation approach to evaluate sawtimber production over three cutting cycles on 10 sugar maple (Acer saccharum Marsh.) dominated plots of varying initial forest structure. Treatments on each plot included light, moderate, and heavy intensities of selection system silviculture and diameter-limit cutting. Harvested sawtimber volumes were initially higher on all plots using diameter-limit cutting, but selection system outperformed diameter-limit cutting at later entries on 7 of the 10 plots. Volume differences between cutting types ranged among plots from 0.3 to 26 m3·ha–1, equating to a less than 1% to as much as a twofold difference. Average volumes from selection system at later entries were 20%–40% greater than diameter-limit cutting, due in part to consistent production in large sawtimber (≥46 cm). Yields from real stands could vary from these simulations where mortality losses (not modeled here) differ between treatments as a result of competition or logging damage. Findings suggest that cumulative sawtimber volumes from repeated selection system silviculture could eventually surpass that of diameter-limit cutting, but at a rate depending on initial stand conditions and harvesting intensity.