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

Abstract

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.