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 m 3 ·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.Résumé : Les comparaisons entre les systèmes de jardinage et de coupe à diamètre limite ont souvent produit des résultats divergents lorsqu'elles étaient basées sur des essais réalisés dans des cadres spécifiques. Nous avons utilisé une approche par simulation pour évaluer la production de bois de sciage au cours de trois cycles de coupe appliqués à 10 parcelles dominées par l'érable à sucre (Acer saccharum Marsh.) et qui se distinguaient par la structure initiale de la forêt. Les traitements simulés dans chaque parcelle comprenaient trois intensités (faible, modérée et forte) pour chaque système sylvicole. Le volume de bois de sciage récolté était initialement plus élevé dans toutes les parcelles soumises à une coupe à diamètre limite, mais le rendement de la coupe de jardinage a dépassé celui de la coupe à diamètre limite lors d'interventions ultérieures dans 7 des 10 parcelles. Les différences de volume entre les types de coupe variaient de 0,3 à 26 m 3 ·ha -1 selon la parcelle, ce qui correspond à de différence de moins de 1 % jusqu'à de différence double. Le volume moyen des interventions ulté-rieures de la coupe de jardinage étaient de 20 % à 40 % plus grand que celui de la coupe à diamètre limite, notamment grâce à la production soutenue de grosses billes de sciage (≥46 cm). Le rendement de peuplements réels peut être différent de ces simulations à cause des pertes dues à la mortalité (non simulées ici) qui peuvent varier selon le traitement en fonction de la compétition ou des blessures d'exploitation. Les résultats indiquent que le volume cumulé de bois de sciage provenant d'interventions répétées dans le cadre d'un système de jardinage pourrait éventuellement surpa...

Potential Yields and Economic Returns of Natural Disturbance-Based Silviculture: A Case Study from the Acadian Forest Ecosystem Research Program

“…Furthermore, selection systems may homogenize forest structure and composition beyond the patterns present in late-successional or oldgrowth forests by using strict size-based regulation (Angers et al 2005, Keeton 2006, Franklin et al 2007. For example, in this study, a single-tree selection system achieved greater production rates and more sustained yields of merchantable products over time than other naturally regenerated systems, probably because the homogeneous application of the system enabled better redistribution of available growing space to quality trees throughout the stand (Crow et al 2002, Saunders and Wagner 2008, Bohn et al 2011.…”

Improving tree selection for partial cutting through joint probability modelling of tree vigor and quality

“…When applying selection cuttings in Quebec, tree marking rules generally include a maximum diameter for the residual stand (Nyland 1998;Bohn et al 2011), and all trees above this threshold are systematically marked. To harvest around one-third of the standing volume at each 15-to 25-year cutting cycle, additional trees are marked in all of the diameter class with a focus on LV trees.…”

The importance of large-tree retention for the persistence of old-growth epiphytic bryophyte Neckera pennata in selection harvest systems

“…Selection cutting promotes regeneration of shade-tolerant and commercially important tree species, such as sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis) and its goal is to recreate or maintain an uneven aged structure with balanced diameter distributions (cohorts) (Nyland, 1998 intensity to provide fairly constant production of high quality timber (Nyland, 1998;Bohn et al, 2011). However, when comparing old-growth forests to stands treated through selection cutting, there are substantial differences in forest structure and composition.…”