Hardwood-dominated forests in south-central Chile have shade-tolerant and mid-tolerant tree species capable of regenerating and growing well in partial shade. To test the potential for using an uneven-aged silviculture in these forests, we established single-tree selection treatments at two mid-elevation sites within the Evergreen forest type in the Coastal range (Llancahue and Los Riscos, 40–42° S Lat). They had an average initial basal area of 70–80 m² ha⁻¹. In each stand, we established four 2000 m² plots with a residual basal area of ~40 m² ha⁻¹, and four with a residual basal area of ~60 m² ha⁻¹. We planned for a maximum residual diameter of 80 cm, but needed to leave 20%–25% of the residual basal area in larger trees due to their great abundance in these old-growth forests. We re-measured these plots 5–6 years after the cuttings. We used mixed-effects models to evaluate the periodic annual increment (pai) in diameter and the abundance of tree regeneration, and linear models to evaluate ingrowth and changes in the basal area and volume. At Llancahue, the diameter pai of individual trees was significantly greater in the treatment with lower residual densities, especially for mid-tolerant species in lower diameter classes (5–20 cm). At both sites, the pai in the stand basal area and volume was greater in the more heavily stocked treatment, but differences were significant only at Llancahue. Regeneration was dominated by shade-tolerant species at both sites but was more abundant and more diverse at Llancahue. Taller tree regeneration (50–<200 cm) significantly increased after the cuttings at both sites, while small regeneration (5–<50 cm) overall remained at pre-cut levels. This pattern was similar for mid- and shade-tolerant species. However, we found no differences in regeneration responses between the lower and higher levels of the residual basal area. Sapling densities did not differ at both sites for shade-tolerant species, but for mid-tolerant species these were more abundant at Los Riscos. While both sites had many similar trends after implementing selection cuts (a greater individual growth in the treatment with lower basal areas but a higher stand-level growth in the treatment with a high basal area, more abundant regeneration of shade-tolerant species, etc.), they illustrate a differential potential for implementing uneven-aged silviculture, especially due to site-species interactions. These results are a first step towards evaluating the prospects for selection cuttings in these experiments and elsewhere in Valdivian temperate rainforests.

The January 1998 ice storm broke off tree crowns across a wide geographic area in northeastern North America, and forest tent caterpillar (Malacosoma disstria Hubner) defoliated some of the same stands in 2004–2007. We assessed the post-event growth responses of upper canopy sugar maples (Acersaccharum Marsh.) in previously thinned and recently rehabilitated even-aged northern hardwood stands in New York State, USA. Cores from ice-storm-damaged trees showed an initial radial growth reduction, a recovery after one year, and an increase to or above pre-storm levels after three years. A later forest tent caterpillar defoliation in the same stand caused a second reduction of growth, and another recovery after one year. We observed greater post-storm radial growth on trees released by a post-ice storm rehabilitation treatment than in the untreated control, with growth exceeding pre-storm rates. Cores from another site thinned 38 years earlier and impacted only by the forest tent caterpillar showed a more moderate growth reduction, and a prompt but smaller post-defoliation growth response than among trees affected by both the ice storm and defoliation. Findings reflect the potential for growth of upper canopy sugar maple trees to recover after a single or two closely occurring crown disturbances, and provide guidance to managers who must decide about removing or continuing to manage stands after similar kinds of ice storm damage or defoliation.

The research evaluated opportunities for cutting off small understory beech root suckers at 0.6-0.9 m above ground. By six years (pilot test) after cutting with lopping shears in a closed-canopy uneven-aged northern hardwood stand, 91% of high stumps lacking a residual live branch had died. Of those cut above the lowest living branch, all survived. In a later operational trial by contract crews using chainsaws two growing seasons before a selection system cutting, 75% of high stumps without a residual live branch had died by the fifth year. Of stumps cut below the lowest living branch and that initially sprouted, only 7% had a live sprout by the sixth year. Among high stumps cut above the lowest branch, 84% survived.

Tree diameter growth models for northern hardwoods commonly used large data sets representing a composite of stands with varying management histories, structural characteristics, and age distributions. Yet common predictor variables like diameter can show differences in growth patterns for stands with different age structures and management histories. To address that, we modeled growth and mortality for sugar maple, red maple, and yellow birch in thinned even-aged Adirondack northern hardwoods. Findings indicate that change in diameter depends on initial diameter for sugar maple, with the rate decreasing exponentially from the largest size class to the smallest. Initial diameter did not prove significant with red maple and yellow birch in these thinned stands, perhaps because of the limited sample of trees of small diameter. Stand relative density and time since treatment affected growth for all three species. Those variables also proved significant for predicting mortality of sugar maple. Analyses revealed fewer losses of sugar and red maples among the larger diameter classes, but no relationship with diameter for yellow birch. Plot relative density did not affect mortality with red maple, but time after thinning had a significant effect on survival of all species.