Infrequent, intense wind disturbance is an important factor in northeastern U.S. forests, yet little is known about the early stages of vegetation reorganization, or the processes that facilitate biotic regulation of ecosystem function after such storms. We designed an experiment, based on a simulated hurricane blowdown, to examine the relationship of tree damage patterns to mortality and regeneration, community dynamics, vegetation recovery, and ecosystem processes. In October 1990, selected canopy trees in a 50 × 160 m area within a 75‐yr‐old Quercus rubra–Acer rubrum forest in central Massachusetts were pulled over by a winch, using records from the 1938 hurricane to determine the number of trees and direction of fall. The resulting damage to 65% of trees closely approximated effects of the 1938 storm on New England forests. Damage and mortality varied by tree species and size, indicating the importance of pre‐disturbance forest structure and composition in determining the range and severity of impact. Measurements of vegetation and environment in the experimental area and control indicated that, although the manipulated stand sustained dramatic damage and structural reorganization, resilience of trees and understory vegetation provided tight biotic control of ecosystem processes, including nutrient cycling. Continued leaf‐out and induced sprouting by damaged trees, increased growth by saplings and understory plants, and seedling establishment on disturbed microsites stabilized the microenvironment. Our findings are in contrast to studies of disturbances in which mortality was higher when damaged trees were removed from the site. This suggests that salvage logging following wind disturbance may have serious long‐term implications.

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Abstract. Infrequent, intense wind disturbance is an important factor in northeastern U.S. forests, yet little is known about the early stages of vegetation reorganization, or the processes that facilitate biotic regulation of ecosystem function after such storms. We designed an experiment, based on a simulated hurricane blowdown, to examine the relationship of tree damage patterns to mortality and regeneration, community dynamics, vegetation recovery, and ecosystem processes. In October 1990, selected canopy trees in a 50 X 160 m area within a 75-yr-old Quercus rubra-Acer rubrum forest in central Massachusetts were pulled over by a winch, using records from the 1938 hurricane to determine the number of trees and direction of fall. The resulting damage to 65% of trees closely approximated effects of the 1938 storm on New England forests. Damage and mortality varied by tree species and size, indicating the importance of pre-disturbance forest structure and composition in determining the range and severity of impact. Measurements of vegetation and environment in the experimental area and control indicated that, although the manipulated stand sustained dramatic damage and structural reorganization, resilience of trees and understory vegetation provided tight biotic control of ecosystem processes, including nutrient cycling. Continued leaf-out and induced sprouting by damaged trees, increased growth by saplings and understory plants, and seedling establishment on disturbed microsites stabilized the microenvironment. Our findings are in contrast to studies of disturbances in which mortality was higher when damaged trees were removed from the site. This suggests that salvage logging following wind disturbance may have serious long-term implications.

Abstract:The development of a dense tree layer in young coniferous stands can suppress understory plants, leading to very low herb abundance and diversity. In this study, clonal development of the rhizomatous herb Maianthemum dilatatum (Wood) Nels & Macbr. was compared among four types of coniferous forest (young, closed canopy; young, silviculturally thinned; mature; and old growth) on the western Olympic Peninsula, Washington. We predicted that (i) ramet turnover would be lowest, (ii) clonal fragment size would be smallest, and (iii) allocation of resources to leaves would be greatest in young, closed-canopy forests, and that these traits would increase (or decrease for leaves) as understory conditions became more favorable with stand development or thinning. The low frequency of new ramets in young, closed-canopy stands supported the first prediction. The second prediction was also supported: lateral spread and rhizome mass were smallest in these stands. However, allocation to leaves was not higher in dense young stands, indicating that Maianthemum does not respond to stress by increased investment in leaves. Clonal fragments in thinned, mature, and old stands showed no differences in traits, suggesting that once tree canopies rise, canopy gaps form, or young stands are thinned, resource levels are favorable for clonal growth. Maianthemum appears to persist in dense, young stands by maintaining long-lived ramets that produce leaves annually, rather than by increasing rhizome spread, rhizome storage, or allocation to leaves.Key words: age structure, biomass allocation, canopy closure, forest herb, rhizome.Résumé : Le développement d'une dense canopée dans les jeunes peuplements de conifères peut supprimer la végéta-tion de sous-bois et conduire à de très faibles abondances et diversités de petites plantes herbacées. Dans cette étude, les auteurs comparent le développement clonal d'une plante herbacée, le Maienthemum dilatatum (Wood) Nels & Macbr., dans quatre types de forêts conifériennes (jeune à canopée fermée, jeune éclaircie par sylviculture, mature, surannée), situés dans la péninsule Olympique occidentale de l'état de Washington. Les auteurs ont prédit que (i) le cyclage des ramettes serait le plus faible, (ii) la dimension des rameaux clonaux serait la plus faible, et (iii) l'allocation aux feuilles serait la plus élevée dans les jeunes forêts à canopée fermée, et que ces caractéristiques augmenteraient (ou diminueraient) à mesure que les conditions de sous-bois deviendraient plus favorables avec le développement ou l'éclairci du peuplement. La faible fréquence des nouvelles ramettes dans les peuplements jeunes à canopée fermée supportent la première prédiction. La seconde prédiction s'avère également juste : le développement latéral et la masse de rhizome sont plus faibles dans ces peuplements. Cependant, l'allocation aux feuilles n'est pas plus forte dans les jeunes peuplements denses, ce qui indique que le Maienthemum ne réagit pas à l'ombrage par un investissement accru dans les feuilles. Les fragme...