Survivors, not invaders, control forest development following simulated hurricane

Abstract

Abstract. Wind disturbance profoundly shapes temperate forests but few studies have evaluated patterns and mechanisms of long-term forest dynamics following major windthrows. In 1990, we initiated a large hurricane simulation experiment in a 0.8-ha manipulation (pulldown) and 0.6-ha control area of a maturing Quercus rubra-Acer rubrum forest in New England. We toppled 276 trees in the pulldown, using a winch and cable, in the northwesterly direction of natural treefall from major hurricanes. Eighty percent of canopy trees and two-thirds of all trees !5 cm dbh (diameter at breast height) suffered direct and indirect damage. We used 20 years of measurements to evaluate the trajectory and mechanisms of forest response after intense disturbance. Based on the patch size and disturbance magnitude, we expected pioneer tree and understory species to drive succession.The first decade of analyses emphasized tree seedling establishment and sprouting by damaged trees as the dominant mechanisms of forest recovery in this extensive damaged area. However, despite 80% canopy damage and 8000-m 2 patch size, surviving overstory and advance regeneration controlled longer-term forest development. Residual oaks make up 42% of stand basal area after 20 years. The new cohort of trees, dominated by black birch advance regeneration, contributes 30% of stand basal area. There were shifts in understory vegetation composition and cover, but few species were gained or lost after 20 years. Stand productivity rebounded quickly (litterfall recovered to pre-disturbance levels in six years), but we predict that basal area in the pulldown will lag behind the control (which gained 6 m 2 /ha over 20 years) for decades to come. This controlled experiment showed that although the scale and intensity of damage were great, abundant advance regeneration, understory vegetation, and damaged trees remained, allowing the forest to resist changes in ecosystem processes and invasion by new species.

Evaluating the ecological impacts of salvage logging: can natural and anthropogenic disturbances promote coexistence?

“…Our results demonstrate that wind disturbance alone largely fails to promote tree coexistence in forests dominated by shade-tolerant and browse-tolerant sapling cohorts and a recalcitrant non-tree vegetation layer (Royo and Carson 2006, Dietze and Clark 2008, Nuttle et al 2013, Plotkin et al 2013. Beyond the recruitment of sub-canopy tree species and the short-lived, shadeintolerant pin cherry (Burns and Honkala 1990), the sapling cohort in areas lacking scarification remained dominated by beech advance regeneration and newly recruited birch (see Kramer et al 2014 for similar results in European beech forests).…”

“…1). Birches often proliferate following disturbance (Carlton and Bazzaz 1998, Fischer et al 2002, Plotkin et al 2013. Moreover, found the birches had the highest absolute growth rate of the regenerating seedlings, particularly when protected from herbivory, at these sites.…”

“…, Plotkin et al. ). Beyond the recruitment of sub‐canopy tree species and the short‐lived, shade‐intolerant pin cherry (Burns and Honkala ), the sapling cohort in areas lacking scarification remained dominated by beech advance regeneration and newly recruited birch (see Kramer et al.…”

Sprouting and seed production may promote persistence of green ash in the presence of the emerald ash borer

“…Of particular interest are processes that may heavily influence post‐outbreak recovery, such as the ecological role of surviving trees (Plotkin et al. ), seed production and dispersal (Turnbull et al. ), and recruitment limitation (Clark et al.…”

Windthrow Dynamics in Boreal Ontario: A Simulation of the Vulnerability of Several Stand Types across a Range of Wind Speeds

“…The duration of each cycle will depend upon species growth rates and site productivity. Stand types that experience partial damage (in our study, the mixed conifer-hardwood stands), even at high wind speeds are more likely to persist as multi-aged and mixed species stands, promoting structural diversity [36].…”