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Harvard Forest Symposium Abstract 2016
- Title: The Simulated Hurricane Experiment at 25
- Primary Author: Audrey Barker Plotkin (Harvard Forest)
- Additional Authors: Olutoyin Demuren (Harvard University); Katrina Fernald (Wheaton College (MA)); David Foster (Harvard University)
- Abstract:
Major hurricanes affect central New England every 50-100 years and can cause catastrophic forest disturbance, but few studies have addressed the long term legacies of wind disturbance on forest vegetation change. In 1990, the Harvard Forest began its Long-Term Ecological Research (LTER) program and initiated a large (0.8 hectare) hurricane simulation experiment in a maturing red oak-red maple forest Long term vegetation plots were established at the site, and in a nearby unmanipulated control site. In the experimental plot 250 trees were mechanically toppled in a northwesterly direction, using a winch and a skidder. Eighty percent of the canopy trees, and two-thirds of all trees >5cm dbh, were damaged resulting from direct and indirect effects of the manipulation. In addition, pits and mounds covered 8% of the site and 13% was covered by uprooted tree stems after the pulldown. We now have trajectories of vegetation response for 25 years.
In year 25, most vegetation responses remained on the same trajectories as in year 20. Both the pulldown and control plots gained basal area at the same rates as in prior years (Table 1); herb and shrub community composition changed little over the past 5 years, and litterfall remained steady. However, the number of trees with basal sprouts increased slightly in both the pulldown and control plots in year 25, after declining numbers of sprouts over the prior 10 years. Shrub cover in the control seems to be plateauing at year 25, after steadily increasing over the prior 20 years.
Overall, at year 25, the manipulated plot has stable species composition in the overstory and understory layers. The forest canopy is multi-layered, including emergent surviving red oak stems, a mid-story of surviving red maple, and a rapidly growing new cohort dominated by black birch. In contrast, red oak is becoming increasingly dominant in the control plot, with little recruitment over the past quarter-century.
- Research Category: Large Experiments and Permanent Plot Studies
- Figures: HurricaneResultsYear25.jpg
