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Harvard Forest Symposium Abstract 2014

  • Title: Building a foundation: land-use history and dendrochronology reveal temporal dynamics of a Tsuga canadensis (Pinaceae) forest
  • Primary Author: Aaron Ellison (Independent)
  • Additional Authors: Audrey Barker Plotkin (Harvard Forest); Peter Kerson (N/A); Michael Lavine (University of Massachusetts - Amherst ); David Orwig (Harvard Forest)
  • Abstract:

    We used historical documents, stand mapping, and new methods of dendrochronological analysis to reconstruct 250 years of land-use history of the Simes Tract in Petersham, Massachusetts. These data were then used to interpret the origin of the current forest stand structure of the experimental plots of the Harvard Forest Hemlock Removal Experiment within the Simes Tract; this experiment examines the effects on forest ecology of the ongoing decline of Tsuga canadensis. Trees in the experimental plots are < 150 years old, and have established continually since the 1870s, with recruitment pulses following successive episodes of land division and re-aggregation, logging, irruptions of pathogens and pests, two moderate droughts, and the 1938 hurricane. Tsuga canadensis, hypothesized to be a foundation species in this system, achieved its current dominance at the Simes Tract by responding rapidly, both positively and uniformly across age classes, in the 1920s to three concomitant environmental changes that occurred in the preceding two decades: loss of Castanea dentata to the chestnut blight; selective logging; and a ≈7-year drought. In contrast, the other common species in this tract – Betula lenta, Quercus rubra, Acer rubrum, and Pinus strobus – currently are less important in this tract. Quercus rubra, A. rubrum, and P. strobus were selectively harvested or severely damaged by the 1938 hurricane and the 1981 gypsy moth outbreak, whereas the peak of Betula lenta establishment followed the 1938 hurricane. The data illustrate the contingent nature of the establishment dynamics of a foundation species in a New England forest and the potential long-term impermanence of this foundation, and suggest a more nuanced approach to the role of T. canadensis as a foundation species.

  • Research Category: Historical and Retrospective Studies, Large Experiments and Permanent Plot Studies