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Harvard Forest Symposium Abstract 2015

  • Title: Long-term structural dynamics of virgin Tsuga canadensis-Pinus strobus forests on the Harvard Tract, Pisgah, NH
  • Primary Author: Anthony D'Amato (University of Vermont (UVM))
  • Additional Authors: Audrey Barker Plotkin (Harvard Forest); David Foster (Harvard Forest); David Orwig (Harvard Forest)
  • Abstract:

    An understanding of the influence of disturbance on the structure and function of forest ecosystems has long been a central element in the development of forest conservation and management approaches, as well as forest and ecosystem simulation models. In many cases, investigations from old-growth systems have been used both to approximate natural forest patterns and processes to guide this work and serve as natural benchmarks for comparison with contemporary managed forests or those developing following historic periods of intensive land use. The frequency of stand replacing disturbance is quite low for many temperate regions of the globe and correspondingly much of our understanding of structural and compositional dynamics of temperate old-growth forest systems is within the context of fine-scale and occasionally mesoscale disturbances. Nevertheless, historical accounts of disturbance regimes for these regions highlight the historical importance of infrequent, high severity disturbances such as hurricanes, straight-line wind events, and crown fire.

    This study took advantage of a unique, long-term (> 70 year) history of detailed Harvard Forest research in an old-growth landscape in southern New Hampshire spanning a range of site qualities and conditions to quantify the impacts of a stand-replacing hurricane event on long-term coarse woody debris (CWD) volume and biomass development. Reconstructions of pre-hurricane conditions from CWD highlight the tremendous range and magnitude of structural conditions and aboveground biomass historically characterizing old-growth hemlock (Tsuga canadensis)-white pine (Pinus strobus) systems and the persistence of woody debris legacies in shaping forest development and biomass pools 70 years removed from a stand-replacing event. CWD biomass ranged considerably across the landscape, with localized accumulations approaching those observed for Pseudotsuga menziesii forests in the Pacific Northwest (~503 Mg/ha), particularly in areas where Pinus strobus was present in the pre-disturbance canopy. These findings provide important insights on the potential upper bounds for aboveground carbon storage for forests in northeastern North America and underscore the importance of considering the impacts of post-disturbance management treatments on deadwood legacies and associated functions.

  • Research Category: Conservation and Management; Historical and Retrospective Studies; Large Experiments and Permanent Plot Studies; Regional Studies