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Harvard Forest Symposium Abstract 2016

  • Title: Placing the record warmth of 2012 in the Northeast US in a long-term perspective
  • Primary Author: Kevin Anchukaitis (Woods Hole Oceanographic Institution)
  • Additional Authors: Kevin Anchukaitis (Woods Hole Oceanographic Institution); Daniel Bishop (Harvard Forest); Jeffrey Donnelly (Brown University); Jessie Pearl (Massachusetts Institute of Technology); Neil Pederson (Harvard Forest)
  • Abstract:

    The record warmth of 2012 comes at the end of a sharp uptick in warming across the Northeastern US. 2012 ended up as the warmest year in the instrumental record of the past 118 years for 8 of the 10 states in the Northeastern US; the remaining two ranked 3rd and 4th all time. While nighttime and winter warming has been significant in this region, warming during the growing season has generally lagged the pace observed at the global scale. Yet, we do not know whether warmth of 2012 stands and recent warming of the last three decades stands in a long-term perspective. The northeastern US is one of the few mid- to high-latitude regions lacking an annually-resolved centennial length reconstruction of paleotemperature. We are in the process of developing multimillennial reconstructions of temperature from the northeastern United States using living and subfossil Atlantic white cedar (Chamaecyparis thyoides) trees. It is possible to make a temperature reconstruction of this length for two reasons. First, earlier work indicates Atlantic white cedar to be one of the most temperature-sensitive tree species in the region. Red spruce (Picea rubens) is the other, but its signal is complicated by acid rain. Second, Atlantic white cedar has been shown to be well-preserved in wetland environments for centuries, providing the potential for reconstructing an extra-long record for reconstruction. Preliminary findings indicate that many living Atlantic white cedar forests are 150 years or younger. Results from those data suggest 2012 to be the warmest year over that period. However, recent field excursions are unveiling even older trees and the collection of subfossil material continues. In 2015, we updated and improved sample depth of living collections at Saco Heath (MA), Appleton Bog (ME), Westminster (MA), Cape Cod (MA), Woods Hole (MA), Putnam County (NY), Bellevale Mountain (NY), Uttertown (NJ), and North Madison (CT). Subfossil records, samples buried in the upper layers of wetlands and lakes, have been collected from southern New Jersey (Dennis Creek) and the Meadowlands (NJ) to Cape Cod in eastern Massachusetts. We observed an increasing growth trend across most Atlantic white cedar stands since 1950. The one exception to this are the trees at Bellevale Mountain in New York State, which experienced a prolonged decline in growth that we hypothesize to be the result of an ice storm in 2002. The subfossil material has the potential to extend this record back 1000 or more years. We are also investigating whether a multi-species approach to a temperature reconstruction strengthens the climate signal in New England versus those based solely upon Atlantic white cedar. Once developed, our annually-resolved late Holocene reconstruction will be used to characterize variability in regional temperatures at time scales from interannual to millennial, to evaluate climate model simulations over the last millennium, and identify the signature of internal, remote, and global forcing on the climate of the northeastern United States.

  • Research Category: Forest-Atmosphere Exchange
    Historical and Retrospective Studies
    Regional Studies