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Harvard Forest Symposium Abstract 2018

  • Title: Response of trees to extreme events in temperate forests
  • Primary Author: Caitlin Keady (Bates College)
  • Additional Authors: Ross Alexander (Illinois Mathematics and Science Academy); Emery Boose (Harvard Forest); Matthew Lau (Harvard Forest); Neil Pederson (Harvard Forest)
  • Abstract:

    Temperate forests in the Northeastern United States are experiencing higher temperature and precipitation variability, which potentially increases the occurrence of extreme events that could threaten plant communities. We compare climate response from 1964 to 2002 for several species present in sites in central Massachusetts, Southwestern New Hampshire, Southern New York, and the Adirondacks to identify years when trees are particularly sensitive to temperature and precipitation. Furthermore, we use principal component analysis on narrow and wide ring years to describe climatic factors driving or limiting growth. Climate response reveals significant correlations with current year temperature and precipitation during the first half of the 20th century in southern New York State that nearly disappears in the second half of the 20th century. From 1964 to 2002, we hypothesize that the climate response is weak across sites, potentially due to favorable growing conditions and elevated CO2, attributable to global climate change. In our analysis of extreme ring width years, 1991 is the most common narrow ring year across several sites and species, however there is no clear climatic variable limiting growth across sites and species. The 1960's also appear as narrow ring years, however that is likely due to widespread drought. Our work here indicates that the vulnerability of trees to extreme events can supersede the prevailing conditions of the growing season.

  • Research Category: Regional Studies; Historical and Retrospective Studies; Group Projects