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Harvard Forest REU Symposium Abstract 2017

  • Title: The complexity of tree response to extreme climatic events in temperate forests
  • Author: Caitlin A Keady (Bates College)
  • Abstract:

    Temperate forests in the northeastern US are experiencing greater temperature and precipitation variability, which potentially increases the occurrence of extreme events that could threaten plant communities. Using daily temperature and precipitation data, we investigate the consistency of tree response to climate across space and time and how it changes during extreme years. We compare climate response from 1964 to 2002 for several species present in central Massachusetts, Southwestern New Hampshire, Southern New York State, and the Adirondacks to identify years when trees are particularly sensitive to temperature and precipitation. Also, we use principal component analysis on narrow and wide ring years to describe climatic factors driving or limiting growth. In southern New York State, climate response reveals significant correlations with current summer temperature and precipitation during the first half of the 20th century, however that signal nearly disappears in the second half of the 20th century. From 1964 to 2002, climate response is weak across all sites, especially Harvard Forest. This is likely due to favorable growing conditions, possibly 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 at that time throughout sites. This is true of several narrow ring years, highlighting the potential for site elevation, soil moisture, light availability, etc. to affect climate response. This study also stresses the importance of using daily data to reveal nuances in monthly climate response.

  • Research Category: Regional Studies