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Harvard Forest Research Project 2022

  • Title: Lymantria dispar & Oak Dynamics at Harvard Forest and Central Massachusetts
  • Principal investigator: Audrey Barker Plotkin (
  • Institution: Harvard Forest
  • Primary contact: Audrey Barker Plotkin (
  • Team members: Meghan Blumstein; Robert Fahey; Danelle Laflower; David Orwig; Valerie Pasquarella; Keenan Rivers; Dominick Sullivan; Danielle Tanzer; Greta VanScoy
  • Abstract:

    For most of the 20th century, spongy moth (Lymantria dispar) was the most serious insect threat to forests and shade trees in the northeastern United States, but outbreaks have been sporadic and light since 1989, after the successful establishment of a fungal pathogen, Entomophaga maimaiga. However, in 2016 a surprising new outbreak of gypsy moth began in southern New England, resulting in dramatic oak (Quercus spp.) mortality across thousands of forested hectares by 2018. Defoliation severity varied across the landscape, resulting in a patchwork of sites that were defoliated 0, 1, 2, or 3 years by the time the outbreak wound down in 2019. Biomass loss to oak mortality ranged from 12% for sites defoliated one year only to >60% for sites defoliated three years. We seek to understand the predictors of oak mortality and dieback, and the long-term consequences of defoliation on forest productivity, structure, and composition. Our study sites are primarily located in the Quabbin Watershed Forest. We also established 2 plots on Harvard Forest land.