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Harvard Forest Research Project 2022

  • Title: Ecosystem processes associated with intact and logged hemlock forests
  • Principal investigator: David Orwig (
  • Institution: Harvard Forest
  • Primary contact: David Orwig (
  • Team members: David Orwig
  • Abstract:

    The recent unimpeded infestation of the hemlock woolly adelgid (HWA; Adelges tsugae Annand) across the northeastern U.S. has created a situation in which large-scale hemlock decline and mortality is occurring. HWA has already infested over 40% of the towns in Massachusetts and, as a result, many landowners are choosing to pre-emptively harvest their hemlock stands. Information from timber harvesters, state agencies, and studies of landscape patterns of hemlock decline in southern New England indicate that the recent broad scale increase in logging associated with HWA is occurring with little ecological assessment and in the absence of scientific background for conservationists, land managers, or policy makers.

    We are continuing soil and micorenvironmental monitoring in eight large (0.8 ha) experimental plots at the Simes Tract of the Harvard Forest. There are two replicates of the following treatments: hemlock girdling (to simulate many of the effects of HWA), hemlock commercial logging (to simulate the preemptive logging that is occurring in hemlock forests in our region), hemlock control (no treatment), and hardwood control (representing a possible future composition of post-hemlock forest). In addition we are comparing results from the Simes plots with recently logged and uncut infested plots at the urban Arnold Arboretum site, an infested forest in Quabbin Reservation (Shay�s Brook) and eight long-term sites in Connecticut. Baseline sampling of the now infested hemlock grid plots will also continue.