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Harvard Forest Research Project 2022

  • Title: Trends in soil carbon stocks and fluxes in a hemlock stand infested by the hemlock woolly adelgid
  • Principal investigator: Adrien Finzi (
  • Institution: Boston University
  • Primary contact: Audrey Barker Plotkin (
  • Team members: Marc-Andre Giasson; Mark VanScoy
  • Abstract:

    The main objective of this research is to study changes in soil carbon stocks (soil C, root biomass) and fluxes (soil respiration, i.e. soil CO2 efflux) in a hemlock stand that is currently infested by the hemlock woolly adelgid, an invasive insect, and where trees are declining in vigor and dying off. Because our team has collected similar data in the same stand (circa 2010) prior to the infestation, it gives us a rare opportunity to study soil carbon dynamics before, during, and after a major disturbance event.

    Soil respiration will be measured using two automated soil respiration chamber systems comprising six chambers each. Soil respiration will be measured once every 30 minutes on each of 12 collars throughout the growing season. This time and space data resolution will allow us to calculate a good estimate of soil respiration in the stands.

    In previous years, we collected soil samples in 17 plots located in two different areas in the hemlock stand: 13 plots south-west of the Hemlock Tower and 4 plots in the Bigelow Brook Weir area to quantify soil carbon and fine root biomass. Samples were processed at Boston University to determine live and dead root biomass, and root and soil C and N content. A second set of samples will be collected in a few years to study the change in these C pools following hemlock die off.