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Harvard Forest REU Symposium Abstract 2016

  • Title: Measuring Soil Respiration in an Infested Hemlock Stand
  • Author: Sarah B Goldsmith (Rochester Institute of Technology)
  • Abstract:

    Eastern Hemlock (Tsuga canadensis) stands are in decline throughout the eastern United States due the Hemlock Woolly Adelgid (HWA, Adelges tsugae) and due to their significance to carbon cycling, there is particular interest in understanding how their deterioration will influence soil respiration and carbon storage. The intent of this project was to determine how soil respiration differs between infested and relatively healthy stands of hemlock forest. Automated chamber systems were installed in two hemlock stands-- one where HWA has caused significant damage (damaged stand) and one where the forest is still fairly intact (intact stand). Each system consists of six automated chambers that measure CO2 concentration, six soil temperature probes, and two soil water content probes in the mineral layer. The rate of soil respiration was determined by a linear regression of CO2 concentration over time. Despite higher temperatures at the damaged stand than the intact stand and similar soil moisture contents between stands, rates of respiration were lower at the damaged stand. This result indicates that, accordant with estimations by Raymer et al. (2013), rates of respiration in damaged hemlock stands will initially decrease following HWA invasion due to the decrease in autotrophic respiration. It was also observed that while soil water content appears to have less of an impact on overall respiration than temperature, rapid increases in soil moisture following rain events tended to correspond with spikes in soil respiration, likely due to concurrent stimulation of heterotrophic respiration.

  • Research Category: Soil Carbon and Nitrogen Dynamics