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Harvard Forest Data Archive

HF130

Soil Respiration in Hemlock Removal Experiment at Harvard Forest since 2003

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Data

Overview

  • Lead: Eric Davidson, Kathleen Savage
  • Investigators:
  • Contact: Kathleen Savage
  • Start date: 2003
  • End date: 2009
  • Status: completed
  • Location: Simes Tract (Harvard Forest)
  • Latitude: +42.47 to +42.48
  • Longitude: -72.22 to -72.21
  • Elevation: 200 to 240 meter
  • Taxa: Tsuga canadensis (eastern hemlock)
  • Release date: 2012
  • Revisions:
  • EML file: knb-lter-hfr.130.16
  • DOI: digital object identifier
  • Related links:
  • Study type: long-term measurement
  • Research topic: soil carbon and nitrogen dynamics
  • LTER core area: inorganic nutrients
  • Keywords: hemlock, hemlock woolly adelgid, soil respiration, soil temperature, timber harvest
  • Abstract:

    Soil respiration (SR) is a combination of autotrophic (root respiration) and heterotrophic (microbial respiration). As a combination of these two belowground processes, separating their relative contributions to SR from is difficult. The hemlock removal experiment provided an opportunity to look at these two components of SR. Girdling and logging result in the death and/or removal of aboveground biomass (trees) and subsequently death of root biomass. As a result the measured respiration in these treatment plots should then be comprised primarily of the microbial respiration component of SR. By measuring SR in control plots, and taking the difference with girdled and logged plots, we may determine the relative contribution of root and microbial respiration.

  • Methods:

    There are 6 collars at each site. Collars (10” diameter thin walled PVC pipe cut to 10cm lengths) are placed in the ground (approximately 5cm depth) and left during the course of the experiment. Soil CO2 flux (mg C m-2 h-1) is measured by placing a chamber over collars. The sampling duration is a 5 minute period, where the first 30secs are ambient air CO2 concentrations. The chambertop is then placed over the collar and air from the chamber headspace is pumped into an Infrared Gas Analyzer (LICOR 6252) at a rate of 0.5L/min for a 4.5 minute period. The change in headspace CO2 concentration is recorded every 12s for 4.5 minutes using an HP200LX palmtop. A linear regression in the change in headspace concentration over time, along with air temperature, atmospheric pressure and chamber surface area are used to convert these measurements to units of mg C m-2 hr-1. Soil temperature and moisture are measured concurrently with SR. Soil temperature (degrees Celsius) is taken using thermocouples located at 10cm depth at each of the collars. Measurements are read using a Barnant Temperature Reader. Soil moisture is measured using a Campbell Scientific handheld water content reflectometer. This system has two 10cm long probes that are inserted vertically from the surface into the ground. Measures soil moisture represents and integrated estimate of soil moisture over the top 10cm of the soil horizon.

  • Use:

    This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.

  • Citation:

    Davidson E, Savage K. 2012. Soil Respiration in Hemlock Removal Experiment at Harvard Forest since 2003. Harvard Forest Data Archive: HF130.

Detailed Metadata

hf130-01: soil respiration

  1. datetime: date and time
  2. date: date
  3. doy: day of year (unit: nominalDay / missing value: NA)
  4. plot: plot number
  5. treat: treatment
    • Girdled: Girdled
    • Logged: Logged
    • Control: Control
  6. collar: collar number
  7. time: time
  8. s.resp: soil respiration (mg C m-2 hr-1) (unit: milligramPerMeterSquaredPerHour / missing value: NA)
  9. s.temp: soil temperature at 10 cm depth (unit: celsius / missing value: NA)

hf130-02: soil moisture

  1. date: date of measurement
  2. year: year of measurement
  3. ym: year and month of measurement
  4. ymd: year, month and day of measurement
  5. doy: day of year (unit: nominalDay / missing value: NA)
  6. moist1: percent soil moisture in plot 1 (unit: dimensionless / missing value: NA)
  7. moist2: percent soil moisture in plot 2 (unit: dimensionless / missing value: NA)
  8. moist3: percent soil moisture in plot 3 (unit: dimensionless / missing value: NA)
  9. moist4: percent soil moisture in plot 4 (unit: dimensionless / missing value: NA)
  10. moist5: percent soil moisture in plot 5 (unit: dimensionless / missing value: NA)
  11. moist6: percent soil moisture in plot 6 (unit: dimensionless / missing value: NA)