Hemlock Removal Experiment - Soil Respiration

Data

• hf130-01: soil respiration

Overview

• Lead: Eric Davidson, Kathleen Savage
• Investigators:
• Contact: Kathleen Savage
• Start date: 2003-07-01
• End date: ongoing
• Location: Simes Tract (Harvard Forest)
• Latitude: +42.47 to +42.48
• Longitude: -72.22 to -72.21
• Elevation: 200 to 240 meters
• Taxa: Tsuga canadensis (eastern hemlock)
• Research topic: soil
• Study type: long-term measurement
• LTER core area: inorganic nutrients
• Keywords: girdled, heterotrophic respiration, logged
• Release date: 2009
• EML version: knb-lter-hfr.130.3
• Revisions:
• Related links:
• EMS - Soil Respiration, Temperature and Moisture
• Abstract:

  Soil respiration (SR) is a combination of autotrophic (root respiration) and heterotrophic (microbial respiration). As a combination of these two belowground processes, separating the contribution to SR from one component or the other is difficult. The hemlock removal experiment provided the opportunity to look at SR and possibly examine these two components. The effects of girdling and logging both resulted in the death of the aboveground biomass (trees) and subsequently its corresponding root respiration. The measured SR in these treatment plots should then be comprised primarily of microbial respiration. By measuring SR in controlled plots, along with these two treatments plots, we may glean the relative contribution of root and microbial respiration from the difference in measurements between control and treatments.

• Methods:

  There are 6 collars at each site. Collare (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 (degrees Celsius) is taken using a 10cm probe inserted vertically from the surface.

• Use:

  This dataset is released to the public and may be freely downloaded. 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. For more information on LTER Network data access and use policies, please see: http://www.lternet.edu/data/netpolicy.html.

• Citation:

  Davidson E, Savage K. 2009. Hemlock Removal Experiment - Soil Respiration. Harvard Forest Data Archive: HF130.

Detailed Metadata

hf130-01: soil respiration

1. Date: date (YYYY-MM-DD)
2. DOY: day of year (DDD)
3. Plot: plot number
4. Treat: treatment
   • Girdled: Girdled
   • Logged: Logged
   • Control: Control
5. Collar: collar number
6. Time: time (hh:mm)
7. S-Resp: soil respiration (mg C m-2 hr-1) (milligramsPerMeterSquaredPerHour )
8. S-Temp: soil temperature at 10 cm depth (celsius )