Forest soil:atmosphere fluxes of carbon dioxide, nitrous oxide and methane at the Hubbard Brook Experimental Forest, 1997- present
TITLE
Forest soil:atmosphere fluxes of carbon dioxide, nitrous oxide and methane at the Hubbard Brook Experimental Forest, 1997- present
PRINCIPAL INVESTIGATOR(s)
Peter M. Groffman
Cary Institute of Ecosystem Studies
Box AB
Millbrook, NY 12545
USA
OTHERS INVOLVED
Adam Welman
Jason Demers
Lisa Martel
Abraham Parker
Evan Grant
Jackie Wilson
Lynn Christenson
ABSTRACT:
Soil atmosphere fluxes of the trace gases; carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) have been measured at several locations at the Hubbard Brook Experimental Forest (HBEF) including 1) the “freeze” study reference plots that provide contrast between stands dominated (80%) by sugar maple versus yellow birch and low and high elevation areas, 2) the Bear Brook Watershed where trace gas sampling is coordinated with long-term monitoring of microbial biomass and activity and 3) watershed 1 where trace gas sampling locations were co-located with long-term microbial biomass and activity monitoring sites that are located near a subset of the lysimeter sites established for the calcium addition study on this watershed.
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
carbon dioxide, fluxes, forests, gases, HBEF Bear Brook Watershed, HBEF Freeze Plots, HBEF Watershed 1, HBR, Hubbard Brook LTER, methane, nitrous oxide, soil, trace gases, watersheds.
BEGIN DATE
1997
END DATE
2015
LOCATION
Bear Brook Watershed, located west of Watershed 6
West bounding coordinate: -71.743462
East bounding coordinate: -71.735649
North bounding coordinate: 43.957001
South bounding coordinate: 43.949928
Watershed 1
West bounding coordinate: -71.731339
East bounding coordinate: -71.726311
North bounding coordinate: 43.959286
South bounding coordinate: 43.952053
SM1
West bounding coordinate: -71.741392
East bounding coordinate: -71.741392
North bounding coordinate: 43.950408
South bounding coordinate: 43.950408
SM2
West bounding coordinate: -71.747275
East bounding coordinate: -71.747275
North bounding coordinate: 43.939433
South bounding coordinate: 43.939433
YB1
West bounding coordinate: -71.735058
East bounding coordinate: -71.735058
North bounding coordinate: 43.936356
South bounding coordinate: 43.936356
YB2
West bounding coordinate: -71.746986
East bounding coordinate: -71.746986
North bounding coordinate: 43.928469
South bounding coordinate: 43.928469
UV
West bounding coordinate: -71.717232
East bounding coordinate: -71.717232
North bounding coordinate: 43.949860
South bounding coordinate: 43.949860
LV
West bounding coordinate: -71.717155
East bounding coordinate: -71.717155
North bounding coordinate: 43.948059
South bounding coordinate: 43.948059
EK
West bounding coordinate: -71.778091
East bounding coordinate: -71.778091
North bounding coordinate: 43.918686
South bounding coordinate: 43.918686
WK
West bounding coordinate: -71.778091
East bounding coordinate: -71.778091
North bounding coordinate: 43.918686
South bounding coordinate: 43.918686
LOCATION DESCRIPTION
Soil atmosphere fluxes of the trace gases, carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), have been measured at several locations at the Hubbard Brook Experimental Forest. (HBEF):
1. “Freeze” study reference plots. In 1997, as part of a study of the relationships between snow depth, soil freezing and nutrient cycling (http://www.ecostudies.org/people_sci_groffman_snow_summary.html), we established eight 10 x 10-m plots located within four stands; two dominated (80%) by sugar maple and two dominated by yellow birch, with one snow reduction (freeze) and one reference plot in each stand. Trace gas fluxes were measured at approximately monthly intervals on these plots from October 1997 through September 2000. In 2001, we established eight new 10-m x 10-m plots (4 treatment, 4 reference) in four new sites; two high elevation, north facing and two low elevation, south facing maple-beech-birch stands. Trace gas fluxes were measured at approximately monthly intervals on these plots from May 2001 through November 2004. To establish plots for the “freeze” study, we cleared minor amounts of understory vegetation from all (both freeze and reference) plots (to facilitate shoveling). We then installed soil solution samplers (zero tension lysimeters), thermistors for soil temperature monitoring, water content (time domain) reflectometers (for measuring soil moisture), soil atmosphere sampling probes, minirhizotron access tubes, and trace gas flux measurement chambers (described below). All plots were equipped with dataloggers to allow for continuous monitoring of soil moisture and temperature. Treatments (keep plots snow free by shoveling through the end of January) were applied in the winters of 1997/98, 1998/99, 2002/2003 and 2003/2004. Only data from the reference (non-treated) plots are included in this data set.
2. Bear Brook Watershed. Trace gas sampling is coordinated with long-term monitoring of microbial biomass and activity: (http://www.hubbardbrook.org/data/dataset.php?id=67) that is keyed to the “west of watershed 6 litter trap transects” described by Hughes and Fahey (1994) (See also http://www.hubbardbrook.org/data/dataset.php?id=49) These are four 100 m transects, 50 m apart with five traps per transect located at low, mid, upper and high elevations - 20 traps per elevation. Trace gas sampling locations are located within 15 m of five traps at each elevation. Litter quality, quantity and composition have been monitored on these transects since 1984 and microbial biomass and activity have been monitored since 1994. Trace gas sampling on this watershed began in August 2002 and is ongoing.
3. Watershed 1. Trace gas sampling locations were co-located with long-term microbial biomass and activity monitoring sites that are located near a subset of the lysimeter sites established for the calcium addition study on this watershed (See http://www.hubbardbrook.org/data/dataset.php?id=132) Our sites include the "SpruceFir" Lysimeter Site 2 at the top of Watershed 1, the "High" Lysimeter Site 3, the "Mid" Lysimeter Site 4, and the "Low" Lysimeter Site 6. These site types and elevations correspond to those in the Bear Brook Watershed. At each lysimeter site we chose replicate plots that were all within ~30 m of the center lysimeter stake. Trace gas sampling on this watershed began in October 2002 and is ongoing.
DATA DESCRIPTION
When plots were snow free, trace gas fluxes were measured using the in situ chamber design identical to that described by Bowden and others (1990, 1991). Chambers (three per plot) of 287-mm diameter (ID) by 40-mm high polyvinyl chloride (PVC) were placed on permanently installed PVC base rings immediately prior to measurement. At 0, 10, 20 and 30 min following placement of the chamber on the base, 9-mL gas samples were collected from gas sampling ports in the center of the chamber top by syringe. Samples were transferred to evacuated glass vials and stored at room temperature prior to analysis by gas chromatography (GC). N2O and CO2 were analyzed on a Shimadzu GC-14 GC with electron capture (N2O) and thermal conductivity (carbon dioxide, CO2) detectors. CH4 was analyzed on a Shimadzu GC-8a GC with a flame ionization detector. These GC’s were capable of detecting ambient levels of these gases. Fluxes were calculated from the linear rate of change in gas concentration, the chamber internal volume and soil surface area. Flux rate calculations were not corrected for actual in situ temperature and pressure. Single points were removed from regressions if they were more than six times higher or lower than the other three values or if they contradicted a clear trend in the other three points. This procedure prevents inclusion of high flux rates based on non-significant regressions. Non-significant regressions were used in flux calculations to avoid biasing the statistical distribution of rates by setting all non-significant regressions to zero.
For snow-covered plots, aluminum chambers (approximately 5 L) fitted with septa were inserted 5 cm into the snowpack just prior to measurement.
REFERENCES
  • Bowden, R ., Melillo, J., Steudler, P., and Aber, J. 1991. Effects of nitrogen additions on annual nitrous oxide fluxes from temperate forest soils in the northeastern United States. Journal of Geophysical Research – Atmospheres 96(D5):9321-9328.
  • Bowden, R ., Steudler, P., Melillo, J., and Aber, J. 1990. Annual nitrous oxide fluxes from temperate forest soils in the northeastern United States. Journal of Geophysical Research – Atmospheres 96(D5):13,997-14,005.
  • Groffman, P., Hardy, J., Driscoll, C., and Fahey, T. 2006. Snow depth, soil freezing and trace gas fluxes in a northern hardwood forest. Global Change Biology 12:1748-1760.
  • Groffman, P., Fisk, M., Driscoll, C., Likens, G., Fahey, T., Eagar, C., and Pardo, L. 2006. Calcium additions reduce nitrogen cycling in a northern hardwood forest. Ecosystems 9:1289-1305.
  • Groffman, P.M., Hardy, J.P., Fisk, M.C.., Fahey, T.J., and Fahey, C.T. 2009. Climate variation and nitrogen and carbon cycle processes in a northern hardwood forest. Ecosystems 12:927–943.
  • Groffman, P.M., Hardy, J.P., Fashu-Kanu, S., Driscoll, C.T., Cleavitt, N.L., Fahey, T.J., and Fisk, M.C.. 2010. Snow depth, soil freezing and nitrogen cycling in a northern hardwood forest landscape. Biogeochemistry 102:223-238.
  • Hughes, J.W., and Fahey, T. 1994. Litterfall dynamics and ecosystem recovery during forest development. Forest Ecology and Management 63:181-198.
DATA ACCESS GUIDELINES
Data from the 1997 – 2000 freeze plot studies (sugar maple and yellow birch) are published in Groffman et al. (2006a). Data from the 2002 – 2004 freeze plot studies are published in Groffman et al. (2009, 2010). Data from the Bear Brook and watershed 1 sites from 2002 and 2003 are published in Groffman et al. (2006b). Other data will be published in manuscripts that are currently in preparation by the investigators. People are free to use these data for informational purposes but they cannot be used in any publication without permission of the author.



Data Use Policy



The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, government or other not-for-profit professional purposes.

2) Redistribution. The data and metadata are provided for use by the Data User. The Data User will not redistribute the original Data Set or metadata to others without the explicit permission of the Principal Investigator.

3) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly attribute the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier.

Citation example: Holmes, R.T. 2012. Bird Abundances at Hubbard Brook (1969-2010) and on three replicate plots (1986-2000) in the White Mountain National Forest. Durham, NH. Hubbard Brook Data Archive [Database]. http://hubbardbrook.org/data/dataset.php?id=81 (23 July 2012)

4) Acknowledgment: The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed to its content. Acknowledgments should identify the supporting party, the party that received the support, and any identifying information such as grant numbers.

Acknowledgment example: Data on [topic] were provided by [name of PI] on [date]. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station, Newtown Square, PA. Significant funding for collection of these data was provided by [agency]-[grant number], [agency]-[grant number], etc.

5) Consultation and questions. Data users are strongly encouraged to consult with the Principal Investigator(s) who collected these data for further information. Also, when appropriate, Data Users should consider including the Principal Investigator as a collaborator and/or co-author in the use of these data.

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CONTACT PERSON

Information Manager, Hubbard Brook LTER
234 Mirror Lake Road
North Woodstock, NH 03262
USA

Phone: (603) 726-8902
Email: hbr-im@lternet.edu

Data file: trace_gas.txt
Description: Soil:atmosphere fluxes of carbon dioxide, nitrous oxide and methane at the Hubbard Brook Experimental Forest
Notes on Data: DATA DESCRIPTION Data from the 1997 – 2000 freeze plot studies (sugar maple and yellow birch) are published in Groffman et al. (2006a). Data from the 2002 – 2004 freeze plot studies are published in Groffman et al. (2009, 2010). Data from the Bear Brook and watershed 1 sites from 2002 and 2003 are published in Groffman et al. (2006b). Other data will be published in manuscripts that are currently in preparation by the investigators. People are free to use these data for informational purposes but they cannot be used in any publication without permission of the author. The data is physically located at the Cary Institute of Ecosystem Studies in Millbrook, NY and was updated in March 2013.
ColumnVariableDescriptionUnitsCoded?Missing value label
1DATESample dateYYYY-MM-DDnnone
2SITELocation of plotsnoneynone
3ELEVElevation within watershednoney
-9999
4CHAMBERIndividual flux chambernoneynone
5CO2Carbon dioxide flux as grams of CgramPerMeterSquaredPerHourn
-9999
6N2ONitrous oxide flux as nanograms of NnanogramPerCentimeterSquaredPerHourn
-9999
7CH4Methane flux as milligrams of CH4milligramPerMeterSquaredPerDayn
-9999

CODES

Variable: SITE
Code
Description
WS1
Watershed 1
BearBrook
Bear Brook "West of Watershed 6"
SM1
“Freeze” study reference plot sugar maple 1
SM2
“Freeze” study reference plot sugar maple 2
YB1
“Freeze” study reference plot yellow birch 1
YB2
“Freeze” study reference plot yellow birch 2
UV
“Freeze” study reference plot “upper valley”
LV
“Freeze” study reference plot “lower valley”
EK
“Freeze” study reference plot “east Kineo”
WK
“Freeze” study reference plot “west Kineo”
Variable: ELEV
Code
Description
SpruceFir
Approx. 790m, SF (WS6); Lysimeter Site #2 (WS1)
High
Approx. 750m, litter traps 101-120 (WS6); Lysimeter Site #3 (WS1)
Upper
Approx. 675m, litter traps 121-140 (WS6)
Mid
Approx. 600m, litter traps 141-160 (WS6); Lysimeter Site #4 (WS1)
Low
Approx. 525m, litter traps 161-180 (WS6); Lysimeter Site #6 (WS1)
Variable: CHAMBER
Description:
integer as text

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
ELEV
-9999
Data missing or not taken at this time
CO2
-9999
Data missing or not taken at this time
N2O
-9999
Data missing or not taken at this time
CH4
-9999
Data missing or not taken at this time