Mass and Chemistry of Organic Horizons and Surface Mineral Soils on Watershed 6 at the Hubbard Brook Experimental Forest, 1976 - present
TITLE
Mass and Chemistry of Organic Horizons and Surface Mineral Soils on Watershed 6 at the Hubbard Brook Experimental Forest, 1976 - present
PRINCIPAL INVESTIGATOR(s)
Chris Johnson
Department of Civil and Environmental Engineering, Syracuse University
151 Link Hall
Syracuse, NY 13244
USA

Phone: (315) 443-4425
Steven Hamburg
Environmental Defense Fund
18 Tremont Street, Suite 850
Boston, MA 02108
USA
OTHERS INVOLVED
Mary Margaret Koppers
Department of Civil and Environmental Engineering, Syracuse University
151 Link Hall
Syracuse, NY 13244
USA
Ellen Denny
National Phenology Network
Thomas G. Siccama
Yale School of Forestry and Environmental Studies
ABSTRACT:
The forest floor of Watershed 6 was first sampled in 1969-70. These data include forest floor thickness, soil mass, organic matter content, and major-element composition for samples collected since 1976. Watershed 6 has been resampled at intervals varying from one to ten years. Sampling at five to ten year intervals is expected to continue. This dataset includes samples from 1976, 1977, 1978, 1982, 1987, 1992, 1997, 2002, and 2013.
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
base cations, calcium, forests, forest floor, HBEF Watershed 6, HBR, Hubbard Brook LTER, organic matter, soil, soil horizons, trace metals, watersheds.
KEYWORD SET: LTER Core Research Areas
inorganic nutrients, organic matter.
BEGIN DATE
1976
END DATE
2013
LOCATION
Watershed 6 is a 13.23 ha watershed extending from the weir at 560 m to the ridge at 790 m.
West bounding coordinate: -71.742990
East bounding coordinate: -71.735175
North bounding coordinate: 43.957070
South bounding coordinate: 43.949996
Elevation
Minimum: 560
Maximum: 790
(Unit: meter)
SITE DESCRIPTION
Samples were collected in Watershed 6 of the Hubbard Brook Experimental Forest. Watershed 6 is forested by typical northern hardwood species (sugar maple, beech and yellow birch) on the lower 90% of its area and by a montane boreal transition forest of red spruce, balsam fir and white birch on the highest 10%. Hydrology and stream water chemistry have been monitored since 1963. A grid system of 208 plots, each 25 x 25 m square, was created in Watershed 6 in 1965. For more spatial information please visit the following links:
http://www.hubbardbrook.org/watersheds/maps/w6_zones.htm
http://www.hubbardbrook.org/watersheds/w6_grid_elevations.shtml
SAMPLING DESIGN
From 1976 to 2002, each row of the Watershed 6 grid system of 25 x 25 m plots was considered a stratified sampling set and one or more plots was randomly chosen from these lines as plots to be sampled. Some rows are short, with only 1 to 4 plots, and others are longer, up to 10 plots across. The longer rows may have 2 or 3 plots sampled. The short rows may not have any plots sampled. After 2002, a random number generator was used to identify 100 plots over the entire watershed to sample. The location of the sampling site within each plot was determined by selecting two random integers between 0 and 24 ("x" and "y") and navigating to the selected coordinates from the northwest corner of the 25 x 25 m plot. The target number of samples changed year by year, and the number of plots sampled varies from 58 to 101.
FIELD COLLECTION PROCEDURES
Once a sampling point was located by taping or pacing, a 15 x 15 cm template was placed on the forest floor and 4 nails were inserted through pre-drilled holes, one on each corner. The nails hold the template in place on the forest floor and retain the forest floor material within the sample area beneath the template. A keyhole saw, pruning shears and a trowel were used to make a clean cut around the template, thus isolating a block of forest floor. The surrounding forest floor material was scraped back from the block leaving it as a pedestal. This block was then undercut in the mineral soil with a saw or trowel to sever any roots. Using a trowel inserted beneath the block and hands on top, the block was carefully picked up and turned over such as to rest on the template. Any remaining mineral soil was carefully scraped away "up" to the bottom of the Oa layer of the forest floor. After all mineral soil was removed, the thickness of the block was measured at the highest and lowest point on each of the 4 sides (1976-1982) or at 5 cm intervals along each of the four sides (1987 onward) for a total of 8 measurements. Beginning in 2002, the total thickness and the thickness of the combined Oi and Oe horizons (referred to in this data set as "Oie") were measured at each point. The average thickness of the Oa horizon could then be determined by subtraction of the average Oie thickness from the average total thickness for each block. In 1976, 1977, and 1982, the entire block was returned to the laboratory for analysis. In 1978, the sample was split into Oi, Oe, and Oa horizons in the field. From 1987 on, the block was separated into Oie and Oa horizons in the field. Each horizon was placed in a separate plastic bag for return to the laboratory.
Beginning in 1997, the upper 10 cm of the mineral soil was sampled by coring. After sampling the O horizons, a stainless steel corer (diameter 1.362 inches 1997-2002, diameter 1.374 inches 2013 onward) was inserted in the soil below the forest floor. If the core length exceeded 10 cm, the core was cut to 10 cm and bagged. If the core length was less than 10 cm, usually due to refusal by stones, the entire core was bagged. Two full 10-cm cores, or up to four partial cores, were collected at each site, unless mineral soil was absent.
LABORATORY PROCEDURES
The whole sample (1976, 1977, and 1982), all horizons (1978 and 1987), or Oie samples only (1992 onward) were oven dried at 80oC to a constant weight, and ground in a Wiley mill to pass a 2-mm screen. Large solid sticks and roots larger than the size of a pencil and obviously alive or fresh material were removed and weighed. These were not ground and were not included in the mass calculations.
The Oa horizon was air dried (1992 onward), weighed and then sieved through a 5-mm stainless steel screen. Sticks, roots and debris (coarse fraction) not passing through the screen with mild pressure were weighed. Stones, which were rarely present in the Oa, were also included in the coarse fraction. Material passing through the screen was weighed and rebagged. A subsample of this air dry screened soil was weighed, oven dried at 80oC, and weighed again. An air dry to oven dry conversion factor was determined in order to express the total Oa soil mass on an oven dry weight basis.
The mineral soils (1997 onward) were air dried, weighed, and passed through a 2-mm stainless steel screen. Material passing through the screen was weighed and rebagged. Material not passing through the screen, including sticks, roots, and stones, was weighed. A subsample of this air dry screened soil was weighed, oven dried at 80oC, and weighed again. An air dry to oven dry conversion factor was determined in order to express the total mineral soil mass on an oven dry weight basis.
Samples of the ground/screened Oie, Oa, and mineral soils were put in 4 oz. glass jars for long-term preservation in the Hubbard Brook archives.
For determination of organic content and acid-extractable metals determination, a known mass of the oven dry ground material was placed in a pre-weighed crucible and ashed overnight at 450-500oC. The ashed material was cooled and weighed. The loss-on-ignition was computed and used as a measure of organic matter content. The ash was eluted with 10 ml of 6N HNO3 and heated for a few minutes (to a simmer) on a hot plate. The hot extract solution was poured into a filter paper (Whatman # 41 ashless) in a funnel and into a 50 ml volumetric flask. The crucible and the material on the filter paper were rinsed several times with distilled deionized water. The volume in the flask was brought up to 50 ml with distilled deionized water. The 50 ml of extract solution was stored at room temperature until chemical analysis. The mass of sample, analytes measured, and instrument used each year are listed below. Analysis of plant tissue standard reference materials (e.g. apple leaves, pine needles) has consistently yielded near-100% recoveries, indicating that this digestion procedure is effective for digesting organic matter. However, digestion of Oa horizon and mineral soil samples is incomplete, as evidenced by residual mineral matter on the filter paper. It is therefore safest to refer to the results as "acid-extractable" rather than "total" element content.
Total carbon and nitrogen were determined using oven-dried ground material on a CHN analyzer.
CALCULATIONS
For organic horizons, total mass is the sieved mass of soil for the horizon multiplied by the ratio of oven dry soil to air dry soil masses and divided by the area of the template used for sampling (15 x 15 cm). For the mineral horizon, total mass is the average sieved mass of soil in the cores multiplied by the ratio of oven dry soil to air dry soil masses and divided by the diameter of the soil corer. Organic mass is the total mass of soil in the horizon multiplied by the loss on ignition for the horizon. Concentrations of elements in the forest floor were calculated on an oven dry weight basis. Total amounts of the elements were estimated on a per square meter basis by extrapolating up from the 15 x 15 cm sample mass. Amounts of Ca, Mg, K, P, Mn, Cu, Zn, Pb, Al, and Fe are presented in Table ff_a. Concentrations of Ca, Mg, K, P, Mn, Cu, Zn, Pb, Al, and Fe are presented in Table ff_c. Field data Forest floor thickness, species contributing litter to the sample site, and E horizon intensity for each plot are given in Table ff_e. Total mass, organic matter mass, and LOI of the forest floor are presented in Table ff_m.
INSTRUMENTATION
Sample analysis varied between years in the mass of soil used, analytes measured and instrumentatation used for each element.
Year_______Soil mass (g)__Analytes__Instrument
1976-1978____2.0_________Zn, Pb, Cu: AA
1976-1978____0.5_________Ca, Mg: ICP (analyzed in 1995)
1982_________2.0_________Zn, Pb, Cu: AA *
1982_________0.5_________Ca, Mg, K, P, Mg, Cu, Pb, Zn: ICP (analyzed in 1998)
1987_________2.0_________Zn, Pb, Cu: AA
1987_________0.5_________Ca, Mg: ICP
1992_________0.5_________Ca, Mg, K, P, Mn, Zn, Pb, Cu: ICP
1997_________0.5_________Ca, Mg, K, P, Mn, Zn, Pb, Cu: ICP
2002_________0.5_________Ca, Mg, K, P, Mn, Zn, Pb, Cu: ICP
2013_________0.6_________Mg, K, P, Mn, Zn, Pb, Cu: ICP-MS
2013_________0.6_________Ca: AA
* All data included in the data table are from ICP analysis, except plot 27 which had insufficient volume available for reanalysis.
NOTES
The primary objectives of the forest floor samplings in 1976-1978 were 1) the determination of the amount of lead (Pb) in the forest floor, 2) monitoring the total mass of the forest floor over time and 3) development of a field collection methodology that was efficient and easily implemented. It was determined that separation of the forest floor at least into Oie and Oa horizons, would have been better than no separation whatsoever, so this procedure was implemented from 1987 onwards. It was also determined that air drying the Oa horizon would have been preferable to oven drying. Air drying makes possible the determination of exchangeable nutrients, whereas oven drying may alter the cation exchange complex. Air drying of the Oa horizon samples was implemented from 1992 onward.
The forest floor of Watershed 6 was sampled twice in 1969 and once in 1970. Since sampling technique differed significantly from the sampling technique used from 1976 onward, the earlier data are not included in this dataset. They may be requested in hard copy format from Chris Johnson at Syracuse University.
DATA ACCESS GUIDELINES
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.

6) Notification. The Data User will notify the Principal Investigator of any publication or derivative work based on the Data Set. The Data User will also provide the Principal Investigator and/or the administrator of the Hubbard Brook Ecosystem Study with a pdf or two reprints of any publication(s) resulting from use of the Data Set.

7) Disclaimer. While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

8) Terms of Agreement. By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.



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: w6_ffa.txt
Description: Hubbard Brook Forest Floor Data, Watershed 6. Element amounts measured in 15x15 cm excavated organic horizon soil blocks; exact number of samples varies by sampling year.
Notes on Data: Original field data sheets are at Syracuse University, Civil and Environmental Engineering. Data was last updated in March 2013. Samples of forest floor material in jars will be located in the USFS archive building at the HBEF in Woodstock, NH.
ColumnVariableDescriptionUnitsCoded?Missing value label
1Sample_IDSite ID consists of the sample's year collected, watershed, plot, and horizon noneynone
2YearSample yearYYYYnnone
3WatershedWatershed Numbernoneynone
4PlotPlot Numbernoneynone
5HorizonSoil Horizonnoneynone
6Ca_g_m2Calcium amount by horizongramPerMeterSquaredn
-9999.99
7Mg_g_m2Magnesium amount by horizongramPerMeterSquaredn
-9999.99
8K_g_m2Potassium amount by horizongramPerMeterSquaredn
-9999.99
9P_g_m2Phosphorous amount by horizongramPerMeterSquaredn
-9999.99
10Mn_g_m2Manganese amount by horizongramPerMeterSquaredn
-9999.99
11Cu_g_m2Copper amount by horizongramPerMeterSquaredn
-9999.99
12Zn_g_m2Zinc amount by horizongramPerMeterSquaredn
-9999.99
13Pb_g_m2Lead amount by horizongramPerMeterSquaredn
-9999.99
14Al_g_m2Aluminum amount by horizongramPerMeterSquaredn
-9999.99
15Fe_g_m2Iron amount by horizongramPerMeterSquaredn
-9999.99

CODES

Variable: Sample_ID
Description:
Unique Sample ID
Variable: Watershed
Description:
Watershed number is 6 for this dataset
Variable: Plot
Description:
A counting number representing an existent plot
Variable: Horizon
Code
Description
Oie
Oie horizon
Oa
Oa horizon
Oie+a
Oie + Oa horizon

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
Ca_g_m2
-9999.99
Data not available
Mg_g_m2
-9999.99
Data not available
K_g_m2
-9999.99
Data not available
P_g_m2
-9999.99
Data not available
Mn_g_m2
-9999.99
Data not available
Cu_g_m2
-9999.99
Data not available
Zn_g_m2
-9999.99
Data not available
Pb_g_m2
-9999.99
Data not available
Al_g_m2
-9999.99
Data not available
Fe_g_m2
-9999.99
Data not available

Data file: w6_ffc.txt
Description: Hubbard Brook Forest Floor Data, Watershed 6. Element concentrations measured in 15x15 cm excavated organic horizon soil blocks; exact number of samples varies by sampling year.
Notes on Data: Original field data sheets are at Syracuse University, Civil and Environmental Engineering. Data was last updated in March 2013. Samples of forest floor material in jars will be located in the USFS archive building at the HBEF in Woodstock, NH.
ColumnVariableDescriptionUnitsCoded?Missing value label
1Sample_IDSite ID consists of the sample's year collected, watershed, plot, and horizon noneynone
2YearSample yearYYYYnnone
3WatershedWatershed Numbernoneynone
4PlotPlot Numbernoneynone
5HorizonSoil Horizonnoneynone
6Ca_mg_kgCalcium concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
7Mg_mg_kgMagnesium concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
8K_mg_kgPotassium concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
9P_mg_kgPhosphorous concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
10Mn_mg_kgManganese concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
11Cu_mg_kgCopper concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
12Zn_mg_kgZinc concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
13Pb_mg_kgLead concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
14Al_mg_kgAluminum concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9
15Fe_mg_kgIron concentration by horizon as ppm of oven dry samplemilligramPerKilogramn
-8888.8
-9999.9

CODES

Variable: Sample_ID
Description:
Unique Sample ID
Variable: Watershed
Description:
Watershed number is 6 for this dataset
Variable: Plot
Description:
A counting number representing an existent plot
Variable: Horizon
Code
Description
Oie
Oie horizon
Oa
Oa horizon
Oie+a
Oie + Oa horizon

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
Ca_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Mg_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
K_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
P_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Mn_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Cu_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Zn_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Pb_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Al_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.
Fe_mg_kg
-8888.8
-9999.9
No sample collected.
Data not available.

Data file: w6_ffe.txt
Description: Hubbard Brook Forest Floor Data, Watershed 6. Field data and measurements for 15x15 cm excavated organic horizon soil blocks; exact number of samples varies by sampling year.
Notes on Data: Original field data sheets are at Syracuse University, Civil and Environmental Engineering. Data was last updated in March 2013. Samples of forest floor material in jars will be located in the USFS archive building at the HBEF in Woodstock, NH.
ColumnVariableDescriptionUnitsCoded?Missing value label
1YearSample yearYYYYnnone
2PlotPlot Numbernoneynone
3E_CodeE horizon development intensitynoney
-9999
4Sp_1One of the three most important canopy tree species over the plotnoney
-9999
5Sp_2One of the three most important canopy tree species over the plotnoney
-9999
6Sp_3One of the three most important canopy tree species over the plotnoney
-9999
7FF_Thickness1One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
8FF_Thickness2One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
9FF_Thickness3One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
10FF_Thickness4One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
11FF_Thickness5One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
12FF_Thickness6One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
13FF_Thickness7One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
14FF_Thickness8One of eight measures of thickness of forest floor block (in centimeters)centimeternnone
15Oie_Thickness1One of eight measures of thickness of Oie (in centimeters)centimeternnone
16Oie_Thickness2One of eight measures of thickness of Oie (in centimeters)centimeternnone
17Oie_Thickness3One of eight measures of thickness of Oie (in centimeters)centimeternnone
18Oie_Thickness4One of eight measures of thickness of Oie (in centimeters)centimeternnone
19Oie_Thickness5One of eight measures of thickness of Oie (in centimeters)centimeternnone
20Oie_Thickness6One of eight measures of thickness of Oie (in centimeters)centimeternnone
21Oie_Thickness7One of eight measures of thickness of Oie (in centimeters)centimeternnone
22Oie_Thickness8One of eight measures of thickness of Oie (in centimeters)centimeternnone
23Core_1 Core depth for one of four possible mineral soil cores collected.centimetern
-9999.9
24Core_2 Core depth for one of four possible mineral soil cores collected.centimetern
-9999.9
25Core_3 Core depth for one of four possible mineral soil cores collected.centimetern
-9999.9
26Core_4 Core depth for one of four possible mineral soil cores collected.centimetern
-9999.9

CODES

Variable: Plot
Description:
A counting number representing an existent plot
Variable: E_Code
Code
Description
0
absent
1
weak "salt and pepper"
1.5
moderate
2
good, clearly present
3
excellent, deep and well-developed
Variable: Sp_1
Code
Description
ABBA
Abies balsamea (Balsam fir)
ACSA3
Acer saccharum (Sugar Maple)
ACSP2
Acer spicatum (Mountain maple)
ACPE
Acer pensylvanicum (Striped maple or moose wood)
ACRU
Acer rubrum (Red maple)
BEAL2
Betula alleghaniensis (Yellow birch)
BEPA
Betula papyrifera (White or paper birch)
FAGR
Fagus grandifolia (American beech)
FRAM2
Fraxinus americana (White ash)
PIRU
Picea rubens (Red spruce)
SOAM3
Sorbus americana (Mountain ash)
Variable: Sp_2
Code
Description
ABBA
Abies balsamea (Balsam fir)
ACSA3
Acer saccharum (Sugar Maple)
ACSP2
Acer spicatum (Mountain maple)
ACPE
Acer pensylvanicum (Striped maple or moose wood)
ACRU
Acer rubrum (Red maple)
BEAL2
Betula alleghaniensis (Yellow birch)
BEPA
Betula papyrifera (White or paper birch)
FAGR
Fagus grandifolia (American beech)
FRAM2
Fraxinus americana (White ash)
PIRU
Picea rubens (Red spruce)
SOAM3
Sorbus americana (Mountain ash)
Variable: Sp_3
Code
Description
ABBA
Abies balsamea (Balsam fir)
ACSA3
Acer saccharum (Sugar Maple)
ACSP2
Acer spicatum (Mountain maple)
ACPE
Acer pensylvanicum (Striped maple or moose wood)
ACRU
Acer rubrum (Red maple)
BEAL2
Betula alleghaniensis (Yellow birch)
BEPA
Betula papyrifera (White or paper birch)
FAGR
Fagus grandifolia (American beech)
FRAM2
Fraxinus americana (White ash)
PIRU
Picea rubens (Red spruce)
SOAM3
Sorbus americana (Mountain ash)

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
E_Code
-9999
Data not available
Sp_1
-9999
Data not available
Sp_2
-9999
Data not available
Sp_3
-9999
Data not available
Core_1
-9999.9
Soil core not collected.
Core_2
-9999.9
Soil core not collected.
Core_3
-9999.9
Soil core not collected.
Core_4
-9999.9
Soil core not collected.

Data file: w6_ffm.txt
Description: Hubbard Brook Forest Floor Data, Watershed 6. Mass data for 15x15 cm excavated organic horizon soil blocks; exact number of samples varies by sampling year.
Notes on Data: Original field data sheets are at Syracuse University, Civil and Environmental Engineering. Data was last updated in March 2013. Samples of forest floor material in jars will be located in the USFS archive building at the HBEF in Woodstock, NH.
ColumnVariableDescriptionUnitsCoded?Missing value label
1Sample_IDSite ID consists of the sample's year collected, watershed, plot, and horizon noneynone
2YearSample yearYYYYnnone
3WatershedWatershed Numbernoneynone
4PlotPlot Numbernoneynone
5HorizonSoil Horizonnoneynone
6OM_TMOven dry wt of total mass of horizon (kg/m2)kilogramPerMeterSquaredn
-9999.99
7OM_OMOven dry wt of organic matter mass of horizon (kg/m2)kilogramPerMeterSquaredn
-9999.99
8OM_LOILoss on ignition (percent)dimensionlessn
-9999.99

CODES

Variable: Sample_ID
Description:
Unique Sample ID
Variable: Watershed
Description:
Watershed number is 6 for this dataset
Variable: Plot
Description:
A counting number representing an existent plot
Variable: Horizon
Code
Description
Oie
Oie horizon
Oa
Oa horizon
Oie+a
Oie + Oa horizon

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
OM_TM
-9999.99
Data not available
OM_OM
-9999.99
Data not available
OM_LOI
-9999.99
Data not available