uid=HFR,o=lter,dc=ecoinformatics,dc=org
all
public
read
doi:10.6073/pasta/abf59a218a5868baf5b2c073a7dd1d7f
Prospect Hill Soil Warming Experiment at Harvard Forest since 1991
Serita
Frey
https://orcid.org/0000-0002-9221-5919
Jerry
Melillo
Kristen
DeAngelis
https://orcid.org/0000-0002-5585-4551
Researcher
Melissa
Knorr
https://orcid.org/0000-0002-8365-7918
Researcher
2024
English
The soil warming experiment was installed on the Prospect Hill tract in 1991 to allow us to investigate the effects of a 5 deg C temperature increase on soil processes fundamental to the global cycling of carbon and nitrogen. The experiment is located in an even-aged mixed hardwood forest. Six replicates of three treatments, Heated (resistance heating cables buried at 10cm and maintained at a 5 deg C differential from the control plots), Disturbance Control (cables installed but not powered) and Control treatments make up the randomized block design. The temperature differential is maintained with monitoring at five minute increments by an automated thermistor network in the plots, wired to a multiplexer and a datalogger in the control shed. In the plots, measurements of trace gasses (CO2, N2O and CH4), nitrogen mineralization, soil moisture and soil water chemistry have allowed us to quantify changes in the soil system.
Ten years of elevated soil temperatures at the Harvard Forest soil warming experiment suggest that there are limits to a positive feedback to the global warming cycle. After many early years of increased CO2 fluxes from the warmed plots, years nine and ten have revealed no significant differences in releases of CO2 between the heated and control plots. Nitrogen mineralization has shown a large response to warming as well, with twice the rate of N mineralized in years 1-4, followed by a gradual decrease in rates to about the 40% level in 1998. Resumption of mineralization measurements in 2001 reveals a continued decrease in mineralization rates.
Field results from the soil warming experiment indicate that only a small fraction of the soil carbon in this mid-latitude forest ecosystem will be lost to the atmosphere in response to warming. We find that a 5 deg C warming of the soil for a decade results in a loss of about 11% of the carbon stored in the top 60 cm of soil, with most of this loss occurring in the first four to five years. By the end of the decade, warming no longer stimulates soil carbon loss. In addition, we find that warming accelerates the soil nitrogen cycle, particularly in the early years of warming. This acceleration has the potential to stimulate plant carbon storage.
Calculations based on nitrogen uptake in vegetation at the Chronic N Experiment (Magill, Aber et al. 2000) allow us to estimate how much additional carbon might be stored in plants as a result increased N availability at soil warming. Our calculations show that the potential increase in carbon stored is large enough to more than compensate for the soil carbon loss, so that warming may actually stimulate carbon storage at the ecosystem level in this mid-latitude forest.
We are currently expanding our research from the original soil warming experiment to investigate this important feedback at the Harvard Forest. The existing 6x6m plots on the Prospect Hill tract are not large enough to allow for the study of treatment effects on trees, so we are installing a larger warming experiment. The new experiment will have two 30x30m plots, a heated and a control plot, in the Slab City Tract of the Harvard Forest. Many aspects of this experiment will be the same as the original. Using resistance heating cables and thermistors, we will maintain a 5 deg C differential between the heated and control plots, year-round. In addition to the trace gas, nitrogen mineralization and soil water parameters measured to date, we will also be measuring woody increment and other vegetation metrics to allow us to investigate the plant response to perturbations in the carbon and nitrogen cycles.
carbon
carbon dioxide
climate change
methane
nitrogen
nitrogen mineralization
nitrous oxide
soil moisture
soil respiration
soil temperature
soil warming
LTER controlled vocabulary
inorganic nutrients
disturbance
LTER core area
Harvard Forest
HFR
LTER
USA
HFR default
This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.
Creative Commons Zero v1.0 Universal
https://spdx.org/licenses/CC0-1.0.html
CC0-1.0
https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf005
Prospect Hill Tract (Harvard Forest). Coordinates based on WGS84 datum.
-72.18
-72.18
+42.54
+42.54
365
365
meter
1991
2021
ongoing
Information Manager
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
hf-im@lists.fas.harvard.edu
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
(978) 724-3595
https://harvardforest.fas.harvard.edu
Gas measurements were made by placing chamber lids over anchored collars for 15 min and sampling the headspace at 5-min intervals. Samples were analyzed for trace gas concentrations by gas chromatography or infrared analysis, and the changes in concentration were used to calculate net flux rates. On each sampling date, fluxes were measured at early morning and afternoon intervals. N2O and CH4 fluxes were measured from 1991 to 1995 along with the CO2 measurements using the same static chamber method.
Soil temperatures were measured at the surface and 2 and 4cm at the time of each gas sampling. Plot temperatures were also constantly monitored by an automated thermistor system, allowing comparison between control and heated plots at 5 minute intervals, with according powering up or down of the plots as needed.
Soil moisture measurements were conducted using gravimetric techniques for the first 4 years of the study and by time domain reflectometry (TDR) from 1995-2002.
Net N mineralization and nitrification were measured for the forest floor and mineral soil using an on-site buried bag incubation. Incubations were for 6 weeks, April- November, and for 5 months through the winter. Initial samples were collected and analyzed for extractable (2N KCl, 48 hours) NH4+ and NO3- content. The same analysis was carried out on the incubated samples. The difference in total mineral N content between initial and incubated soils is the net mineralization rate.
Concentrations of inorganic N in water leaching below the rooting zone were measured using high-tension lysimetry. Soil water samples were collected from one porous cup lysimeter per plot on two occasions every month for the first 2 years of the experiment, then monthly. Lysimeters were installed at a depth of 50 cm and evacuated to 15 in Hg 24 h before sampling. Samples were frozen until they were analyzed for NH4+ and NO3-.
Harvard Forest Long-Term Ecological Research
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
(978) 724-3595
https://harvardforest.fas.harvard.edu
https://ror.org/059cpzx98
pointOfContact
The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts.
National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210.
hf005-01-trace-gas.csv
trace gas flux
hf005-01-trace-gas.csv
96166
7c46d5da8bde695d1669313b3b7508a1
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-01-trace-gas.csv
year
year
YYYY
NA
missing value
rep
replicate number
replicate number
NA
missing value
date
sample date
YYYY-MM-DD
NA
missing value
treatment
treatment code
1
control
2
disturbed control
3
heated 5 deg C
NA
missing value
block
block number. There are 3 blocks, each with 6 plots grouped in a randomized block design.
block number. There are 3 blocks, each with 6 plots grouped in a randomized block design.
NA
missing value
co2_flux
CO2 flux (mg C/m2/hr). Samples collected every 5 min for 15 min using a static chamber method. Samples analyzed by infrared analysis
milligramPerMeterSquaredPerHour
0.01
real
NA
missing value
ch4_flux
CH4 flux (mg C/m2/hr). Samples collected every 5 min for 15 min using a static chamber method. Samples were analyzed by gas chromatography.
milligramPerMeterSquaredPerHour
0.01
real
NA
missing value
n2o_flux
N2O flux (ug N/m2/hr). Samples collected every 5 min for 15 min using a static chamber method. Samples were analyzed by gas chromatography.
microgramPerMeterSquaredPerHour
0.01
real
NA
missing value
temp_2cm
soil temperature at 2 cm depth taken at the time of gas sampling
celsius
0.01
real
NA
missing value
temp_4cm
soil temperature at 4 cm depth taken at the time of gas sampling
celsius
0.01
real
NA
missing value
grav_h2o_org
organic gravimetric soil water (g H2O/g soil)
gramsPerGram
0.01
real
NA
missing value
grav_h2o_min
mineral gravimetric soil water (g H2O/g soil)
gramsPerGram
0.01
real
NA
missing value
vol_h2o
soil water (cm3 H2O/cm3 soil) measured using time domain reflectometery (TDR)
cubicCentimetersPerCubicCentimeters
0.01
real
NA
missing value
1593
hf005-02-lysimeter.csv
lysimeter
hf005-02-lysimeter.csv
62772
a59b4f62fec5586fc4ec4005626dc0dd
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-02-lysimeter.csv
date
sample date
YYYY-MM-DD
NA
missing value
year
year
YYYY
NA
missing value
plot
plot number
plot number
NA
missing value
treatment
treatment code
C
control
DC
disturbed control
H
heated 5 deg C
NA
missing value
lys_no3
samples were collected from a high-tension lysimeter installed at a depth of 50cm. Samples were analyzed for dissolved NO3-
milligramsPerLiter
0.001
real
NA
missing value
lys_nh4
samples were collected from a high-tension lysimeter installed at a depth of 50cm. Samples were analyzed for dissolved NH4+
milligramsPerLiter
0.0001
real
NA
missing value
volume
volume of sample collected
milliliter
0.1
real
NA
missing value
notes
notes
notes
NA
missing value
1561
hf005-03-nmin.csv
nitrogen mineralization
hf005-03-nmin.csv
167450
c9d88d041ea8c6ffc724b3a187019adc
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-03-nmin.csv
year
year
YYYY
NA
missing value
rep
replicate number
replicate number
NA
missing value
date
sample date
YYYY-MM-DD
NA
missing value
horizon
soil horizon
0
organic
3
mineral
NA
missing value
treatment
treatment code
C
control
DC
disturbed control
H
heated 5 deg C
NA
missing value
plot
plot number
plot number
NA
missing value
net_no3
net N mineralization in the form of NO3- (mg N/kg) released during incubation period
milligramPerKilogram
0.01
real
NA
missing value
net_nh4
net N mineralization in the form of NH4+ (mg N/kg) released during incubation period
milligramPerKilogram
0.01
real
NA
missing value
net_ion
combined net mineralization (mg N/kg) released during incubation period
milligramPerKilogram
0.01
real
NA
missing value
days_incu
number of days of on-site buried bag incubation
number
0.1
real
NA
missing values
depth
depth of soil horizon
centimeter
0.001
real
NA
missing value
bd
bulk density greater than 2mm
gramPerMeterCubed
0.001
real
NA
missing value
2942
hf005-04-soil-temp.csv
soil temperature
hf005-04-soil-temp.csv
2742575
cb203bbf914a1de75e8572a4daf17dea
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-04-soil-temp.csv
date
date
YYYY-MM-DD
NA
missing value
year
year
YYYY
NA
missing value
doy
Julian date
nominalDay
1
whole
NA
missing value
month
month
month of measurement
NA
missing value
day
day
day of measurement
NA
missing value
plot1h
temp measured at 5 cm depth in plot 1 (heated)
celsius
0.001
real
NA
missing value
plot6h
temp measured at 5 cm depth in plot 6 (heated)
celsius
0.001
real
NA
missing value
plot8h
temp measured at 5 cm depth in plot 8 (heated)
celsius
0.001
real
NA
missing value
plot12h
temp measured at 5 cm depth in plot 12 (heated)
celsius
0.001
real
NA
missing value
plot15h
temp measured at 5 cm depth in plot 15 (heated)
celsius
0.001
real
NA
missing value
plot16h
temp measured at 5 cm depth in plot 16 (heated)
celsius
0.001
real
NA
missing value
plot3d
temp measured at 5 cm depth in plot 3 (disturbance control)
celsius
0.001
real
NA
missing value
plot5d
temp measured at 5 cm depth in plot 5 (disturbance control)
celsius
0.001
real
NA
missing value
plot9d
temp measured at 5 cm depth in plot 9 (disturbance control)
celsius
0.001
real
NA
missing value
plot10d
temp measured at 5 cm depth in plot 10 (disturbance control)
celsius
0.001
real
NA
missing value
plot13d
temp measured at 5 cm depth in plot 13 (disturbance control)
celsius
0.001
real
NA
missing value
plot17d
temp measured at 5 cm depth in plot 17 (disturbance control)
celsius
0.001
real
NA
missing value
plot2c
temp measured at 5 cm depth in plot 2 (control)
celsius
0.001
real
NA
missing value
plot4c
temp measured at 5 cm depth in plot 4 (control)
celsius
0.001
real
NA
missing value
plot7c
temp measured at 5 cm depth in plot 7 (control)
celsius
0.001
real
NA
missing value
plot11c
temp measured at 5 cm depth in plot 11 (control)
celsius
0.001
real
NA
missing value
plot14c
temp measured at 5 cm depth in plot 14 (control)
celsius
0.001
real
NA
missing value
plot18c
temp measured at 5 cm depth in plot 18 (control)
celsius
0.001
real
NA
missing value
avg_heat
average temp in Heated plots
celsius
0.001
real
NA
missing value
avg_cont
average temp in Control plots
celsius
0.001
real
NA
missing value
avg_dcon
average temp in Disturbance Control plots
celsius
0.001
real
NA
missing value
shed_air
average air temp taken at the Prospect Hill Soil Warming site
celsius
0.001
real
NA
missing value
11138
hf005-05-soil-respiration.csv
soil respiration
hf005-05-soil-respiration.csv
357576
0e0421231d6b073688ada446d804e137
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-05-soil-respiration.csv
datetime
date and time
YYYY-MM-DDThh:mm
1 minute
NA
missing value
year
year that the data was collected
YYYY
month
month that the data was collected
month of measurement
NA
missing value
day
day the data was collected
day of measurement
NA
missing value
time
time data was collected rounded to the nearest hour
hh:mm
NA
missing value
treatment
treatment code
C
control
DC
disturbance control
H
heated plot
NA
missing value
plot
Plot ID
Plot ID
NA
missing value
co2_flux
CO2 flux in mg C m-2 h-1
milligramPerMeterSquaredPerHour
0.01
real
NA
missing value
temp_4cm
soil temperature at 4 cm depth
celsius
0.1
real
NA
missing value
moisture
soil moisture (% volumetric moisture content)
dimensionless
0.01
real
NA
missing value
rainflag
whether or not sampling was likely affected by a respiration pulse from a recent (within 2 days) significant precipitation event
0
not likely affected by rain pulse
1
likely affected by rain pulse
NA
missing value
measurement
measurement type
Li8100-a
automatic LI-COR measurement
static
static chamber gas syringe measurement
NA
missing value
5681
hf005-06-fine-root-biomass.csv
fine root biomass
hf005-06-fine-root-biomass.csv
7732
3f3ca9c4a51f0ecc5de6ea0437a7090d
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-06-fine-root-biomass.csv
date
sample date
YYYY-MM-DD
NA
missing value
plot
plot number
plot number
NA
missing value
treatment
treatment code
DC
disturbed control
H
heated
NA
missing value
horizon
soil horizon
M
mineral
O
organic
NA
missing value
sorter
technician who sorted roots into live and dead pools
1
technician 1
2
technician 2
1,2
both techician 1 and technician 2 worked on this sample
NA
missing value
live_dead
whether live or dead roots
Live
live roots
Dead
dead roots
NA
missing value
size_class
root diameter size class (mm)
root diameter size class (mm)
NA
missing value
biomass
root biomass
gramsPerSquareMeter
0.01
real
NA
missing value
n_per
percent nitrogen content of bulked roots of this class, expressed as a decimal
dimensionless
0.0001
real
NA
missing value
c_per
percent carbon content of bulked roots of this class, expressed as a decimal
dimensionless
0.0001
real
NA
missing value
d15n
nitrogen isotope ratio content of bulked roots of this class, expressed as d15N (o/oo vs. AIR)
dimensionless
0.01
real
NA
missing value
d13c
carbon isotope ratio of bulked roots of this class, expressed as d13C (o/oo vs. PDB)
dimensionless
0.01
real
NA
missing value
132
hf005-07-soil-moisture.csv
soil moisture
hf005-07-soil-moisture.csv
468571
ae74877ae86a43a6bbdbfbff2f1dcd98
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-07-soil-moisture.csv
date
date
YYYY-MM-DD
1 day
NA
missing value
p1_sm
TDR volumetric soil moisture in Plot 1 (Heated)
dimensionless
0.000000001
real
NA
missing value
p2_sm
TDR volumetric soil moisture in Plot 2 (Control)
dimensionless
0.000000001
real
NA
missing value
p3_sm
TDR volumetric soil moisture in Plot 3 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p4_sm
TDR volumetric soil moisture in Plot 4 (Control)
dimensionless
0.000000001
real
NA
missing value
p5_sm
TDR volumetric soil moisture in Plot 5 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p6_sm
TDR volumetric soil moisture in Plot 6 (Heated)
dimensionless
0.000000001
real
NA
missing value
p7_sm
TDR volumetric soil moisture in Plot 7 (Control)
dimensionless
0.000000001
real
NA
missing value
p8_sm
TDR volumetric soil moisture in Plot 8 (Heated)
dimensionless
0.000000001
real
NA
missing value
p9_sm
TDR volumetric soil moisture in Plot 9 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p10_sm
TDR volumetric soil moisture in Plot 10 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p11_sm
TDR volumetric soil moisture in Plot 11 (Control)
dimensionless
0.000000001
real
NA
missing value
p12_sm
TDR volumetric soil moisture in Plot 12 (Heated)
dimensionless
0.000000001
real
NA
missing value
p13_sm
TDR volumetric soil moisture in Plot 13 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p14_sm
TDR volumetric soil moisture in Plot 14 (Control)
dimensionless
0.000000001
real
NA
missing value
p15_sm
TDR volumetric soil moisture in Plot 15 (Heated)
dimensionless
0.000000001
real
NA
missing value
p16_sm
TDR volumetric soil moisture in Plot 16 (Heated)
dimensionless
0.000000001
real
NA
missing value
p17_sm
TDR volumetric soil moisture in Plot 17 (Disturbance Control)
dimensionless
0.000000001
real
NA
missing value
p18_sm
TDR volumetric soil moisture in Plot 18 (Control)
dimensionless
0.000000001
real
NA
missing value
2304
hf005-08-swlayout.gif
soil warming layout
hf005-08-swlayout.gif
17538
a1fcf529f207b890bf8a8db1821a1766
gif
https://harvardforest.fas.harvard.edu/data/p00/hf005/hf005-08-swlayout.gif
image
plot
soil
long-term measurement
4
https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf018
milligramPerMeterSquaredPerHour
microgramPerMeterSquaredPerHour
gramPerMeterCubed