Harvard Forest Data Archive / Exchange

These projects have been funded from a variety of sources, including Harvard Forest, the U.S. Long-Term Ecological Research Network (LTER), the National Institute for Global Environmental Change (NIGEC), DoE Terrestrial Carbon Program, NASA Terrestrial Ecosystem Program, National Institute for Climate Change Research (NICCR), and others. Most projects were completed or are ongoing at Harvard Forest, Massachussetts or Howland Forest, Maine.  Each set of measurements includes explanatory information in a read.me file.  Please read our statement on Fair Use, below, before proceeding to data. 



The data contained on this site is freely available and we encourage others to use it. Kindly keep us informed of how you are using our data and of any publication plans. Please acknowledge the data source as a citation, or in the acknowledgments if the data have not yet been published. If we feel that we should be offered participation as authors, we will let you know and we assume that an agreement on such matters will be reached prior to publishing the data. If your work directly competes with our analysis we may ask that we have the opportunity to submit a manuscript before you submit one that uses unpublished data. These data may be updated or reprocessed from time to time, and it is your responsibility to insure that your publication contains the most recent revision of the data.

In order to maintain these measurements we periodically need to demonstrate progress to our sponsoring agencies. In addition to informing us of your plans, we kindly request that you help us by providing preprints and updates on publication status.

Harvard Forest

Harvard Forest Environmental Measurement Site (EMS – flux tower) Data

Harvard University Atmospheric Sciences, Wofsy Group

Lead Investigator, J. William Munger

  • The Harvard Forest Environmental Measurement Site (EMS) was established in October 1989 and has been collecting data on the concentrations and fluxes of NOy, NOx, CO2, H2O, O3, and CO, as well as carbon storage since 1990. Further information on the EMS is available, as well as a detailed catalog of measurements. The available data files described below:
    • Preliminary data for current and recent years contains the results of initial data processing. It is intended to provide quick preliminary access to the data, but not for final analysis. Please use the FINAL data sets.
    • The final quality-assured data set is available as a cumulative file starting in 1992 up to the latest year (yy) processed, the file is compressed with gzip.
      All valid data is included in this file.
    • Filled data sets have missing observations are replaced by model estimates and NEE is separated into GEE and R components.
      Meteorological parameters have been filled in based on redundant measurements and nearby station data.
    • Atmospheric chemistry data are given in atmos chem.
    • Profiles present profile concentrations of CO2, O3, NO/NO2 arranged by years.
  • Links to the biometry plot data, and observations from collaborating investigators are given below.

Ecological Measurements to compliment eddy-flux measurements at Harvard Forest

Harvard University, Division of Engineering and Applied Sciences and Dept. of Earth and Planetary Sciences

Evan Goldman, Steve Wofsy , and J. William Munger

Contact: Evan Goldman (egoldman@seas.harvard.edu)

 In 1993, we installed 40, 10 m radius, circular biometric plots in the footprint of the EMS tower on Prospect Hill. We randomly placed the plots within 100 m increments along 10, 500 m transects that point away from the tower in the northwest and southwest directions. In 2001, we removed three plots (G3, H3, H4) from the datasets and ceased measurements there due to their inundation by a beaver pond. In 1999, with permission from the owner, we installed 6 additional, 10 m radius, circular biometric plots on the privately-owned land (also called the Simes Lot) adjacent to Prospect Hill to study the effects of a selective harvest that occurred in the winter of 2000-01. In the summer of 2001, the harvested plots were expanded in size to 15 m radius and one plot (X4) was removed from the data because it was unaffected by the harvest. The harvest also affected 3 of the tower plots (A4, A5, B5), which were expanded in size as a part of the harvest plot group. Consequently, there are 34 tower plots and 8 harvest plots. Please refer to the plot map for further clarification.

We have taken the following ecological measurements at each site: tree growthwoody debrislitter fallleaf litter decomposition, leaf area increment (LAI), foliar nitrogen content, and soil respiration and soil moisture.
Methodological details are provided in README files included with the data files.

Halocarbon Data

Harvard University (in cooperation with NOAA/CMDL)

Elaine Gottlieb, Steve Wofsy, Jim Elkins, and Geoff Dutton

Contact: Elaine Gottlieb (ewg@io.harvard.edu)

Measurements of 14 ozone-depleting and/or greenhouse gases are taken above the forest canopy at Harvard Forest, downwind of the New York City — Washington, D. C. corridor, every 24 minutes using a four-channel gas chromatographic system called FACTS (Forest and Atmosphere Chromatograph of Trace Species). The species measured are H2, CO, CH4, methyl chloroform (CH3CCl3), chloroform (CHCl3), carbon tetrachloride (CCl4), CFC-11 (CCl3F), CFC-12 (CCl2F2), CFC-113 (C2Cl3F3), halon-1211 (CBrClF2), perchlorethylene (C2Cl4), trichlorethylene (C2HCl3), nitrous oxide (N2O), and sulfur hexafluoride (SF6). Observations began in January 1996 and are continuing.

Fluxes of Nitrogen Oxides over a Temperate Deciduous Forest

Harvard University (in cooperation with Aerodyne Research, Inc)

Cassandra Volpe Horii, J. William Munger, Steven C. Wofsy, Mark Zahniser, David Nelson, J. Barry McManus

Contact: Cassandra Volpe Horii (cvolpe@fas.harvard.edu)

This dataset includes hourly averaged HNO3 and NO2 concentrations collected using a Tunable Diode Laser Absorption Spectrometer (TDLAS) at Harvard Forest during the year 2000. The TDLAS was installed on a scaffolding tower approximately 100m southeast of the main EMS tower. HNO3 and NO2 were measured at a sampling height of 22m. The dataset also includes data from the sonic anemometer on the TDLAS tower. NO2 fluxes in this dataset were determined by eddy covariance; HNO3 by a Dry Deposition Inferential Method (DDIM).

Soil Flux, Moisture, and Temperature Measurements at Harvard Forest

Joseph Blanchard (jblanchard@mbl.edu)

This data includes CO2, CH4, and N2O soil fluxes, soil temperatures at two depths, soil moisture calculated via several different methods, and surrounding environmental information.

Soil Respiration, Air & Soil Temperature, and Water Content at Harvard Forest

The Woods Hole Research Center

E. Davidson, E. Belk, K. Savage (savage@whrc.org)

  • Measurements of air temperature, soil respiration, soil temperature, and soil volumetric water content are taken at six (6) sites, representing differing drainage characteristics, located within the footprint of the EMS tower at Harvard Forest, Petersham, MA.
    • The sites are located to the northwest and southwest of the EMS tower. The sites to the southwest are the far site, SWF (225m), which is well-drained, the mid site, SWM (100m), which is moderately well drained, and the near site, SWN (20m), which is poorly drained. The sites to the northwest are the far site, NWF (500m), which is very poorly drained swamp, the mid site, NWM (375m), which is moderately well drained, and the near site, NWN (100m), which is well-drained. The dominant vegetation is mixed hardwoods except for the NWF site, located in a swampy area, and the NWM site, located among hemlocks.
    • Soil CO2 flux (mg C m-2 h-1) is measured by placing a chamber over collars (that are left in place) in the soil. CO2 is recorded every 12s for 4.5 min. There are 6 collars per site and values presented are the mean followed by the standard error of the measurements per site for each sampling date.
    • Soil temperature (°C) is taken using a 10cm probe inserted vertically from the surface. Air temperature is taken approximately 15-20cm above the forest floor.
    • Soil volumetric water content is determined using Time Domain Reflectometry (TDR). Probes (15cm in length) were inserted vertically into the soil. There are 3 to 4 probes per site and values presented are the mean of each probe measurement per site for each sampling date.

Radiation Measurements at Harvard Forest


David Fitzjarrald (fitz@asrc.cestm.albany.edu), Ralf Staebler (staebler@asrc.cestm.albany.edu)

Hourly-averaged measurements of radiation from the SUNYA boom at 27 m on the EMS tower and soil heat flux at Harvard Forest, Petersham, MA.

Harvard Forest Back Trajectories

University of Virginia

Jennie L. Moody and J. Clay Davenport

Back trajectories were calculated to define the origin of air in the mixed layer over Harvard Forest. The nature of the mixed layer varies as a function of time of day and the current meteorological situation. High resolution wind and temperature fields of the National Meteorological Center Nested Grid Model provided the necessary meteorological data for deriving the back trajectories. The files contain the modelled endpoints at two hour intervals, going back 72 hours. The data is organized into quarterly files from 1990-1993.

Hourly Averaged Methane Values for 1992-1994 at Harvard Forest

Monthly Methane Values for 1991-1994 at Harvard Forest

University of New Hampshire

Patrick Crill (patrick@kaos.unh.edu)

Methane data recorded at the Harvard Forest Environmental Monitoring Site.

Harvard Forest Phenology Measurements

Harvard Forest

John O'Keefe and Susan Johnson

Data description and data are available at Harvard Forest LTER site.

Harvard Forest Canopy Photosynthesis Data, June 1995

Harvard University

Susan L. Bassow and Fakhri A. Bazzaz

Measurements were made from 2 canopy access towers in a time period between July 1991-October 1992. Four species were observed: Oak - red oak (Quercus rubra); RM - red maple (Acer rubrum); WB - white birch (Betula papyrifera); YB- yellow birch (Betula alleghaniensis). There are 1950 records; each represents a single measurement of a leaf in the canopy.

Microclimate Data Collection and Development of Models of Ecosystem Carbon Exchange, Harvard Forest

Harvard Forest

Julian L. Hadley (jhadley@fas.harvard.edu)

This data set includes microclimatic measurements and estimates of all easily distinguishable forms of carbon exchange in an old-growth eastern hemlock (Tsuga canadensis L.) forest in the Harvard Forest, Petersham, Massachusetts, USA. Maximum tree age is about 220 years, and the data presented here are from four hemlocks 126 to 195 years old and 26 to 30m tall, which surround a 22m canopy access tower. Eastern hemlock composed over 90% of the basal area in eight randomly located plots within 50m of the tower. The measurements include air, wood and soil temperatures, atmospheric humidity, windspeed, photosynthetically active radiation (PAR), respiration, and photosynthesis. PAR is measured at 4 levels, above the canopy and in the upper, middle and lower canopy. The wood temprature is also measured at 4 levels, in the upper, middle amd lower canopy and in the boles of the trees. All easily separable types of respiration in the forest (night respiration by foliage plus wood, soil, and seed cone respiration) are measured separately.

Howland Forest

Howland Forest (Maine) Eddy Flux Measurements

University of New Hampshire

David Hollinger (davidh@christa.unh.edu)

Surface flux measurements were made at the Northern Experimental Forest study site, located at approximately 45°12' N latitude and 68°8' W longitude, near Howland, Maine. Vegetation consists of northern hardwood transitional species including aspen-birch, hemlock-spruce-fir, and hemlock-hardwood mixtures. Topographically, the region varies from flat to gently rolling with a maximum elevation change of less than 68m. Eddy correlation measurements of CO2, H2O and sensible heat and latent heat fluxes were made from a 25.5 m walk-up platform tower. The forest around the tower is relatively uniform in height with a mean height of 19.5m and living biomass density of 43 kg/m2; the leaf area index was approximately 5.3.

Soil Respiration, Air & Soil Temperature, and Water Content at Howland Forest.

The Woods Hole Research Center

E. Davdison, H. Hikel, K. Savage (savage@whrc.org)

  • Measurements of soil respiration and soil temperature are taken at 6 sites, representing differing drainage characteristics, located within the footprint of a tower measuring NEE at Howland Forest, Maine.
    • The Tower site (15 m W) is moderately well-drained, the Swamp site (70m SW) is very poorly drained, the Nutrient Cycling site (100m NNE) is moderately well-drained, the Town Line Swamp site (120 m NW) is very poorly drained, the Howland Mountain site (270 m WNW) is well-drained, and West Tower site (1000m NW) is moderately well-drained. Sampling at the Tower, Swamp, Nutrient Cycling, and Town Line Swamp sites started in the summer of 1996; sampling at the Howland Mountain site began in May, 1997 and at the West Tower site in May 1999.
    • Soil CO2 flux (mg C m-2 h-1) is measured by placing a chamber over collars (that are left in place) in the soil. CO2 is recorded every 12s for 4.5 min. There are 8 collars per site and values presented are the mean followed by the standard error of the measurements per site for each sampling date.
    • Soil temperature (°C) is taken using a 10 cm probe inserted vertically from the surface. A soil temperature was measured adjacent to each collar; values presented are the mean of all soil temperatures per site for each sampling date.

CO2 Profiles from the Howland Integrated Forest Study Site, Howland, Maine

The Woods Hole Research Center

E. Davidson and E. Belk

Since 1991, profiles of CO2 have been measured from a walk-up tower in the Howland Integrated Forest Study Site, Howland, Maine. The CO2 profiling system continuously draws in air from four levels of the tower, located 8.5m, 13.5m, 19.5m, and 26.5m above the ground. All four levels are completed every twelve minutes. Air from the sample line is delivered to and analyzed by a LI-COR 6251 infrared gas analyzer.