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Harvard Forest Data Archive


Tree Growth and Above-Ground Biomass at Harvard Forest HEM and LPH Towers since 2001

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  • Lead: David Orwig, Julian Hadley
  • Investigators: Mark VanScoy, Liza Nicoll
  • Contact: Information Manager
  • Start date: 2001
  • End date: 2023
  • Status: ongoing
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.539 to +42.542 degrees
  • Longitude: -72.185 to -72.180 degrees
  • Elevation: 355 to 380 meter
  • Datum: WGS84
  • Taxa:
  • Release date: 2024
  • Language: English
  • EML file: knb-lter-hfr.149.27
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: long-term measurement
  • Research topic: large experiments and permanent plot studies
  • LTER core area: primary production
  • Keywords: aboveground biomass, carbon, tree growth
  • Abstract:

    Tree diameter (“dbh”) at 1.25 m above ground were recorded and stainless steel dendrometer bands for trees above 10 cm dbh were attached. Increases in tree diameter were calculated from increases in the distance between holes punched in the dendrometer bands. Tree diameters and diameter increases were used to estimate aboveground biomass and aboveground carbon storage in order to characterize the forest at the flux tower sites, and to quantify the amount of carbon being stored aboveground annually.

  • Methods:

    Initial tree circumferences and diameters were measured at 1.25 m above the ground, and stainless steel dendrometer bands are then fitted to the trees at this height. Each dendrometer band has two small holes punched in the band, around the point at which the band begins to overlap itself. A stainless-steel spring holds the band snugly around the tree. The distance between the two holes is measured with a digital caliper at least once annually, in late October or November, and the annual increase in tree circumference is calculated by subtracting the reading during the previous autumn from the current reading. This circumference increase is converted to a diameter increase, with the assumption that the tree is circular in cross-section. Allometric equations (see data set HF 069-16) are used to calculate a dry aboveground biomass estimate for each tree in each year, from the diameter at 1.25 m. Carbon is assumed to form 50% of dry aboveground biomass.


    Circular plots of 6 m radius were established at distances of 50, 100, 150 and 200 m from the Harvard Forest Hemlock eddy flux tower in March 2001, along transects with compass bearings from 180 to 315 degrees, by 15-degree increments. Tree diameters within the plots were measured and dendrometer bands were fitted to all trees greater than 15 cm diameter at breast height. Dendrometer band measurements to calculate circumferential increase were made several times per year during 2001 and 2002 and once to twice annually until 2012. Starting in 2012 measurements are taken monthly during the growing season. Tree mortality was also noted.

    Little Prospect Hill (LPH)

    Circular plots of 6 m radius were established at distances of 50, 100, and 150 m from the flux tower in March 2002, along transects with compass bearings of 195 to 330 degrees. Plots with a larger radius of 9 m were established at 200 m, 300 m and later 400 m along the same transects. (Plots at greater distances were larger owing to larger tree sizes and lower stem density at these distances.) In late 2003, new plots were established along a transect at a 345-degree compass bearing from the tower, and measurements were discontinued on plots with 195- and 210-degree compass bearings from the tower. This change was made because examination of eddy flux data from 2002 and 2003 showed that valid carbon exchange measurements could not be obtained with wind directions below 215 degrees, and since aboveground biomass estimates were designed primarily for comparison with eddy flux measurements, biomass increments at 195 and 210 degrees were not useful. Dendrometer band installation and measurements at plots near the LPH tower was similar to those at hemlock. Measurements were discontinued in 2010.

  • Organization: Harvard Forest. 324 North Main Street, Petersham, MA 01366, USA. Phone (978) 724-3302. Fax (978) 724-3595.

  • Project: 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. (ROR).

  • Funding: National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210.

  • Use: 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.

  • License: Creative Commons Zero v1.0 Universal (CC0-1.0)

  • Citation: Orwig D, Hadley J. 2024. Tree Growth and Above-Ground Biomass at Harvard Forest HEM and LPH Towers since 2001. Harvard Forest Data Archive: HF149 (v.27). Environmental Data Initiative:

Detailed Metadata

hf149-01: Hemlock dendrometer

  1. date: date of measurement
  2. plot: unique plot identifier represents transect (compass bearing, degrees from north, of transect on which plot occurs) and distance (in meters) from Hemlock tower base
  3. tag: tree tag number
  4. ctfs: CTFS tag number if tree is located in the CTFS plot
  5. species_code: tree species code
  6. band: dendrometer band number
  7. dbh_i: DBH of tree when dendrometer band was installed (unit: centimeter / missing value: NA)
  8. f_dbh_i: flag for DBH_i. C = calculated DBH. No flag = DBH measured when the band was installed
  9. caliper_mm: distance between holes in diameter band. NA indicates tree is dead. (unit: millimeter / missing value: NA)

hf149-02: Little Prospect Hill dendrometer

  1. date: date
  2. year: year
  3. doy: day of year (unit: nominalDay )
  4. distance: distance from LPH tower base (unit: meter / missing value: NA)
  5. transect: compass bearing (degrees from north) of transect on which plot occurs (unit: degree / missing value: NA)
  6. plot_radius: radius of the plot containing the tree (unit: meter / missing value: NA)
  7. species: genus and species of tree. For genus, A = Acer, B = Betula, F = Fagus, P = Pinus, Q = Quercus
  8. id: tag number or, in case of duplicate tag numbers, tag number plus 1000
  9. orig_circ: circumference at 1.25 m when tree was first measured, just prior to first measurement of dendrometer band (unit: centimeter / missing value: NA)
  10. dend_meas: distance between holes in diameter band (unit: centimeter / missing value: NA)
  11. repunch: whether band was repunched
    • 0: acceptable for growth calculation
    • 1: repunched or new dendrometer band