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Harvard Forest Data Archive


Canopy Photosynthesis Study at Harvard Forest 1991-1992

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  • Lead: Susan Bassow, Fakhri Bazzaz
  • Investigators:
  • Contact: Information Manager
  • Start date: 1991
  • End date: 1992
  • Status: completed
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.54
  • Longitude: -72.17
  • Elevation: 340 meter
  • Taxa: Acer rubrum (red maple), Betula alleghaniensis (yellow birch), Betula papyrifera (white birch), Quercus rubra (red oak)
  • Release date: 1999
  • Revisions:
  • EML file: knb-lter-hfr.59.19
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: short-term measurement
  • Research topic: forest-atmosphere exchange
  • LTER core area: primary production
  • Keywords: canopies, photosynthesis, physiology
  • Abstract:

    Tree photosynthesis measurements were made from two canopy access towers on the Prospect Hill Tract, Harvard Forest, Petersham, Massachusetts between July 1991 and 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).

  • Methods:

    The dataset contains 1950 records. Each record represents a single measurement of a leaf in the canopy.

  • 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.

  • Citation:

    Bassow S, Bazzaz F. 1999. Canopy Photosynthesis Study at Harvard Forest 1991-1992. Harvard Forest Data Archive: HF059 (v.19). Environmental Data Initiative:

Detailed Metadata

hf059-01: photosynthesis data

  1. datetime: date and time
  2. date: date
  3. tower: refers to the Canopy Access Tower from which measurement was made
    • 1: Tower 1
    • 2: Tower 2
  4. height: refers to either the top of the canopy (T) or the sub-canopy (L) heights. The sub-canopy height was the lowest height where there were sufficient leaves accessible from the towers on the canopy trees.
    • L: sub-canopy heights
    • T: top of the canopy heights
  5. species: species observed
    • OAK: red oak (Quercus rubra)
    • RM: red maple (Acer rubrum)
    • WB: white birch (Betula papyrifera)
    • YB: yellow birch (Betula alleghaniensis)
  6. rep: at least 5 replicate leaves of each tree were measured in a given 2 hour time period on each observation date. October 3, 1992 has only a limited set of data.
  7. hour: hour of day with fraction EST (unit: nominalHour )
  8. time: time of day
  9. psn: in situ photosynthetic rate of the leaf (unit: micromolePerMeterSquaredPerSecond / missing value: NA)
  10. cond: in situ conductance rate of the leaf (unit: micromolePerMeterSquaredPerSecond / missing value: NA)
  11. par: photosynthetically active radiation (light levels) (unit: micromolePerMeterSquaredPerSecond / missing value: NA)
  12. lpar: ln transformed PAR levels (unit: number / missing value: NA)
  13. co2: CO2 concentration in the leaf chamber during the measurement in units of ppm (unit: dimensionless / missing value: NA)
  14. ci: calculated internal CO2 concentration in units of ppm (unit: dimensionless / missing value: NA)
  15. e: calculated transpiration rates (unit: micromolePerMeterSquaredPerSecond / missing value: NA)
  16. ratio of Ci to CO2 concentration (unit: dimensionless / missing value: NA)
  17. tleaf: leaf temperature measured by a leaf thermocouple touching the underside of the leaf when enclosed in the leaf cuvette (unit: celsius / missing value: NA)
  18. tair: air temperature measured in the cuvette during the measurement (unit: celsius / missing value: NA)
  19. rh: relative humidity (%) measured in the cuvette during the measurement (unit: dimensionless / missing value: NA)
  20. esleaf: calculated vapor pressure of the leaf (unit: kilopascal / missing value: NA)
  21. eair: calculated vapor pressure of the air in the cuvette during the measurement (unit: kilopascal / missing value: NA)
  22. vpd: vapor pressure deficit (unit: kilopascal / missing value: NA)