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Harvard Forest Data Archive


Tree Ring Data from the Harvard Forest EMS Tower 1896-2014

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  • Lead: Neil Pederson
  • Investigators: Daniel Bishop, Javier Martin Fernandez, Tessa Mandra
  • Contact: Information Manager
  • Start date: 1896
  • End date: 2014
  • Status: complete
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: 42.53 degrees
  • Longitude: -72.17 degrees
  • Elevation: 356 meter
  • Datum: WGS84
  • Taxa: Acer rubrum (red maple), Betula alleghaniensis (yellow birch), Betula lenta (black birch), Fagus grandifolia (american beech), Picea abies (norway spruce), Pinus strobus (eastern white pine), Quercus rubra (northern red oak), Tsuga canadensis (eastern hemlock)
  • Release date: 2023
  • Language: English
  • EML file: knb-lter-hfr.407.4
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: long-term measurement, historical, paleological
  • Research topic: forest-atmosphere exchange; historical and retrospective studies; large experiments and permanent plot studies
  • LTER core area: primary production, population studies, disturbance patterns
  • Keywords: climate change, community composition, defoliation, dendrochronology, disturbance, net primary production, permanent plots, tree rings
  • Abstract:

    Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted annually. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 20m radius plots set within the footprint of the EMS tower plot at the Harvard Forest installed and continuously operated since 1989. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. Dye et al. (2016) have shown that these data fall within the range of uncertainty of census data sampled in the Harvard Forest Lyford plot going back to 1969.

    Dye, A., Barker Plotkin, A., Bishop, D., Pederson, N., Poulter, B., Hessl, A. 2016. Comparing tree-ring and permanent plot estimates of aboveground net primary production in three eastern U.S. forests. Ecosphere 7: e01454.

  • Methods:

    Vegetation and tree-ring data

    Vegetation and tree-ring data associated with this dataset were collected by the “PalEON Protocol”. Three plots were established in the EMS Plot where all trees greater than 10 cm diameter at breast height (DBH) in a 13 m radius were mapped (using distance and azimuth from plot center), measured for DBH, placed into canopy strata (dominant, co-dominant, intermediate, and suppressed, life status (live or dead), structural position if dead (snag, log, or stump hole), and cored. Two to three cores were removed from all trees sampled, live or dead, when possible; some were too rotten to core. Decay classes were determined for all deadwood (1 = recent to 5 = nearly soil) following Bunnell and Houde (Bunnell, F.L. and Houde, I., 2010, Down wood and biodiversity--implications to forest practices, Environmental Reviews, 18, pp.397-421) and surveys were made of saplings (all stems 2.5-4.99 cm DBH from plot center out to 5 m) and poles (all stems 5-9.99 in DBH from plot center out to 9 m). This protocol was repeated for 13-20 m from plot center, but only for trees greater than 20 cm DBH, to increase representation and possibly sample a higher proportion of old trees. Tree-ring measurements were taken from all usable cores and portions of usable cores for each plot. Some cores had too much rot or other issues to be useful. The occurrence of a missing or locally absent ring, where a tree did not fully form a ring on the side of the tree that was cored, is designated with a zero.

    Tree-ring file formats

    Data are provided in both traditional Tucson and csv formats. Tucson files are organized by species where the species code is the first two letters of the genus plus the first two letters of the species. Tuscon files contain total raw ring width (.rwl), earlywood ring width (.ewr), or latewood ring width (.lwr). Tucson data can be read as a space-delimited file in most coding languages. In R, package dplR has built-in function read.rwl that converts .rwl files to a data frame (rows become years; columns become ring-width series). For more information on the Tucson data format, please see: Brewer, P.W., Murphy, D. and Jansma, E., 2011. TRiCYCLE: a universal conversion tool for digital tree-ring data. Tree-Ring Research, 67(2), pp.135-144.

    Notes about the data

    TP1 Tree 037 (ACRU) and TP2 Tree 002 (BEAL) are both missing from the ring-width files. The causes of the missing data are accounted for in the “comments” column of the field notes file (hf407-02-tp-core.csv).

    Due to sampling early in the growing season (May 2013), some hardwood samples (all ACRU, FAGR, and BEAL) from TP1 Trees 1-42 did not have measurable partial rings for 2013. In contrast, samples from QURU and TSCA had measurable earlywood from 2013, which is included in the ring-width files. Details of the range of years measured for each series are included in the core notes.

    Red oak and black oak have been merged into QURU files due to species ID uncertainty. However, field notes have current species ID (QURU or QUVE).

  • 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: Pederson N. 2023. Tree Ring Data from the Harvard Forest EMS Tower 1896-2014. Harvard Forest Data Archive: HF407 (v.4). Environmental Data Initiative:

Detailed Metadata

hf407-01: trees

  1. site: site and plot identifier
    • TP1: EMS Tower Plot 1 (Plot center at 42.53928 N, -72.17614 W)
    • TP2: EMS Tower Plot 2 (Plot center at 42.53791 N, -72.17581 W)
  2. tree: tree number
  3. species: species
    • ACRU: Acer rubrum
    • BEAL: Betula alleghaniensis
    • BELE: Betula lenta
    • FAGR: Fagus grandifolia
    • PIAB: Picea abies
    • PIST: Pinus strobus
    • QURU: Quercus rubra
    • QUVE: Quercus velutina
    • TSCA: Tsuga canadensis
  4. date: date of sampling
  5. canopy: canopy position
    • codominant: codominant
    • dominant: dominant
    • intermediate: intermediate
    • suppressed: suppressed
  6. status: alive, dead or non-standing tree position
    • dead: status is unknown
    • Li: live
    • Lo: log
    • Sh: stump hole
    • Sn: snag
    • St: stump
  7. dbh: diameter at breast height (unit: centimeter / missing value: NA)
  8. distance: distance from plot center (unit: meter / missing value: NA)
  9. azimuth: degrees from due north (unit: degree / missing value: NA)
  10. tag: tree tag number from the Lyford Plot permanent plot data
  11. dist_top: distance from center for top of dead log (unit: meter / missing value: NA)
  12. az_top: degrees from due north for top of dead log (unit: degree / missing value: NA)
  13. decay: decay class
    • 1: solid wood, recently fallen, bark and twigs present
    • 2: solid wood, significant weathering, branches present
    • 3: wood not solid, bark may be sloughing but nail still must be pounded into wood
    • 4: wood sloughing and/or friable, nail may be forcibly pushed into wood
    • 5: wood friable, barely holding shape, nail may be easily pushed into wood

hf407-02: core data

  1. site: site and plot identfier
    • TP1: EMS Tower Plot 1 (Plot center at 42.53928 N, -72.17614 W)
    • TP2: EMS Tower Plot 2 (Plot center at 42.53791 N, -72.17581 W)
  2. tree: tree number
  3. core: core cardinal direction
    • A: no associated cardinal direction
    • B: no associated cardinal direction
    • E: east
    • N: north
    • S: south
    • W: west
  4. species: species ID of individual series
    • ACRU: Acer rubrum
    • BEAL: Betula alleghaniensis
    • BELE: Betula lenta
    • FAGR: Fagus grandifolia
    • PIAB: Picea abies
    • PIST: Pinus strobus
    • QURU: Quercus rubra
    • QUVE: Quercus velutina
    • TSCA: Tsuga canadensis
  5. inner_year: observed innermost year (not always measured)
  6. outer_year: observed outermost year (not always measured)
  7. meas_inner: year of innermost measured ring
  8. meas_outer: year of innermost measured ring
  9. rings: total number of rings measured (unit: number / missing value: NA)
  10. pith: estimated number of rings from pith or at pith (unit: number / missing value: NA)
  11. gap: location, in dates, when there is an observed gap(s) in mounted cores
  12. missing: list of years with missing rings in series
  13. false: list of years with false rings in series
  14. incomplete: list of years with incomplete/partial rings in series
  15. reaction: list of years with “reaction wood” in series
  16. canopy: estimated condition of tree during early growth years
    • G: gap
    • N: non-gap
    • U: unknown
  17. comments: core-specific comments

hf407-03: tree ring measurements

  1. site: site
    • TP: EMS Tower Plot
  2. species: species
    • ACRU: Acer rubrum
    • BEAL: Betula alleghaniensis
    • BELE: Betula lenta
    • FAGR: Fagus grandifolia
    • PIAB: Picea abies
    • PIST: Pinus strobus
    • QURU: Quercus rubra
    • QUVE: Quercus velutina
    • TSCA: Tsuga canadensis
  3. core: core number
  4. type: ring measurement type
    • ewr: earlywood ring width
    • lwr: latewood ring width
    • rwl: raw ring width
  5. year: year of ring width
  6. rw: measured ring width (unit: millimeter / missing value: NA)

hf407-04: field notes

  • Compression: none
  • Format: pdf
  • Type: document

hf407-05: PalEON sampling protocol

  • Compression: none
  • Format: pdf
  • Type: document

hf407-06: Tuscon files

  • Compression: zip
  • Format: Tuscon ring data
  • Type: document

hf407-07: R script to convert Tucson files

  • Compression: none
  • Format: R script
  • Type: script