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Harvard Forest Data Archive


Tree Ring Data from the Lyford Mapped Tree Plot at Harvard Forest 1861-2014

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  • Lead: Neil Pederson
  • Investigators: Daniel Bishop, Javier Martin Fernandez, Tessa Mandra
  • Contact: Information Manager
  • Start date: 1861
  • End date: 2014
  • Status: completed
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: 42.53
  • Longitude: -72.18
  • Elevation: 345 meter
  • Taxa: Acer rubrum (red maple), Betula alleghaniensis (yellow birch), Betula lenta (black birch), Fagus grandifolia (American beech), Hamamelis virginiana (witch hazel), Pinus strobus (eastern white pine), Quercus rubra (northern red oak), Quercus velutina (black oak), Tsuga canadensis (eastern hemlock)
  • Release date: 2021
  • Revisions:
  • EML file: knb-lter-hfr.358.1
  • 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, populations, disturbance
  • Keywords: climate change, community composition, 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 three 20m radius plots set within the Lyford Plot at the Harvard Forest. The Lyford Plot has been remeasured, on average, decadally since 1969. 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 similar plots going back to 1969.

    Dye, A., Barker Plotkin, A., Bishop, D., Pederson, N., Poulter, B. and Hessl, A., 2016. Comparing tree‐ring and permanent plot estimates of aboveground net primary production in three eastern US forests. Ecosphere, 7(9).

  • Methods:

    Vegetation and tree-ring data

    Vegetation and tree-ring data were collected according to PalEON sampling protocol. Three plots were established in the Lyford Plot. 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 and measured for DBH. Canopy strata (dominant, co-dominant, intermediate, and suppressed), life status (live or dead) and structural position if dead (snag, log, or stump hole) were determined for each tree. The trees were then 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 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). 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.

    Field notes

    Initial written deadwood entries from May 2013 (pages 5, 6, and 9) were not used and were resampled in June 2015 (pages 12-14) following updated protocol.

    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

    LF3 Tree 36 (ACRU) is missing from the ring-width files. The cores were unaccounted for from the field and presumed lost in transit.

    Due to sampling early in the growing season (May 2013), some hardwood samples (all ACRU, FAGR, BELE, HAVI, and BEAL) from LF1 trees 1-21, LF2 trees 1-31, and LF3 trees 1-27 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. All other samples were taken in November 2014, and should have full rings through 2014, unless otherwise indicated. 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 identification uncertainty. However, field notes have current species ID (QURU or QUVE). Plots will be revisited to confirm identification on other potential QUVE trees.

    Lyford census tag numbers were determined by mapping and co-locating trees using distance, DBH, and species identification. Trees were not tagged in the field during the census, but mapped Cartesian coordinates are available in Harvard Forest dataset HF032, Lyford Mapped Tree Plot at Harvard Forest since 1969. Dead trees were co-located as best as possible, although some were not located due to a lack of nearby trees with similar DBH and species IDs. Trees that were too decayed to obtain a species ID (e.g., stump holes, and decay class 5 logs and stumps) were not assigned census plot tag numbers.

    Corrections to original data

    Discrepancies were found between the PalEON and Harvard Forest census data, including four trees whose most recent census DBH and the PalEON plot DBH were in disagreement by more than 5 cm. Andria Dawson and Audrey Barker Plotkin located the trees in the field and determined the reasons for the discrepancies. The data was corrected according to their notes:

    PalEON id 107 [LF1, tree 7] – PalEON DBH was listed as 22.6 cm, while the 2011 census DBH was 31.2 cm. This tree is recently dead. We found it and measured the DBH and got 30 cm. It was losing bark which may explain why the DBH decreased in size from the last census data.

    PalEON id 241 [LF2, tree 41] – This tree had been assigned the census id of 2114. Tree 221 [LF2, tree 21] was also assigned this same census id. We found that tree 241 should be linked with census id 2160.

    PalEON id 314 [LF3, tree 14] – The 2011 census DBH for this tree was 47.1 cm, while the PalEON data had a DBH of 35.8 cm. We found and measured this tree, and the DBH was 48.5 cm.

    PalEON id 328 [LF3, tree 28] – PalEON DBH was measured as 26 cm, while the census DBH was measured to be 20.1 cm. We took the maps out and found that 302 corresponded with census id 997m, tree 328 with census id 995, and tree 329 with census id 1013. This was based on their positions, sizes and the field notes.

  • 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:

    Pederson N. 2021. Tree Ring Data from the Lyford Mapped Tree Plot at Harvard Forest 1861-2014. Harvard Forest Data Archive: HF358 (v.1).

Detailed Metadata

hf358-01: trees

  1. site: site and plot identifier
    • LF1: Lyford Plot 1 (Plot center at 42.53065 N, -72.18346 W)
    • LF2: Lyford Plot 2 (Plot center at 42.53128 N, -72.18271 W)
    • LF3: Lyford Plot 3 (Plot center at 42.53008 N, -72.18246 W)
  2. tree: tree number
  3. species: species
    • ACRU: Acer rubrum
    • BEAL: Betula alleghaniensis
    • BELE: Betula lenta
    • FAGR: Fagus grandifolia
    • HAVI: Hamamelis virginiana
    • 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: decimeter / 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

hf358-02: core data

  1. site: site and plot identfier
    • LF1: Lyford Plot 1 (Plot center at 42.53065 N, -72.18346 W)
    • LF2: Lyford Plot 2 (Plot center at 42.53128 N, -72.18271 W)
    • LF3: Lyford Plot 3 (Plot center at 42.53008 N, -72.18246 W)
  2. tree: tree number
  3. core: core cardinal direction
    • A: no associated cardinal direction
    • B: no associated cardinal direction
    • C: 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
    • HAVI: Hamamelis virginiana
    • 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

hf358-03: tree ring measurements

  1. site: site
    • LF: Lyford Plot
  2. species: species
    • ACRU: Acer rubrum
    • BEAL: Betula alleghaniensis
    • BELE: Betula lenta
    • FAGR: Fagus grandifolia
    • HAVI: Hamamelis virginiana
    • 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)

hf358-04: PalEON sampling protocol

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

hf358-05: field notes

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

hf358-06: Tuscon files

  • Compression: zip
  • Format: rwl
  • Type: zip

hf358-07: R script to convert Tucson files

  • Compression: none
  • Format: R code
  • Type: R code