Harvard Forest

Data Archive

HF053

Hemlock History Plots at Harvard Forest since 1995

Related Publications

Data

• hf053-01: tree data (preview)

Overview

• Lead: David Foster, Jason McLachlan
• Investigators: Audrey Barker Plotkin
• Contact: Information Manager
• Start date: 1995
• End date: 2022
• Status: ongoing
• Location: Prospect Hill Tract (Harvard Forest), Slab City Tract (Harvard Forest)
• Latitude: +42.45 to +42.55 degrees
• Longitude: -72.22 to -72.18 degrees
• Elevation: 250 to 350 meter
• Datum: WGS84
• Taxa: Tsuga canadensis (eastern hemlock)
• Release date: 2023
• Language: English
• EML file: knb-lter-hfr.53.22
• DOI: digital object identifier
• EDI: data package
• DataONE: data package
• Related links:
• INTERPNT Software for Mapping Trees Using Distance Measurements
• Overstory Mapped Tree Plots at Harvard Forest since 1990
• Hemlock Understory Vegetation Plots at Harvard Forest since 2002
• Study type: long-term measurement
• Research topic: invasive plants, pests and pathogens; large experiments and permanent plot studies
• LTER core area: disturbance patterns
• Keywords: hemlock, land use, permanent plots, tree maps, vegetation dynamics
• Abstract:

  Hemlock (Tsuga canadensis) forests in New England are changing rapidly with the invasion of the hemlock woolly adelgid (HWA, Adelges tsugae), a non-native insect pest that kills hemlock trees. The adelgid is just beginning to be observed at Harvard Forest, making this the right moment to begin intensive physiological, ecological and monitoring studies of our hemlock forests. We gathered detailed baseline information for several hemlock stands across Harvard Forest. We surveyed community vegetation structure and composition, and began to monitor soil nitrogen cycling. These measurements will allow us to link the long-term history of these hemlock stands to other current studies of hemlock response to adelgid infestation, and will provide the basis for intensive study of hemlock dynamics with the stands' anticipated decline.

• Methods:

  Four 30m x 30m plots were established in 1995. Species, crown class, size (diameter at breast height) were determined. Trees were mapped using INTERPT software (HF023). Trees were remeasured in 2002, 2012, 2022. Starting in 2002, hemlock trees were rated for vigor. Starting in 2012, hemlock trees with low branches were inspected for hemlock woolly adelgid presence.

• 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: Foster D, McLachlan J. 2023. Hemlock History Plots at Harvard Forest since 1995. Harvard Forest Data Archive: HF053 (v.22). Environmental Data Initiative: https://doi.org/10.6073/pasta/a90bff379ea75ff7dc2fbde24097cdc5.

Detailed Metadata

hf053-01: tree data

1. plot: one of four plots
   • PH2: 30m x 30m hemlock history plot located on Prospect Hill, Compartment 2
   • PH7: 30m x 30m hemlock history plot located on Prospect Hill, Compartment 7
   • SC9: 30m x 30m hemlock history plot located on Slab City, Compartment 9
   • SC10: 30m x 30m hemlock history plot located on Slab City, Compartment 10
2. tree: all trees are tagged in the field with their number. Number system not continuous.
3. species: first two letters of genus and species name of tree
   • ACRU: Acer rubrum
   • BEAL: Betula alleghaniensis
   • BELE: Betula lenta
   • BEPA: Betula papyrifera
   • FAGR: Fagus grandifolia
   • FRAM: Fraxinus Americana
   • FRNI: Fraxinus nigra
   • PIST: Pinus strobes
   • PRSE: Prunus serotina
   • QURU: Quercus rubra
   • TSCA: Tsuga canadensis
   • UNK: Unknown
4. cc95: crown class rating, noted in 1995
   • D: dominant and codominant
   • C: intermediate
   • I: suppressed
   • S: second layer (umbrella shaped hemlocks)
   • NA: not applicable (e.g. tree is dead)
5. cond95: condition, noted in 1995
   • D: dead
   • L: live
   • miss: tree not measured in 1995 and was added in the 2002 census
6. dbh95: diameter at breast height (1.37m) in 1995 (unit: centimeter / missing value: NA)
7. dbh02: diameter at breast height (1.37m) in summer 2002 (unit: centimeter / missing value: NA)
8. vigor02: vigor class. Non-hemlocks classified as 1(living) or 5 (dead) only.
   • 1: 0-25% foliage loss
   • 2: 25-50% loss
   • 3: 50-75% loss
   • 4: 75-99% loss
   • 5: dead
9. dbh12: diameter at breast height (1.37m) in summer 2012 (unit: centimeter / missing value: NA)
10. vigor12: vigor class. Non-hemlocks classified as 1(living) or 5 (dead) only.
    • 1: 0-25% foliage loss
    • 2: 25-50% loss
    • 3: 50-75% loss
    • 4: 75-99% loss
    • 5: dead
    • NA: in a few cases, a tree wasn’t located
11. hwa12: assessed on hemlocks with branches within arm’s reach only. Presence or absence of hemlock woolly adelgid (Adelges tsugae) was based on visual inspection of two branches.
    • 0: no hemlock woolly adelgid observed
    • 1: hemlock woolly adelgid observed
    • NA: not assessed (branches too high, dead tree, or non-hemlock individual)
12. x: corresponds with the X axis of the plot, which ranges from 0-30 m (meter). Not available for plot SC10. (unit: meter / missing value: NA)
13. y: corresponds with the Y axis of the plot, which ranges from 0-30 m (meter). ). Not available for plot SC10. (unit: meter / missing value: NA)
14. sigeo.num: for plot PH2 only. Many of these trees are also tagged and included in the 35-hectare forest dynamics plot (SIGEO, aka ForestGEO, plot). In these cases, the SIGEO plot number is listed.
15. dbh22: diameter at breast height (1.37m) in August/September 2022 (unit: centimeter / missing value: NA)
16. vigor22: vigor class in 2022. Non-hemlocks classified as 1(living) or 5 (dead) only.
    • 1: 0-25% foliage loss
    • 2: 25-50% loss
    • 3: 50-75% loss
    • 4: 75-99% loss
    • 5: dead
    • NA: in a few cases, a tree wasn’t located
17. hwa22: assessed on hemlocks with branches within arm’s reach only. Presence or absence of hemlock woolly adelgid (Adelges tsugae) in 2022 was based on visual inspection of two branches.
    • 0: no hemlock woolly adelgid observed
    • 1: hemlock woolly adelgid observed
    • NA: not assessed (branches too high, dead tree, or non-hemlock individual)
18. notes: notes about whether a tree is dead, fallen, or unusual