Harvard Forest

Data Archive

HF031

Hemlock Mapped Tree Plot at Harvard Forest since 1990

Related Publications

Data

• hf031-01: tree data (preview)

Overview

• Lead: David Foster, Audrey Barker Plotkin
• Investigators: Ann Lezberg, David Orwig
• Contact: Information Manager
• Start date: 1989
• End date: 2019
• Status: ongoing
• Location: Prospect Hill Tract (Harvard Forest)
• Latitude: +42.54 degrees
• Longitude: -72.18 degrees
• Elevation: 355 meter
• Datum: WGS84
• Taxa: Tsuga canadensis (eastern hemlock)
• Release date: 2023
• Language: English
• EML file: knb-lter-hfr.31.25
• DOI: digital object identifier
• EDI: data package
• DataONE: data package
• Related links:
• Long-term Stand Dynamics in Central Massachusetts 1500-2000
• Hemlock Understory Vegetation Plots at Harvard Forest since 2002
• Ecosystem Response to Hemlock Woolly Adelgid in Southern New England since 1998
• Study type: long-term measurement
• Research topic: invasive plants, pests and pathogens; large experiments and permanent plot studies
• LTER core area: population studies, disturbance patterns, land use and land cover change
• Keywords: hemlock, land use, permanent plots, tree maps, vegetation dynamics
• Abstract:

  Most of the central New England landscape was cleared for agriculture in the mid-19th century and then naturally reforested into "secondary forests" with the abandonment of agricultural land. Some sites, often poorly drained, remained forested, but were usually subjected to intensive fuelwood cutting or logging and are termed "primary forests." The Hemlock Woodlot was never cleared for agriculture, but has a history of cutting and natural disturbance. The hemlock woodlot is located in the center of Harvard Forest's Prospect Hill Tract, adjacent to a spruce-blackgum swamp. Soils are moist and rocky, with a thick organic layer. Hemlock dominates tree species composition (62% by basal area), with hardwoods and scattered large white pine comprising the remainder. Most of the trees are 100-150 years old, with a few hemlock trees up to 230 years old. While the site was never cleared for agriculture, it was logged several times and chestnut blight removed a chestnut-dominated overstory in the 1910s. The 0.72 ha stem-mapped plot is at the center of a 4-ha hemlock-dominated forest. This plot serves as a major reference site and is part of a network of hemlock forests that are being intensively sampled as the hemlock woolly adelgid arrives.

• Methods:

  In 1990, the 120m x 60m plot was established with a 10m x 10m grid. The long axis of the plot runs approximately East-West and the 0,0 point is the northwest corner. All trees greater than or equal to 5 cm dbh were mapped using a technique in which inter-tree distances were measured to the nearest centimeter (Boose, E.R., E.F. Boose and A.L. Lezberg. 1998. A practical method for mapping trees using distance measurements. Ecology 79:819-827). For each tree, species, canopy position, health, and diameter were recorded. Trees with multiple stems originating from a single base were measured as separate individuals if the stems forked at less than 1.3m high. Tree diameter and condition was re-measured in 1999, 2009, 2014 and 2019; hemlock vigor was also recorded.

  In 2002, sapling density and understory cover was sampled in three 20x20m subplots in or adjacent to the stem-mapped plot. In 2002 a nitrogen cycling study was initiated in the same three 20m x 20m plots.

  Hemlock woolly adelgid was detected on 20% of the hemlock trees examined in 2009. In 2014, adelgid infested 98% of hemlock trees examined, and the forest canopy was noticeably thinning.

• 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, Barker Plotkin A. 2023. Hemlock Mapped Tree Plot at Harvard Forest since 1990. Harvard Forest Data Archive: HF031 (v.25). Environmental Data Initiative: https://doi.org/10.6073/pasta/354ae980bb525f356ffe39073ecc584d.

Detailed Metadata

hf031-01: tree data

1. tree: tag number (#1-744 present in 1989; 800 and up recruited in 1999, 2009 or 2014)
2. x: x-coordinate within grid (meter; 0,0 is northwest corner; X is the 60m axis of the plot) (unit: meter / missing value: NA)
3. y: y- coordinate within grid (meter; 0,0 is northwest corner; Y is the long axis of the plot) (unit: meter / missing value: NA)
4. cc: canopy class
   • CD: codominant
   • D: dominant
   • I: intermediate
   • S: suppressed
5. spec: species code
   • ACRU: Acer rubrum
   • BEAL: Betula alleghaniensis
   • BELE: Betula lenta
   • BEPA: Betual papyrifera
   • CADE: Castanea dentata
   • FAGR: Fagus grandifolia
   • HAVI: Hamamelis virginiana
   • PIRU: Picea rubens
   • PIST: Pinus strobus
   • QURU: Quercus rubra
   • TSCA: Tsuga canadensis
   • UNK: unknown
6. dbh90: diameter at breast height in 1990 (unit: centimeter / missing value: NA)
7. cond89: tree condition in 1989
   • D: dead
   • L: living
   • M: moribund
8. cond93: tree condition in 1993
   • D: dead
   • L: living
   • M: moribund
9. dbh99: diameter at breast height in 1999 (unit: centimeter / missing value: NA)
10. cond99: tree condition in 1999
    • D: dead
    • G: tree could not be located
    • L: living
    • M: moribund
11. vigor99: tree vigor in 1999
    • 1: 0-25% foliar loss
    • 2: 25-50% foliar loss
    • 3: 50-75% foliar loss
    • 4: 75-99% foliar loss
    • 5: dead
12. dbh09: diameter at breast height in 2009 (unit: centimeter / missing value: NA)
13. cond09: tree condition in 2009
    • D: dead
    • L: living
14. vigor09: tree vigor in 2009
    • 1: 0-25% foliar loss
    • 2: 25-50% foliar loss
    • 3: 50-75% foliar loss
    • 4: 75-99% foliar loss
    • 5: dead
15. hwa09: presence/absence of hemlock woolly adelgid in 2009, assessed on two branches. Only trees with branches within reach were assessed (49 of the 309 live hemlocks in the plot in 2009)
    • 1: present
    • 0: absent
16. dbh14: diameter at breast height in 2014 (unit: centimeter / missing value: NA)
17. cond14: tree condition in 2014
    • D: dead
    • L: living
18. vigor14: tree vigor in 2014
    • 1: 0-25% foliar loss
    • 2: 25-50% foliar loss
    • 3: 50-75% foliar loss
    • 4: 75-99% foliar loss
    • 5: dead
19. hwa14b1: presence/absence of hemlock woolly adelgid in 2014, first branch. Only trees with branches within reach were assessed (41 of the 284 live hemlocks in the plot in 2014)
    • 1: present
    • 0: absent
20. hwa14b2: presence/absence of hemlock woolly adelgid in 2014, second branch. Only trees with branches within reach were assessed (41 of the 284 live hemlocks in the plot in 2014)
    • 1: present
    • 0: absent
21. ehs14: presence/absence of elongate hemlock scale. Only trees with branches within reach were assessed (41 of the 284 live hemlocks in 2014)
    • 1: present
    • 0: absent
22. cond16: tree condition in 2016
    • D: dead
    • L: living
23. vigor16: tree vigor in 2016
    • 1: 0-25% foliar loss
    • 2: 25-50% foliar loss
    • 3: 50-75% foliar loss
    • 4: 75-99% foliar loss
    • 5: dead
24. hwa16b1: presence/absence of hemlock woolly adelgid in 2016, first branch. Only trees with branches within reach were assessed (41 of the 271 live hemlocks in the plot in 2016)
    • 1: present
    • 0: absent
25. hwa16b2: presence/absence of hemlock woolly adelgid in 2016, second branch. Only trees with branches within reach were assessed (41 of the 271 live hemlocks in the plot in 2016)
    • 1: present
    • 0: absent
26. ehs16: presence/absence of elongate hemlock scale. In 2016 Only trees with branches within reach were assessed (41 of the 271 live hemlocks in 2016)
    • 1: present
    • 0: absent
27. dbh19: diameter at breast height in 2019 (unit: centimeter / missing value: NA)
28. cond19: tree condition in 2019
    • D: dead
    • L: living
29. vigor19: tree vigor in 2019
    • 1: 0-25% foliar loss
    • 2: 25-50% foliar loss
    • 3: 50-75% foliar loss
    • 4: 75-99% foliar loss
    • 5: dead
30. hwa19b1: presence/absence of hemlock woolly adelgid in 2019, first branch. Only trees with branches within reach were assessed (28 of the 244 live hemlocks in the plot in 2019)
    • 1: present
    • 0: absent
31. hwa19b2: presence/absence of hemlock woolly adelgid in 2019, second branch. Only trees with branches within reach were assessed (14 of the 244 live hemlocks in the plot in 2019)
    • 1: present
    • 0: absent
32. ehs19: presence/absence of elongate hemlock scale in 2019, first branch. Only trees with branches within reach were assessed (28 of the 244 live hemlocks in the plot in 2019)
    • 1: present
    • 0: absent
33. megatag: tree tag number for those trees that fall within the 35-ha Forest Dynamics Plot
34. note: notes from 1989, 1993 and 1999
35. note2009: notes from 2009
36. note2014: notes from 2014
37. note2019: notes from 2019