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Harvard Forest Data Archive


Adult Population Survey of Hemlock Woolly Adelgid in Massachusetts 2003-2005

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  • Lead: Scott Costa, David Orwig
  • Investigators: Joseph Brown, Bruce Parker
  • Contact: Information Manager
  • Start date: 2003
  • End date: 2005
  • Status: completed
  • Location: Massachusetts
  • Latitude: +41.24 to +42.89
  • Longitude: -73.51 to -69.93
  • Elevation: 0 to 420 meter
  • Taxa: Adelges tsugae (hemlock woolly adelgid), Tsuga canadensis (eastern hemlock)
  • Release date: 2006
  • Revisions:
  • EML file: knb-lter-hfr.104.19
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: short-term measurement
  • Research topic: invasive plants, pests and pathogens; regional studies
  • LTER core area: populations
  • Keywords: hemlock, hemlock woolly adelgid, populations, surveys
  • Abstract:

    To effectively document insect presence and abundance a statistically based sampling plan is necessary. No such plan for the hemlock woolly adelgid is currently available in the published literature. Two interrelated sampling strategies allow a researcher to enter a site and determine with a given level of probability whether or not an HWA infestation is present and the level of infestation. A ground based sampling plan is also critical to the ‘ground truthing’ of aerial survey systems. A fully developed sampling plan requires relatively extensive datasets obtained over time, and may include the use of computer-generated data obtained through re-sampling techniques. The results obtained through the Harvard Forest Summer Research Program should provide a firm foundation for further development of an HWA sampling program. Data collection is on-going.

  • Methods:

    For each site that is sampled there are 4 blocks/site, 25 trees/block, 2 branches/tree and 5 branch fronds/branch. Each site is roughly divided into 4 blocks. The blocks should be large enough to prevent overlap. Go to the middle of the block you intend to sample. Look at your datasheet to ascertain the Card #. The numbers range from 1 – 8 and represent the cardinal directions every 45 degrees starting with North as 1. Walk 25 paces and select the closest tree along that azimuth with branches that you can reach. Understory trees are fine for sampling.

    The following samples are taken: (1) Whole tree sample - Spend up to 30 seconds examining the underside of branches throughout the canopy for indications of HWA, i.e. the presence of white wooly tufts. If you find any signs of HWA stop searching and mark the Tstat as 1, if no sign after 30 seconds then enter a 0. You only need one entry for each tree within a block. Record the length of time to make determination if tree is positive. (2) Go to point where you came up to the tree and select the closest 1-meter-long branch. (3) Examine 5 fronds, each approx. 25 cm long, for the presence or absence of HWA. Pick each frond from the top so you don’t select only those with HWA. Count the number of wooly tufts on the branchlet closest to where you are grasping the frond. Mark the data sheet accordingly under F1-F5 for presence or absence. If adelgids are present record the number of adelgids in the F1-F5 slots. If none were present a 0 was recorded. (4) If any adelgids were found mark the Bstat (branch statistic) with an 1. If no adelgids were found then examine the underside of the 1 meter branch for the presence or absence of adelgids and record the results. (5) Go to a branch on the opposite side of the tree and repeat steps 5 and 6. (6) Now repeat tree selection by using the next random Card# on the datasheet. (7) Repeat steps 3 – 8 until the entire block (25 trees) is sampled then go to the next block.

  • 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:

    Costa S, Orwig D. 2006. Adult Population Survey of Hemlock Woolly Adelgid in Massachusetts 2003-2005. Harvard Forest Data Archive: HF104 (v.19). Environmental Data Initiative:

Detailed Metadata

hf104-01: survey data

  1. date: date sample was taken
  2. tract: Harvard Forest tract
    • Prospect Hill: Prospect Hill
    • Simes: Simes
    • Slab City: Slab City
    • Tom Swamp: Tom Swamp
  3. plot: subdivision of tract. Approximate size = 6 ha
  4. block: division of plot
  5. component: hemlock component
    • A-B: plot contains areas representing both A and B
    • A: more than 50% hemlock
    • B: less than 50% hemlock
  6. trees: number of trees examined (unit: number / missing value: NA)
  7. infested: number of infested trees found (unit: number / missing value: NA)