Hemlock Woolly Adelgid Adult Population Survey (Massachusetts)

• Investigators: Joseph Brown, Scott Costa, David Orwig, Bruce Parker
• Contact: Scott Costa
• Start date: 2003-05-29
• End date: ongoing
• Location: Massachusetts
• Latitude: +41.24 to +42.89
• Longitude: -73.51 to -69.93
• Elevation: 0 to 420 meters
• Taxa: Adelges tsugae (hemlock woolly adelgid), Tsuga canadensis (eastern hemlock)
• Keywords: hemlock, hemlock woolly adelgid, sampling
• Release date: 2006
• EML version: knb-lter-hfr.104.2
• Revisions:
• 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 and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement. For more information on LTER Network data access and use policies, please see: http://www.lternet.edu/data/netpolicy.html.

• Related datasets: