Hemlock Removal Experiment - Light Environment

Data

• hf107-01: light data

Overview

• Lead: Aaron Ellison
• Investigators: Audrey Barker Plotkin, Rachel Stahr
• Contact: Aaron Ellison
• Start date: 2004-12-01
• End date: ongoing
• Location: Simes Tract (Harvard Forest)
• Latitude: +42.47
• Longitude: -72.22
• Elevation: 200 to 240 meters
• Taxa: Acer spp. (maple), Betula spp. (birch), Pinus strobus (white pine), Quercus spp. (oak), Tsuga canadensis (eastern hemlock)
• Research topic: plot
• Study type: long-term measurement
• LTER core area: disturbance
• Keywords: canopy photographs, hemlock, hemlock woolly adelgid, light, Tsuga canadensis
• Release date: 2005
• EML version: knb-lter-hfr.107.10
• Revisions: data updated 2009-02-21
• Related links:
• Ecosystem Response to Hemlock Woolly Adelgid in Southern New England
• Hemlock Removal Experiment - Understory Vegetation
• Landscape Response to Hemlock Woolly Adelgid in Southern New England
• Abstract:

  The impending loss of hemlock trees due to hemlock woolly adelgid (Adelges tsugae) infestation is expected to lead to changes in the light environment of the forest understory. These changes will both drive succession and will themselves be altered by successional processes. The light reaching the forest floor is measured using hemispherical canopy photographs. Photographs were taken in December 2004 and May 2005 (both deciduous-tree leaf-off condition), prior to the application of the logging and girdling treatments, and then in September 2005 (deciduous tree leaf-on condition) after logging and girdling. Subsequent photographic series will be taken annually in spring (leaf-off) and summer/fall (leaf-on).

• Methods:

  Overview

  Every 15 m in each of the 8 experimental plots in the Simes Tract (i.e., at coordinates [15,15], [15,30], ... , [75, 60], [75.75]), we take a photograph of the canopy using a Nikon 8mm fish-eye lens mounted on a Nikon F3 (non-digital) camera. The camera is mounted on a tripod and positioned 1-2 m above ground. The camera is leveled (using self-leveling gimbals) and oriented with magnetic north at the top of the negative. For archival purposes, we use Kodak T-max 100 or T-max 400 black-and-white negative film. Negatives are individually cut, mounted, labeled, and scanned (300 dpi) for analysis. Original negatives (in acid-free slide sheets) and scans (on compact disks) are deposited in the Harvard Forest archives. Digital scans are analyzed using HemiView 2.1 SR1 software for canopy photograph analysis (Delta-T Devices, Ltd., UK: http://www.delta-t.co.uk).

  For analysis purposes, latitude was set at 42.47, longitude was set at -72.22, altitude was set at 200m a.s.l., declination was set at -14 degrees. Lens calibration file (Linear 180) was provided within the software.

  Beginning in September 2008, canopy photos were taken digitally using a Nikon D-3 digital camera body. We continue to use the same lens (Nikon 8mm AI fisheye lens) for images.

  Key references for software and analysis

  Anderson, M. C. 1964. Light relations of terrestrial plant communities and their measurment. Biological Reviews 39: 425-486.

  Delta-T Devices, Ltd. 1999. HemiView Manual Revision Number 2.1. Delta-T Devices, Ltd., Cambridge, U.K.

  Rich, P.M. 1989. A manual for analysis of hemispherical canopy photography. Los Alamos National Laboratory Report LA-11733-M.

  Rich, P.M., D.B. Clark, D.A. Clark, and S.F. Oberbauer. 1993. Long-term study of solar radiation regimes in a tropical wet forest using quantum sensors and hemispherical photography. Agricultural and Forest Meteorology 65: 107-127.

• 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.

• Citation:

  Ellison A. 2005. Hemlock Removal Experiment - Light Environment. Harvard Forest Data Archive: HF107.

Detailed Metadata

hf107-01: light data

1. Date: date photograph taken (YYYYMMDD)
2. Leaf: deciduous trees’ leaves off or on
   • 0: leaves off
   • 1: leaves on
3. Treatment: treatment
   • girdle: girdled
   • log: logged
   • hemlock.control: hemlock control
   • hardwood.control: hardwood control
4. Blcok: block
   • 1: valley: plots 1-3, 8
   • 2: ridge: plots 4-7
5. Plot: plot number of the Simes Tract Hemlock Removal Experiment
6. x: x-coordinate location, in meters, of the sample. Each plot of the Simes Tract is 90 x 90 m. (meter )
7. y: y-coordinate location, in meters, of the sample. Each plot at the Simes Tract is 90 x 90 m. (meter )
8. GSF: estimated proportion of global radiation (direct plus diffuse) under a plant canopy relative to that in the open (range: 0 – 1). (number )
9. DSF: estimated proportion of direct solar radiation reaching a given location, relative to that in a location with no sky obstruction (range: 0 – 1). (number )
10. ISF: estimated proportion of diffuse solar radiation reaching a given location, relative to a location with no sky obstruction (range: 0 – 1). (number )
11. TotBe: estimated total radiation below the canopy, corrected for interception surface orientation (units: MJ m-2 yr-1) (range: greater than 0). (megaJoulesPerMeterSquaredPerYear )
12. DirBe: estimated direct radiation below the canopy, corrected for interception surface orientation (units: MJ m-2 yr-1) (range: greater than 0). (megaJoulesPerMeterSquaredPerYear )
13. LAI: estimated leaf area index for the entire canopy (range: greater than 0) (number )
14. GndCover: estimated overall fraction of ground covered by canopy (range: 0 – 1). (number )
15. LAIDev: estimated uniformity of the canopy across the image (range: greater than 0) (number )
16. Threshold: user-specified value used to classify the image into black and white pixels (range 0 – 255) (number )