HEM and LPH Towers - Tree Growth and Above-Ground Biomass

Data

• hf149-01: Hemlock dendrometer
• hf149-02: Little Prospect Hill dendrometer

Overview

• Lead: Julian Hadley
• Investigators:
• Contact: Julian Hadley
• Start date: 2001-03-01
• End date: ongoing
• Location: Footprint areas of Harvard Hemlock and Little Prospect Hill eddy flux towers, located in the Prospect Hill Tract of Harvard Forest.
• Latitude: +42.539 to +42.542
• Longitude: -72.185 to -72.180
• Elevation: 355 to 380 meters
• Taxa:
• Research topic: plot
• Study type: long-term measurement
• LTER core area: primary production
• Keywords: aboveground biomass, carbon storage, tree growth
• Release date: 2009
• EML version: knb-lter-hfr.149.5
• Revisions: data updated 2009-11-03
• Related links:
• EMS - Biomass Inventories
• Abstract:

  Tree diameter (“dbh”) at 1.25 m above ground were recorded and stainless steel dendrometer bands for trees above 10 cm dbh were attached. Increases in tree diameter were calculated from increases in the distance between holes punched in the dendrometer bands. Tree diameters and diameter increases were used to estimate aboveground biomass and aboveground carbon storage in order to characterize the forest at the flux tower sites, and to quantify the amount of carbon being stored aboveground annually.

• Methods:

  Initial tree circumferences and diameters were measured at 1.25 m above the ground, and stainless steel dendrometer bands are then fitted to the trees at this height. Each dendrometer band has two small holes punched in the band, around the point at which the band begins to overlap itself. A stainless steel spring holds the band snugly around the tree. The distance between the two holes is measured with a digital caliper at least once annually, in late October or November, and the annual increase in tree circumference is calculated by subtracting the reading during the previous autumn from the current reading. This circumference increase is converted to a diameter increase, with the assumption that the tree is circular in cross-section. Allometric equations (see data set HF 069-16) are used to calculate a dry aboveground biomass estimate for each tree in each year, from the diameter at 1.25 m. Carbon is assumed to form 50% of dry aboveground biomass.

  Cicrular plots of 6 m radius were established at distances of 50, 100, 150 and 200 m from the Harvard Forest Hemlock eddy flux tower in March 2001, along transects with compass bearings from 180 to 315 degrees, by 15 degree increments. Tree diameters within the plots were measured and dendrometer bands were fitted to all trees greater than 15 cm diameter at breast height. Dendrometer band measurements to calculate circumferential increase were made several times per year during 2001 and 2002 and once to twice annually thereafter. Tree mortality was also noted.

  Near the Little Prospect Hill (LPH) flux tower, circular plots of 6 m radius were established at distances of 50, 100, and 150 m from the flux tower in March 2002, along transects with compass bearings of 195 to 330 degrees. Plots with a larger radius of 9 m were established at 200 m, 300 m and later 400 m along the same transects. (Plots at greater distances were larger owing to larger tree sizes and lower stem density at these distances.) In late 2003, new plots were established along a transect at a 345 degree compass bearing from the tower, and measurements were discontinued on plots with 195 and 210 degree compass bearings from the tower. This change was made because examination of eddy flux data from 2002 and 2003 showed that valid carbon exchange measurements could not be obtained with wind directions below 215 degrees, and since aboveground biomass estimates were designed primarily for comparison with eddy flux measurements, biomass increments at 195 and 210 degrees were not useful. Dendrometer band installation and measurements at plots near the LPH tower was similar to those at hemlock.

• 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:

  Hadley J. 2009. HEM and LPH Towers - Tree Growth and Above-Ground Biomass. Harvard Forest Data Archive: HF149.

Detailed Metadata

hf149-01: Hemlock dendrometer

1. Date: date (YYYY-MM-DD)
2. Distance: distance from Hemlock tower base (meter )
3. Transect: compass bearing (degrees from north) of transect on which plot occurs (degree )
4. Species: genus and species of tree. For genus, A = Acer, B = Betula, F = Fagus, P = Pinus, Q = Quercus
5. ID#: tree tag number or, in case of duplicate tag numbers, tag number plus 1000
6. OrigCirc: circumference at 1.25 m when tree was first measured, just prior to first measurement of dendrometer band (centimeter )
7. DendMeas: distance between holes in diameter band (centimeter )
8. RepunchOrError: whwether band was repunched or measurement made in error
   • 0: acceptable for growth calculation
   • 1: repunched or new dendrometer band
   • 2: error

hf149-02: Little Prospect Hill dendrometer

1. Date: date (YYYY-MM-DD)
2. Year: year (YYYY)
3. DOY: day of year (DDD)
4. Distance: distance from LPH tower base (meter )
5. Transect: compass bearing (degrees from north) of transect on which plot occurs (degree )
6. PlotRadius: radius of the plot containing the tree (meter )
7. Species: genus and species of tree. For genus, A = Acer, B = Betula, F = Fagus, P = Pinus, Q = Quercus
8. ID#: tag number or, in case of duplicate tag numbers, tag number plus 1000
9. OrigCirc: circumference at 1.25 m when tree was first measured, just prior to first measurement of dendrometer band (centimeter )
10. DendMeas: distance between holes in diameter band (centimeter )
11. Repunch: whwether band was repunched
    • 0: acceptable for growth calculation
    • 1: repunched or new dendrometer band