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Harvard Forest Data Archive
Crown Geometry Measurements of 14 Species in the CTFS-ForestGEO Plot at Harvard Forest 2013Related Publications
- Lead: Franklin Sullivan, Mark Ducey, Michael Palace
- Investigators: David Orwig, Bruce Cook
- Contact: Information Manager
- Start date: 2013
- End date: 2013
- Status: completed
- Location: Prospect Hill Tract (Harvard Forest)
- Latitude: +42.54
- Longitude: -72.18
- Elevation: 340 to 368 meter
- Taxa: Acer rubrum (red maple), Betula alleghaniensis (yellow birch), Betula lenta (black birch), Betula papyrifera (paper birch), Fagus grandifolia (American beech), Fraxinus Americana (white ash), Kalma latifolia (mountain laurel), Picea abies (Norway spruce), Picea rubens (red spruce), Pinus resinosa (red pine), Quercus rubra (red oak), Quercus velutina (black oak), Tsuga canadensis (eastern hemlock)
- Release date: 2020
- EML file: knb-lter-hfr.339.1
- DOI: digital object identifier
- EDI: data package
- DataONE: data package
- Related links:
- Study type: short-term measurement
- Research topic: biodiversity studies; ecological informatics and modelling; large experiments and permanent plot studies
- LTER core area: populations
- Keywords: allometry, diameter at breast height, forest dynamics, lidar, remote sensing, tree maps
Tree crown geometry and height, especially when coupled with remotely sensed data, can aid in the characterization of tree and forest structure. In this study, we collected crown geometry data (tree height, crown radius, and crown depth) in order to develop mixed-effects model allometric equations. We leveraged the already existing Center for Tropical Forest Science (CTFS) and Smithsonian Institute’s Forest Global Earth Observatory (ForestGEO) MegaPlot on Prospect Hill at Harvard Forest, Massachusetts to apply allometric equations. In total, we sampled 374 trees across 14 species. Developed allometry was applied to 2014 CTFS-ForestGEO census data to develop allometric canopy height models, which were compared to a lidar canopy height model acquired by NASA’s G-LiHT.
Field-based measurements of canopy geometry
In September and October 2013, variable radius plot sampling (Bitterlich, 1984) was completed within the extent of the ForestGEO plot. Thirty-nine randomly selected plots were located approximately using a handheld Garmin GPSmap 76CSx handheld GPS unit (error± approx. 5 m). Actual plot centers were recalculated post hoc by calculating the centroid of the UTMx,y locations of tagged trees in the Prospect Hill Tract plot space relative to the x,y locations of the same trees in the local coordinates of the variable radius plot. At each plot, a 4.59 m2/ha basal area factor prism was used to sample trees 5 cm and greater DBH; the sample trees thus represent a size-weighted sample of the full population of the trees over 5 cm DBH on the tract (Kershaw et al., 2016, ch. 9). At each sampled tree, we recorded species and tag number (except where they had fallen off or not been measured for census yet), as well as measured the distance and bearing from plot center, DBH, tree height, crown base height, and crown radius toward and away from plot center. This pair of crown radii can be used to estimate crown area without bias, irrespective of crown shape (Gregoire and Valentine, 1995). Crown radii and tree height measurements were made using a laser range finder with a viewfinder and integrated tilt sensor (DISTO D5, Leica Geosystems). Crown radii were measured by using the viewfinder to determine when the observer was under the dripline of the tree crown toward and away from plot center, and by measuring the distance to the stem using a laser range finder which was subsequently adjusted for the distance between stem face and stem center.
Allometric equations for tree height, crown depth, and crown radius were developed in R (version 3.0.1) using a mixed effects modeling approach in the lme4 package. Developed equations were applied to MegaPlot census data. For more details on analysis and application, see Sullivan et al. 2017.
Bitterlich, W., 1984. The relascope idea: relative measurements in forestry, 1st ed. Commonwealth Agricultural Bureaux, Slough, UK.
Gregoire, T.G., Valentine, H.T., 1995. A sampling strategy to estimate the area and perimeter of irregularly shaped planar regions. For. Sci. 41, 470–476.
Kershaw Jr., J.A., Ducey, M.J., Beers, T.W., Husch, B., 2016. Forest Mensuration, fifth ed. Wiley, New York.
Sullivan, F. B., Ducey, M. J., Orwig, D. A., Cook, B., Palace, M. W. 2017. Comparison of lidar- and allometry-derived canopy height models in an eastern deciduous forest. Forest Ecology and Management 406: 83-94.
This dataset is released to the public under Creative Commons license CC BY (Attribution). 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.
Sullivan F, Ducey M, Palace M. 2020. Crown Geometry Measurements of 14 Species in the CTFS-ForestGEO Plot at Harvard Forest 2013. Harvard Forest Data Archive: HF339.
hf339-01: Harvard Forest tree data
- date: date
- plot: randomly assigned name
- species: genus/species 6 letter codes (4 genus, 2 species)
- si.offset.e: east offset relative to SW corner (unit: meter / missing value: NA)
- si.offset.n: north offset relative to SW corner (unit: meter / missing value: NA)
- tree.easting: calculated position from SW corner in UTM coordinates (unit: number / missing value: NA)
- tree.northing: calculated position from SW corner in UTM coordinates (unit: number )
- sensor.est.e: estimated easting position of plot center from tree position, distance and bearing from observer in UTM coordinates (unit: number / missing value: NA)
- sensor.est.n: estimated northing position of plot center from tree position, distance and bearing from observer in UTM coordinates (unit: number / missing value: NA)
- dbh: diameter at breast height (unit: centimeter / missing value: NA)
- height: top tree height in meters, measured w/ hypsometer (unit: meter / missing value: NA)
- cbh: height in meters of the base of the crown (unit: meter / missing value: NA)
- rad.in: radius measured of tree crown towards plot center (unit: meter / missing value: NA)
- rad.out: radius measured of tree crown away from plot center (unit: meter / missing value: NA)
- distance: distance of tree pith from plot center (unit: meter / missing value: NA)
- bearing: azimuth from plot center to tree (unit: degree / missing value: NA)
- east.center: easting component of position relative to plot center (unit: number / missing value: NA)
- north.center: northing component of position relative to plot center (unit: number / missing value: NA)
- tag: if available, MegaPlot tag number of tree
hf339-02: species codes
- species.code: species code
- species.name: genus and species name