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Harvard Forest Data Archive

HF228

Leaf Area in the Clearcut Site at Harvard Forest 2010-2012

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Data

Overview

  • Lead: Christopher Williams
  • Investigators: Myroslava Khomik, Richard MacLean, Melanie Vanderhoof
  • Contact: Christopher Williams
  • Start date: 2010
  • End date: 2012
  • Status: completed
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.546
  • Longitude: -72.174
  • Elevation: 403 meter
  • Taxa: Acer pensylvanicum (striped maple), Acer rubrum (red maple), Aralia nudicaulis (wild sarsaparilla), Betula alleghaniensis (yellow birch), Betula lenta (black/sweet birch), Betula papyrifera (paper birch), Carex spp. (sedge), Comptonia peregrina (sweetfern), Dennstaedtia punctilobula (hayscented fern), Dryopteris spp. (woodfern), Fagus grandifolia (American beech), Maianthemum canadense (Canadian may-lily), Oryzopsis asperifolia (rough-leaved rice grass), Picea abies (Norway spruce), Picea glauca (white spruce), Pinus strobus (white pine), Polygonum sp. (knotweed), Prunus pensylvanica (pin cherry), Prunus serotina (black cherry), Quercus rubra (red oak), Rumex acetosella (field sorrel), Rubus allegheniensis (Allegheny blackberry), Rubus idaeus (American red raspberry), Rubus sp. (dewberry), Sambucus pubens (elderberry), Treintalis borealis (starflower), Tsuga canadensis (eastern hemlock), Vaccinium angustifolium (lowbush blueberry)
  • Release date: 2015
  • Revisions:
  • EML file: knb-lter-hfr.228.3
  • DOI: digital object identifier
  • Related links:
  • Study type: short-term measurement, modeling
  • Research topic: ecological informatics and modelling; forest-atmosphere exchange; physiological ecology, population dynamics and species interactions
  • LTER core area: primary production, disturbance
  • Keywords: canopy cover, foliage, leaf area index, leaves, plant physiology
  • Abstract:

    This dataset contributed to an estimate of leaf area by species at the Prospect Hill clearcut regeneration site, used in a publication to attribute measured changes in gross primary productivity over time to either changes in species composition and associated traits versus changes in total leaf area. The file reports data on leaf area by species from destructive harvest in select plots. It also reports leaf area and leaf weight from destructive harvest of the foliage of select individual species to characterize the vertical distribution of foliage for those species. Corresponding measurements of total plant area recorded with a LAI-2000 before and after harvest of this foliage is reported as well, useful for inferring the leaf versus stem/branch portions of light interception as needed for improved estimates of LAI with the light-interception method. Lastly, below we report the result of an August 2012 site-level survey of plant area index measured with the LAI-2000 and converted to leaf area index.

  • Methods:

    Study Site

    The study site occupies roughly a 200 m x 400 m area (8 ha) near the top of Prospect Hill, within the Harvard Forest Long Term Ecological Research Site.

    Leaf Area by Species – Destructive Harvests

    Species-specific leaf area (projected, one-sided leaf area per ground area occupied by an individual plant of a particular species) was sampled for a select number of species by destructive sampling. Two to five representative individuals of each species were selected. To minimize the method’s impact, the number of individuals destructively sampled was based on the prevalence of the species within the study area. Individuals were chosen to represent the size spectrum observed along the vegetation transects. The aerial ground coverage of each individual was estimated using two tape meters placed perpendicular to each other and estimating the enclosed square, oval or triangular shape occupied by the individual. Each individual was destructively sampled by removing all green leaves from the individual. Total (one-sided) leaf area was determined by scanning the leaves in the lab, using a LI-3000 leaf area meter (Li-COR Biosciences, Lincoln, NB, USA). The scanned leaf area was divided by the ground area occupied by the individual plant, to produce a leaf area estimate (LA) for the species. This value was used to calculate species-specific leaf area index from the line-intercept vegetation cover.

    Tree Destructive Harvest in 2012

    In summer 2012, our group sampled a few key species, similar to the way it was done in 2010, but covering a larger clump/area. We found patches of the same species in designated areas (i.e. out of the tower's footprint) and measured the area occupied by the crown of the clump, as projected on the ground. We destructively harvested all of the leaves in the canopy, in 50 cm layers (where applicable), starting from the ground and up. Then we scanned all of the harvested leaves using the LI-3000 leaf area meter, available at Harvard Forest Torrey Lab. The leaves were then packed into paper bags and oven dried. The weight of each layer and overall was measured once dried. - all this done at HF at Torrey labs.

    The leaves were then brought back to Clark and stored in a box in a cool, dry place (our growth chamber room). Only a single cluster per species was harvested. Measurements within each cluster (two on each side of the ellipse - farthest apart - pointing the instrument inside the cluster and using the 45deg angle cap) were also performed using the LI-2000 before and after the harvest (dawn/dusk, time permitting). For blackberry and fern patches, the sampling patch was square in shape and measurements with the LI-2000 were taken from two sides. Also for blackberry and fern, the harvest was completed in a single layer and everything was harvested from bottom up (logistically that was the best approach for bb), so no stalks remained to measure the post-harvest LAI. The difference in LI-2000 measurements before the harvest and post-harvest give "true" LAI, since contribution of branches is excluded by the post-harvest measurement.

    Notes on Harvest in 2010

    Melanie Vanderhoof and REUs harvested numerous species at the site and estimated their leaf area per canopy area, by estimating the projected canopy area of an individual, then harvesting all leaves of that individual, measured the harvested projected one-sided leaf area of that individual, and finally divided the total projected one-sided leaf area by the projected canopy area (this we call LA). Leaf area was measured by spreading out flat, in a single layer in a box of a fixed area, all the harvested leaves - per individual. To get the LAI (leaf area per ground area), one needs to multiply these LA numbers by the % ground covered by that species' canopy - get from line intercept method (then get leaf area per ground area).

    LAI-2000 Sampling

    In late August 2012, site-level LAI was also estimated with the LAI-2000 Plant Canopy Analyzer (LI-COR Biosciences, Inc.) optical plant area meter. Measurements were performed along one of the five line-intercept transects used for species abundance and composition surveys, and were made just below the canopy, along 8 points, at dusk. A 45-degree angle cap was used and data were corrected accordingly. Two additional measurements were performed before and after the transect survey, but in an adjacent open area free of shading. The difference between the mean open and mean transect value provided an estimate of plant area index at our site. Measured plant area index (PAI) was translated to leaf area index (LAI), by correcting for branches sampled during our destructive harvesting campaign (described above for estimation of species-level leaf area, involving select patches of trees: red maple – Acer rubrum (6.6 m2); pin cherry – Prunus pensylvanica (9.7 m2) and black cherry – Prunus serotina (11.1 m2)). During that sampling campaign, we took measurements with the LAI-2000 instrument before and after leaf harvest within each patch. The corresponding ratio of LAI to PAI in defoliated patches was used to correct the measured site-total PAI to provide just the portion related to leaves (i.e. LAI).

    Data Files

    The two data files represent two distinct samplings. The first data file corresponds to a vertically-stratified destructive harvest of leaves on select species, as described above under “Tree Destructive Harvest in 2012”. The second data file contains the total leaf area for species that were sampled within a particular ground area that contained vegetation cover primarily composed of that species, as described above under “Leaf Area by Species – Destructive Harvests."

  • Use:

    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.

  • Citation:

    Williams C. 2015. Leaf Area in the Clearcut Site at Harvard Forest 2010-2012. Harvard Forest Data Archive: HF228.

Detailed Metadata

hf228-01: vertically stratified

  1. year: year of sampling
  2. date: date of sampling
  3. sample: sample identification
  4. leaf.area: scanned and corrected leaf area collected from the plant (unit: squareCentimeters / missing value: NA)
  5. dry.weight: dry weight of the sample leaves collected (unit: gram / missing value: NA)
  6. ground.area: ground area occupied by the projected-shadow of the plant that was harvested (unit: squareCentimeters / missing value: NA)
  7. species: species sampled
    • pc: Prunus pensylvanica
    • rm: Acer rubrum
    • bc: Prunus serotina
    • bb: Rubus allegheniensis
    • fern: Dennstaedtia punctilobula or Dryopteris spp.
  8. lai: calculated leaf area index (leaf per ground) (unit: dimensionless / missing value: NA)
  9. li2000.pre: LI-2000 reading below canopy before the leaves were harvested (unit: dimensionless / missing value: NA)
  10. li2000.post: LI-2000 reading below canopy after the leaves were harvested (unit: dimensionless / missing value: NA)
  11. level 1.la: total leaf area of leaves collected in the layer from 0-50cm height above the ground (unit: squareCentimeters / missing value: NA)
  12. level 2.la: total leaf area of leaves collected in the layer from 0-50cm height above the ground (unit: squareCentimeters / missing value: NA)
  13. level 3.la: total leaf area of leaves collected in the layer from 100-150cm height above the ground (unit: squareCentimeters / missing value: NA)
  14. level 4.la: total leaf area of leaves collected in the layer from 150-200cm height above the ground (unit: squareCentimeters / missing value: NA)
  15. level 5.la: total leaf area of leaves collected above 200cn height above the ground (unit: squareCentimeters / missing value: NA)
  16. level 1.wgt: dry leaf weight of leaves collected in the layer from 0-50cm height above the ground (unit: gram / missing value: NA)
  17. level 2.wgt: dry leaf weight of leaves collected in the layer from 50-100 cm height above the ground (unit: gram / missing value: NA)
  18. level 3.wgt: dry leaf weight of leaves collected in the layer from 100-150cm height above the ground (unit: gram / missing value: NA)
  19. level 4.wgt: dry leaf weight of leaves collected in the layer from 150-200cm height above the ground (unit: gram / missing value: NA)
  20. level 5.wgt: dry leaf weight of leaves collected above 200cn height above the ground (unit: gram / missing value: NA)

hf228-02: whole plant

  1. year: year of sampling
  2. sample: sample identification
  3. leaf.area: scanned and corrected leaf area collected from the plant (unit: squareCentimeters / missing value: NA)
  4. dry.weight: dry weight of the sample leaves collected (unit: gram / missing value: NA)
  5. ground.area: ground area occupied by the projected-shadow of the plant that was harvested (unit: squareCentimeters / missing value: NA)
  6. species: species sampled
    • ws: Aralia nudicaulis
    • canadian: Maianthemum canadense
    • fern: Dennstaedtia punctilobula or Dryopteris spp.
    • kw: Polygonum sp.
    • rb: Rubus idaeus
    • bb: Rubus allegheniensis
    • sf: Comptonia peregrina
    • hf: Dennstaedtia punctilobula
    • wf: Dryopteris spp.
    • sedge: Carex spp.
    • rg: Oryzopsis asperifolia
    • sorrel: Rumex acetosella
    • starflower: Treintalis borealis
    • db: Rubus sp.
    • eb: Sambucus pubens
    • blue: Vaccinium angustifolium
    • sm: Acer pensylvanicum
    • rm: Acer rubrum
    • yb: Betula lenta
    • pb: Betula papyrifera
    • be: Fagus grandifolia
    • sp: Picea abies or Picea glauca
    • wp: Pinus strobus
    • pc: Prunus pensylvanica
    • bc: Prunus serotina
    • ro: Quercus rubra
    • eh: Tsuga canadensis
  7. lai: calculated leaf area index (unit: dimensionless / missing value: NA)