The BOREAS Information System
Terrestrial Ecology (TE)


TE-10: CO2 and Water Fluxes in the Boreal Forest Overstory: Relationship to fAPAR and Vegetation Indices for Needles/Leaves


P.I.(s): Elizabeth Middleton -- NASA/Goddard Space Flight Center
Co-I(s): Joseph H. Sullivan -- Univ. of Maryland

Objectives: In this study we will correlate physiological processes at the leaf/needle level with optical measurements amenable to remote sensing. Specifically, in situ measurements for gas exchange flux rates for CO2 and water, plant stress as indicated by chlorophyll-a fluorescence, and other supporting measurements will be acquired for dominant species of the boreal forest overstory at the BOREAS Southern sites (old aspen, old jack pine, young jack pine, black spruce, and mixed aspen/white spruce). In the laboratory, further measurements of photosynthetic capacity will be made in conjunction with continuous visible/near-infrared spectral optical properties and pigment analyses. Nitrogen will be determined from dry foliar material. This data set will be utilized to estimate the vertical gradients of carbon assimilation, nitrogen use efficiency, and photosynthetic efficiency for different species as a function of phenology and environmental conditions, especially available water, nitrogen, and PAR. These data will be used to examine the relationships between the physiological parameters, especially photosynthesis and conductance rates, and the optical parameters (fAPAR and spectral vegetation indices, or SVIs). They will also be used to parameterize the canopy level radiative transfer and physiological models utilized in landscape in landscape analyses by other investigators.


TE-10 Data Sets

  • Leaf Optical Properties - Broad Leaf
  • Leaf Optical Properties - Conifer
  • Leaf Characteristics (size, wgt, etc)
  • Gas Exchange
  • Leaf Biochemistry

  • Get some TE-10 data using FTP (BOREAS Investigators only, password required). [FTP Help]


    TE-10 BOREAS Operations 1994


    Objectives:
    In this study we will correlate physiological processes at the leaf/needle level with and optical measurements amenable to remote sensing. Specifically, in situ measurements

    Approach:
    For gas exchange fluxes for CO2 and water, plant stress as indicated by chlorophyll-a fluorescence, and other supporting measurements will be acquired for dominant species of the boreal forest overstory at the BOREAS Southern sites (mature aspen, mature jack pine, young jack pine, black spruce, and mixed aspen/white spruce). In the laboratory, further measurements of photosynthetic capacity will be made in conjunction with continuous visible/near-infrared spectral optical properties and pigment analyses. Nitrogen will be determined from dry foliar material. This data set will be utilized to estimate the vertical gradients of carbon assimilation, nitrogen use efficiency, and photosynthetic efficiency for different species as a function of phenology and environmental conditions, especially available water, nitrogen, and PAR. These data will be used to examine the relationships between the physiological parameters, especially photosynthetic and conductance rates, and the optical parameters (Fapar and spectral vegetation indices, or SVIs). Ultimately, these data will be used to test hypotheses relating leaf physiology to canopy physiology and remotely acquired SVIs. They will also be used to parameterize the canopy level radiative transfer and physiological models utilized in landscape analyses by other investigators.


    Study Objectives:


    Measurements Acquired During 1994 IFC's:

    1. I. Gas Exchange
      • In Situ (light-saturated): Photosynthesis, Conductance, Transpiration etc.
      • Lab: Photosynthetic Capacity (25°C < T < 29°C), with light curves

    2. II. Leaf/Shoot Characters
      Broadleaf Conifers
      (Aspen, Hazelnut, Misc.) (Jack Pine, Black spruce, White Spruce)
      Fresh Weight Fresh Wt., needles + stem
      Dry Weight Dry Weight/ needles, stem separately
      Projected Area Projected Area (by age class)
      L, W L, W, H (needle sample)
      # needles per age class
      Munsell Color (both sides) Munsell Color (both sides)
      Pigments: Chl a, Chl b, Total Carotenoids Pigments: Chl a, Chl b, Total Carotenoids

    3. Spectral Optical Properties (By Age Class)
      • Reflectance and Transmittance of abaxial and adaxial surfaces at 5 nm sampling rate (400-1000 nm). Spectral Absorbance (400-1000 nm) determined.

    4. Fluorescence (By Age Class):
      • Spectra (360-800 nm), with excitation at 340 nm (IFCs 2-3).

    5. Chemistry (By Age Class) from Dried Material: Nitrogen, Carbon (TBD).
      • Terrestrial Ecology Group 10 (TE-10)
      • CO2 and Water Fluxes in the Boreal Forest Overstory:


      1994 Sites Studies (SSA):
      Old Aspen (aspen, hazelnut), Young Aspen (aspen, hazelnut), Old Jack Pine (jack pine, understory), Young Jack Pine (jack pine), Black Spruce, White spruce @ "Young Aspen".

      SSA Site Species 1994 IFC Field Dates
      Old Aspen
      (SSA-OA)
      aspen 1 5/25 &29
      poplar 1 6/10
      hazelnut 2
      2
      3
      3
      7/21
      8/03
      9/02
      9/15
      Young Aspen
      (SSA-YA)
      aspen 1 5/24 & 26
      hazelnut 1
      2
      3
      3
      6/04
      7/28
      9/02
      9/12
      Old Jack Pine
      (SSA-OJP)
      jack pine 1 5/31
      understory 1
      2
      3
      6/03
      7/25
      9/07
      Young Jack Pine
      (SSA-YJP)
      jack pine 1
      1
      2
      3
      5/26
      6/07
      7/22
      9/07
      Black Spruce
      (SSA-OBS)
      black spruce 1
      1
      2
      3
      6/01
      6/05
      7/28
      9/09
      Young Aspen
      [Snow Castle]
      white spruce 2
      3
      7/30
      9/08


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      Last Updated: October 2, 1998