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.
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:
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 |
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