Leaf Optical Properties

Walter‐Shea, Elizabeth A.; Norman, John M.

doi:10.1007/978-3-642-75389-3_8

Cited by 43 publications

(11 citation statements)

References 25 publications

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“…Among grasses, the lowest leaf reflectance variation was in the PAR region (CV ϭ 6-7%), while the highest was in the NIR (CV ϭ 10-11%). Conservative scattering in the visible range results from the biochemical constraints imposed by the presence of chlorophyll (Gausman 1982, Boyer , Maas and Dunlap 1989, Walter-Shea and Norman 1991, Poorter et al 1995. A comparison of the woody plant and grass leaf transmittance spectra showed no statistically significant differences throughout the entire shortwave region (Fig.…”

Section: Leaf Optical Propertiesmentioning

confidence: 99%

“…Soil reflectance characteristics are a function of moisture content, surface texture, and parent material (Stoner andBaumgardner 1981, Jacquemoud et al 1992). Leaf-level scattering characteristics (or leaf optical properties) are primarily determined by leaf structure and chemistry, including water content, the concentration of structural carbon constituents (e.g., cellulose, lignin), chlorophyll, and other biologically active pigments (Gates et al 1965, Thomas et al 1971, Wooley 1971, Walter-Shea and Norman 1991, Fourty et al 1996. Scattering by stem surfaces is influenced by carbon constituents, roughness, and moisture (Murray andWilliams 1987, Asner andWessman 1997).…”

Section: Introductionmentioning

confidence: 99%

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Scale Dependence of Absorption of Photosynthetically Active Radiation in Terrestrial Ecosystems

Asner

Wessman

Archer

1998

Ecological Applications

119

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The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification of fAPAR determinants at the landscape level is needed to improve the interpretation of remote sensing data, to facilitate its use in constraining ecosystem process models, and to improve synoptic‐scale links between carbon and nutrient cycles. Most canopy radiation budget studies have focused on light attenuation in plant canopies, with little regard for the importance of the scale‐dependent biophysical and structural factors (e.g., leaf and stem optical properties, leaf and stem area, and extent of vegetation structural types) that ultimately determine fAPAR at canopy and landscape scales. Most studies have also assumed that nonphotosynthetic vegetation (litter and stems) contributes little to fAPAR. Using a combined field measurement and radiative transfer modeling approach, we quantified (a) the relative role of the leaf‐, canopy‐, and landscape‐level factors that determine fAPAR in terrestrial ecosystems and (b) the magnitude of PAR absorption by grass litter and woody plant stems. Variability in full spectral‐range (400–2500 nm) reflectance/transmittance and PAR (400–700 nm) absorption at the level of individual leaf, stem, and litter samples was quantified for a wide array of broadleaf arborescent and grass species along a 900‐km north–south Texas savanna transect. Among woody growth forms, leaf reflectance and transmittance spectra were statistically comparable between populations, species within a genus, and functional types (deciduous vs. evergreen, legume vs. nonlegume). Within the grass life‐form, spectral properties were statistically comparable between species and C3/C4 physiologies. We found that tissue‐level PAR absorption among species, genera, functional groups, and growth forms and between climatologically diverse regions was statistically similar, and for fresh leaves, it represented the most spectrally similar region of the shortwave spectrum. Subsequent modeling analyses indicated that the measured range of leaf, woody stem, and litter optical properties explained only a small proportion of the variance in tree and grass canopy fAPAR. However, the presence of nonphotosynthetic vegetation (e.g., stem and litter) had a significant effect on canopy fAPAR. In trees with a leaf area index (LAI) <3.0, stem surfaces increased canopy fAPAR by 10–40%. Standing grass litter canopies absorbed almost as much PAR as green grass canopies. Modeling the radiation regime in plant canopies should therefore account for the absorption of PAR by nonphotosynthetic plant components. Failure to do so may lead to overestimates of primary production, especially in woodlands, savannas, and shrublands dominated by species with optically thin canopies and in grasslands that accumulate senescent material. Further sensitivity analyses revealed that the extent and LAI of vegetation structural types (trees and...

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Section: Leaf Optical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Scale Dependence of Absorption of Photosynthetically Active Radiation in Terrestrial Ecosystems

Asner

Wessman

Archer

1998

Ecological Applications

119

View full text Add to dashboard Cite

show abstract

“…Nevertheless, plants themselves modify the light environment by absorbing, reflecting or transmitting the incident light. The result is an internal light environment, which is very different from outside according to intensity, spectral composition and direction and which strongly depends on the optical properties of the involved plant tissues (Wallter-Shea and Norman, 1991). Optical properties of plant tissues have been investigated mostly in leaves, because of their importance in photosynthesis and/or photomorphogenesis (see Vogelmann, 1993;Vogelmann and Han, 2000).…”

Section: Introductionmentioning

confidence: 99%

The optical, absorptive and chlorophyll fluorescence properties of young stems of five woody species

Wittmann

Pfanz

2016

Environmental and Experimental Botany

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“…Typical Leaf BRDFs have both diffuse and specular components, whereas the directional distribution of transmitted light (BTDF) is closer to Lambertian (Walter-Shea and Norman 1991). The BRDF and BTDF measurements of individual leaves are difficult to attain (Walter-Shea and Norman 1991;Bousquet et al 2005), particularly in hot-spot geometry and using laser light (Kaasalainen et al 2005). Figure 2.…”

Section: Transmitted Pulsementioning

confidence: 99%

Towards an enhanced understanding of airborne LiDAR measurements of forest vegetation

Hovi¹

2015

Diss. For.

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Leaf Optical Properties

Cited by 43 publications

References 25 publications

Scale Dependence of Absorption of Photosynthetically Active Radiation in Terrestrial Ecosystems

Scale Dependence of Absorption of Photosynthetically Active Radiation in Terrestrial Ecosystems

The optical, absorptive and chlorophyll fluorescence properties of young stems of five woody species

Towards an enhanced understanding of airborne LiDAR measurements of forest vegetation

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