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This article in JEQ

  1. Vol. 33 No. 3, p. 956-964
    Received: Mar 4, 2003

    * Corresponding author(s): nicholas.coops@csiro.au
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Assessment of Crown Condition in Eucalypt Vegetation by Remotely Sensed Optical Indices

  1. Nicholas C. Coops *a,
  2. Christine Stoneb,
  3. Darius S. Culvenora and
  4. Laurie Chisholmc
  1. a CSIRO Forestry and Forest Products, Private Bag 10, Clayton South, VIC 3169, Australia
    b Research & Development Division, State Forests of NSW, PO Box 100, Beecroft, NSW 2119, Australia
    c School of Geoscience, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia


Leaf and crown damage and discoloration characteristics are important variables when defining the health of eucalypt tree species and have been used as key indicators of environmental quality. These indicators can vary significantly over a few hectares, especially in mixed-species forests, making field-based environmental surveillance of crown condition an extremely expensive and logistically impractical task. Reflectance in narrow spectral wavelengths obtained from a field-based spectroradiometer and a Compact Airborne Spectrographic Imager 2 (CASI-2) were collected over eucalypt vegetation of varying condition in southeastern Australia and compared with leaf- and crown-based attributes including percent red foliage discoloration, percent leaf damage, and crown density and crown foliage condition. Of the leaf attributes sampled, percent leaf damage was well correlated with a red-green spectral index (r = 0.68, p < 0.01), and percent red discoloration was well correlated with the slope of the red-edge for selected species (r = 0.89, p < 0.001). Within-tree crown density was well correlated with the slope of the red-edge (r = 0.77, p < 0.001) and a previously published index of plant stress with crown foliage condition (r = 0.88, p < 0.01) for selected species. Despite evidence of strong interspecific variability, a set of narrow spectral wavelengths in the visible and near-infrared regions of the spectrum have been identified that will be useful in the development of forest ecosystem environmental quality indicators.

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Copyright © 2004. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyASA, CSSA, SSSA