A New Reflectance Index for Remote Sensing of Chlorophyll Content in Higher Plants: Tests using Eucalyptus Leaves

The visible/near infrared reflectance properties of leaves from several Eucalyptus species were studied to determine appropriate indices for remote sensing of chlorophyll content. Reflectance near 710 nm wavelength showed a higher sensitivity to chlorophyll content than reflectance near 550nm. The near infrared band with the least sensitivity to chlorophyll content was located at 850 nm. The use of R710 nm as the sensitive band and R850 nm as the insensitive band, increased the correlation of the reflectance indices to chlorophyll content. Among several reflectance indices tested, the ratio (R850-R710)/(R850-R680) performed best, and is proposed as a new index for the remote estimation of chlorophyll content in higher plants. This new index is insensitive to the effects of leaf scattering on reflectance, and relates strongly to the variation in reflectance caused by chlorophyll absorption.