Variation in Infrared Reflectance of Eucalyptus Radiata Dc.

Abstract

Various workers have reported that green plants which are diseased or in need of water have a lower infrared reflectance and consequently a blue image on false colour film. The infrared reflectance of E. radiata leaves rises as they become dry, and produces no blueness of the false colour image. It is suggested that blue images of E. radiata recorded in the field are due to lower reflectance of the infrared wavelengths by flowers. Water stress is not likely to be detected on false colour film until the plants are visibly affected.