Remote sensing of photosynthetic-light-use efficiency of boreal forest

Using a helicopter-mounted portable spectroradiometer and continuous eddy c ovariance data we were able to evaluate the photochemical reflectance index (PRI) as an indicator of canopy photosynthetic light-use efficiency (LUE) in four boreal forest species during the Boreal Ecosystem Atmosphere experi ment (BOREAS). PRI was calculated from narrow waveband reflectance data and correlated with LUE calculated from eddy covariance data. Significant line ar correlations were found between PRI and LUE when the four species were g rouped together and when divided into functional type: coniferous and decid uous. Data from the helicopter-mounted spectroradiometer were then averaged to represent data generated by the Airborne Visible Infrared Imaging Spect rometer (AVIRIS). We calculated PRI from these data and relationships with canopy LUE were investigated. The relationship between PRI and LUE was weak ened for deciduous species but strengthened for the coniferous species. The robust nature of this relationship suggests that relative photosynthetic r ates may be derived from remotely-sensed reflectance measurements. (C) 2000 Elsevier Science B.V. All rights reserved.