The remote sensing of biophysical properties has generally relied on the use of data acquired in red and near-infrared channels only, often combined in a vegetation index such as the Normalized Difference Vegetation Index (NDVI). This is wasteful of information acquired in other channels and may prevent the accurate estimation of biophysical properties. The use of vegetation indices based on red and near-infrared radiation to estimate biophysical properties of tropical forests has met with little success and this may be due to the asymptotic nature of the relation between the indices and biophysical properties, the variable sensitivity of vegetation indices to vegetation biophysical properties in different environments, the low radiation reflected in red and near-infrared channels, and severe attenuation by atmospheric water and aerosols.