of how radiation interacts with a vegetation canopy,
and on our methodologies. Remotely sensed data
were used first to categorize vegetation and then
to estimate the physical contents of canopies. Today
there is evidence that we can also use remotely
sensed data to estimate the chemical contents
of canopies (Asrar, 1989).
The two questions explored in this paper are,
first, why and, second, how remotely sensed data
should be used to estimate foliar chemical content.
The paper concludes with recommendations for
future long- and short-term research strategies.