Many major forests are situated in tropical areas where there is
cloud cover for much of the year or at high latitudes where
there are long periods of darkness during the winter months.
Initial results achieved using ERS data (C-band) for forest
mapping were rather disappointing in comparison with what
is possible using longer radar wavelengths such as L-band.
However, the situation has now improved significantly using
multi-temporal analysis and interferometric techniques, and
ERS data are beginning to be used in operational mapping
programmes