EXPLORATORY-STUDY OF THE RELATIONSHIP BETWEEN TROPICAL FOREST REGENERATION STAGES AND SIR-C-L AND SIR-C-C DATA

In this article, the relationship between secondary forest regrowth st age and SIR-C SAR data is assessed for an area located near to the Tap ajo's National Forest, south of Para State, in the Amazon region. Thes e regeneration stages are mapped by making use of a consecutive annual sequence of Landsat TM (Thematic Mapper) images. Using this map as a mask over the radar images, the tonal means (expressed in dB) and coef ficient of variation (CV) for several second-growth succession stages classes are calculated. It is shown that the discrimination between re generation stages is difficult when individual ''small areas are used, but this discrimination might be possible when L-band means over a '' large area are computed. In particular, the L-HV band seems to carry m ore information. The maximum difference of means among classes occurre d in this band and it is of about 5 dB. The CV appeared to be less wel l suited than the mean value for regeneration stage discrimination, al though some discrimination among early stages of regeneration may be p ossible using this measure at L-band. (C) Elsevier Science Inc. 1997.