Corina da C. F. Yanasse 
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Sidnei J. S. Sant'Anna -
Alejandro C. Frery 
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Camilo Daleles Rennó -
João Vianei Soares -
Adrian John Luckman 
Instituto Nacional de Pesquisas Espaciais
DPI and DSR
Avenida dos Astronautas, 1758
12227-010 São José dos Campos, SP, Brazil
Universidade Federal de Pernambuco
Departamento de Informática
Caixa Postal 7851
50732-970 Recife, PE, Brazil
British National Space Centre
Remote Sensing Applications Development Unit
Monks Wood, Abbots Ripton
Huntingdon, PE17 2LS, UK
In this paper the relationship between secondary forest regrowth stage and SIR-C SAR data is assessed, for an area located near to the Tapajós National Forest, south of Pará State, in the Amazon region. These 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 coefficient of variation (CV) for several second-growth succession stages classes are calculated. It is shown that the discrimination between regeneration 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 more information. The maximum difference of means among classes occured in this band and it is of about 5 dB. The CV appeared to be less well suited than the mean value for regeneration stage discrimination, although some discrimination among early stages of regeneration may be possible using this measure at L-band.
Keywords: classification, SAR, secondary forest regrowth.