Biophysical parameter retrieval in production forest stands using C-band polarimetric radar

A 40-km strip of polarimetric AIRSAR imagery over New Zealand´s Kaingaroa Forest was analysed for retrieval of biophysical parameters. The imagery was collected in November 2000 as part of the PACRIM-2 mission. Only the C-band data were analysed, as we are most interested in the potential of applications using future C-band satellite imagery. A series of regressions between stand age and radar information are reported where the level of radar complexity or use of additional covariate input is increased for each regression. The results show that stand age cannot be predicted using any single C-band polarisation. Promising results are found for dual-polarisation data, which will be available from future satellites. A regression using full-polarisation information yielded an adjusted R² of 82.3%. However, many of the common decomposition indices were found to be of little significance in this regression. The result is an improvement on methods based on backscatter intensity alone, and has important implications for inventory monitoring of commercial forestry stands.