Résumé
Ecosystem modeling requires information about canopy chemistry. This is usually obtained through chemical analysis and laboratory spectrometric measurements. the potential of spectrometric remote sensing was investigated with an ISM (Imaging SpectroMeter) airborne campaign (1993, Les Landes, France). This spectrometer operates in the 800-3200 nm range. The study area consists of a mosaic of homogeneous parcels of maritime pines with a wide variety of ages (2-48 years). During the airborne campaign, 21 parcels were sampled and chemically analyzed for lignin, cellulose, and nitrogen. Samples were spectrally analyzed in laboratory with a Technicon InfraAlyser 450 and a NIR 6500 system. Correlations between the similar bands of the two spectrometers were surprisingly low. Predictive equations of nitrogen, lignin, and cellulose were obtained by stepwise regression analysis on spectral data. The stability of predictive relationships from laboratory to remote sensing level was especially analyzed. Technicon-derived predictive equations used with ISM data led to encouraging results for nitrogen and cellulose. Lignin could not be predicted NIR 6500-derived predictive equations were also tested with raw ISM data and data processed to minimize atmospheric effects. Minimization of atmospheric effects improved results for nitrogen and lignin.