Verification of the potential of various remote sensing data sources for forest inventory

Due to recent advances in developing new airborne instruments and spaceborne missions, advances in SAR technology, especially in interferometry and coherence estimation, the explanatory power and information contents of several remote sensing data sources on the retrieval of stem volume were verified in this paper. Data included Landsat TM, SPOT Pan and XS, ERS-1/2 PRI and SLC (coherence estimation), airborne data from imaging spectrometer AISA, radar-derived forest canopy profiles (obtained with HUTSCAT), and aerial photographs. Ground truth data included two sets: traditional forest inventory data and field checking. Multivariate methods were applied in data analysis. The results suggested that: (1) ERS-1/2 coherence images were of comparable accuracy with SPOT XS and Landsat TM (without stratification by species), and the usability of ERS and JERS backscatter information, even by using multitemporal images, was very limited; (2) combined use of ranging radar and aerial photograph/imaging spectrometer are suggested for further studies concerning standwise forest inventory, and the combined use of ERS coherence with optical, preferably very-high-resolution, satellite data is recommended for further studies concerning large-area forest inventory.