Accuracy comparison of various remote sensing data sources in the retrieval of forest stand attributes

Recent advances in developing new airborne instruments and space-borne miss ions and in SAR technology, especially in interferometry and coherence esti mation, have roused questions: can such new SAR data be utilized in operati onal forest inventory? What is the accuracy of different satellite data for forest inventory? This paper verifies the explanatory power and informatio n contents of several remote sensing data sources on the retrieval of stem volume, basal area, and mean height, utilizing the following data: Landsat TM, Spot PAN and XS, ERS-1/2 PRI and SLC (coherence estimation), airborne d ata from imaging spectrometer AISA, radar-derived forest canopy profiles (o btained with HUTSCAT), and aerial photographs. Ground truth data included t hree different sets ranging from conventional forest inventory data to inte nsive field checking where one man-day was spent for assessing one stand. M ultivariate and neural network methods were applied in data analysis. The r esults suggested that (1) radar-derived stand profiles obtained with 100 m spacing was the most accurate data source in this comparison and was of equ ivalent accuracy with conventional forest inventory for mean height and ste m volume estimation, (2) aerial photographs (scale 1 :20,000) gave comparab le results with the imaging spectrometer AISA, (3) the satellite images use d for the estimation in the decreasing explanation power were Spot XS, Spot PAN, Landsat TM, ERS SAR coherence, JERS SAR intensity images (PRI); and E RS SAR intensity images (PRI). It appears that optical images still include more information for forest inventory than radar images, (4) from all sate llite radar methods, the coherence technique seemed to be superior to other methods. (C) 2000 Elsevier Science B.V. All rights reserved.