Climate change is a factor that largely contributes to the increase of forest areas affected by natural damages. Therefore, the development of methodologies for forest monitoring and rapid assessment of affected areas is required. Space-borne synthetic aperture radar (SAR) imagery with high resolution is now available for large-scale forest mapping and forest monitoring applications. However, a correct interpretation of SAR images requires an adequate preprocessing of the data consisting of orthorectification and radiometric calibration. The resolution and quality of the digital elevation model (DEM) used as reference is crucial for this purpose. Therefore, the primary aim of this study was to analyze the influence of the DEM quality used in the preprocessing of the SAR data on the mapping accuracy of forest types. In order to examine TerraSAR-X images to map forest dominated by deciduous and coniferous trees, High Resolution SpotLight images were acquired for two study sites in southern Germany. The SAR images were preprocessed with a Shuttle Radar Topography Mission (SRTM) DEM (resolution approximately 90 m), an airborne laser scanning (ALS) digital terrain model (DTM) (5 m resolution), and an ALS digital surface model (DSM) (5 m resolution). The orthorectification of the SAR images using high resolution ALS DEMs was found to be important for the reduction of errors in pixel location and to OPEN ACCESSRemote Sens. 2012, 4 662 increase the classification accuracy of forest types. SAR images preprocessed with ALS DTMs resulted in the highest classification accuracies, with kappa coefficients of 0.49 and 0.41, respectively. SAR images preprocessed with ALS DTMs resulted in greater accuracy than those preprocessed with ALS DSMs in most cases. The classification accuracy of forest types using SAR images preprocessed with the SRTM DEM was fair, with kappa coefficients of 0.23 and 0.32, respectively. Analysis of the radar backscatter indicated that sample plots dominated by coniferous trees tended to have lower scattering coefficients than plots dominated by deciduous trees. Leaf-off images were only slightly better suited for the classification than leaf-on images. The combination of leaf-off and leaf-on improved the classification accuracy considerably since the backscatter changed between seasons, especially in deciduous-dominated forest.

For many aspects of the human life the world's forests are crucial. Only microwave remote sensing provides the means of all day weather independent monitoring of those pristine areas. Multi-temporal ENVISAT ASAR and ALOS PALSAR data for mapping boreal forest in central Siberia proved to be quite successful in diverse research projects. So far, TerraSAR-X High Resolution Spotlight images have been effectively used in the verification process of the resulting land cover area maps. Part of this knowledge will be transferred within the framework of the Remote Sensing Survey of the next global Forest Resources Assessment. Altogether 350 TerraSAR-X scenes all over the cloudy tropics will be analysed in a project called FRA-SAR 2010. The combined analysis of ALOS PALSAR, ENVISAT ASAR and TerraSAR-X on five areas inside the project will foster the expertise on forest structure parameters.

Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the * 38 U chain nuclides, T^ie sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the U and Th nuclides, In total airborne dust measurements, the °Ra and l Pb nuclides were found to be depleted by 20 and 25$, respectively. Bulk ore samples showed depletions of 10% for the Ra and Pb nuclides, Impactor samples show disequilibrium of Ra as high as ±50%' for different size fractions. In these samples the Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ^m with a median diameter of 11 ym. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15$ of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement iii