Stephan Seeling

Fusion of full-waveform lidar and imaging spectroscopy remote sensing data for the characterization of forest stands

Full-waveform small-footprint laser scanning and airborne hyperspectral image data of a forest area in Germany were fused to get a detailed characterization of forest reflective properties and structure. Combining active laser scanning data with passive hyperspectral data increases the information content without adding much redundancy. The small-footprint light detection and ranging (lidar) waveforms on the area of each 5 m × 5 m HyMap pixel were combined into quasi-large-footprint waveforms of 0.5 m vertical resolution by calculating the mean laser intensity in each voxel. As exemplary applications for this data set, we present the estimation of crown base heights and the ease of displaying vertical and horizontal slices through the three-dimensional data set. As a consequence of the identical geometry of the voxel bases and the hyperspectral image, they could be joined as a multi-band image. The combined spectra are well suited for interpretations of pixel content. In a test classification of tree species and age classes, the joint image performed better than the hyperspectral image alone and also better than the hyperspectral image combined with lidar percentile images.

Large Scale Approach to Forest and Water Interactions

Assessing the impacts of forests and forest management on the water cycle and discharge in large scaled watersheds requires innovative methods and modeling because besides forestry the topography, geology, pedology and climate conditions cause a considerable external forcing. Progresses were made to show the spatial-temporal variability of rainfall-runoff behavioral patterns in meso-scaled basins by remote sensing methods and GIS-based approaches. Forest stabilization measures have an essential relevance for the drinking water resources in large scale groundwater appearances since the contamination by atmospheric nitrogen and acid deposition increased. An integrated land and water management at larger scale needs to find the way combining an engineering watershed management and a scientific based precautionary land-use management. A large scale European approach across political borders was laid down by the European Water Framework and Floods Directives to protect and enhance the status of inland surface water, transitional water, coastal water and groundwater and to mitigate the effects of floods and droughts.