Lars T. Waser

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Forest disturbances in central Europe caused by fungal pests may result in widespread tree mortality. To assess the state of health and to detect disturbances of entire forest ecosystems, up-to-date knowledge of the tree species diversity is essential. The German state Mecklenburg–Vorpommern is severely affected by ash (Fraxinus excelsior) dieback caused by(More)
Sustainable forest management practices allow for a range of harvest prescriptions, including clearcut, clearcut with residual, and partial or selective cutting, which are largely distinguished by the amount of canopy cover removed. The different prescriptions are aimed to emulate natural disturbance, encourage regeneration (seed trees), or offer other(More)
Forest mapping is an important source of information for assessing woodland resources and a key issue for any National Forest Inventory (NFI). In the present study, a detailed wall-to-wall forest cover map was generated for all of Switzerland, which meets the requirement of the Swiss NFI forest definition. The workflow is highly automated and based on(More)
This study presents a methodology for derivation of fractional canopy cover, detection of main tree species, and extraction of forest stands using logistic regression, airborne remote sensing data and field samples. In a first step, canopy height models (CHMs) are generated using medium point density LiDAR DSM and DTM and a high-quality matching DSM. Then,(More)
Landscape structure was investigated on six test sites in Switzerland, selected along a land-use intensity gradient. The test areas were captured with remote sensing images on three spatial resolutions: 1) fused Landsat ETM-IRS and 2) Quickbird satellite images as well as 3) CIR aerial photos. Segmentation and fuzzy classification were implemented on the(More)
Temporally frequent, cost-efficient and precise forest information requirements for national forest inventories, monitoring or protection tasks have grown over time and will continue to do so in the future. New perspectives are given by the airborne digital sensor ADS40, which provides entire image strips with high geometric, radiometric and temporal(More)
In this study, airborne laser scanning-based and traditional field-based survey methods for tree heights estimation are assessed by using one hundred felled trees as a reference dataset. Comparisons between remote sensing and field-based methods were applied to four circular permanent plots located in the western Italian Alps and established within the(More)
Remote-sensing plays an important role in wetland monitoring on the regional and global scale. In this study we assessed the potential of different optical sensors to map floristic indicator gradients across complex mire habitats at the stand level. We compared traditional CIR photographs from RC30 cameras with modern digital ADS40 data and SPOT5 satellite(More)
Airborne laser scanner (ALS) data are used operationally to support field inventories and enhance the accuracy of forest biomass estimates. Modelling the relationship between ALS and field data is a fundamental step of such applications and the quality of the model is essential for the final accuracy of the estimates. Different modelling approaches and(More)