A substrate classification for the northern limestone alps as a basis for a forest site assessment

Site maps for land use, especially for forestry, are complex compilations of pedological, topographical, climatic and vegetation information. Here, the pedological information is usually the limiting factor and often not available in sufficient spatial and content resolution. In none of the alpine countries soil maps are countrywide available. Where no pedological information is available, no site-specific maps can be created. Where pedological maps are available, they are not always comparable in their information, which makes cross-regional evaluation and use more difficult. The substrate classification presented here uses the comprehensive geological maps as a proxy in order to partially compensate for the lack of pedological information in this way. In addition to the presentation of the classification, their uses are presented. In this substrate classification, three parameters are evaluated, which are of great importance for potential plant growth. The geogenetic parameter describes the processing of the parent rock material, differing in particle sizes and sorting. The substrate chemical parameter characterizes the parent material, according to its carbonate content for carbonate rocks respectively to its base content for siliciclastic rocks. The class limits for carbonate levels of the individual classes do not always follow the geologically defined limit, but are based on the soil development series according to Rehfuess (1990), since the target is a proxy for the missing pedological data. The substrate physical parameter assesses the water holding capacity, evaluating mineral soil thickness, skeletal content and nFK on a rough scale. All rocks that are classified by the same three-parameter combinations represent a substrate type. The advantage of this substrate classification is that it is not hierarchical, which simplifies query capabilities and map display. The interpretation of the map and its possible uses are also shown in intersecting with other information such as terrain or vegetation information. Also, the limitations of the classification are discussed. As no information on an inventory level can be derived, the system is useful for regional and transnational planning.