Aggregated Forest Soil Condition Database of the Level II, 2nd soil survey in its version 2

(i) Context:The ICP Forests database is probably the most comprehensive forest ecosystem database in Europe and contains the accumulated results of several decades of harmonised monitoring all over Europe. (ii) Aims: Goal of this paper is to open the soil information of the ICP Forests Level II plots for broader use among forest scientists. (iii) Methods: The soil data were gathered according to the ICP Forests manual, purified, validated, and aggregated to meaningful variables and summarizing soil properties. (iv) Main features and potential use of database: The aggregated Level II forest soil database provides the occasion for the combined evaluation of up to 130 unique soil variables per plot with dynamic data on tree growth, ground vegetation, foliage chemistry, crown condition, tree phenology, leaf area index, ground vegetation, ozone injury, litterfall, soil solution, deposition, ambient air quality, and meteorological data assessed on the same plots. (v) Conclusions:The database covers nearly all member states of the European Union, but it is not representative for this area in terms of tree species and soil types due to the original selection criteria for the plots.