NFI 2012 water budgets and drought stress indicators database

(i) Key message: The NFIWADS database contains aggregated results for the German National Forest Inventory (NFI) plots based on process-based water balance simulations. More than 150 water budget, soil moisture, and drought stress indicators were derived for mature, closed-canopy beech and spruce stands, and provide a basis for the assessment of forest productivity and risks. (ii) Context: The NFI is an important data source for research on forest growth, tree species distribution and wood supply predictions in Germany. The NFIWADS database extends the environmental vector of explanatory variables by results from water balance simulations. (iii) Aims: The aim of this paper is to share the data for a broad use among forest scientists and to ease data handling by thoroughly describing the methods, background and structure of the data. (iv) Methods: For 24610 NFI plots, two site-specific water balance simulations were carried out, using the process-based hydrological model LWF-BROOK90, respectively for a retrospective period (1961-2013) and for each of three climate change scenarios (2011-2050). The two simulations in each climate representation describe the hydrological conditions of European Beech (Fagus sylvatica, L.) and Norway Spruce (Picea abies [L.], H.Karst) forests. (v) Main features and potential use of database: The daily simulation results were aggregated to monthly and vegetation period representations of water fluxes, soil moisture conditions and drought stress that can be used as explanatory variables for analysing long-term climate-sensitive site-productivity relationships and risk potentials, as well as intra-annual and seasonal variations of forest growth conditions. (vi) Conclusions: The connection of yield data and a broad set of environmental explanatory variables at the NFI opens up new opportunities for forest research at the national scale.