Water supply via the water conducting wood structure is essential for tree productivity, growth of energy plants, and food supply. However, water transport relies on a fragile system and the mechanisms of xylem vulnerability are still under debate which gains in importance if facing extended drought periods as predicted for Central Europe. Combining techniques established in ecophysiology and engineering will for the first time provide evidence at which point hydraulic failure occurs under severe drought and to what extent recovery from embolism is possible in young and adult trees of Norway spruce and European beech, but also in poplar and apple trees. The species differ widely in foliage type, wood structure and drought response. Embolies are induced experimentally in young potted trees grown in the greenhouse as well as in adult plants of the two forest species taking advantage of a new type of through-fall exclusion experiment which has started in 2013 at 'Kranzberger Forst' near Freising (KROOF). Samples from woody axes will be analyzed for embolies and their repair potential by combining methods used in ecophysiology, process engineering and material science (including hydraulic conductivity, nuclear magnetic resonance, X-ray microtomography, isotopic labelling). This analysis will be complemented by the characterization of xylem material properties as well as of anatomical traits, transport capacity, and hydraulic redistribution in roots. Coupling material science with the study of transport processes is widespread in engineering and allows for a deeper insight into the mechanisms of xylem water transport and its vulnerability. These findings prepare the ground for novel water management strategies in woody plant systems as well as for improvements in technical solutions of water transport (bionics).