Epiphyte surveys are often limited to the lower trunk sections of the host trees. This largely overlooks species that occur preferentially in tree crowns. Considering the vertical distribution patterns of epiphytic mosses and lichens in alluvial hardwood forests, such surveys would be incomplete and their results would differ from whole-tree surveys. This would be particularly critical with respect to surveys of the overall species diversity of such forest stands, assessments of their worthiness for protection, and for bioindication (e.g., the influence of climate change). In the present study, performed in the largest protected complex of alluvial forests in central Germany, we examined 20 sample trees wind-thrown and broken in recent storm events. Here epiphyte communities were recorded section-wise from the trunk base to the outer tree crown. 75 % of the epiphytic lichens were confined to the crown and upper trunk parts, while 30 % of the bryophyte taxa were restricted to the tree crowns and another 30 % were found only on the lower trunk and the trunk base. For both lichens and bryophytes, species of conservation concern were observed only in the tree crowns, as were most indicator species for climate warming. Using Ellenberg indicator values, we also found significant differences in moisture and light conditions, substrate reaction, continentality, and nutrient supply across the different tree sections. Thus, whole-tree samplings for bryophytes and lichens, especially in alluvial hardwood forests, yield much more accurate and sophisticated results about epiphyte diversity and ecological conditions than conventional lower-trunk surveys. Key words: climate change, tree canopies, flooding.