Besides its major role for the conservation of saproxylic species, deadwood also contributes to carbon sequestration, nutrient supply, natural regeneration, and protection against falling rocks. The survival of saproxylic species is not only dependent on the quantity, but also on the quality of deadwood, such as the tree species, diameter, or decay stage. However, the presence of a species is not a guarantee for good habitat conditions. It might be a legacy of the time when its habitat was still available. Depending on the forest type, deadwood quantities ranging from 20 to 50 m3/ha have been identified as a threshold to maintain the majority of saproxylic species. Very demanding species require more than 100 m3/ha. Management practices that promote deadwood should be organized on large scales as the infuence of deadwood on saproxylic species increases with increasing spatial scales. The temporal dimension should also be considered because the continuity of forest cover and deadwood availability might play a major role in the protection of saproxylic biodiversity. The diversity of deadwood in terms of tree species, diameter, decay class, and type (lying/standing) has a positive effect on the conservation of saproxylic species assemblages. Most saproxylic species are either specialised on coniferous or broadleaved trees, and few generalists are known. Species with a narrower host-range are also known. However, the effect of tree species declines with the decomposition of deadwood. Few large diameter logs cannot be substituted by many small ones for a given volume of deadwood because both have their own species assemblages. Large decay logs have been identifed as essential for the conservation of saproxylic species as they are missing in most managed forests. During the decay process from fresh deadwood to mould wood, species assemblages and richness evolve in deadwood. Furthermore, how a tree dies has an important effect on the composition of the saproxylic community. Abiotic factors such as temperature and humidity and biotic drivers such as predation and competition also strongly infuence species assemblages occurring on deadwood. Deadwood has been increasing over the last decade throughout Europe. However, the conservation goals for saproxylic species have not yet been achieved as the quantitative thresholds determined for the conservation of most saproxylic species have generally not been reached in commercial forests. The ecological threshold for deadwood quantities of between 20–50 m3/ha should be reached within a network of forest stands at the landscape scale rather than aiming for a lower mean amount in all stands.