Deadwood, whether expressed in volume, diversity or continuity, is nowadays widely acknowledged as being an important component of forest ecosystems and has therefore been addressed in most recent studies dealing with forest conservation and management. However, and despite the growing use of the concept of naturalness in the management plans of French forest reserves, deadwood dynamics remain greatly unknown in European temperate forests. In this context and to answer a growing demand arising from reserve managers, a long-term monitoring scheme has been launched in 2005. Preliminary results from 42 French forest reserves will be presented in this talk. A comprehensive data set of living and dead tree measurements have so far been collected on more than 4000 permanent plots. Sampling is systematic but the density of plots is adjusted to the reserve size, habitat diversity and management practices. Overall, French forest reserves host an average of 35.1 m3/ha of deadwood. More than 2/3 of the reserves had deadwood volumes between 20 and 40 m3/ha, and were considered deadwood rich. For more than 1/3 of these reserves, the estimated volume was even greater than 40 m3/ha, indicative of forests growing under nearly natural conditions. Although most of the reserves showed a significant amount of deadwood, the gap with old-growth forests is still of great magnitude. The following surveys should allow us to better understand these differences.