Storm damage and long-term mortality in a semi-natural, temperate deciduous forest

1. Wind-damaged trees, following the severe storm of 1999, are compared with data from a 50-year monitoring of Draved Forest, Denmark, to assess differing causes of mortality through time in an unmanaged semi-natural forest. Species-specific mortality characteristics and the changing effects of tree size and growth rate (diameter increment) on mortality through time are also investigated. 2. Storm was found to be the major mortality factor affecting large trees in this forest. For smaller trees, competition was an important cause of death, as trees that were found standing dead had a slower growth rate (diameter increment) than survivors. 3. Individual species showed different mortality patterns. Betula died more often and Fagus less often than expected from their abundance. Betula, Fagus and Tilia were mainly wind-thrown, whereas for Alnus and Fraxinus, 50% of the mortality was observed as standing dead trees. 4. Both wind and competition are important mortality factors in Draved Forest.