THE IMPORTANCE OF DEAD WOODY MATERIAL IN FORESTS

In virgin forests and seminatural forests, volume in dead trees ranges from 50 to 200 m3/ha, while in forests under conventional management it is much lower: 1 to 5 m3/ha. The accumulated volume of dead woody material can be roughly considered as an indicator for naturalness and maturity of forests. But it cannot be used for an ecological assessment unless details are given about tree species woody debris comes from, size of logs, abiotic factors of decay, and decomposition classes. With its immense diversity of substrata, dead woody biomass provides habitat for an enormous number of highly specialized organisms: Macromycetes (appr. 1500 specialized species in FRG) and beetles (over 1300 specialized species) can be considered as "featured species". One quarter of saproxylic fungi and 60 % of saproxylic beetles are endangered by habitat reduction. Nature conservation demands increasing the volume of dead woody material, optimizing the quality of woody debris, and sustaining the dead woody biomass and dead woody material on the entire forest area. These demands are directed not only to foresters but certainly also to authorities responsible for mature trees in gardens, parks, and open fields. Finally, a short explanation of research needs is given.