The importance of dead wood for biodiversity is discussed based on estimates of resource abundance and analysis of saproxylic communities of Coleoptera, Diptera-Brachycera, and Formicidae. Attention is paid to lying oak trunks and forest pests. The communities include many threatened and rare species, even such new to science. Lying oak trunks are shown to host few potential pests accompanied by substantial populations of antagonists. Species presenting higher risk were found in low numbers.