Dead wood is an important excursion object that clearly demonstrates the key mechanisms for preserving biodiversity in the forest. This is not just fallen trunks and dead wood, but a whole microecosystem that provides life for hundreds of species. Insects, fungi, lichens, mosses, and even vascular plants find shelter and food in decaying wood: some destroy the wood, others parasitize the destroyers, and others use it as a substrate for growth. For many birds and mammals – owls, chickadees, martens, squirrels, bats-half-rotted trees with hollows serve as reliable nests and shelters, and for hedgehogs, toads and snakes, old stumps become wintering grounds. Dead wood plays the role of a natural «storage» of moisture and nutrients: slowly giving up water, it supports the microclimate of the forest, and decomposing-enriches the soil and creates favorable conditions for the germination of young trees. Thus, this natural feature shows how even after the death of a tree, its wood continues to support life, ensuring the sustainability and diversity of the forest community.