Xylotrophs in spruce stands of the Kologrivsky Forest Nature Reserve, Russia

. The purpose of the study is to study the species composition of xylotrophic fungi in spruce stands of the Kologrivsky Forest Nature Reserve (Kostroma region, Russia). On the territory of the nature reserve, 20 species of pathogenic fungi were found parasitizing on the trunks of living and dead trees. Dead wood (57%) is the main substrate for fungal fruiting bodies. Producing tree trunks use about 28% of xylophytes as a substrate, dry-standing – 15%.


Introduction
In forest ecosystems, autotrophic organisms are distinguished, which accumulate phytomass, and heterotrophic, whose function is the decomposition of organic matter.Among heterotrophs, typical inhabitants of forests are xylotrophs (wood-destroying fungi) that grow on the trunks and roots of living and dead trees, deadwood and stumps [1;3;8].
Dendropathogenic fungi are capable of causing rot diseases of tree species.The defeat of forest stands by fungal organisms leads to their weakening, death and drying of trees, the formation of windfalls and windbreaks, contributes to the loss of ecological, resource, aesthetic, sanitary and hygienic functions by the forest stand [9][10][11].Many researchers attach particular importance to the role of wood-destroying fungi in the food chain.Being decomposers, xylotrophs mineralize wood residues, thus splitting complex organic substances into elements of mineral plant nutrition, contributing to an increase in soil fertility.Wood-destroying fungi can cause stem and root rot of trees, causing damage to forestry [2].The rate of wood destruction is significantly affected by the amount of wood waste and the activity of xylotrophic fungi.Wood rotting is a process widespread in nature, which affects the wood of both dead and producing tree trunks.The purpose of the study is to study the species composition of xylotrophic fungi in spruce stands of the Kologrivsky Forest Nature Reserve.

Methods and Materials
The object of the study is xylotrophic fungi in spruce stands of the Kologrivsky Les Reserve [3].The reserve is located in the taiga zone of the European part of Russia (Kostroma region) and consists of two unconnected clusters (Kologrivsky and Manturovsky).Since 2020, the nature reserve has been the core of the Kologrivsky Forest Biosphere Reserve [4][5][6][7].
Collection of fungal fruiting bodies was carried out on permanent trial plots of the Kologrivsky cluster of the nature reserve with a complete enumeration of trees, the results of which determined the main stand indicators.The selection of specimens of fruiting bodies of xylotrophic fungi with a small amount of substrate was carried out from standing trees and deadwood at various stages of decomposition.The collected field materials were labeled and numbered.
The subsequent identification of sporocarps of parasitic fungi was carried out under laboratory conditions using a determinant according to the appearance of the fruiting body, its size, shape, color, structure, and consistency of the mycelial filaments that form the pulp.
According to the results of the study, 20 species of xylotrophic fungi were identified.Their distribution by families is shown in figure 1.

Conclusion
Considering the distribution of wood-destroying fungi according to their attachment to the substrate, one can note the predominance of species that destroy dead wood (57%).Producing tree trunks use about 28% of xylophytes as a substrate, dry-standing -15%.A distinctive feature of Climacocystis borealis (Fr.)Kotl.et Pouzar and Fomes fomentarius (L.: Fr.) Fr. is the ability to damage both living and dead trees.The results of this study can be applied in assessing the sanitary condition of forest plantations.