Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Fungi can affect forests in a positive way, thanks to mutualistic symbiosis, saprotrophism, or in a negative manner, posing a serious threat to the health of forest stands. Data on the occurrence and diversity of mycobiota in economically used forest areas are presented less frequently compared to other forms, e.g. protected areas. The aim of the study was to determine the species diversity of large-fruiting wood fungi occurring on the wood of stumps, logs, living and dead standing trees and on the forest floor in stands occupying the main forest habitats in the naturally valuable Krzyż Forest District.
Material and methods. For the study, 25 subcompartments were selected, which included forest habitat types such as FCF, FMCF, FBF, FMBF and mMBF, with the largest share in terms of area occupied in the Krzyż Forest District and ranging in age from 80 to 100 years. In selected subcompartments, two to five strip study areas were designated - transects 4 meters wide (2 meters on each side from the center of the strip and 100–400 m long, located parallel to each other at a distance of 30 meters). Mushroom species were measured by walking through the middle of a transect drawn from the west to the east, parallel to each other at a distance of 30 meters. Fruiting bodies were recorded on standing and lying trees, dead wood, branches and stumps.
Results and conclusions. During the study a total of 55 species of wood fungi were found, which occurred singly or in groups on wood and living trees at 494 sites. In the subcompartments with the fresh forest habitat, a large number of taxa were recorded, the highest among all habitat types examined here, but none of them clearly dominated in percentage terms, the most recorded were Schizophyllum commune. The most frequently recorded wood fungus species in the stands in the Bśw, BMśw and LMśw habitats was Trichaptum fuscoviolaceum, which is the first to colonize wood of coniferous species, causing white rot. In the stands of the mixed humid forest the fruiting bodies of Fomes fomentarius were most often found, in most cases on fallen deciduous trees. The shares of Trametes versicolor, Stereum ostrea and Hymenochaete rubiginosa were also clearly visible. The occurrence of these species proves that there are sufficient amounts of dead wood left in these stands; in most of the studied areas these were water-protected forests. In this type of forests you can often find many rare fungal species, because the humidity conditions prevailing there are highly favorable for the development of mushrooms and these stands should be under special attention of foresters. The study confirmed the occurrence of common species that are widespread in Poland. However, several rare species were observed, which are included on the Red List of Plants and Mushrooms of Poland: Artomyces pyxidatus, Exidia glandulosa, Inonotus obliquus, Neofavolus alveolaris, Polyporus tuberaster, Sidera lenis, Trametes cinnabarina, Trichaptum biforme, Xylobolus frustulatus, of which Inonotus obliquus is a species partially protected species.