This work presents a summary of results obtained during a several years long researchfocused on evaluation of the spectrum of macromycetes in forests of Slovakia. The diversity ofthe forests stands was a result of anthropogenic immissions or damage by abiotic factor such aswind. Multiple year monitoring of protected areas shows naturally selected relations betweenthe parts of the ecosystem, as the mushroom spectrum is a direct result of natural development.Due to their relative sensitivity to various factors, the mushrooms can be used to monitor thechanges of environment. Should the environmental conditions change too much, themushrooms die and give place for another fungal species to grow, the ratios betweenectomycorrhizal and wood-inhabiting species shift. These changes are the main focus of thisresearch. In the National Nature Reserve Hrončecký Grúň, the spectrum of fungal speciesreflect natural decay of the forest, as that provides abundant nutrients. The mushroomsdecompose the dead wood and prepare the forest soil for new growth. One of the most importantresults of this research is the discovery of rare wood-inhabiting fungal species (Dentipellisfragilis, Hericium coralloides), which indicates the necessity of protection of the given forest,this is also consistently implemented. The lethal stage of ectotrophic stability of forest wasobserved in Prosisko Natural Reserve, where the high ratio of wood-inhabiting fungi ispromising to decompose the large amounts of dead wood and create new possibilities of naturalafforestation by providing nutrient rich soil on otherwise extremely rocky terrain. Researchresults in beech forests confirmed the assumptions that sudden change in growing conditionsafter windstorm as well as the artificial immission load results in lower numbers ofectomycorrhizal species in favor of saprothrophic ones, thus aggravating the stage ofectotrophic stability of forests. It has also been noted that certain species of ectomycorrhizalfungi are sensitive to immission load. Presence of fruiting-bodies of these genera (Cortinarius,Hydnum, Boletus and Tricholoma) helps in determining the immission load, as they areindicators of clean habitat. Utilising mushrooms to indicate the biodiversity of habitats or todetermine the correct forest management is convenient all around the world. It appears thata regular system of evaluating the presence of mushrooms by international monitoring andselection of natural „mycoindicators“ is crucial to determine the condition of ecosystems.