<p>Lichen communities were investigated due to the high sensitivity to disturbances and as one of the important indicators of measuring the quality and stability of forest ecosystems. The present study was carried out with the aim of investigating the quality of the Hyrcanian forest ecosystem in Mazandaran province in the north of Iran by analyzing the relationship between biodiversity indicators of lichen communities and disturbances. Two managed and unmanaged forests with relatively homogenous physiographic conditions were selected. In both forests, the types of disturbance, their location and the area of canopy gaps caused by them were recorded and calculated. Lichen samples were collected in these gaps using sampling quadrats. The results showed that the frequency of disturbances, the number of gaps, and the frequency of larger gaps in the managed forest were more than unmanaged. The number of lichen species, genera and families, as well as the diversity and richness of lichens in natural forests were more than managed. 7 indicator species of natural forests were recorded in these forests. Lichens <i>Ramalina sinensis</i> and <i>Melanelixia glabra</i> were recorded with the highest abundance in windfall tree disturbances and tree-harvesting disturbances in unmanaged and managed forests, respectively. Disturbances have affected the richness and diversity of lichens in the managed forest. The type of forest management has significantly affected the abundance, biodiversity and stability of vulnerable lichens.</p>