عنوان مقاله [English]
Lichens, as ecological indicators, have great value in forests because of the sensitivity to a wide variety of environmental stresses such as air pollution and climate change. So far, many species of lichens have been collected from the Hyrcanian forests to be identified in the lichen herbarium of Research Institute of Forests and Rangelands. Some of these lichens are able to fix nitrogen and are considered as an indicator of air pollution. In recent years, the destruction of Hyrcanian forests has led to a reduction in the diversity and abundance of lichens. Thus, regular studies on the biodiversity of lichens, especially tree lichens and epiphytic lichens are necessary. A number of factors affect the diversity and growth of lichens. Therefore, understanding these factors and timely action may decrease the negative effects on lichens and, as a result, help the health of the Hyrcanian forests.