Due to climate change, occurrence of both higher and lower plants in forest areas is deteriorated considerably. Keeping this in view, a survey was undertaken to study the distribution of lichen communities in Yercaud hills belonging to Eastern Ghats, Tamil Nadu, India. The results indicated that distribution of lichens was registered from 700 m above msl in silver oak trees and the same was noted from 900 m above msl in rock surface. Distribution of lichen colonies was abundant, while temperature was low along with sunshine and RH was high along with rainfall pattern. Sunshine was negatively correlated with lichen distribution, but rainfall was positively correlated. These biologically important hills exhibited a total of 61 different lichen species covering 13 families with 33 genera in the survey. In addition, about 22 new species of lichens were recorded in the lichen database of Yercaud hills. The results revealed that lichens grew well in the pH range of 4.3-5.5 in silver oak tree barks and 4.5-6.0 in rocks, which coincided with the buffering action of bark and rock. There was a direct relationship between the moisture content of tree barks and rocks and lichen adherence. Estimation of various micro and macro elements including ash contents were found to be more in fruticose than in foliose lichen and lest in crustose lichens. The study revealed that there was a drastic reduction in lichen density due to low tree bark moisture content andpHvalues owing to change in environmental parameters at Yercaud hills. © Triveni Enterprises, Lucknow (India).