Impacts of three Mugla lignite-fired power plants on the vegetation cover and especially on the forests of the region have been investigated. Air quality due to the plants have been assessed and related to the injuries on leaves of the three. Assessments were made by estimations of SO2 as well as by means of some measurements at some fixed stations. A more widespread evaluation program has been applied by analysing the plant leaves for their sulfur concentrations. Sulfur levels in leaves taken from control trees and trees of the suspected impact area have been significantly different. 1-year old and 2-years old pine needles have shown appreciable difference in conformity with the operating history of the power generating units.