Pohan, M. and Hasairin, A. 2025. Correlation of Traffic Density with Sulfur Dioxide (SO₂) Levels and Thallus Chlorophyll of Lichens as Bioindicators on Angsana Trees (Pterocarpus indicus Willd.) in the Medan Industrial Area II. Biospecies. 18, 2 (Jul. 2025), 49–59. DOI:https://doi.org/10.22437/biospecies.v18i2.46547.