AbstractEpiphytic lichens, an important component of epiphytes, play vital roles in biodiversity sustainability, water and nutrient cycling in forest ecosystems. Species composition and distribution of epiphytic lichens on trunk at 0–2.0 m height were surveyed on 525 individual trees, and lichen litterfall was collected over two year (2005–2006) in primary forest and three secondary forests in Xujiaba region of Ailao Mountain, Yunnan. The results showed that the epiphytic lichens were abundant in thses forests. In total, 61 lichens species belonging to 26 genera and 17 families were recorded. Of them, 51 species were found in the primary forest, 53 species in oak coppice and 46 species in Populus bonatii forest, while only 26 species in Zanthoxylum bungeanum plantation. There were significant differences in composition and diversity of epiphytic lichens on trunks between the primary and secondary forests, whereas the main species of lichens was similar in canopies of the primary and secondary forests. The primary forest had more lichen species, with unevenness distribution. The Shannon-Wiener index and Simpson index of lichens on trucks at 0–2.0 m height were 2.71 and 0.89 for the oak coppice, 2.43–2.45 and 0.88–0.89 for the secondary P. bonatii forest and Z. bungeanum plantation, and 1.25 and 0.67 for the primary forest, respectively.The composition and distribution of lichens were influenced by the aspects of the trucks, host trees and their sizes. Richer number and amounts of lichens are found on southern aspect of trunks. Vaccinium duclouxii was the host tree with the richest epiphytic lichens in the forests in the area. Most epiphytic lichens occurred on medium stems of DBH 5.0–25.0 cm. The rich species diversity of epiphytic lichens and their distribution patterns were important for maintaining biodiversity and ecological processes in the montane forest ecosystems.