We investigated the coverage and frequency of four common cyanolichen species: Leioderma sorediatum, Leptogium azureum, Lobaria retigera, and Sticta duplolimbata, on 0-2.0 m trunk in 120 plots of two primary and six secondary forest types in the subtropical Ailao Mountains of Yunnan Province, Southwest China. Thirty trees in each plot and a total of 3600 trees were selected for lichen sampling in the eight forests.

Coverage and frequency of the four epiphytic cyanolichens differed significantly among forest types. While the highest values of S. duplolimbata occurred in the primary dwarf mossy forest, those of other three species occurred in the secondary Ternstroemia gymnanthera and Populus bonatii forests. However, they were relatively rare in the primary Lithocarpus forest. All the target cyanolichen species were found on more than ten host tree species, and showed clear preferences for some tree species such as T. gymnanthera, P. bonatii and Lithocarpus hancei while excluded from other tree species such as Camellia forrestii. The results also highlighted the importance of habitat variables such as stand age, tree diameter, maximum diameter, canopy openness, basal area, host stem density and tree species diversity on the distribution of epiphytic cyanolichens. The correlation coefficients between cyanolichens and habitat variables were generally very small at the forest landscape scale, whereas some of the correlations were strong within forest types. Of the habitat variables, stand age, canopy openness and tree diameter were the major factors determining the distribution of cyanolichens.