Influence of the health status of pine trees on the diversity of epiphytic lichens

This study checked the hypothesis if the diversity of epiphytic lichens on conifer trees far removed from local sources of air pollution and affected by dieback by biotic factors such as fungi and infects is higher than the diversity on nearby healthy trees. The results showed that this hypothesis does not apply to the study area (Chianti Region, Tuscany, C Italy), which experiences low levels of air pollution, and where the lichen vegetation of damaged trees is not different from that of nearby healthy trees. Other site factors such as solar irradiation, air temperature and relative humidity, as well as substrate bark parameters such as water-holding capacity, conductivity, and ammonium, K, Mg and Na content were not different between healthy and damaged trees. Higher bark concentrations of Mn, Ca and Fe on damaged trees are consistent with known effects of these elements on lichens. The higher bark pH measured on healthy trees requires further study, but nevertheless bark pH was not a decisive factor for the epiphytic lichen vegetation.