I'm not used to seeing species of Caloplaca in trees, so initially I thought it was some kind of Lecanora. The chemical tests performed in situ revealed that it had not only was the color of a Caloplaca but also the acids. From here the identification was easy, because there is just another similar species in U.S., C. pinicola, but with a thallus verrucose. The place where it was observed was well supplied of specimens, and this is apparently a local phenomenon, because outside of this habitat, which is a mixed area with pines, oaks and cork trees, only saw one again.