Range of lichens on tree

Range of lichens on tree

Observation - Range of lichens on tree. Description: Same trees with smaller circumferences have a smaller range of species present. Yellow foliose lichen in patches on tree (and I think yellow crustose, but may be the same lichen but much smaller). Two seemingly different types of grey foliose lichens p

Same trees with smaller circumferences have a smaller range of species present.
Yellow foliose lichen in patches on tree (and I think yellow crustose, but may be the same lichen but much smaller).
Two seemingly different types of grey foliose lichens present too, (the lighter in circular patches, the darker all over) and a greener foliose species (one patch on the right).