We have at least seven species of lichen on the trees at Abbey Fields. Look closely – perhaps with a magnifying glass – and you will see exquisite structures of these organisms. See here for more information.

Some lichens can be very sensitive to pollution, especially from sulphur dioxide, nitrogen and ozone. Consequently, they are a good indicator of general air quality, responding quickly to environmental change. Usnea lichens are absent from areas where there is sulphur dioxide pollution, whereas the golden shield lichen Xanthoria parietina is common on trees and structures near farmland as it copes with high levels of nitrogen and ammonia. More details are available here.

Lichens are classed as funga; interestingly they are actually a stable association of at least two life forms: a fungus and algae and/or cyanobacteria.