Two nights ago the strong winds brought an ivy-ravaged sycamore down into our garden, destroying two fences and killing an apple sapling in the process. I spent a few minutes looking over it this morning and found it to be a haven for lichens, there were at least five different types thriving and probably dozens making less of a splash. It was a rare opportunity to see the tops of the trees as they are, without having to scale them. Lichens are very sensitive to air quality so perhaps being thirty feet up was enough to keep them above the heavier pollutants.