Tree infections

Question

We have just moved into a new house with several trees in the garden. The bark of the trees are covered in what looks like tiny green leaves. This can be scratched off showing the bark below, which looks damp. Is this an infection or damp? We have noticed that many of the trees in this area look the same. We live in the Lincolnshire fens, where the soil is very wet and clay like. I look forward to your reply.

Answer 1

This is actually lichen and is perfectly harmless to your trees. Here is more information:
https://www.gardeningknowhow.com/ornamental/fungus-lichen/treatment-tree-lichen.htm