Clean Air Sign

Lichen on trees is a sign that the air quality is good.
Out waking today I saw loads of it on the trees. I must say it always makes a great subject to photograph especially with a macro lens.
After last nights sunset and the cold bright frosty days, this is the best time to take pictures. Even during the summer in the warm weather the light quality is never as good as it is in the depth of winter. Although we don't get enough of it. (light that is)