Silver birch trees are much whiter than they used to be when I was a child. They still have dark marks on their trunks, like upward facing arrows. But the dirty grey bark of polluted air in the past decades has seemingly reduced. But particulates still float in the air, and carbon dioxide is increasing, so maybe the trees will get bigger as they absorb the gas?

This beautiful example is starting to lose it’s leaves. Shown against the white and blue of showery sky.