ONE morning in the summer of 1933, David Brower, future leader of the US environmental group the Sierra Club, bumped into the landscape photographer Ansel Adams on a path in a forest in the Sierra Nevada mountains. As famous encounters go, this was not quite on a par with that of Stanley and Livingstone in Africa. But in the context of the dramatic environmental reform that was to take place in the US during the 20th century and the way images helped effect it, it was auspicious.
It was the time of the Depression, soil erosion had reduced the great…
