He switches into a dead-on impression of one of the members of Earth First appearing in “The Wilderness and the West,” the third part of the series dealing with how America’s landscape shaped her art. The environmental group is shown in a North Carolina North Carolina forest, wailing over the old-growth trees cut down by loggers.

The camera lingers on one woman sobbing to the lost trees, and sitting in his hotel room, Hughes mimics her wickedly, then cackles with delight. He’s aware that the segment makes the group look pretty wacky, but he doesn’t care.

“What a bunch of freaks,” Hughes said. “Am I supposed to be some sort of conservative because these people are self-satirists?”

He said his friend, Peter Matthiessen, author of “At Play in the Fields of the Lord” and several nature books, begged him to remove the piece, saying its presence in “American Visions” would be detrimental to the environmental movement.

It’s in this episode, beginning at the 7:30 mark.