"They tell the story of us as Americans," Johnson said. "They tell the story of ourselves as human beings, in this world, on this planet."
Johnson is one of the country's few African-American park rangers, and his is a rare face of color at Yosemite because less than 1 percent of visitors to the national park in California are black.
"There's not a shortage of African Americans at Disneyland or Disney World," Johnson said. "But when you visit these wild places, like Zion and Arches and Yellowstone, that's when you start seeing less cultural diversity."
Johnson, 51, said he would like that to change, but he believes the disconnect between blacks and nature has deep roots. Slavery, he said, forever altered how African Americans view natural lands.
"There's actual pain, physical and spiritual pain, tied to working the earth," Johnson said. "There's just been this gradual loss of connection with the natural world."
The stirring canvas of Yosemite is in stark contrast to inner-city Detroit, where Johnson grew up. He never dreamed he would become a park ranger until he visited Yellowstone National Park as a young man.
"It was so beautiful, it didn't feel that it could be real," he said of the park, which is located in Wyoming, Montana and Idaho. "Inner-city environments have the power to be very self-contained, and unfortunately they can also contain even one's dreams."
Johnson became a park ranger in 1987. Today, he's more than just a guardian of Yosemite. He's a keeper of its history.
To park-goers, he tells of the Buffalo Soldiers, a group of black cavalrymen who in the late 1800s were charged with protecting Yosemite. They were in essence some of America's first park rangers.
"When [the Buffalo Soldiers] were here, the park was in its infancy," Johnson said. "African Americans are right at the beginning of the whole idea of national parks."
Johnson is featured in a new PBS documentary on national parks from acclaimed filmmaker Ken Burns, and he and Burns have traveled to inner-city schools to spread the documentary's message of diversity.
But Johnson's is just one voice, and his hope is that other African Americans will take up the cause.
"If Oprah Winfrey is recreating in a national park, or if it's Snoop Dogg, then that is actually sending a message that this is an environment that is also for us," Johnson said. "Whenever we visit a national park, we're all going home. We're all tying into our roots."