Environmentalists take note: A movie in praise of mother nature may be hazardous to her health.

The Appalachian Trail gets its closeup on Sept. 2, when Broad Green Pictures releases “A Walk in the Woods,” starring Robert Redford and Nick Nolte in the story from Bill Bryson’s 1998 book. In a kind of preemptive strike, the nonprofit Appalachian Trail Conservancy has been showing a series of videos titled “Don’t Be That Guy,” which stress proper preparation for hikes, and how important it is that backpackers leave no trace behind of their perambulation on the 2,000-mile-long footpath.

The initiative is partly a response to the impact of 2014’s “Wild,” in which Reese Witherspoon played writer Cheryl Strayed, trekking along the 2,650-mile Pacific Crest Trail — which then experienced a boom in hiking traffic.

But when Bryson’s book was published, a similar upsurge occurred in the East. “We saw a 60% increase in people using the trail,” says Appalachian Trail Conservancy CEO Ron Tipton. And since 2010, the number of “through hikers” — who need up to six months to complete the trek — has gone up by 10% each year. The conservancy estimates that 3 million people hike some portion of the trail annually.

The ATC worked with director Ken Kwapis’ crew when he shot “Woods” last year in the Great Smoky Mountains at Nat’s Peak in North Carolina and McAfee Knob, near Roanoke, Va., the iconic precipice above a valley where characters played by Redford and Nolte are seen in a heated argument.

Kwapis says the shot was taken from a drone camera as a lightning storm approached. “It wasn’t like Werner Herzog and ‘Fitzcarraldo,’ but we did have a whole crew that had hiked in with all the equipment, and we had just enough time to get the shot before the storm came in,” he explains.

At one point during the 40-day shoot, Kwapis used Atlanta-based camels to transport equipment to a remote location. “It was sort of my David Lean moment,” he says.

The director — whose resume includes “The Sisterhood of the Traveling Pants” and “He’s Just Not That Into You” — was acutely aware of the strong emotions provoked by the book, and wanted to get even the smallest details right. For example, the sound editors made certain that the birds heard on the soundtrack are native to the film’s geographic location. “If you’re a birder, you’ll know that the birds are right,” Kwapis notes.

As for the continuing impact of “Wild,” Pacific Crest Trail Assn. information specialist Jack Haskel says that permits for hikes of more than 500 miles have soared this year, after hitting 2,655 in 2014.

“The trail was under the radar until Cheryl’s book came out,” Haskel notes. “Our strategy is to encourage acting responsibly and going softly — leaving no trace.” He adds that “Wild” has helped popularize the John Muir Trail, Echo Lake, Mount Hood and especially the Bridge of the Gods over the Columbia River, where Strayed ended her journey after hiking 1,100 miles, and where the movie ends.

Meanwhile, Kwapis is hoping “A Walk in the Woods” will raise consciousness about the environment, explaining that the movie certainly had that effect on him. “Until I made the film,” he says, “I wasn’t even aware of the names of the trees in my backyard.”