LATER IN THE MORNING on Saturday, motionless white puffs hang on the woodsy horizon, underscoring the absence of wind. Normally, a light westerly blows across this gradual southwest-facing slope, picking up toward sundown. But high pressure has stalled over Georgia, stifling any breeze.

Nobody seems worried. Jonathon continues quietly hanging ID tags on the trees—using combinations of letters to identify each artist. Andrew—wearing a button-down shirt, ball cap, and wraparound sunglasses that hide not just his eyes but most of his pillowy, untanned face—corners me. Squatting under a pecan tree, he expertly promotes his book, which he's selling at a display on hay bales in the barn. He says it's the touchstone of the entire Agrifolk movement, describing bizarre passages about how the entrance to Jane Fonda's apartment was built to resemble a vagina. I wriggle away to buy a copy.

At lunchtime, Andrew lays out a huge spread in anticipation of many visitors—pork barbecue sandwiches, Brunswick stew, slaw, RC Cola, MoonPies—but the only person who stops by is his sister, Karen, and she can't stay long enough to linger among the handful of trees that, ever so lightly, have started sketching. Her daughter is competing in a cheerleading competition later today, and she has to make an appearance.

"One time, we lost because our audience participation wasn't loud enough," she says, looking at her watch. "Oh, Gawd. I have to be there! Go, trees!"

As the afternoon wears on, a handful of other visitors will swing by—among others, a writer for a regional magazine, an illustrator of Jewish marriage contracts, Andrew's parents, and the manager of the farm. Nobody seems to get it. Only Catherine Fox, the longtime art critic for The Atlanta Journal-Constitution, gives the trees more than a passing glance.

Wearing smart denim capris, a cool white button-down, and sensible sneakers, she jaunts through the aisles, with sweaty Jonathon following in dutiful attendance.

"That's quite a suit," she points out. "Did you get that just for this?"

"I have a few," he says. "I like to dress well."

Catherine launches into the tough questions—What's your hypothesis? Do you consider this a performance? Aren't you really making the art? Isn't it just a matter of semantics?—which Jonathon fields with typically lengthy replies. Catherine jots a few lines in her reporter's notebook and gets ready to leave.

"Are you gonna write about it?" someone asks.

"Oh, yeah, I think it'll be great fun," she says with a comical snarl.

Having spent a solid 15 minutes among the trees, she leaves an hour after arriving. On the way out, she walks through an enormous spider web. One of the moviemakers chuckles and says, "The spider probably recoiled."