Well, the set is pretty good.

The program for “Nature: a walking play” doesn’t credit anyone, but whoever designed these acres of trees, ravines, flowers, meadows and ponds deserves a salute. What better scenery could exist for a play about two men who drew inspiration from the beauty of the Earth?

“Nature” requires its audiences to spend 90 minutes following actors along a stretch of the Minnesota Landscape Arboretum and to contemplate the fresh air and sunshine that excited the great 19th-century philosophers Ralph Waldo Emerson and Henry David Thoreau. The legroom is ample, but bring a chair unless you’re fine sitting on the ground.

Tyson Forbes shares the prominent nose and sharp chin of Emerson, his great-great-great grandfather, who first espoused the ideals of Transcendentalism in an 1836 essay called “Nature.”

John Catron, burly and bearded, is the woodsy Thoreau, who famously said, “We can never have enough of Nature.” He splits wood with his ax and grumbles that “the world needs less of all of us.”

Forbes, a Twin Cities actor seen on the Guthrie and Jungle stages, created this project with his producer/wife, Markell Kiefer. They operate under the name TigerLion Arts. “Nature” had its debut in 2010 at the arboretum, and returns with a redeveloped script and musical score.

“The spirit of the work is the same,” Forbes said.

The actor grew up near Concord, Mass., heartland of the Emerson family. His mother comes from Ralph Waldo’s line, and this lineage gave him access to wide swaths of property on the Elizabeth Islands, near Martha’s Vineyard.

“I grew up summers on that land and spent my time in the mud,” Forbes said. “It’s always been heavy in my psyche.”

Forbes and Kiefer use TigerLion to produce outdoor walking plays, among other projects. They performed “The Buddha Prince” in Powderhorn Park in Minneapolis, Central Park in New York and Pasadena, Calif. Because of his personal history with Emerson, Forbes was keen on “Nature,” which evolved from a traditional play to “a ritual in nature for an audience,” he said.

And that it is. Audiences travel the literal distance between sloping meadow, tree-sheltered cabin frame and fen (standing in for Walden Pond). They also travel a figurative distance, as Emerson and Thoreau bond on a hillside in their bromance over nature and then fall out over differing philosophies on progress and society.

Catron’s Thoreau despises the railroad being built yonder across the pond — represented by a clattering drum set on a hay wagon some 200 yards away. Forbes’ Emerson loves nature, but he is sociable and accommodates the train as a necessary cost of civilization.

The third key character in a cast of 11 expresses itself in the voice and violin of Norah Long. She is Nature itself, making herself known with a haunting song drifting across the field or the steady drone of her fiddle from the trunk of a tree.

Dick Hensold, who wrote the light score, pitches in with flute and recorder to create a meditative soundscape.

As drama, “Nature” teaches us something of Thoreau and Emerson, their life events and philosophies. Catron and Forbes mime through gesture, far off in the tall grass, while the cast, situated near the audience, speaks the words like a Greek chorus: “I went for a walk today and felt my heart; I went for a walk today and spoke to a friend; I went for a walk today and was held by the Earth; I went for a walk today and touched the sky.”

Emerson and Thoreau were Transcendentalists, who believed in human spirit finding its greatest resonance in an individual relationship with nature. God, Emerson proposed, is in all things.

Drama, though, is but one part of the experience Forbes and his collaborators have created at the arboretum. Whoever stage managed the show on Saturday afternoon perfectly cued a hawk to circle against a blue sky striped with wispy clouds. The apple trees were hung with fresh fruit, and dragonflies hovered near cedars. The show feels about 15 minutes too long, but what were you going to do with that time anyway? — you’re outside at the arboretum!

Forbes would like to take the play to other locations in Minnesota as well as the Arnold Arboretum in Boston and the Mall in Washington, D.C.

To do that, TigerLion wants to polish the production values of “Nature.”

“It has to prove itself this year,” Forbes said.

That set is a good start.