LISLE, Ill. >> The troll dubbed Joe peers out over the Ronald Reagan Memorial Tollway and the suburban sprawl beyond, one hand shielding his brow as he scans the horizon, the other holding a giant spear.

He is a handmade, deliberately secondhand thing, his body pieced together from discarded shipping pallets, his hair a tangle of trimmed branches, the spear a ramrod-straight trunk of a conifer that had to be chopped down.

But he is imposing nonetheless, standing 20-some feet tall, with an expression that is friendly enough but looks ready to veer into menacing, especially if someone tries to broach the massive berm he stands on to disturb the idyll of the Morton Arboretum behind him.

Thomas Dambo, the effervescent Danish artist who created Joe and five of his brethren for a compelling new woodland installation, sees Joe as a kind of border guard between the placid west suburban tree haven and the frenetic, destructive industrial world symbolized by the scurrying automobiles and the soullessly efficient office towers.

“I walked up on this hill, and I’m like, I’m standing on the frontier, the clash between these two different sides of this story,” he said. “And then I was like, I need to have a big troll standing here and guarding so that none of these cars runs up here and tramples down the whole forest.”

Joe and the other pieces that constitute the arboretum’s new “Troll Hunt” aren’t just art works made from salvaged material or symbols of a friendlier way to manage resources. Granted, there is no mistaking the message delivered by the troll closest to the main Morton parking lot, an angry- looking fellow holding a boulder above his head, about to bring it down on the old car mounted at his feet.

But these are also, in Dambo’s fertile mind, ambassadors of ages-old Scandinavian culture and characters in a story he is spreading across the world, first with a troll installation in Copenhagen, then in South Korea, and now in Lisle, Ill.

“I wanted to tell a story where the trolls are representing nature and the struggle between mankind and nature and the problems that we have with that,” said Dambo, who speaks English in great rushes of words and notions. “Mankind is kind of dependent on nature but we are also nature’s biggest enemy in some way because we are slowly just deleting all nature and just filling it in with concrete and digging holes and putting all our trash in there and then we build new residential areas on top of that. So slowly we are just replacing nature with developed areas. I wanted to tell a story about this. I call it ‘The Great Story about the Little People and the Giant Trolls.’ And this is Chapter Three.”

It is Chapter One with Dambo for the arboretum, and it seems to be going well. For the past two months, the lanky 38-year-old has been dubbed an “artist in residence,” and Morton has invited visitors to try to find him and to visit his creations in progress.

They might have spotted him on a platform screwing in the shingle-like pieces that make up the fur of Joe, named for the arboretum worker who donated the car that Dambo’s parking lot troll is about to crush. Or they would see him zipping from Joe to meet with his crew building a seated, treeside troll, pedaling the vintage mountain bike the arboretum provided. Or, if they sneaked into the offstage areas of the institution, they could catch him and his crew after hours at the Morton-owned house they’ve been inhabiting, preparing dinner on the grill Dambo salvaged from a nearby suburban curb on trash day.

Mary Lou Manzo and the two Naperville preschoolers she cares for took the arboretum’s challenge and came upon Dambo one bright spring day as he was being interviewed in the grass at Joe’s feet.

“It’s really beautiful,” she said. “They’re like protectors, and it’s made out of wood so it’s keeping the forest safe.”

“We are also making a top-secret troll hideout,” Dambo said, conspiratorially.

“I didn’t know about the arboretum before they called me,” he said. “One thing that I would really like my trolls to do is try to bring people out of their safe zone in their cars and go exploring nature a little bit because when you explore such a beautiful forest as the Morton Arboretum then obviously you will understand that it’s worth protecting it and saving it.

“Just in my life I’ve been so fortunate to go scavenging, hunting for materials, and go into the alleys and climb trees, and that’s where all the good experiences are. I want to remind people that the world is so much bigger than this triangle we move in from, like, our house to our job to our supermarket and then back to our house again.”

The Morton website makes clear that: “All trolls are located between two feet and three-quarters of a mile from the nearest parking lot on a variety of path surfaces. … Five of the six trolls can be observed from your car on the main driving route.”

Still, to get close to most of them, you do have to at least take a walk.

One 55-foot-long troll lies on its back in a meadow, as in mid-siesta. Another peeks out of some bushes near the park’s central pond.

They may look relaxed in place — they’ll be around two years or more, depending on how long they stay structurally sound.