In the 2007 film Into the Wild, based on a true story, a wealthy 18-year-old, inspired by Jack London, leaves his money and possessions behind and heads into the Alaskan wilderness to test his strength. He survives the winter on his own, but he makes a deadly mistake: He eats the seed pods of the wild potato plant, which are poisonous. In the film, we watch him grow weak and pale and eventually die.

“Wildman” Steve Brill wouldn’t let you eat poisonous plant seeds. Brill has led foraging tours for the naturally curious since 1982, guiding them on how to spot, eat and cook wild plants and avoid the fate of Into the Wild’s protagonist.

Foraging, or identifying and collecting useful wild plants, has become a popular activity for foodies, walkers, health nuts and budding naturalists of all ages. Amateurs don’t have to learn what is edible the hard way: All across the Northeast, experienced foragers are giving lectures and outdoor tours on what to pick and eat from local woods and fields.

Brill has written three books (and made a video) on wild food foraging and preparation. Based out of New York, he travels at least twice a week during the summer season to lead groups of all ages in search of edible and medicinal plants at nature reserves and public parks — even New York City’s Central Park.

On a recent Saturday, he traveled to the Roaring Brook Nature Center in Canton to give a lecture and a tour.

Brill came to foraging through food. Working as a cook and living in Queens, he once biked past a group of Greek women picking leaves off a bush in a park. He stopped, joined them, and made stuffed grape leaves at home that night. At the time, Brill says, there were no useful books on foraging, so he began to experiment with wild foods on his own.

People on Brill’s tours have a leg up when it comes to identifying plants. “I can show people stuff I might have been looking for for two years before,” he says. In Canton, Brill gave a lecture to a rapt audience of 35 parents, children, young couples and professionals, complete with tasting samples in little plastic bags.

Later, in the woods, Brill led the pack down a trail, scouring the forest floor for specimens. First, he found a patch of orpine and invited us to pick it. The soft, juicy leaves tasted like cucumber. Then he showed the children how to blow air below the top layer of the leaf to make a bubble pocket. One girl shrieked with delight when her leaf swelled up.

“Aha!?,” he exclaimed later, tugging on the long branches of a Birch tree. “Here is something very delicious,” he yelled to the crowd trailing behind him. In a few seconds, Brill twisted a pencil-sized twig off a narrow branch, removed its leaves, and popped it in his mouth.

“Ew,” said a teenage girl who’d been watching suspiciously. He broke off another segment and handed it to her. He broke off more for the rest of the group.

The tree bark tasted just like birch beer.

Further along the trail, he stopped at a patch of low, upright green stalks: sarsparilla, a plant commonly seen in the mouths of cowboys in western movies. It is known to fortify the male reproductive system, Brill said. A 60-something-year-old man sneaked up to the patch from the side of the group and surreptitiously pulled up a clump. So did a four-year-old boy. “You’re a little young for that,” Brill said.

Others come to food through foraging, like Massachusetts forager Blanche Derby. She was interested in useful plants in high school, and at 19, when she married, she began to cook with wild plants.

“At that point, I wasn’t much of a cook,” Derby says. Now, after 40 years of experience, she has written two foraging books that include recipes.

The night before we spoke, Derby told me she ate milkweed buds, garlic mustard pesto (substituting garlic mustard plant leaves for garlic and basil), and a cattail loaf (made from the male part of the monoecious cattail plant with onion, cheese and egg). “I’m just experimenting, changing, substituting one ingredient for another,” Derby says.

The climate is right for a resurgence in foraging. Wild edible plants earn most of the labels you might see on a shrink-wrapped vegetable at a fancy food store: locally-grown, sustainably-harvested, nutrient-rich, fresh and organic. Derby says that because wild plants “have not been sitting on the shelf,” they have higher nutrient content and potency. They’re also free, she points out: “Because of the financial problems people are having, they want to find ways to eat more locally, take money off their food bill.”

Bun Lai, the mad scientist–like chef and owner of Miya’s Sushi in New Haven, began foraging as a child when his mother showed him how to dig up wild burdock roots. These days, he gathers pine needles, sassafras tubers and sumac berries to make Miya’s popular house-made sake.

Foraging is important to him, he says, because it reestablishes the connection between the food we eat and its source. “We become so disconnected with the  origins of our food that we forget that [a] ham sandwich comes from an animal that used to cry and suckle,” he writes in an e-mail.

Foraging comes naturally, Lai says: “It is in our blood, to feel at home in the wilderness. We miss it.”

For the novice forager, there are places to avoid: downwind of a factory, close to a busy road or any place that has been sprayed with chemicals. Flower shop blossoms are also off-limits, as most of them have been dusted with pesticides.

Derby tells first-timers to walk out their back door and look for dandelion greens, “as long as you don’t spray,” she says.

Brill tells beginners to start by tracking “the easy ones,” like wood sorrel, jewelweed and black birch, through the seasons, then carefully add new species.

Humans are animals, too, Brill reminds his audience. As a species, our feeding habits are those of the forager. This may be why it’s a lark to pull up a red clover flower from the edge of a Connecticut field and suck on its nectar.

For more info on “Wildman” Steve Brill’s wild food and ecology tours, see wildmanstevebrill.com.