The shore of Birch Lake teemed with folks greeting Dave and Amy Freeman when they emerged from their year in the Boundary Waters wilderness, creating a sensory overload that almost overwhelmed them.

But only when people began to leave did the couple literally get a whiff of what re-entering civilization involved.

“The car exhaust kind of shocked us,” Dave said. “Our senses had gotten so acute.”

For 365 days in 2015 and 2016, the Freemans lived in the Boundary Waters Canoe Area Wilderness, paddling a canoe or towing a toboggan from campsite to campsite.

They fell through the ice. They were trailed by wolves. They drank from the lakes.

Mostly, they bore witness.

They call it “witness activism.” They’re not sure they invented the term, “but it seems like what we are doing,” said Dave, sitting in the office of Milkweed Editions in Minneapolis, publisher of their new book “A Year in the Wilderness: Bearing Witness in the Boundary Waters.” The book builds on what they’d posted on their Instagram account, freemanexplore.

They had one purpose: to focus attention on any environmental consequences of proposed copper-nickel mines near the BWCA. Unlike mining for taconite and iron, copper is contained in sulfide ore. When the mining process exposes that ore to air and water, it forms acid runoff that can threaten rivers and lakes.

The issue is raw, especially around Ely, where the Freemans live, and which is home to many who want the jobs that mining could provide.

Through their posts and myriad photos, they aimed to create “a positive and nonconfrontational way to talk with people in their communities about the issues,” he said.

“Some places are too special to disregard,” Amy said. “And the Boundary Waters is one of those places.”

The Freemans wanted the emphasis to be on the place, rather than on themselves.

But — big surprise! — people want to know how they survived for a whole year outdoors, in a small tent, during snowstorms, amid mosquitoes, cooking over a camp stove, all alone.

Well, for starters, they weren’t as alone as you’d think. The year never was imagined as “humanity vs. the elements,” nor as a Thoreau-esque retreat.

‘Off to find the Freemans’

They arranged for resupply visits every few weeks, although weather delayed some. They hosted visits from students, friends and journalists, including NBC’s Harry Smith. Girl Scouts once paddled toward them singing, with “The Wizard of Oz” inspiration, “We’re off to find the Freemans. … ”

They also were linked to technology, using satellite signals to update their Instagram accounts, respond to Facebook posts, check in with the supporting Campaign to Save the Boundary Waters and set up interviews. They often felt that they walked a fine line, as when they Skyped for a presentation for the Outdoor Adventure Expo in Minneapolis.

They wrote: “The last thing we’d want people to do on their own canoe trips is to Skype with their friends. The wilderness provides a rare opportunity to unplug, slow down, and form real connections with nature. Sometimes it felt intrusive and odd to be making exceptions for ourselves, even though we knew it was in the service of a greater good.”

Outdoors enthusiasts tend to quiz them about gear — what worked, what disappointed. Others ask about being isolated with each other.

It helped that the Freemans are veteran explorers. They met as wilderness guides in Grand Marais, have paddled together down the Amazon and run dogsledding trips in the winter. Dave, 40, said his parents actually were thrilled to learn that he and Amy, 35, would be spending a year in northern Minnesota, having worried through their South American stint, imagining revolutionaries along the riverbanks.

Measuring the impact

Was it worth it?

On a personal level, the yearlong stint deepened their appreciation for a familiar territory, “just realizing this place is out there, all the time,” Dave said.

The measured pace of their lives let them notice small moments, such as when he saw a blue-spotted salamander creeping around “when there was still a foot of ice on the lakes. I never knew they could do that.”

They’d never visited the Boundary Waters in April or November — the shoulder season — “so we’d never experienced the ice forming and then the ice deteriorating,” he said.

That led to their scariest moment, on Newfound Lake in December 2016, when he fell through near-shore ice that had, since they’d last crossed it, been weakened by waves farther out on the open water.

“I’ve fallen through in bogs and closer to shore, never in water deeper than me before,” he said. A spread-eagled dive kept him from going entirely under, but he was caked with ice by the time they reached camp. “We decided not to tell that story right away,” he said.

On a broader level, they were thrilled when the federal government said that it would not automatically renew two expired mineral leases and called for a two-year environmental review of the impact of copper-nickel mining.

“That’s what we wanted to accomplish,” he said.

“But this will take years,” Amy added. “We can’t just say, ‘Oh, we saved the Boundary Waters. We’re done now!’ It’s not a foregone conclusion.”

All told, the Freemans touched 500 bodies of water and stayed in 100 campsites. They emerged in September 2016, but were back that winter running dogsledding trips. Now they’ll start a book tour with a launch party Sept. 25 at the Able Seedhouse & Brewery, 1121 NE. Quincy St. in Minneapolis.

The sensory overload, once again, could prove overwhelming. But that, in a way, was the point of their year.

“What we loved about being out there was paring down to what you need: food, water, basic shelter, people you care about,” Dave said, then added, “and purpose.”