Joe Beelart says he has seen Sasquatch, and he’s written in detail on the topic. I joined him for a trip through the woods of the Pacific north-west – a region whose woods have a sacred feel whether you believe the stories or not

Joe Beelart carefully places a red apple on a mossy stump. “We’re going to set out our first offering here.” He performs the same ritual every time he comes out into Mount Hood national forest.

“We used to call it baiting, but now we call it offering. It changed because we started to think of them as more human. An offering seems to make them more responsive to you.”

He and his fellow enthusiasts cite the Hewkin-Sullivan rule, after the adventurers who coined it: on average, it takes a an observer 200 hours on the ground to encounter any new evidence of Bigfoot.

In the past, he put out an apple a month, but the time and expense of camping is a greater burden in retirement. Still, he’s been up eight times in the last year. He’s always mindful that fewer hours mean fewer rewards.

Facebook Twitter Pinterest Joe Beelart: ‘An offering seems to make them more responsive.’ Photograph: Jason Wilson for The Guardian

By the time he laid out the fruit, we had been driving through pre-dawn darkness and mist for two hours, aiming for a stretch of road that is not only the topic of Beelart’s recently published book The Oregon Bigfoot Highway but also his pole star. The region is known for its reported Sasquatch sightings, and the earliest ones he documents date back more than a century, to 1911.

Our pilgrimage started on Oregon Route 224, which heads south-east from Portland. It sheds lanes as it works its way through the city’s dwindling outskirts, and then into rolling farmlands. In less than an hour, it brings you to the foothill town of Estacada.

This is where the Bigfoot road properly begins. Route 224 continues south west, up into the alders, maples and firs and the gloom and fog of Mount Hood National Forest, all the way to Ripplebrook.

From late fall until the thaw in May, ice and snow mean that this is as far as most cars can go. But there is a forest road that kicks back to the south-west, running downhill along the banks of the Breitenbush and ending at a lake and town both named Detroit.

This dogleg is set in a national forest that sprawls out for more than 1m square acres. Some 345,000 acres of that is old-growth forest, and a little over 311,000 acres is protected wilderness. It’s just about at the center of a joined-up band of temperate rainforest that stretches from northern California to Canada.

It’s all big enough, and empty enough, to invite a certain kind of mind to fill it up.

In his book, Beelart notes that “this is one of the biggest uninhabited areas outside the south-west deserts. There’s at least 1,500 contiguous square miles with no people in it.” Room enough, he thinks, for perhaps 30 Sasquatches. There is no proof that they’re there, nor even any consensus about what exactly they might be, but that’s no barrier to belief.

Beelart insists, eye to eye, that “Bigfoot exists, Sasquatch exists. I believe they’re a kind of human that has persisted alongside us. We’re a very predatory species; that’s why they stay away from us.”

That conviction has drawn him into these forests for 20 years, usually in the company of others who share his yen – a loose band of 14 who call themselves the Clackamas Sasquatchians and include his co-author, Cliff Olson. All of them live in or around Portland. They camp out in the summer months in tents and trucks, hoping for prints, or a cry, or even a fleeting glimpse of the creatures they call “our barefoot friends”.

Beelart is a fit 68 – a bit scruffy, with a twinkle in his eye and an instinct for a well-placed cuss. He also has a prodigious memory, and recalls the details not only of every local Bigfoot sighting, but the history and geography of the wilderness where all sightings have happened. He has a story for every disused service road, every abandoned building, every Indian trail and monument, every lake and every spring.

He was a marine in his youth, but changes in the service after Vietnam led him to the door. For the rest of his working life he was in the pump game, dealing in the rude, mechanical practicalities of getting water from one place to another. This pragmatic life lasted until the moment in the early 1990s that changed everything.

“One Christmas day after dinner, me and my nephews went out looking for deer on logging roads.” Suddenly a hairy, man-like creature emerged from the brush. “It was a normal, traditional Sasquatch. I saw it for 15 seconds.”

His sighting was typical in that it was fleeting. Most of the solid ones, he says, last for eight to 15 seconds. Any longer than that and they’re open to more critical scrutiny.

He says he tried for a long time afterwards to dismiss what he had seen, and forgetting it is still his recommendation to anyone who spots a Bigfoot for the first time. “Put it out your head. Forget it. Your life will be easier.”

Affirming a public belief in Bigfoot is not easy. He nominates a long list of people whose careers were all but destroyed when they decided to take all of this seriously. “It’s a tremendous problem for Forest Service employees who see them,” he says, adding that academics have had their tenure threatened. “Ask people in your tavern what they think of Bigfoot,” he challenges me. “At least half of them will get angry.”

Facebook Twitter Pinterest The Bigfoot road: ‘I saw it for 15 seconds.’ Photograph: Jason Wilson for The Guardian

Eventually, years after his first sighting, he stumbled across a bookshop in north Portland owned by the leader of the Western Bigfoot Society, and he started attending their meetings. Soon, he was hooked.

Beelart thinks that the people who last longest in the Bigfoot movement are those who, like him, unwillingly experience something they cannot later get out of their heads. “We try to recapture that initial experience,” he says. Some of them get lucky. Beelart himself says that one evening in the forest, a Sasquatch stood at the foot of his bed for some 15 minutes. It’s not the only such experience he has had since his first revelation, but it is the most significant.

His book is methodical and exhaustive, in the manner of many autodidacts. Some of the incidents he writes about were uncovered through painstaking archival research, and some were passed on as tales and documents from other members of the sprawling, complex, global Bigfoot community. Like the other subculture Beelart has written books for – fly fishing – it’s a scene that largely writes and publishes for itself.

As for our search that day, I never saw a Bigfoot on our drive, and I can’t say at the end of our long day together that I believe that there are any to see. But there are some things we can agree on. There is something about the forests of the Pacific north-west that exceeds our powers of description and understanding.

Thinkers from Max Weber to Charles Taylor have told us that this is a disenchanted age, whereas once upon a time, the forests were filled with magic. The reductive, modern vocabularies of secularism and protestantism leave us with no language to talk about the parts of nature that put us in touch with something bigger than ourselves.

If Beelart’s work has any political dimension, it is that perhaps we need to protect this forest, Bigfoot or no. If we can agree that this land is somehow sacred, after all, does it matter how we get to that idea?

Perhaps the religious overtones of Sasquatch talk – the sacrifices and pilgrimages, the hints of another world – ought not be vulgarly read as signs of madness, but understood as a way, in a world alienated from nature, to grasp at sanity.