The opening minutes of “A New Kind of Wilderness” promise some kind of documentary advertorial for off-the-grid living. Over idyllic shots of her hippy-hunky husband Nik and their three cherubic children camping, foraging for food and literally hugging trees in verdant Norwegian woodland, photographer Maria Vatne’s voiceover soothingly espouses the liberating virtues of “getting out of the rat race” and “being free and full of love.” It all looks wonderful, like “Swiss Family Robinson” updated for the era of Instagram cottagecore, and a cynic might say that it hardly seems sustainable. It isn’t, though not for the reasons you might guess. Mid-montage, Vatne’s voiceover goes silent, and the lifestyle photos give way to ones of her undergoing cancer treatment, before the family is shown without her altogether.

It’s an elegant bit of wrongfooting right upfront, signaling that, as is often the case with documentaries shot over a long timeframe, “A New Kind of Wilderness” is not the film that director Silje Evensmo Jacobsen initially intended to make. What began in 2014 as a portrait of a bilingual Norwegian-British family abandoning social norms to live as closely as possible with nature changed tack, following Vatne’s untimely death in 2019, to study the challenges of maintaining those ideals as a single-parent household burdened with grief.

It’s hard to say how interesting or idealized the film Jacobsen first conceived would have wound up being; it’s unlikely to have been as affecting as this one, which probes gently but insistently into fragile family dynamics that can’t be repaired with hiking or home schooling. The result, premiering in Sundance’s world documentary competition, may not have the kind of barbed narrative hook or tricky structure to become a documentary conversation piece, but it invites distribution on the strength of its aching emotional candor and continued visual beauty.

“When you choose a life that is so dependent on yourself, there’s a vulnerability there,” observes Maria in one of her earlier interviews with the filmmaker — which resurface over footage of family life without her, sometimes to poignantly ironic effect. She and Nik, an Englishman who happily left his homeland to pursue their joint dream of running a sustainable Scandi farm, never seemed that vulnerable together. As they bedded into the landscape and had three children together — forming a contented blended family with Ronja, Maria’s daughter from a previous relationship — they were strongly unified by a shared fixity of purpose and principle: to cause as little harm to the planet as possible and impart those values to a new generation.

Without Maria, however, Nik has more vocal doubts regarding their mission. “Am I completely ruining my children’s lives here?” he wonders directly to camera: In particular, his and Maria’s joint resolve to completely homeschool the four kids seems more like folly in the cold light of bereavement. The younger three, none yet adolescent, say they prefer it that way, and sure enough, how many children would pick the classroom over unfettered outdoor playtime and spontaneous weekday camping trips? But Ronja, now shorn of her key connection to the family, feels increasingly ill at ease among them, and decides to move in with her biological father in town, where she eventually wants to study nursing.

Ronja’s decision is particularly hard for her adoring younger half-sister Freja to accept: The idea that there might be life outside their self-contained rural idyll is not one she’s yet ready to entertain. But Nik can’t afford to keep the smallholding on his own, which entails a compromised return to civilization: He takes a job as a manual laborer, moving the family into a modest house on another farm, while the children are prodded by the local education board into attending school three times a week. It’s not a happy adjustment, particularly as it feels like leaving another piece of Maria behind; Nik considers breaking ties altogether to move the family to England, confessing that he feels like “an alien” in the country his children adamantly consider home.

But time passes and slowly, haltingly heals — grief may not be something you get over, but you can get used to it, as Nik and the children slowly find rewards and welcome human connections in their new routine. Maria’s stated fears that “school comes at the expense of the wildness and playfulness inherent in all of us” may or may not be founded: Perhaps her children grow more domesticated as they ease into school life, but not to the detriment of their spirit. Relations with Ronja, too, are repaired and strengthened, albeit with the benefit of some distance between them. “A New Kind of Wilderness” still honors the ideals of its late subject, particularly in the camera crew’s organic, pine-fresh appreciation of the surrounding environment. But its tender observation of an evolving family shows there’s value in society too, in living across a wider corner of the world.