Deep Country: Five years in the Welsh Hills, By Neil AnsellThe Smell Of Summer Grass: Pursuing Happiness, Perch Hill 1994-2011, By Adam Nicholson

Neil Ansell lived in a remote Welsh cottage for five years. He had no electricity or gas, no running water or plumbing. He had no clock and no vehicle. He had no adjacent neighbours, and visitors in cars had to pass through seven gates to reach him. He pretty much lived off the land: he planted root vegetables and foraged, baked his own bread and made his own wine, and stocked preserved fruits and mushrooms for each winter.

This wasn't a test – he used the village shop, made use of a friend's washing machine, had B&B breaks, wrote occasionally for the papers, undertook chainsaw work for local farmers. Neither was it an opportunity for some form of "personal development". Ansell didn't expect to "find himself". There is surprisingly little introspection in his account. Rather, Ansell became a tireless observer of the world around him, mainly watching the birds.

"I wanted to know how lightly I could tread the earth," he claims. But deeper reasons for his self-imposed exile emerge. There's a chilly purity to his ascetic life. He is hermit-like, almost monkish. He inadvertently takes a vow of silence, not speaking to anyone for over two weeks until he visits the village shop to discover his voice cracking with unaccustomed effort. He duly notes that he does not speak to himself or sing songs when alone. He becomes part of the landscape: "a stone".

Most monkish is Ansell's almost Franciscan relationship with nature. A butterfly alights on his hand, a young hare sits on his doorstep as if expecting to be invited in, he even rescues a stunned raven that subsequently appears to encourage him to share its lunchtime carrion treats. His imaginative life literally takes flight: he ponders the "whirling rush of pure sensation" that is the consciousness of the hawk, and the synaesthetic echolocation of a brood of long-eared bats that roost under his roof: "it made me wonder how I looked in sound".

The most striking instance of Ansell's submersion in the natural world is when he spots a woodcock at his feet by noticing his own reflection in its shiny black eye: "The eye was a perfect globe, and in it I could see the entire valley in miniature". It is a remarkable moment, giving new meaning to the clichéd "bird's-eye view". The woodcock's perspective gives meaning to this environment, not human perception.

Birds are at the heart of this extraordinary book. Ansell alerts us to the incredible richness of the sky's indigenous wildlife. If centuries of farming have left the hills surrounding his cottage "shaped by hand of man", the air in contrast has an almost pristine, untouched quality. So he traces flight patterns, mapping aerial territories in a sort of avian cartography. This is Ansell's real escape from human society, ascending to the heavens.

Yet even Ansell can be grounded by the thought processes of contemporary culture, comparing the magical experience of watching a kingfisher catching fish to "like something out of a documentary". He may be thinking more of Richard Attenborough than Johnny Morris, but is such a nose-to-beak encounter with a kingfisher really just another version of what you get on the telly?

In fact, it is well-nigh impossible to resist treating the countryside as a spectacle in some way, something that Adam Nicolson is more upfront about in his account of his years restoring a semi-derelict Sussex farm, Perch Hill. The Smell of Summer Grass is almost a manifesto of progress and improvement. When Ansell meets a farmer grubbing out thistles, he remarks that he likes the thistles because they bring goldfinches. Nicolson, in contrast, outlines his attempts to eradicate thistles – by topping and tight grazing patterns. Nicolson's desire for thistle-free fields is unashamedly aesthetic. He doesn't like the crunch of thistle underfoot, and he likes to lie down in his meadows without getting pricked. He also admits that thistle-free hay is favoured by his livestock, and he won't use chemicals out of principle.

Deep Country and The Smell of Summer Grass are both centred on tumbledown properties, but whereas Ansell is content to slip into the rhythms of the land, Nicolson has an agenda to make farming part of the business of aesthetics.

The only crop this landscape can viably produce today, he tells us, is "beauty". The problem, of course, is defining beauty, which inevitably risks lapsing into some version of pastoral literature.

Literary allusions lace the prose: Shakespeare's As You Like It, Kipling's Puck of Pook's Hill,Ted Hughes's Moortown Diary, and other poets are frequently invoked. Nicolson even reads Kipling at a parish council meeting in order to defend (and retain) the dilapidated state of a road, as Kipling had observed that that very same road was "shocking bad". That, for Nicolson, is its essential "historical condition".

I have a grudging admiration for Nicolson's romantic zeal in wishing to preserve and restore the "merrie England" described by such writers, but we shouldn't think that this is somehow authentic.

Shakespeare, for instance, presents the Forest of Arden as a working and managed environment – it is not a natural wilderness. Nicolson meanwhile attaches little bells to his sheep but - save in one market scene where he sells a few - is shy of telling us what else he does with them; do they end up on his dinner table? If not, why keep them at all, except as expensive mowers with bells on?

I also wondered about the finances of the farm. Nicolson reveals that rebuilding an oast house cost as much as a Ferrari Testorossa. He isn't scratching a living from the land and clearly has funds to draw on when needs be.

Indeed, Perch Hill Farm retreats towards the end of the book in an aristocratic coda in which Nicolson, the grandson of Vita Sackville-West, takes over the running of Sissinghurst after the death of his father and turns his attention to working on grand schemes with the National Trust.

Finishing The Smell of Summer Grass and its coming-out into high society, my thoughts returned to Neil Ansell. His five-year solitary idyll came to an end when he fell ill. After his recovery, he remained in his cottage but his confidence and independence had suffered and he reluctantly departed. Evidently those five years had indeed been a retreat, a respite from the hurly-burly of society, from other people.

This is why Deep Country is so powerful. Ansell is a symbolically unnatural figure: the naturalist-hermit isolated in a dilapidated cottage. He reminds us what we can see when we are alone: it is a statement not of solidarity, but of the solitary.

Nick Groom's book 'The Seasons: An Elegy for the English Weather' will be published by Altantic