Heart of an Oak review - an adventure film starring a tree and its inhabitants

On one level, Heart of an Oak is the most spectacular nature film you are ever likely to see. The camera glides over a forest before honing in on a magnificent, 210 year old oak tree. It travels up the gnarled surface of the ancient trunk, which resembles elephant hide, into the canopy.

Time to introduce the cast of what directors Laurent Charbonnier and Michel Sedoux describe as an “adventure movie”: weevils, a red squirrel, woodpecker, robin and pair of jays, field mice and some wild boar. All of them live in or around the tree and this is their story.

It’s high summer, but a storm is brewing. Thunder and lightning herald a downpour; the heavens open and creatures scurry for cover. We descend into the underworld where a colony of field mice lives among the tree roots. It’s cosy down here, but tension mounts as, above ground, the wind blows and rain drenches ladybirds, ants and beetles before flooding the subterranean chambers where the mice huddle together in fear.

Slowly the water soaks away and the clean up begins. We see the mice shift mud and sodden leaves and nibble their fur dry. Meanwhile, up in the branches, the jays ruffle their feathers, the squirrel shakes off the raindrops and life returns to normal.

So begins a year in which we get up close and intimate with the inhabitants of the splendid oak tree. We follow them through the seasons in a narrative built detail on immaculate detail with incredibly beautiful camerawork and Sylvie Lager’s razor sharp editing. There’s no voice over, just the sounds of the forest and occasional music to enhance the mood. It’s as though we have left the human world behind and entered an untrammelled paradise.

The landscape of Sologne, Central France is gorgeous and the filming does it proud. Skeins of geese fly in formation across evening skies while a shot of two swans paddling their feet as they land on a lake is so beautiful it brought tears to my eyes. We are at risk of destroying all this through climate change, I thought – which is exactly the reaction I imagine the film-makers hoping for.

The weirdest of the creatures is the weevil. With its compound eyes and long red proboscis, it resembles a sci-fi alien. The aim of the female is to find a mate, copulate, bore a hole through the shell of an acorn and lay her egg inside. Footage of this fascinating process is accompanied by Dean Martin singing “Sway with Me”. Have you noticed how shots of animals mating are invariably set to music that makes them seem comic?

And now things start to get complicated. No longer content with recording things as they occur, the directors up the ante by staging events and resorting to digital shenanigans. For instance, we are given a grub’s eye view of the world from inside an acorn before seeing the creature riggle out and bury itself in the soil. Later we follow it underground and, in the spookiest of shots, witness the plump white body hardening into the shape of an adult weevil.

The highlight of the film is a high speed chase through the trees as a goshawk pursues one of the jays. The hunt is incredibly exciting, but how did the camera crew manage to capture it? They couldn’t have known where the birds would fly, so multiple cameras is not the answer. At one point the dash through the trees is shown from the hawk’s point of view, which must have involved a drone.

Spoiler: the jay escapes by diving into a thicket. Cut to a shot from inside the thicket of a frustrated hawk peering in through the tangle of twigs. This is obviously a set-up which, on the one hand, makes the danger feel very real but, on the other, undermines one’s faith in the whole project. I began to wonder how much of the footage was either staged or relied on special effects.

Then I became aware that, in this version of paradise, nothing is killed or eaten. We see a snake slithering up the tree in a bid to snatch the chicks from the jays’ nest. At the crucial moment, though, a twig snaps and the snake plummets down to earth. A mouse manages to escape the claws of an owl and a weevil the tongue of a frog so, although there are predators in paradise, there’s always a happy ending.

Despite the superb filming, then, the upshot is a sanitised view of the natural world. Heart of an Oak appears to offer a hands-off experience of woodland life when, in fact, it was story-boarded from start to finish to create an “adventure movie” akin to a sentimental fairy tale. What a shame!

• Heart of an Oak is in cinemas from 12 July
• More film reviews on theartsdesk