Roger Deakin visits a Jaguar factory in Coventry, in the United Kingdom, where he finds—

160 cabinet-makers were at work in two shifts, day and night, selecting and cutting out the shapes of delicate walnut veneer for the dashboards and door panels of the higher animals—“cars” seems too mundane a word—that have evolved from the feral SS Jaguar 100 sports model of 1936, with its sweeping wings, wire wheels, knock-on chrome hubs and immense, dashing bonnet louvered like a cheese grater, a seemingly endless perspective, viewed from the driver’s cockpit.

Deakin, Wildwood, page 138

Watching this, Deakin thinks back to an essay by Roland Barthes (yes, that Roland Barthes), written in 1955 about the new Citroën DS:

[Barthes] believes that modern cars are the exact equivalent of the great Gothic cathedrals: “the supreme creation of an era, conceived with passion by unknown artists, and consumed in image if not in usage by a whole population which appropriates them as a purely magical object.” Barthes sees that mythology as the key to understanding the world of cars: that, considered as objects, they are “messengers of a world above nature.”

Deakin, Wildwood, page 139

From inside that famed driver’s cockpit, from on the road, the world seems insubstantial, ephemeral, passive. So of course the driver comes to see themselves as being apart from it, as being not only separate but also faster, more powerful, more free. You have to stand outside the car to realize it for a cage.

But what is all that walnut doing there?

Why is “walnut” such a potent word in the copywriter’s vocabulary? Its roots lie in the Old English Walhhnutu and the Old German Walhoz. The first syllable, wal, is related to the Old English wale, in the sense of well-being as much as possession. No doubt the well-being, in both body and pocket, referred originally to the benefits of the nut.

Deakin, Wildwood, page 139

So we’ve borrowed a meaning that referred to the fruit of the tree—which could be harvested year after year—and applied it to the wood, which depended on felling so many trees that they became scarce, driving up the price and, incidentally, the perceived value. But there’s something else here, too, about how the warmth and deep color of the walnut looks to the eyes and feels to the hands, the way it brings nature inside—but a tamed, domesticated, polished nature, with none of the wildness or agency or danger that real nature possesses.

The other common use for walnut, of course, was gun stocks.

It is mildly ironic that a tree whose nuts are celebrated as an elixir of long life should find itself reincarnated in guns, and that wars should always have increased demand for the wood. The role of walnut is to mediate between the machine and its owner.

Deakin, Wildwood, page 143

(Emphasis mine.) The walnut makes the machine seem natural, lets the hand grip something warm and comforting, obscures the plastic and metal which we might otherwise find cold and alienating. It’s cousin to designing a robot that can kill but making it look like a dog, an animal to which we are predisposed to friendliness. There’s a bit of an inversion there, I think: the message is that we are above nature, but one of the messengers is our own sense of kinship with that very nature. As if some part of us, an unconscious part perhaps, knows better.