All novels are about time in one way or another, and thus all novels are about mortality. In a book as long as Annie Proulx’s – 700-plus pages that travel from the end of the 17th century to almost the present day – the reader experiences time in an additional sense; not merely as a long act of engagement, but as a form of anxiety. How to remember the exponentially increasing family groups, so frequently shifting location, their members marrying, remarrying, adopting children, disappearing, thriving and then, suddenly, diminishing? This isn’t merely a matter of keeping names straight: the generations of the Sel and the Duquet families are Proulx’s tools for laying bare how dynasties are established, why some flourish and some wither, and their dynamic relationship with their environment and its other inhabitants.

Ultimately, though, it’s the foundations that matter most. Proulx’s story begins with the arrival in “New France” – the vast tract of north America and Canada colonised by the French between the 16th and 18th centuries – of two young men, René Sel and Charles Duquet. Indentured to a harsh if not entirely brutal taskmaster, Monsieur Trépagny, they are set to earn their freedom by clearing an area of forest for him (not least so that he can tempt a classy bride from his homeland to join him in the fanciful house he’s built). Trépagny also believes that colonisation will bring him not merely personal wealth, but a chance to revenge himself on Jesuits, parochialism and “cold-hearted old France with its frozen ideas”.

René and Charles, awestruck by the imposing, often impenetrable and seemingly limitless extent of the forest, react to it in strikingly different ways. René cleaves to his inner woodsman, shaping himself to the land, puzzled by the drive to cut further into the forest than necessary. Eventually, he marries Mari, a Mi’kmaq woman skilled in the therapeutic use of plants, enfolding her existing children with the couple’s own, and setting in train one of the novel’s key strands: the constant tension that their descendants feel as they negotiate their dual heritage.

Proulx is profoundly committed to the novel’s ecological message

Charles, however, is attached to the land for very different reasons – straight off the bat, he sees the potential to make his fortune, and he moves swiftly through commodities, business partners and trading nations until his foothold is secure, marrying for advantage and adopting extra sons just in case. In one of the funniest of the comic interludes that stud Barkskins, he is pictured collecting an absurdly grand wig, which is stolen a short time later by a thief who may well be in the wig-maker’s employ. Retrieved in somewhat shabbier condition, the wig eventually comes to rest, boxed-up, in an attic, where it is discovered by two small boys. Spooked by what they believe to be a monstrous creature, they fling it from the window, whereupon flocks of birds descend to claim it for nesting material. Sic transit gloria mundi.

There are a good few of these sorts of episode – another involves a rather priggish middle-aged man, a late marriage, and a wife with extremely healthy appetites – but Barkskins’ register is more usually found somewhere between the serious and the sombre, and consistently concerned to impart information. It would be unfair to accuse the novel of being a victim of its research because Proulx engages with what she knows on more visceral terms than a writer who has simply alighted on an interesting subject. The pacing of her narrative, with each generation reflecting the further depredations of man against nature, its impact on the indigenous population and the twists and turns of colonial power, delivers a slowly gathering power, accented with the dread of irrevocable change.

But the problem is one of character. When Jan, one of Charles’s adopted sons, is considering relations with England, he puts the case thus: “There is increasing murmuration that the colonies should join together and flout England. We already do so flout when it comes to timber and shipbuilding, to smuggling and molasses. The constant promulgation of punitive acts and taxes do threaten our region’s livelihood. If we were not the creature of England we would thrive greatly.” Whether or not the rhythms of his speech and his vocabulary are historically accurate is beside the point; they sound like someone setting out a position, making sure we’ve got the picture. Similarly, when Theotiste, one of Mari’s children, crops up once again in the narrative, his situation is handily summarised: “Despite his 59 years Theotiste had become a warrior. In August 1749, when Cornwallis, ignoring Mi’kmaq territorial rights, declared Halifax an English settlement, Theotiste’s band attacked some English tree-choppers. He escaped the avenging rangers, but fell the next week to an unknown assassin, his head a prize to a bounty-hunter.” There’s a lot of information there, but the sketch of Theotiste’s later life, despite the fact that he was never a major character, is all too brief. A revelation of concealed transgenderism in another figure means little, since we’ve barely been introduced.

When the Sels and the Duquets – or, as they become, the Dukes – develop a little more, it is easier to pay attention. Some of them stand out – as, of course, people do in a real family. Kuntaw Sel, his wife, Beatrix, and their children, embody much of the psychological pain of those who struggle to reconcile their Native American and French blood, especially when family ruptures occur. Here is Kuntaw, reunited with his troubled and self-hating son, Tonny: “It is not winter, but I will tell you the old stories of our people and the great ones in our lineage.” But Tonny is unmoved, finally responding: “Kuntaw. I do not belong here. I do not belong in Mi’kma’ki – Nova Scotia, they say it now. I am apart from every person, English, Mi’kmaq, French, American. I have no place … No place good for me. I go away. Maybe somebody kill me soon. Then I be done.” Before too long, he is granted his wish to die, “and, like countless other fathers, slipped into the past”.

That slippage of present into past is fiendishly hard to pull off, requiring an incredibly delicately calibrated manipulation of the reader’s empathy. Weaving in commentary on the ramifications of vast historical power struggles and changes makes it even more difficult – and it is clear that Proulx is profoundly committed to the novel’s ecological message; put simply, that a cavalier and rapacious treatment of the earth, and of the people who are most closely attuned to its needs and stewardship, is exceptionally difficult, if not impossible, to reverse. But that can make for didactic reading, even when one agrees with the message. Of recent novels in this vein, the most successful is Amitav Ghosh’s Ibis trilogy, which narrated the background to the 19th-century opium wars with extraordinary brio, moving from wrenchingly painful to hilariously antic with apparent ease, and creating some memorable characters in the process. Barkskins, for all its ambition and integrity, doesn’t quite pull off the same feat: it wants a little more light, a little more space to rest during the relentless march of history.

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