Ben Rawlence's recent book The Treeline is a fascinating study of a specific set of trees - those that make up the boundaries between two climatic regions - the frozen wastelands and the warming, more comfortable bits. "The earth is out of balance" says Rawlence, and "the treeline zone is a terrritory in the grip of a large geological change, confounding and challenging our ideas of the past, present and future."
The book, part travelogue, part scientific account and very much a celebration of trees, ought to have been huge. Not least because the treeline itself, wrapped like a wavey line along the north pole, is very long indeed. But Rawlence explains that the book's length was constrained by his discovery that only "a tiny handful of tree species make up the treeline" and just six of them are the "familiar markers of the northern terroirtoies: three configfers and three broadleaves". For those confused by these terms there is a hand guide at the back of the book.
As the world is warming the treeline is moving, sometimes remarkably rapidly. As Rawlence travels around the Treeline, he meets people that are living, herding, surviving in areas were there should be no trees, and where the arrival of trees is both surprising and transformative. Take his visit to Norway.
The Sámi have been saying for at least fiften years that winters are getting 'weird'. The amount of light hasn't changed and the soil is the same, but more rain and more heat have made all the difference. The downy birch loves the warmer waether. It used to be confined to the dips and gullies on the plateau, out of the icy winds, but, unleashed by the warmth, it is storming over the top and out into the open, moving upslope at the rate of forty metres a year. And enormous amount of territory is being transformed from tundra into woodland at a lightning pace.
Here we encounter the unanticipated problem caused by those who would simply plant more saplings. Trees don't always help ecological systems. This is for several reasons. The trees encroaching onto areas were they were previously absent destroy ecologies and landscapes. Their presence transforms the space they move into:
The greening of the tundra is closely linked to more warming as the birch improves the soil and warms it further with microbial activity, melthing the permafrost and releading methane - a greenhouse gas eight-five times more powerful than carbon dioxide in its warming effects over a shorter timeframe.
Another problem is that that the trees that are exploding outwards aren't creating the same, historic forests that nuture and protect biodiversity. Where "old growth" forest "created a diverse forest full of hundrds of different kinds of plants", the old trees simply cannot grow in time. Instead fast growing species are blocking the potential for other trees to evolve their own space and support biodiversity such as the lichen that feed reindeer. Rawlence paints a picture of sometrees "racing over the tundra" while other species don't get a look in. It has tremendous consequences for animals like reindeer and the people who live on them.
One of the most important strengths of The Treeline is that Rawlence refuses to isolate the ecological systems from human society.
The landscape we have grown up in and taken for granted in a few short generations are not timeless at all, but a human-shaped moment in a continuous drynamic of changing colours of blur ocean, white ice and green forest on a ball of rock, surrounded by gas, spinning in space.
Countless generations have labourerd on their lands, relating to the species, encouraging, nuturing and fighting for an ecological space. Climate change is arriving like a massive hammer, smashing up complex relationships and undermining historically viable systems. The people who suffer first and foremost are some of the poorest - indigineous communities that are forgotten and neglected - yet also are often those with some of the best answers to solving ecological problems. Though it is very likely that many, such as the reindeer herders, will simply disappear from their current economic niche.
Rawlence also identifies as second factor. If we cannot ignore the role of humans in shaping a landscape, we cannot also ignore the role of the economic systems they create. Its unusual to read it in a book on ecology, so its worth highlighting this:
The breaching of the ecological ceiling of the planet was only enabled and accelerated by a specific recent economic model: industrial capitalism and its political export, colonialism.... our collective survival on the planet almost certainly depends on moving beyond it.
It's a stark choice. For readers who like easy solutions, there are plenty of examples that Rawlence gives, were small groups of people and individuals are fighting to protect and understand trees and the related economic systems. But these brief moments, in time and space, of rewilding are likely to be swallowed up by the vast forces unleased by industrial capitalism. Planting trees on its own is not going to cut it. Ben Rawlence's book is a celebration of trees, ecology and human life - through a study of the tree line in many different places. It's also a call to arms.