Ben Rawlence’s latest book is The Treeline: The Last Forest and the Future of Life on Earth.
Just under half of Canada is forest. Once upon a time it was more than that. But before the trees, before the soil even, was ice. The last ice age ended 9,000 years ago when the Laurentide ice sheet covering most of the Canadian shield melted, sending the waters of what was called Lake Agassiz into the ocean, raising sea levels around the world and inspiring myths of floods and arks. As the ice retreated, the treeline slowly followed, taking root in meagre soil, photo-synthesizing, shedding its needles, then dying to create the rich fertile crust of the Earth, laying the foundations for the habitats of all other terrestrial life. There is scarcely a patch of the Northern Hemisphere over which the treeline has not passed.
The ice has come and gone many times. Ever since the Pliocene period, roughly three million years ago, when the explosion of plants cooled the atmosphere to its modern equilibrium, the ice ages have marked our planet in 100,000 year pulses. The pulse is because the Earth does not spin evenly, it wobbles like a top. The wobble is called the Milankovitch cycle. It tilts the planet slightly away from the sun every 100,000 years, chilling it ever so slightly and causing the ice at the poles to expand and retreat in a millennial version of our annual seasons. Time lapse photography of geological time on planet Earth would show a sheet of ice descending and retreating in a rhythmic pattern, and a green mass of forest rising towards the North Pole then falling again, like breath.
But now the planet is hyperventilating. This bright green halo is moving unnaturally fast, crowning the planet with a laurel of needles and leaves, turning the white Arctic green. The migration of the treeline north is no longer a matter of inches per century. Instead it is hundreds of feet, every year. The trees are on the move. They shouldn’t be. And this sinister fact has enormous consequences for all life on Earth.
The next ice age was due to be on its way about now but humans have postponed it, perhaps indefinitely. The age-old tango between ice and trees has been disrupted. This is a problem. The trees do more than keep Earth’s temperature cool enough that glaciation can occur every 100,000 years. The boreal forest is the largest biome, or living system, on land. The planet’s largest is the ocean.
The forest that covers much of Canada is not just an ecosystem or a habitat (or a resource) but one third of the whole of the planet’s boreal forest: the most critical terrestrial engine that sets the terms for much of life on Earth. Canada’s northern woods are a natural asset of strategic importance to all other countries. This is an awesome responsibility. Halting forest degradation and deforestation was one of the key planks of the Intergovernmental Panel on Climate Change’s plan for keeping global warming below two degrees.
More than the Amazon, the boreal is truly the lung of the world. Globally, forests take up around 25 per cent of human emissions. One third of those trees are in the boreal. If we consider the “ecosystem services” provided by the boreal in its entirety then timber is probably the least valuable commodity in the forest.
First of all, forests create rain. Trees fire volatile chemicals into the atmosphere that bond to water molecules, making them heavier so they fall as rain. More than that, they can suck rain and moisture across continents. As they transpire, the pressure deficit acts like a vacuum and pulls moisture into the void. A contiguous forest can transport water in a “flying river” over thousands of miles; as the rain falls, it is transpired again into the air and moved along further inland.
Second, those trillion trees (a third of all the trees on the planet are in the boreal) create the wind. The process of transpiration and the “biotic pump” of the vacuum influence gas exchange in the atmosphere and hemispheric wind patterns. And other research has shown how the capacity for the trees to absorb radiation in summer creates a heat differential between the forest and the tundra that plays a role in driving the jet stream. It is a wind that is antiseptic and cleansing, containing as it does billions of particles called pinenes – the same chemicals that make your bathroom freshener smell nice.
Third, at the same time the boreal forest regulates much of the freshwater of the Northern Hemisphere, receiving and discharging increasing amounts into the Arctic Oceans which in turn affects ocean systems, habitats, ice dynamics and ocean currents far away.
Fourth, all the fertile agricultural land in the Northern Hemisphere was once forest – billions of tonnes of organic life composted to perfection. Once that soil is depleted with fertilizers, herbicides and pesticides, it will be useless and we will need to turn to trees to make it whole again.
Fifth, as Irish-Canadian botanist Diana Beresford-Kroeger has shown in numerous books and as the First Nations peoples know only too well, there are literally hundreds of medicinal and other applications for the bark, sap, leaves and fruits of trees that have yet to be “discovered” by modern society.
But most of all, collecting all these functions together, the boreal forest is a habitat for so many other temperate species, including us. Humans and trees share the same climate niche. We evolved in the forest. And since trees create the optimum conditions for more trees, they create the optimum habitat for humans.
More trees in the Arctic does not necessarily mean more forest. Instead, the southern reaches of the boreal are burning up. As the treeline jumps north, some Canadians might be able to move with the forest across contiguous territory. Most of us elsewhere, however, will not have that option.
If Canada seeks to take meaningful steps on climate, then protecting the boreal forest and the extraordinary functions and services it provides to people everywhere should be top of the list.
Instead, at present, Canada vies with Russia and Brazil for the accolade of highest forest degradation rate – much of it going for toilet paper in the USA. We are literally wiping our behinds with our children’s futures. The government likes to say that clear-cutting does not count as deforestation since the forest is allowed to grow back. But call it what you will, the waste will seem crazy to our kids, if it doesn’t already.
Canada, though, is also lucky. It has home-grown solutions and examples to hand. First Nations peoples across the country have been stewarding landscapes since, as the Anishinaabe of Lake Winnipeg say, the creator Manitou raised the land out of the melt waters of Lake Agassiz and set the forest upon it. The newest and largest designated forest in North America is called Pimachiowin Aki on the shores of Lake Winnipeg and it is one of several showcases for how to harvest the bounty of the forest – including burning it sometimes – but without cutting it down and chewing up the precious soil with machines.
The national reckoning with the histories of encounter between settlers and First Nations in Canada offers a chance for reparations and healing, not just among peoples but between humans and the natural systems that sustain them. That sacred knowledge: the names of the species, the places they grow, the amazing things they can do is soon to become critical and strategic as climate breakdown hits. No amount of money is going to save us from heat domes and crop failures. Those best placed to adapt to species moving north are those who have invested in thousands of years of knowledge, of noticing and of relationships with the natural world. It could be that Canada’s best future lies in reversing the educational transaction that has caused so much pain. Is it perhaps time to learn from First Nations teachers in learning to see and value the whole wood rather than just the individual trees?
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