New insights from the deep past should transform the way we work with forests.
By George Monbiot, published in BBC Wildlife magazine, June 2015
Why is it possible to lay a hedge? In other words, why did trees evolve to survive the mangling that traditional hedgelayers inflict on them? They almost sever the living wood, twist it, split it and trample it down. Yet, the trees bounce back, as lively as before. Why do most deciduous trees in Britain and Europe coppice and pollard: resprout from wherever the trunk is broken? Why do birch trees have black and white bark? Why do understorey trees, like box and holly and yew, have tougher roots and branches than big canopy trees, such as oak and beech and lime, though they carry less weight and are subject to lower shear forces from the wind?
I believe that in all cases the answer is the same. Elephants.
During the last interglacial period in Britain (the Eemian stage, that ran from 130,000 to 113,000 years ago) and in southern Europe until about 30,000 years ago, our ecosystems were dominated by the straight-tusked elephant, Elephas antiquus. It was a monster, built on such a scale that it made the African elephant look like a ballet dancer. Its great neck suggests that it specialised in ripping trees to bits. Any edible tree unable to hedge or coppice would have been wiped out. Black and white bark might have confused an animal with limited colour vision, much as a zebra’s coat bamboozles predators. Understorey trees that, even when mature, are small enough for monstrous elephants to reach their crowns need be fantastically strong to survive.
The climate during the Eemian was similar to our own. Britain then contained much of our familiar wildlife, living alongside monsters. When Trafalgar Square was excavated in the 19th Century, the river gravels were found to be stuffed with bones. Most of the large ones belonged to hippos: Hippopotamus amphibius, the same species that still lives in Africa. The diggers also found the remains of elephants, rhinos, giant deer, aurochs, hyaenas and lions. (Yes, there were lions in Trafalgar Square, long before Sir Edwin Landseer got to work). In other words, like almost everywhere on earth, both on land and at sea, we had a megafauna. Megafaunas are the default state of most ecosystems. That they are now confined to a few pockets in Africa and Asia appears to be the result of hunting and habitat wreckage by humans. Wherever we go, we walk in the shadows of the past.
Why does blackthorn put out vicious spines two or three inches long when it has been cut or flailed? They appear to be wildly overengineered to resist browsing by deer or cattle, but not perhaps by rhinoceros. Why are there so many marginal species: plants that live on the edges of ponds and rivers? Could it be because they evolved to use the niches created by wallowing hippos, aurochs and wild boar? Why are robins so tame in Britain, but not on the Continent? Perhaps because the robin is to the wild boar what the oxpecker is to the Cape buffalo. In the absence of boar, they have chosen the next best thing: for them, we are simply fake pigs. Ours is a ghost ecosystem, adapted to species that no longer live here.
Of the ecological engineers I’ve mentioned, elephants are likely to have been the most powerful. Their attacks on trees would have created niches for hundreds of species. As ecologists often remind us, there is more life in dead wood than in living wood. A healthy forest ecosystem contains trees in every stage of decrepitude and death. Diseased or hollow trees, dead standing timber, recently fallen trees, older corpses; each stage provides habitats and food sources for a different collection of birds, mammals, invertebrates and fungi. By toppling some trees and leaving others mashed or mortally wounded, straight-tusked elephants would have produced plenty of life-enhancing death and decay.
Compare this to the state of our woods today. Partly because foresters and woodland managers tend to be tidy minded, partly because trees are seldom allowed to become old enough to die off naturally, partly because the tree smashers are extinct, our woodlands are almost bereft of the niches that many species need. Bird and bat boxes – to me they are a sign of failure.
I believe the disappearance of our megafauna impoverishes human life as well as wildlife. We evolved in a wonderful, terrible world, of horns and tusks and fangs and claws, and we carry with us the vestigial psychological equipment – a ghost psyche – required to navigate it. I believe we miss the thrill and fear the great beasts inspired, just as our ecosystems miss their interventions. So you can probably guess what I want to do. I want to bring them back.
According to one estimate, 30 million hectares will be vacated by farmers on the European continent by 2030. That’s an area the size of Poland. It’s happening largely because of globalisation, that makes farming in infertile places, like the European uplands, uncompetitive. It’s a tragedy – and an opportunity. Already, the medium-sized animals that were missing until recently from much of the Continent – wolves, bears, bison, moose, boar, lynx, jackals, wolverines and beavers – are spreading rapidly across Europe. But why stop there? If it is true that so much land could become available for wildlife, why should we not raise our ambitions to match the opportunity? Why should we not have a Serengeti or two on our doorsteps?
The obvious answer is that some of the species that used to live here are not just missing from Europe but extinct altogether. The lions, hyaenas and hippos that used to live in Britain and Europe are the same species as those that still cling on in Africa. But the straight-tusked elephants, Mercks and narrow-nosed rhinoceros that lived here have gone forever. But might that elephant’s closest living relative, the Asian elephant, be a good substitute? And could the black rhinoceros replace the rhino species we have lost? Not only would they help to restore ecological function to our impoverished living systems, but Europe could also become a refuge for them, enhancing their chances of survival. Crazy as it now appears, as people become accustomed to the idea, I believe it will come to seem both rational and enchanting.
Sadly, however, while within the next decades we are likely to see lynx, wolves and other species return to these shores through the work of groups like Rewilding Britain (which will be launched this summer), bringing back the Eemian giants will probably never be feasible in Britain, as our land area is small. But perhaps there is something we can do for the ecosystems that miss the megafauna. The management of woodland for wildlife should mimic the way that nature would have done it. We should start thinking like an elephant.
I believe that we overmanage our woods, just as we overgraze the hills and overfish the seas. In general I would like ecosystems to be left alone as much as possible. But there are a few small and clever things we could do to replace the work of the beasts we have lost. One of them is to increase the amount of dead and broken wood.
Plenty of reserve managers would agree. But they tend to think like people, not elephants. In other words they do it tidily, cutting and clearing and stacking and cording. I believe we should learn to love mess. To start ripping and toppling and leaving.
In a woodland reserve in Devon this spring, I watched a pair of marsh tits working in the scar left where a branch had just sheared off a poplar tree. Amid the splintered wood they had found a crevice of just the right size for nesting. Two weeks later, in the Scottish Highlands, I saw a pair of coal tits raising their young in an older scar, made when an alder tree had snapped about 12 foot up. When the top came down, it tore a great tongue from the rest of the trunk, all the way to the ground. The exposed timber, now soft with decay, was easier for the tits to tunnel into than the other side of the trunk, that was still covered in bark. They also foraged across the scar, digging invertebrates from the rotting wood around the nest.
Had the poplar branch and the top of the alder tree been neatly removed with chainsaws, these opportunities would not have arisen. The birds here needed no nesting boxes, because they had a natural mess with which to work. If we want wildlife to thrive, we need fewer tree surgeons and more tree butchers.
In some places, enlightened foresters are experimenting with a process they call veteranisation: accelerating the ageing of trees. Their techniques include fracture pruning (making strategic cuts at weak points to encourage branches to shear off); coronet cuts (slicing the end of a cut branch into jagged spikes); and even the use of explosives, to make a proper mess. In some places they topple trees with winches, providing not just dead wood on the forest floor but also root plates (wide fans of roots and soil that lift from the ground when a tree falls), that offer homes to many species. Though I have never heard them say so, it seems to me that these people are unwittingly thinking like elephants.
People expect the countryside to be tidy, so if such techniques are to become widely accepted, plenty of public persuasion is required. This means, above all, explaining our prehistory.
To me, palaeoecology – the study of past ecosystems – feels like a portal through which we may pass into an enchanted kingdom. While most people are aware of our Ice Age megafauna, such as woolly mammoths and woolly rhinoceros, hardly anyone knows about the temperate megafauna that preceded it (and which survived alongside it in southern Europe). One of my ambitions is to ensure that people come to know as much about the Eemian monsters as they do about woolly mammoths, or for that matter, dinosaurs.
Unless we engage with the past, we cannot fully understand the ecology of the present, or secure a better future for our wildlife. So let’s pass through that portal, and recharge the world with understanding and with wonder.
George Monbiot’s book Feral: rewilding the land, sea and human life is published in paperback by Penguin.