RICHARD MABEY
In the race to stem the loss of biodiversity and offset carbon emissions through reforestation, we may be guilty of not being able to see the wood for the trees.
In the race to offset carbon emissions through reforestation, nature writer Richard shares his view. “Our automatic reflex to the need for more trees is that humans must deliberately plant them within a decade,” he says.
I’m loath to give succour to Brazil’s odious President Bolsonaro, who did little to stop the destructive fires in Amazonia last year. But he had a point when he rebuffed Western protests by observing that Brazil was simply doing what Europe had done to its forests over the past few thousand years. The UK was particularly successful in its long programme of deforestation. We currently have about 12 per cent of land under trees, less than half the European average. So it was good news when a raft of reforestation plans and ambitions surfaced just a week before news of the Amazonian fires broke. The Government reiterated its very modest targets, Tetley Tea announced it was planting a million trees, and Friends of the Earth insisted that Britain should double its forest cover in the next couple of decades. This would make a contribution to carbon capture, but nothing like the extravagant claims currently being made. In their first five years of growth, a million newly planted saplings would lock up the average carbon emissions of no more than 100 cars over the same period.
Though trees filter out pollution, aid human well-being and provide a rich substrate for animal life, could a wholesale dedication to tree-planting to ameliorate climate change compromise other urgent conservation goals? There is, for a start, the question of where this considerable area of tree-land (one and a half times the area of Wales) might be accommodated. Second-rate farmland is the obvious answer, but with food security now a political issue, this might not be available. The various forecasts also talk vaguely of “poor quality” land, which brings into focus the heaths, bogs, commons and downland (all good carbon sinks, incidentally) in which so much of the UK’s biodiversity is situated. Could tree planting against global heating come into head-on conflict with efforts to minimise the sixth mass extinction?
There are other obstacles when it comes to siting. The Lake District – 2,300km² of sheep-ravaged and ecologically barren fells – would be an obvious target. As early as 1810, the Lakes’ champion, poet William Wordsworth, celebrated the natural treeing of the hills, in a beautiful and ecologically precise account: “From low and sheltered places, vegetation travels
upwards to the more exposed, and the young plants are protected, and to a certain degree fashioned, by those that have preceded them... Contrast the liberty that encourages, and the law that limits, this joint work of nature and time, with the disheartening necessities, restrictions and disadvantages, under which the artificial planter must proceed...”
The sheep farmers could be compensated, but it might not be so easy to buy off the 20 million annual visitors for whom the Lakes represent the epitome of English scenic beauty.
There is also the major question of how these trees might be propagated, regardless of site. Our automatic reflex to the need for more trees is that humans must deliberately plant them – an odd assumption when you consider that trees have perfectly adequate reproductive systems and are marvellously adept at propagating themselves. Any piece of open ground with seed trees not too far away will turn into a recognisable young wood within a decade, if left to itself. I have seen birch-sallow woods springing up spontaneously on derelict industrial sites in East London and mining spoiltips in the Midlands. When I was helping with survey work for Flora of Hertfordshire, oak seedlings were in the top five ‘weed’ species in any arable field with oaks in the surrounding hedgerows. As for all those prize habitats of chalk grassland, fens and the like, they are all so eager to turn into woodland that removing their trees makes the nature conservation business the most active deforester in the country.
One Scottish laird planted up a hillside with the letters of his estate’s name, on a scale that would have made it visible from space.
But does it matter how the trees arrive, provided they do? I think it does – on practical, economic, ecological and ethical grounds. There is an unchallenged assumption that a collection of planted trees constitutes a wood. It doesn’t, except in the long term. A new plantation is more like an arboreal intensive-care ward. The young saplings, often even aged and sourced from a narrow genetic source, are planted in regimented rows, and the trees positioned where the planter wants them, not where they would naturally ‘choose’ to grow. They are staked, which prevents their root systems spreading and adapting to wind-sway, and pruned to make their shapes conform to conventional tree images – in ecologist Oliver Rackham’s phrase, “gateposts with leaves”. All scrub around the trees is cleared regularly, and the ground often mown like a lawn. In addition, planters are instructed to sterilise – with weedkiller or plastic – a wide circle of ground around each sapling’s trunk, as trees supposedly cannot compete with grass – a curious myth, regularly trotted out on reputable gardening programmes, which is easily rebutted by looking at any patch of ungrazed downland, with its forest of aspirational yews and hawthorns thrusting through the sward.
By contrast, woodland sprung naturally from seed sown by animals or carried on the wind, is self-supporting. It is intrinsically diverse genetically, which as a bonus helps disease resistance. The seedlings prosper where the soil and terrain suits their species. They seem, mysteriously, to survive without watering or staking. They grow up through a protective layer of brambles and scrub, which eventually provides the wood’s natural understory. These scruffy beginnings may be one of the reasons behind our cultural hostility towards natural regeneration. In our obsession with tidiness, any woody growth not obviously planted by us is dismissed derisively as ‘scrub’ – which the landscape architect Nan Fairbrother notoriously described as “the state of original sin in our landscape”.
There are plenty of examples of how natural reforestation works in the field. Following World War I, large areas of neglected English farmland ‘tumbled down’ to wood. There was also spectacular natural regeneration in the woods of southern England in the wake of the great storm of 1987. I toured many of the worst affected areas the following summer. In places, it was possible to see, adjacent to one another, areas that had been cleared and replanted and areas that had been abandoned. The former presented a depressing vista of stunted saplings struggling out of bare earth. The latter had hectic sheaves of naturally regenerated maple, ash, birch and beech thriving under the shelter of the fallen trees. Untidy, but undeniably a burgeoning natural wood. There are comparable examples across the temperate zone. Indigenous evergreen woodland is increasing dramatically in the Mediterranean, partly as a result of the colonisation of (sadly) abandoned vineyards and olive groves. The rich and extensive second-growth woodlands along the eastern seaboard of the United States, which cover 90 per cent of the land in some regions, are a consequence of the agricultural depression that stretched from the late 19th century until the 1930s.
Tree planting can be a valuable and necessary strategy in many situations. For example, ashdepleted hedgerows, which may need species that are not locally native; urban roundabouts; public parks; school nature corners; small and isolated sites that are unlikely to get much natural colonisation, and areas a long distance from seed trees. But I’m not sure this explains why planting is our default position, why what is – in effect – captive breeding is the first option with trees, not the last resort. I suspect there are cultural and psychological pressures at work, beyond the objective desire for more trees.
There are no records of woods being planted in Britain before the mid 16th century. The following century, there was political pressure to plant oak because of a presumed shortage of naval timber. But most historians believe this was just a war of spin between the Royalist and Commonwealth parties, and that no actual shortage existed.
(Rackham calculated that an entire fleet of 25 ships could have been built with the oaks from just 1,000ha of coppice-with-standards.)
The real surge in planting took off in the 18th century, not out of patriotism, but from the zeal for ‘improvement’. Planted woods could improve your wealth, the look of your estate, your status. German forest science, forstwissenschaft – the geometric planting of trees to maximise return – became fashionable. Landowners competed for prizes for the number of trees they had planted, and the coniferisation of Wales began in this frenzy. One early 19th-century Scottish laird planted up a hillside with the letters of his estate’s name, on a scale that would have made it visible from space. The social paraphernalia that surrounds and sometimes bedevils modern planting – regimentation, targets, promotional stunts – was established more than two centuries ago.
The modern enthusiasm for planting can be dated to the late 1950s and Jean Giono’s classic The Man Who Planted Trees. This tells the moving story of a French peasant in the first half of the 20th century, who revived a large stretch of the barren landscape of Provence by sowing acorns as he tended his sheep. Except that it wasn’t, as its readers presumed, a true story, but a fiction. Giono had even joined in the sleight of hand by publishing a fake photo of the peasant. The author had lived through the human (and tree) destroying horror of the World War I trenches, and had wanted to create a fable about how planting trees might be an act of reparation for the damage we had inflicted on the Earth.
And tree-planting as a ritual of atonement continues to be a major motivation, from Plant a Tree in ’73 through all the succeeding hubbub of fund-raising campaigns, corporate sponsors desperate to establish their green credentials, and civic promotional events with the wrong trees in very wrong places. But behind the razzmatazz, planting does have one great social – rather than ecological – virtue. It helps people, children especially, feel they are engaged with restoring the tree cover of the planet, to have a sense of responsibility for it. If non-intervention entails our physical exclusion from the processes of renewal, a recognition of our irrelevance, where does that put us in the scheme of things as we try to rediscover our place in nature?
But paternal responsibility and custodianship are double-edged feelings. They can easily morph into a sense of entitlement to control, to the belief that we have dominion over nature, which led us into environmental crisis in the first place. When I owned and ran a community wood in the Chilterns, we discouraged treeplanting and found that our helpers felt just as engaged (and astonished) being witness to the wood’s natural regeneration. This process can not only be spectacular, and the most reliable way of establishing tree cover, but generate woody systems that would never be dreamed of in organised planting – like the purple-emperor-attracting sallow thickets on the rewilded Knepp estate.
In his famous essay On Liberty, the philosopher John Stuart Mill suggested that allowing beings “freedom to” – permitting them to follow their own agendas as subjects – liberated their “spontaneity, originality, genius”. He was talking about humans, but as we try to narrow the gap between ourselves and the natural world, perhaps we could grant the potential for such creativity to trees.
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