Last November, amid the charged and turbulent weeks of Cop26, I found myself on a sunlit hillside in the Brecon Beacons watching saplings being planted. Families – grandparents, parents, grandchildren – followed a rugged tractor track snowy with autumnal willowherb, each carrying a foot-high tree destined for a high hillside above the steep valley. With world leaders in Glasgow deciding our planet’s future, this felt like a pretty good place to be: witnessing an optimistic, physical gesture of climate action amid so much talk. “Hope is taking action,” Greta Thunberg declared in her lauded “blah, blah, blah” speech at Milan’s Youth4Climate conference last September.
With their natural capacity to sequester carbon – to draw it from the atmosphere and lock it up as wood – trees are a simple, easy-to-understand way of tackling the climate emergency. Indeed, the most headline-grabbing action ultimately pledged at Cop26 was an end to deforestation by 2030.
The UK, however, is no forest frontrunner; we are one of the least-forested countries in Europe. According to the Woodland Trust, UK tree cover is well below the EU average, at 13% of land cover compared with 37%. The Climate Change Committee has advised that to achieve net zero emissions by 2050, tree cover must rise to 19% of the UK – about 1.5bn more trees, says the Woodland Trust. This means 22 trees each for everyone in the UK.
To this end, tree-planting initiatives are booming, from politically driven targets and charity campaigns to private firms looking to offset carbon emissions. The government has pledged to plant 30,000 hectares of woodland a year by 2024; AstraZeneca has partnered with Forestry England to plant a million trees across the UK, including restoring native woodland in southern Scotland; the National Trust aims to have 20m new trees on trust land by 2030. Coldplay has vowed to plant a tree for every ticket sold for its 2022 world tour; dating app The Sauce will plant a tree with every match; and energy suppliers are offering “greener” tariffs that support woodland regeneration. There’s even a tree planting scheme to mark the Queen’s Platinum Jubilee. Trees, trees, trees.
Like most people, I would like to see more trees planted. And I’d like to know that the initiatives I support are future-proofed and environmentally sound – the Royal Botanic Gardens in Kew has warned that poorly planned tree planting could actually increase CO2 emissions and reduce biodiversity. It recently published 10 golden rules for reforestation, urging schemes to consider factors such as site suitability and sustainability.
But where do I start? Which trees are best? Where will they be planted? And who will maintain them?
Those trees I saw being planted in the Brecon Beacons were giant sequoias – the enormous conifer native to California’s Sierra Nevada range. Their planting was organised by tree enterprise One Life One Tree. At its site near Abergavenny (one of four), paying patrons had come to offset a lifetime’s carbon footprint by planting one of the world’s largest trees.
Some argue that planting non-native species can affect native biodiversity. Over thousands of years, a network of interconnected flora, fauna and fungi has evolved alongside our native trees; replace the trees with foreign ones and those relationships may suffer.
To this end, One Life One Tree is planting native trees, including oak and rowan, alongside the sequoias. “We’re only planting on previously felled monoculture timber plantation land,” says founder Henry Emson. “If we weren’t to take this project on, this land would just be bought by a timber business and restocked with non-native conifers – we are creating a biodiversity increase, not a decrease.”
These trees are the most powerful on the planet for capturing carbon, he says. Unlike other conifers, such as Douglas fir and Sitka spruce, whose growth plateaus at a certain age, giant sequoias continue to grow and accumulate wood beyond maturity. “So their value for carbon capture keeps going for a millennium.”
Another common concern with planting non-natives is the potential for “invasiveness”; plants outcompeting UK flora, or harbouring potentially destructive pathogens. To this, Emson says his sequoias are grown in the UK from seed, “so there’s no import of any disease or bugs. Giant sequoias can’t propagate in the UK – they need wildfires – so there’s no threat of them breaking out into the countryside.”
He began the project by planting a sequoia for each of his children, to give them a head start on their carbon footprint. Emson calculates that, with life expectancy in the UK at about 80 years, and per capita carbon emissions at 6.5 tonnes per annum, a giant sequoia growing to 500 cubic meters can offset a person’s lifetime carbon footprint. “Per hectare, native woodland will capture 400-600 tonnes of CO2 over 100 years. Sequoias spaced as we have them here will capture 6,000 tonnes.” Patrons pay £395 a tree, which contributes to the land cost and maintenance.
Talking to patrons planting their lifelong sequoias was a heartening experience: parents Richard and Eva were planting a tree for their young son Leon (“it’s for his future”). “I haven’t met a single patron who has been like, ‘I’m doing this so that I can carry on as I was’,” Emson says. “They are conscientious, doing it out of love for the planet. People who are off-setters don’t bother coming out to Wales to plant a tree.”
“Climate adaptability” is another of Kew’s 10 golden rules. In its tree species database, Forest Research (the UK’s principal organisation for tree studies) lists the giant sequoia as “a species that could be grown more widely throughout Britain with climate warming”. So, colossal conifers native to North America could prove advantageous in their suitability for a warmer climate (there are 150-year-old examples growing well in Welshpool, mid Wales), but Kew’s Dr Kate Hardwick urges caution: “A lot of foresters assume we’re going to need non-native species to deal with climate change. But we just don’t know yet,” she told me. “There’s a huge amount of genetic diversity in our native species and there may well be enough to adapt to the climate change we’re going to experience.”
Another route to reforestation and carbon capture is through farmland. A little way north of the sequoia grove, in the Black Mountains, is Bryn Arw, pilot site of Stump Up For Trees (Suft), a charity that tries to persuade landowners to include more trees on their land. Winding lanes lead to the 64-hectare hillside plot, where nurtured saplings face bracing winds and a breathtaking view of the Beacons.
Its co-founders are Keith Powell, a seventh-generation Black Mountains farmer, and writer Robert Penn, author of The Man Who Made Things Out of Trees. “We think carbon sequestration is really important,” says Powell, “but it comes quite low on the list of the benefits of planting trees.” Improving soil and water quality, and providing for wildlife, are among Suft’s priorities, along with natural flood management. Last winter, 130,000 native trees, including birch, sorbus and oak, were planted here by Suft volunteers and contractors, the first significant tree plant on common land in Wales.
But Suft has wider intentions. The charity is persuading farmers to designate a proportion of their least-productive land for tree planting. Carbon capture can then play a role as, once new tree plantings have been validated for Woodland Carbon Units (as regulated by the government-backed Woodland Carbon Code), their carbon sequestration can be sold in the form of carbon credits. “We’re trying to get farmers to see carbon as a crop on marginal or non-food-producing land,” says Powell. “It could provide a sustainable income for farms – and that way it’ll be acceptable all over the country”. Penn tells me that selling carbon credits on a new two-hectare native woodland project could easily realise £10,000 for the landowner. Indeed, “Make it pay”, is the 10th of Kew’s golden rules, recognising that income streams will ensure the sustainability of reforestation projects.
Cities can play a role in reforestation, too – in the form of urban “forests”, parks, workspace courtyards, roadside verges and traffic islands. Rewilding organisation Sugi plants native saplings densely, so they will mature into forest quickly, and thin naturally as the trees compete for light.
At one central London primary school, a corner of concrete playground is being replaced with a pocket forest of diverse native species including hazel, dogwood, spindle and holly. “The concept is that the forest becomes self-sustaining very quickly,” says Sugi’s lead forest-maker, James Godfrey-Faussett. “From an environmental point of view, a forest ecosystem is probably the most impactful thing you can do in an urban area; it can affect biodiversity, air quality, communities and the local environment.”
Employing the “Miyawaki Method” – a reforestation approach using densely planted, locally native species saplings that will naturally thin and mature – Godfrey-Faussett has worked with local businesses and schools across UK cities, establishing plantings as compact as a few square meters. At one central London primary school, he told me, a corner of concrete playground is being replaced with a pocket forest, bringing a dose of nature into the children’s playtime. “The concept is that the forest becomes self-sustaining very quickly.”
Keeping things community-based was a recurring theme among the initiatives I spoke with. Looking for tree projects around my home in Suffolk, I discovered the Suffolk Tree Warden Network, a voluntary branch of the Tree Council which has been cultivating trees for donation from locally collected seeds. “We’re growing them in containers and back gardens,” says volunteer Fe Morris. “A couple of our members have set up tree nurseries in schools.” These trees are given away.“There’s been a really good uptake because everyone is rightly terrified about the climate crisis.”
But it’s not all about planting new trees. The Woodland Trust, aligning with Kew’s rule “Protect existing forests first”, is seeking to preserve vulnerable ancient woodland. “At one point, woodland would have been the dominant landscape feature of the UK,” says the trust’s Bridget Fox. “But only 3%, on average, of the UK is now ancient woodland.” Places like Wychwood in Oxfordshire or Epping Forest on the outskirts of London are brimming with veteran oaks, lichens, fungi and flowers. “Soil that has only ever been wooded is so rich, supporting not only trees but other plants, bugs, birds, mammals and so on,” says Fox.
It is this well-established ecosystem that makes ancient woodland so effective at carbon capture. The Woodland Trust says woodlands in the UK hold 213m tonnes of carbon, and ancient and long-established woodlands hold 36% of that, even though they make up just 25% of all woodland. “Yet only 7% of our woodlands – ancient and modern – are in good ecological condition,” adds Fox. “We’re calling for ancient woodlands to have buffer zones around them, which could be newly planted woodland, or just land left for natural regeneration, so it’s protected from noise, pollution and buildings hard up against it, which can compact the soil.”
The Woodland Trust details numerous ways in which people can get involved. It runs several preservation initiatives, from recording the health of veteran trees in their area via the trust’s Ancient Tree Inventory, to helping map urban tree cover, which can then be used to lobby councils for more trees or better protection for existing ones.
It’s clear from the conversations I’ve had that carbon capture reforestation efforts – large or small – must be multifaceted, tackling in particular the growing biodiversity crisis, which scientists say is just as catastrophic as climate change. The Natural History Museum warned recently that the UK has only half of its entire biodiversity left, with an average of just 53% of its native wildlife – plants, animals and fungi – intact. Their analysis cautions: “This is significantly below the 90% average set as the ‘safe limit’ to maintain the ecological processes such as pollination and nutrient cycling that are vital to our survival.” At Cop26, a Kew group launched the Global Biodiversity Standard, which aims to assure people that the tree-planting projects they support do not prioritise quantity over provision for nature. This will soon be a certification logo to look out for.
The world my two-year-old son is growing up in will continue to face the carbon challenge, but the thought of it being a world in which our trees and forests might be more valued is comforting.
Five things you can do
Plant a tree in your garden
The RHS website is a helpful resource for choosing a site-suitable variety of tree.
Protect existing trees
Keep an eye on the health of nearby street and park trees by becoming a tree warden.
Help reforest your local area by lobbying your council for more trees. There are campaigning resources at friendsoftheearth.uk.
Help the Woodland Trust build up a better picture of UK biodiversity by recording and submitting observations on selected flora and fauna.
Check that the tree-planting schemes you support prioritise sustainability over greenwashing; question their species selection and their future safeguarding plan.