Planting trees to tackle climate change might feel nice, but it could be doing more harm than good

In the race to capture carbon, we are mass planting trees at the expense of conservation and protecting biodiversity

We face an epidemic of the wrong sort of tree hugging. With climate crisis awareness now at its peak almost every big party politician, land owner and charity seems to be racing to embrace tree planting to capture carbon. Are we seeing ecological salvation all packaged up in those therapeutically earthy smelling root balls? Not if the effort is misguided.

In the wise words of the late, great author Oliver Rackham, in 1986: “Tree planting is not synonymous with conservation; it is an admission that conservation has failed.”

He likened a modern wooded landscape to a library in which thousands of ancient books are destroyed each year by people who cannot read them and do not appreciate their value, then the shelves are simply restocked with “bad paperback novels and pamphlets containing meaningless jumbles of letters.”

Rackham understood that one of the biggest threats to what remains of our dilapidated wildlife heritage, aside from habitat loss, is the introduction of alien species and diseases through soil and transplanted tree stock, and through a loss of genetic diversity in favour of monocultures of unnaturally grown nursery trees.

Add to that, the enlarged water and carbon footprints of growing and transporting, the plastic pots, tree guards and ties, ongoing watering, possibly peat usage, lower resilience, lack of regional, wild or native provenance, and suddenly those neat rows of dream trees – all the same age and genetic stock – might feel closer to a manufactured Disneyland forest than a wild wood.

Yet politicians never tire of being photographed planting trees. It is the easy, celebrated crowd-pleaser, loved by schools, charities and funders, even though it is often a poor surrogate for a more environmentally sound tree choice that would help tackle climate change and the ecological crisis.

In October, Extinction Rebellion symbolically gifted a tree to every eager politician in parliament.

Now we have the Tories and the Lib Dems locking spades in a manifesto duel: the blues are promising 30 million new trees, so the yellows have pledged to double it. Labour says it will take advice from scientists. Those millions are still only one per cent of the committee on climate change’s advice on how many trees Britain needs to plant to meet our climate change limiting commitment, and yet still there is no promise on how ecologically valuable or carbon-useful the trees will be.

The Woodland Trust is calling on one million people to plant a tree or donate to have one planted, on November 30, for Tree Charter Day, with events across the UK. Amid the race, we risk losing sight of the other crisis: tackling the ecological emergency and halting the sixth mass extinction, which require massive habitat protection measures: not just any old trees, but ecologically and climate-resilient, relevant ones. The trees should be selected to fulfil all their important purposes beyond merely storing carbon. Therefore it is vital that we do not plant the wrong sorts of trees in the wrong ways.

As funding across local authorities and conservation charities has evaporated amid a decade of austerity, I have witnessed local nature reserves and wildlife sites committing eco-vandalism by planting up precious grass wildlife sites as new woodlands. This seems driven by a feel-good factor, easy access to funding for tree planting and pressure because of a lack of resources to continue with hay cuts or grazing needed to preserve the site as species-rich grassy ecosystems.

While we only have 2 per cent of ancient woodland cover left in Britain, we also only have 1 per cent of species rich meadows, and they need saving too. Both habitats harbour rich diversities of declining wildlife.

Meanwhile scientists are widely disagreeing on how much CO2 each tree will sequester, as well as how many and which are needed to partially photosynthesis our way out of our climatic mess and how much land would be needed to reduce CO2 levels in the atmosphere back down to safe pre-industrial levels. There remains uncertainty on whether there is even enough suitable land and whose land it should be.

Forest researchers recently found that 45 per cent of new forests globally were monoculture plantations of fast growing trees, usually intended for harvest, holding little carbon, ecologically poor and even decreasing biodiversity.

Meanwhile mass tree planting in grasslands and savannahs threatens unique biodiversity, not just in the UK but elsewhere too. And afforestation for offsetting is plagued by complaints of fraud and colonialism.

On 4 November, the UK government launched a new £50m Woodland Carbon Guarantee scheme, with payments to farmers and landowners to plant more trees to help tackle climate change.

A potential flaw is that trees may be used by industries wanting to offset future carbon emissions rather than capturing existing CO2. To add insult, the government is calling one of its new schemes the HS2 Woodland Fund. As they carve up 108 ancient woodlands for the new rail link, guilt money will be spent on newly planted nursery trees, and with no promise they will all be native either.

It looks like options might be sold to businesses that want to keep pumping out more carbon, thereby scoring two home goals in not reducing existing CO2 or biodiversity loss.

These remaining, irreplaceable ancient woodlands are ecological symphonies, the last hints of our native wildwood, temperate rainforests, rich in wildlife. Irreplaceable. New native plantings will bolster tomorrow’s heritage, but lack that key ancient woodland wildlife. In contrast, more plantations will be dark, comparatively joyless factories.

There is an old saying that a person should plant a tree under whose shade she will never sit. Often it would be better to step back and let acorns grow.