A eureka moment for the planet: we’re finally planting trees again

China plans to plant forests the size of Ireland. Latin American countries have pledged to restore 20m hectares of degraded forest and African countries more than 100m hectares. India is to plant 13m hectares, and on a single day last year 1.5 million people planted 66m trees in Madhya Pradesh alone.

Much of Europe is physically greener than it was just a few years ago. England is to plant 50m trees in a new coast-to-coast forest and newly planted saplings now cover tens of thousands of hectares of former farmland in Ireland, Norway and France. From Costa Rica to Nepal and Peru to Mongolia, tree planting has become a political, economic and ecological cause, and a universal symbol of restoration, regrowth and faith in the future. More than 120 countries promised in 2015 to plant and restore large areas of forest as a response to the climate crisis, and the UN has set a target to restore 350m hectares by 2030 – an area bigger than India.

This enthusiasm for a greener world, expressed in trees, is inspiring and overdue. For 200 years forested countries barely knew what to do with their trees. They were treated as expendable and a waste of space. But in a great cultural shift, they have changed from being dark and fearsome places to semi-sacred and untouchable.

And why not? In this new ecological age, we have learned that trees have far more value than providing timber: they keep soils moist, prevent floods and provide shelter, store carbon, beautify landscapes, protect water sources, increase biodiversity, improve conservation and induce human wellbeing. So woe betide councils such as Sheffield that want to cut down trees. From the Newbury bypass protests 20 years ago to today’s battles to save the ancient woodlands along the route of the HS2 rail link, there are few surer ways of angering people than cutting down their trees.

We are seeing a great global attempt to plant and restore forest land but paradoxically we are still losing tree cover. The rate of global deforestation has slowed by more than half in 25 years but tree loss jumped 50% in 2016, and 2017 is likely to have been worse.

The greatest threat to trees used to be loggers and the expansion of farming. These are still a threat, but human-caused deforestation and degradation make forests more fire-prone, and disease, droughts linked to climate change and harmful beetles are likely to kill trees in greater numbers.

In two years, many millions of hectares of forest have burned across North America, South America, Australia and Europe. Some of the wild fires were deliberately set, but the spike reflects the warming of the land and is just one of the many consequences of climate change. Equally, tree diseases are now rampant and forests are succumbing to drought, disease and insects – much of it driven by climate change.

We must keep planting trees but think differently. Mass, state-sponsored tree-planting has a reputation for being expensive and badly managed. When forests are planted on an industrial scale, up to 20% of the trees may die within a few years. It costs around £720 a hectare to plant a forest, so it would cost around £250bn to plant the 350m hectares that countries have signed up to. That money is just not available to developing countries.

But there is a solution. Increasingly a system known as agro-forestry is proving itself. Here, trees and shrubs are being grown around or among crops, often on degraded forest land. There are around 2bn hectares of this land around the world and restoring it with agro-forestry can not only put food on tables, but create hundreds of thousands of jobs and address climate change.

There have been remarkable successes. Just 30 years ago Niger was an impoverished, drought-prone country. It had been persuaded by development experts from rich countries to intensify its farming by clearing large areas of land and planting huge fields of wheat and maize. It largely failed and the soil blew away. The story, recounted by the author Fred Pearce, goes that, to save  time, young men returning from working abroad in the 1980s planted their crops without first clearing the land. To their surprise, their grain yields were much better than in neighbouring fields that had been cleared of all woody plants. When the same thing happened the next year, the villages got the message: trees were good for their crops.

Since then, something like 200m trees in Niger have been planted or encouraged to naturally regenerate on 5m hectares. Food production has increased by 600,000 tonnes a year in the places where the trees have returned.

The government’s part in this success story has been minimal. Agro-forestry spreads spontaneously as farmers and landowners see the benefit of combining crops with trees. The trees provide fodder for livestock, fuel, medicines, fruits and cooking oil and regenerating the land has cost perhaps $20 a hectare. The Niger government helped mainly by changing the law to allow farmers who plant trees to profit more.

Pakistan, too, has shown spectacularly how to combat climate change and reduce instances of flooding and natural disasters. Thousands of nurseries have been set up in the past three years in Khyber Pakhtunkhwa province, communities have distributed for free more than 150m trees from the nurseries, existing forests have been densely planted and expanded, and large areas of degraded land have been allowed to regenerate naturally. The result will not be seen for many years, but more than one billion trees have been planted, and 350,000 hectares of forest and farmland regenerated for not much more than £100m – roughly what it would cost to build two miles of dual carriageway road in Britain.

Similarly, in Malawi, Mali, Ethiopia and elsewhere, farmers are now planting, protecting and managing many more trees on their farms. The Seno plains of Mali are unrecognisable from 30 years ago and in the Tigray region of Ethiopia, nearly 1m hectares of unused land have been regreened and transformed. Crop yields are increasing, and fewer young people are leaving their villages.

And in India, the Araku project has seen local communities plant millions of fruit trees and coffee bushes. Nearly 15,000 acres have been revitalised.

Agro-forestry is changing farming and addressing climate change in many countries as surely as the “green revolution” swept through the world promising higher yields with chemicals in the 1960s and 70s. It depends for its success on changes in attitudes, shifts in behaviour and improved management practices. It requires communities to work together, local knowledge and governments to reform land laws and help to educate. But it does not need large amounts of money.

Great areas of Indonesian, Congolese and Latin American forests are still being lost to the loggers and the palm oil companies, but we are seeing a heartening response to the linked climate and food crises. It is too early to think that we are ecologically more literate, but there is a real sense that governments are beginning to understand that change best comes from the grassroots and is both needed and possible.

• John Vidal is the Guardian’s former environment editor