Wales plans to offer ‘free trees for every household’ to fight climate change. But scientists warn of downsides if planned poorly

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Wales is best known for its castles, coal mines and sheep. But the Welsh government is hoping to add something else to that list: trees.

The government plans to hand out a free tree to every household, roughly 1.3 million in total, starting in March. Residents will have the choice of planting one at home or contributing it to a community garden, and they’ll be able to select from a range of native species including hawthorn, hazel and birch.

“Trees are amazing,” said Lee Waters, the deputy minister for climate change. “They save lives by keeping our air clean, they improve people’s physical and mental health, they are essential for tackling our nature emergency, improving biodiversity and, of course, in tackling climate change.”

The Welsh program is the latest in what’s become a global frenzy of tree-planting initiatives. A growing number of governments, corporations and concerned individuals see planting trees as a critical, and high-profile, way to meet carbon-reduction targets and contain global warming to 1.5 degrees Celsius above preindustrial levels, as set out in the Paris Agreement.

The appeal of trees is easy to see. Most children learn at an early age about the principles of photosynthesis – the process of how leaves use sunlight and carbon dioxide, a main cause of global warming, to produce carbohydrates and oxygen. That CO2 is stored in trees for as long as they live, which can be decades or centuries. So, in theory, planting more trees should soak up more CO2 and slow global warming.

That idea took hold in 2019 after a study by a group of Swiss scientists concluded that there was enough space on Earth to plant one trillion trees, which the researchers said could cut the amount of carbon dioxide in the atmosphere by up to 25 per cent.

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The Swiss study inspired a flurry of tree-planting projects. The World Economic Forum set up a program to plant one trillion trees by 2030 and governments from countries as diverse as Britain, India and the United Arab Emirates have launched massive tree-planting efforts. In Canada, the federal government has committed to planting two billion trees over the next decade.

The business community has gotten involved too, with many firms seizing on carbon offset programs – planting trees to counter greenhouse gas emissions. During the recent United Nations COP26 climate summit in Glasgow, Amazon and 18 other companies set up a US$1-billion fund to promote tree planting and 141 countries signed a commitment to stop deforestation.

Many climate scientists and environment campaigners, however, have grown increasingly concerned about this rush to plant trees. The 2019 study has been widely criticized for being far too optimistic and based on flawed assumptions – for example, much of the available land cited is already covered with plants. The criticism led the Swiss scientists to issue a lengthy revision.

Activists have also become wary of carbon offset programs. They argue that offsets do little to cut current emissions and let polluters off the hook. “Offsetting doesn’t stop carbon entering the atmosphere and warming our world, it just keeps it off the ledgers of the governments and companies responsible,” Jennifer Morgan, the executive director of Greenpeace, said during COP26.

The effectiveness of massive tree-planting campaigns has also come under scrutiny. These programs can often do more harm than good if they are rushed out too quickly with poor planning, scientists argue. For example, adding trees to areas where they have not historically grown can damage existing plants and ruin animal habitats. And while trees can help ease soil erosion, they also deplete groundwater if planted in the wrong place.

Government tree-planting programs also tend to put a premium on fast delivery and pay less attention to long-term maintenance to ensure that the trees actually survive.

A study released last summer by researchers at Oxfam concluded that it was “mathematically impossible to plant enough trees to meet the combined net-zero targets announced by governments and corporations, as there is simply not enough land to do this.” Oxfam and other researchers have argued that while planting trees is worthwhile, the real focus should be on better land management and conservation.

“Planting trees is wonderful. The right tree in the right place brings many benefits,” Forrest Fleischman, an associate professor of forestry and environmental policy at the University of Minnesota, recently said on Twitter. “But the wrong tree in the wrong place is harmful. We should focus on our overall goals, not on the number of trees we plant.”

The Welsh government has acknowledged that previous tree-planting drives have failed to deliver and that the “free trees for every household” program won’t do much to meet the U.K.’s commitment to being carbon neutral by 2050. A recent report from the Wales Land Management Forum noted that planting rates remained low despite ambitious woodland targets and financial incentives to encourage farmers to get involved. “This picture is mirrored elsewhere in the U.K., where except for in Scotland woodland creation targets have not been met,” the report said.

“Primarily we need farmers to be planting more trees on their land,” Mr. Waters told reporters. “There’s a lot of anxiety in the farming community at the moment and it’s easy to see the tree as the boogeyman. Actually trees are a part of the solution of how we deal with the current crisis and it needn’t be at the expense of farming.”

Despite the challenges of tree-planting programs, environmental groups say these campaigns still offer a host of worthwhile benefits. More trees help improve people’s well-being, lower stress levels and can even reduce crime. A 2012 study by researchers at the University of Vermont found that a 10-per-cent increase in tree canopy produced a roughly 12-per-cent decrease in crime, partly because trees encourage people to spend more time outdoors, which acts as a check on criminal behaviour.

“Trees do provide a number of other benefits in terms of people’s well-being, particularly in urban community spaces and for biodiversity, which is also in crisis,” said Natalie Buttriss, director of Coed Cadw, the Woodland Trust in Wales. Ms. Buttriss said that tree-planting is only part of the solution, and that the government should encourage conservation and better land use. “But I think it is a really good way of getting people engaged, and community engagement, to help people understand why trees are important.”

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