Unplanned tree planting could increase global warming and damage the environment, experts warn

However, a new report from the Government’s independent advisors, the Natural Capital Committee (NCC), shows that unless the massive expansion of tree planting promised in the run up to the last UK general election is planned with an eye to its wider effects, it could cause problems for the environment, or even result in increased greenhouse gas emissions globally.

The report lists a number of ways in which unregulated planting could increase global warming. Boggy peatland soils lock up vast quantities of carbon, but planting trees here can dry these soils out, leading them to emit far more greenhouse gas than will ever be captured by those trees.

There is also uncertainty regarding the extent to which planting trees on some types of farmland might cause the UK to increase its imports of meat from countries which farm beef by cutting down rainforests, thereby releasing huge quantities of carbon into the atmosphere.

These problems might well arise if tree planting subsidies simply focus on the cheapest land available, such as wetlands or upland farming areas.

Also, many of these areas provide vital habitats for some of Britain’s rarest species, so again a “single focus” policy of trying to get the largest amount of carbon stored in trees at the lowest price could result in wider damage to the environment. 

With this in mind, the NCC strongly support plans to expand Britain’s woodlands.

Their report, Advice on using nature based interventions to reach net zero greenhouse gas emissions by 2050, published today, urges the Government to have a more joined-up approach to tackling climate change with coordination and targeting from the top and local delivery.

The report warns that the current siloed approach, with several departments and other bodies involved but with no overall coordination, will fail to deliver the intended outcome and could even contribute to increased greenhouse gas emissions and further degradation of the natural environment if the wider effects of planting are ignored.

NCC committee member Professor Ian Bateman, Professor of Environmental Economics and Director of the Land, Environment, Economics and Policy Institute at the University of Exeter, said: “It’s a well-worn phrase but the devil really is in the detail here.

“Planting trees can either be really good or really bad for both climate change and the environment.

“The mantra has to be ‘the right tree in the right place’. We really do have to be strategic about where we plant.

“As a nation, we will only meet targets to reduce greenhouse gas emissions if these nature-based interventions allow for the effects of planting on emissions elsewhere."

Professor Ian Bateman, who is part of the Global Systems Institute, added: “And we would be crazy to undertake the massive scale of planting being considered if we did not also consider the wider effects upon the environment including impacts on wildlife, benefits in terms of reducing flood risks and effects on water quality, improvements to recreation and so on.”

The committee also recommends the Government should “urgently” replace what it sees as the limited policy of requiring that building and infrastructure development delivers “biodiversity net gain” with the wider requirement of delivering “environmental net gain”.

This would mean that the environmental damage caused by development has to be more than compensated for in ways that consider improvements for wildlife, carbon storage, the water environment, access to greenspace and outdoor recreation.

This would ensure improvement efforts apply to all nationally significant infrastructure and the marine environment. Otherwise it will be “incredibly difficult, if not impossible” to reach net zero greenhouse gas emissions, the report says.

It says planning for infrastructure – including solar farms, wind turbines, buildings, railways and roads, all of which apply pressure on natural assets – should be fully joined up with any spatial planning for nature-based interventions.

It also recommends the Government should develop a “holistic” strategy to reach net zero, which should include changes in energy, transport, housing, infrastructure, industry and land and sea use.

Priority should be given to evaluating, managing and increasing tree cover, maintaining and increasing soil carbon, including peatland restoration, improving wildlife and biodiversity, managing freshwaters and wetlands and sea use changes.

The committee have previously urged ministers to develop a comprehensive baseline of natural capital assets in order to determine whether initiatives such as Government’s new £640m “Nature for Climate” fund earmarked for tree planting and peat restoration will deliver the required environmental improvements.