Planting trees to increase woodland cover in the UK can result in many environmental benefits but it has also been advocated to help towards getting to net zero in 2050.
Introduction
Trees take carbon dioxide from the atmosphere and convert it to carbon and then store it. Woodland soil also contributes to the overall woodland carbon sink. Trees then are an important means of removing carbon dioxide from the atmosphere an important means of offsetting the impact of emissions.
The environmental benefits of trees are considerable. “Beyond carbon, all trees and woodlands – wherever they are in the landscape, including our towns and cities – can also provide a range of other benefits. They improve air quality, reduce the ‘urban heat island’, provide timber, wood and wood fibre products, provide opportunities for people to re-connect with nature and new spaces to improve health and well-being, help to reduce flood risk and can reduce the costs of water treatment too.”
[Forestry Commission, (2022), Responding to the climate emergency with new trees and woodlands].
It is accepted that trees are an integral component of any policy to improve our environment. Policies to increase and enhance the extent of woodlands and trees elsewhere are to be welcomed.
The question then is how much carbon can trees capture and how many need to be planted to have an impact on removing carbon dioxide. This is an area where there are a number of factors to consider. These include the species used, location, and woodland management regime.
Scenarios
Three scenarios were used to estimate how much land in the UK might be required to take out the 90Mt of net Co2w remaining in 2050. These are based on figures from an Exmoor study, a Committee for Climate Change report and figures from Carbon Brief. The assumptions underlying each one are different and consequently the area of land required to capture the net carbon in 2050 differ.
Each scenario assumes a standard area is planted with trees each year. As the table indicates the figures range from 70% to 96%.
Scenario base | Existing forest cover (Km2) | Additional area needed (Km2) | Total area required(Km2) | % of UK land area |
Exmoor study | 31,800 | 138,700671 | 170,400 | 70 |
Carbon Brief | 31,800 | 188500 | 220,288 | 90 |
Committee for Climate Change | 31,800 | 202,500 | 234,300 | 96 |
Apart from the area of land required, there would be issues regarding the availability of trees and how such planting would be funded.
[Alternative forecasts of how much land would be required are welcomed].
Conclusion
Increasing the area of woodland is justifiable on the grounds of benefits to the environment, landscape and well-being. Capturing and storing carbon is an important component of this. It is apparent however that we cannot mitigate all the emissions of greenhouse gases by tree planting. There just is not enough room even under the most optimistic scenario.
The answer must be to take a range of measures to cut emissions. Some might be relatively easy to implement but others will require lifestyle changes. Those who currently create the most greenhouse gas emissions will be required to make the biggest sacrifices – the era of private jets will definitely be over.
Changes in economic and social policy will also be necessary – any thought of enabling or allowing the UK population to continue increasing should be rejected. Ideally, the UK population should be allowed to decline to a more sustainable level.
Dr Charlotte Wheeler, a forestry scientist at the University of Edinburgh, told Carbon Brief that planting more trees cannot be regarded as a panacea: “It’s being readily promoted by governments and big international organisations because it sounds very positive…but in some cases I think people are anxious that it could become a distraction from reducing fossil-fuel emissions.”
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