We talked to Carbon Brief about tree planting in the UK. If the UK government’s tree-planting targets are achieved, even with optimistic estimates of carbon sequestration they would only provide a small proportion of the total carbon capture required to reach net-zero emissions by 2050. The Committee on Climate Change (CCC) predicts that (with a given emissions reduction pathway) by 2050 the UK will have 90MtCO2e/year of ‘residual emissions’ which need to be removed the atmosphere to achieve net-zero. It’s estimated that if the government achieves it target of increasing forest cover from 13% to 17% by 2050 and improves woodland management, this would draw down just 14Mt/CO2e/year. Based on these estimates, that leaves 76MtCO2e/year not accounted for which must be removed by other means, e.g. Bioenergy Carbon Capture and Storage (BECCS) or Direct Air Capture (technology that needs further development), or alternatively not must be released in the first instance, requiring cuts in polluting industries such as aviation.
We need more mixed-species, broadleaf-dominant woodland. The CCC pathway for 2050 is based on forest creation split 60:40 broadleaf to conifers. Whether this ratio would be followed through is not certain, and those who like fast-growing, lucrative conifer plantations could push for more conifers. Whilst broadleaf species accumulate carbon slower than coniferous species, they generally store more carbon in the long-term due to having denser wood and living to an older age. There is agreement among scientists that forests with a high diversity of species are more resilient to pests, diseases and extreme weather events, making them more reliable carbon stores in the long-term.
Improving forest management plays a key role in increasing the UK forest carbon sink. The CCC estimates that one third of the 2050 forest carbon sink will come from improved management, but this method is less attractive to politicians than creating a given number of hectares of forests (which makes for better headlines).
We need research into where to plant trees. It’s estimated that we need 0.9-1.5 million ha of land for tree planting in order to reach 17% cover by 2050. Whilst 3.2 million ha of land have been identified in England alone as being suitable for tree planting (e.g. low quality agricultural land), the optimum locations for afforestation on a finer scale have not been mapped. Many factors need to be considered in this process, such as the carbon, biodiversity, and other values of alternative uses of land designated to tree planting.
We need greater investment in forestry in order to meet targets. Tree planting rates would need to be slightly higher than the historical peak rate in the UK which was achieved in the late 1980s. This will require retraining land managers in woodland management, and giving nurseries a guarantee that there will be demand for saplings over coming years, enabling them to up-scale production.
The new Environmental Land Management system will be rolled out over the next 7 years. This replaces the European Common Agricultural Policy, and holds promise since land managers will be paid for provision of public goods (e.g. afforestation for carbon sequestration) rather than per hectare of land. However, it requires significant refinement if it is to enable the UK to achieve its forest creation targets.
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