How do soil properties influence carbon storage and sequestration in newly established woodland across the UK?
Abstract
The aim of this review is to synthesize the current evidence on how pre-afforestation soil properties can impact the carbon balance of an area of woodland creation, and to put this into context in terms of relevance for the Woodland Trust's work. There is strong evidence that the higher the existing carbon content of a soil, the lower the carbon sequestration benefit that can be achieved through woodland creation, and the higher the risk of overall carbon emissions for a significant period. Afforestation of organo-mineral soils can lead to substantial overall emissions for 30-40 years because of carbon loss from the soil. Woodland creation on organo-mineral soils for carbon sequestration is at best sub-optimal or ineffective, at worst counter-productive on the relevant time scale. The current policy against afforestation on peat >50cm should be reviewed considering recent evidence on the significance of organo-mineral soils for carbon storage and the risk of soil carbon loss during the decisive next few decades for action on the climate emergency. A more nuanced approach to an evaluation of soil carbon stocks prior to planting is warranted. The reduction of carbon emissions at source must be a priority with trees contributing to offsetting unavoidable and historic carbon emissions. Nevertheless, woodlands created for meaningful sequestration as recommended by the Committee on Climate Change must act as a carbon sink as soon as possible and then store carbon for the long term.