Planting hedgerows: Biomass carbon sequestration and contribution towards net-zero targets

Area of Science:

• Environmental Science
• Agricultural Science
• Climate Change Mitigation

Background:

• Agroforestry practices, including hedgerow planting, are crucial for climate change mitigation.
• Assessing the contribution of hedgerows to national net-zero targets is essential.

Purpose of the Study:

• To evaluate the impact of different hedgerow planting rates on UK net-zero goals by 2050.
• To analyze carbon sequestration rates of native hedgerow species.

Main Methods:

• Analysis of carbon content in native hedgerow species.
• Determination of aboveground biomass (AGB) carbon stock through destructive sampling of hedges of known ages.
• Calculation of annual average AGB carbon sequestration rates based on hedge age.

Main Results:

• AGB C stocks varied from 8.34 Mg C ha⁻¹ in young hedges to 40.42 Mg C ha⁻¹ in old hedges.
• Annual average AGB C sequestration rates were highest in young hedges (2.09 Mg C ha⁻¹ yr⁻¹) and decreased with age.
• Current planting rates are insufficient to meet the UK's 2050 net-zero goal; an increased rate of 7148.1 km yr⁻¹ is required.

Conclusions:

• Widespread hedgerow planting can significantly contribute to atmospheric CO₂ capture and storage.
• Achieving the UK's 40% increase in hedgerow length by 2050 necessitates a fourfold increase in current planting rates.
• Over 40 years, increased planting could store substantial CO₂ and offset a notable percentage of UK agricultural emissions.