Biomass carbon stocks and stock changes in managed hedgerows

Area of Science:

• Agricultural landscape ecology
• Remote sensing
• Carbon sequestration

Background:

• Hedgerows are significant landscape features in North-western Europe.
• They contribute to terrestrial carbon sinks, but their management's impact on biomass is understudied.
• Few studies link aerial imagery to ground-truthed biomass and management effects.

Purpose of the Study:

• Develop relationships between hedgerow biomass and drone-derived digital elevation model (DEM) data.
• Assess changes in above- and below-ground biomass stocks.
• Apply an inventory framework to a pilot study area in Ireland.

Main Methods:

• Utilized drone and aircraft DEM data to measure hedgerow volume.
• Developed volume-biomass regression models.
• Conducted systematic grid sampling for biomass assessment.
• Applied inventory framework to a 419,701 ha pilot area in Ireland.

Main Results:

• Established robust relationships between DEM data and hedgerow volume and above-ground biomass.
• Above-ground biomass density linearly correlated with hedge volume.
• Wider, less intensively managed, irregular hedges showed higher biomass stocks per km.
• Hedgerow management intensity, type, and species confounded below-ground biomass models.

Conclusions:

• Hedgerow management, particularly flailing or coppicing, significantly impacts the biomass carbon balance.
• Intensive management and removals can lead to net carbon emissions.
• Reintroducing traditional practices like layering and increasing hedgerow width can enhance carbon sink potential.