Does Intercropping Carinata with Loblolly Pine for Sustainable Aviation Fuel Production Save Carbon? A Case Study from the Southern United States

This study determines carbon savings related to intercropping carinata (Brassica carinata A. Braun) with loblolly pine (Pinus taeda L.) and compares it with the carbon savings associated with the production of loblolly pine only. We performed an integrated life cycle assessment to quantify the overall carbon stored under both production systems. The functional unit for analysis was a hectare of intensively managed loblolly pine plantation in the Southern United States. The system boundary started from forest management with carinata, use of wood products, the decay of wood products in landfills, and the substitution of conventional aviation fuel with carinata-based sustainable aviation fuel (SAF). Carbon stored in wood products was 5.46 t, 6.75 t, and 11.52 t C ha(-1) higher than carbon stored in landfill at the end of the simulation period (100-years) for the intercropping production system for site indices 15.3 m, 18.3 m, and 21.3 m, respectively. At the end of the simulation period, the total avoided carbon savings from carinata-based SAF were 2.57 t, 4.15 t, and 4.76 t C ha(-1) for site indices 21.3 m, 18.3 m, and 15.3 m, respectively. Over the simulation period, devoting the forestland for intercropping to produce SAF decreased the total carbon storage by 2.55 t, 4.08 t, and 12.49 t C ha(-1) than loblolly pine only management scenario for site indices 15.3 m, 18.3 m, and 21.3 m, respectively. Our results indicate that a system-level approach should be taken for analyzing the carbon benefits related to intercropping of bioenergy crops in existing forest stands.