Carbon Footprint and Variable Costs of Production Components for a Container-grown Evergreen Shrub Using Life Cycle Assessment: An East Coast US Model

摘要

The production components of an evergreen shrub (Ilex crenata Bennett's Compacta') grown in a no. 3 container in an east coast U.S. nursery were analyzed for their costs and contributions to carbon footprint, as well as the product impact in the landscape throughout its life cycle. A life cycle inventory was conducted of input materials, equipment use, and all cultural practices and other processes used in a model production system for this evergreen shrub. A life cycle assessment (LCA) of the model numerated the associated greenhouse gas emissions (GHG), carbon footprint, and variable cost of each component. The LCA also included the transportation and transplanting of the final product in the landscape as well as its removal after a 40-year useful life. GHG from input products and processes during the production (cutting-to-gate) of the evergreen shrub were estimated to be 2.918 kg CO(2)e. When considering carbon sequestration during production weighted over a 100-year assessment period, the carbon footprint for this model system at the nursery gate was 2.144 kg CO(2)e. Operations, combining the impact of material and equipmerit use, that contributed most of GHG during production included fertilization (0.707 kg CO(2)e), the liner and transplanting (0.461 kg CO(2)e), the container (0.468 kg CO(2)e), gravel and ground cloth installation (0.222 kg CO(2)e), substrate materials and preparation (0.227 kg CO(2)e), and weed control (0.122 kg CO(2)e). The major contributors to global warming potential (GWP) were also major contributors to the cutting-to-gate variable costs ($3.224) except for processes that required significant labor investments. Transporting the shrub to the landscaper, transporting it to the landscape site, and transplanting it would result in GHG of 0376, 0.458, and 0 kg CO(2)e, respectively. Variable costs for postharvest activities were $6.409 and were dominated by labor costs (90%).