Carbon dioxide emissions, embodied energy, material use efficiency of lumber manufactured from planted forest in Brazil

Abstract

Global warming is a fact that requires quick and effective actions. Wood products have carbon dioxide mitigation potential due to carbon capture from the atmosphere and temporary storage. The use of planted wood in Brazilian construction could be a strategy for mitigating carbon dioxide emissions. However, studies on the possible long-term benefits are scarce. Therefore, the goal of this study was to estimate CO2 emissions, embodied energy, and material inputs and outputs associated with the production of lumber for the construction industry, from Brazilian planted forest, using the life cycle assessment approach. A life cycle inventory, from cradle-to-gate, was conducted using primary data from ten companies with production phases located in Brazil, and complementary information was based on the literature. One dry metric ton of lumber emits between 41 and 726 kgCO2 (155 kgCO2/t, median). Approximately 34% of carbon emissions are due to transportation distances between the industry and consumer (from 150 to 4,169 km). The embodied energy varied from 945 to 15,451 MJ/t (9,062 MJ/t, median). The embodied energy increased (approximately 82%) in the oven-drying phase, due to the high moisture content of the biomass used as a fuel. The material use efficiency varied from 1.1 to 5.9 t/t (2 t/t, median), where significant loss occurred at sawmill during the primary processing, which transformed log into lumber, with a median yield of 50% (from 45 to 79%). Values are equivalent to international references, and the differences observed are due to variations in kiln technology, travel distances, and moisture content of the biomass fuel.