Paper

Carbon Cequestering and Structural Abilities of Eucalyptus Cloeziana

---

Abstract

In our time of urgency of climate action in the architecture/engineering/construction industry, new low-carbon building materials can very well be part of the solution, especially when these materials exhibit superior performance compared to existing materials. Low-carbon Eucalyptus Cloeziana (kloh-zee-ah-nuh), commonly known as Gympie Messmate, is a fast-growing hardwood native to Australia. Its quick growth makes it advantageous for carbon sequestering while its strength class lends itself to structural applications. Market research in the US shows a trend of growing demand for timber, especially mass timber. This is in line with SE 2050 Challenge which states that “All structural engineers shall understand, reduce, and ultimately eliminate embodied carbon in their projects by 2050”. This research paper reports on applied research in which the first author, with the help of two faculty, experimented with the use of Eucalyptus to replace Douglas Fir in roof structures. A life cycle carbon analysis was conducted and resulted in defining the measurable performance of Eucalyptus Cloeziana. This paper investigates market potential as well as the environmental benefits and challenges to using Eucalyptus Cloeziana as a structural material for buildings. Although it may grow in the North American climate, Eucalyptus is currently not commonly found in the US. It grows and is commonly used in Australia, where its manufacturers provide the necessary environmental impact information in the standard format of an Environmental Product Declaration (EPD). An EPD follows a product throughout its life cycle, including values for global warming potential, ozone depletion potential, acidification potential, eutrophication potential, photochemical ozone creation potential, and abiotic depletion potential. The author used the material’s EPD to conduct a comparative study, in which the performance of Eucalyptus was compared to the structural use of steel and Douglas Fir, using data of the same geographical region. The case study demonstrates the comparative properties and performance of Steel, Douglas Fir, and Eucalyptus in terms of embodied carbon and structural weight within a single structural bay. Although Eucalyptus has higher carbon content (negative carbon) than Douglas Fir per weight, the study showed that because the softwood system requires larger volume of wood than the hardwood system, the Eucalyptus structure weighs less than Douglas Fir. Because softwood sequesters more carbon due to its slow growth, Douglas Fir sequesters more carbon per structural bay. Eucalyptus sequesters less carbon (per structural bay) but since it grows twice as fast compared to Douglas Fir, it has market advantages that are not measured by the simple metric of embodied carbon.

Keywords: decarbonization, sustainability, structural systems, eucalyptus cloeziana, life cycle analysis

How to Cite:

Sandberg, H., McCoy, C. & Mansy, K., (2023) “Carbon Cequestering and Structural Abilities of Eucalyptus Cloeziana”, Building Technology Educators’ Society 2023(1), 85–92. doi: https://doi.org/10.7275/btes.1937