Market Potential for Reclaiming CCA from Decommissioned Utility Poles

Port-Orford cedar (Chamaecyparis lawsoniana), Alaska yellow cedar (Chamaecyparis nootkatensis), and Eastern red cedar (Juniperus virginiana) were submitted to supercritical fluid extraction with CO2 (SCC) and Soxhlet extracted (SE) with hexane. The components in the extracted oils were identified by GC-MS. The oils were evaluated against two common wood decay fungi, brown-rot fungus (Gloeophyllum trabeum) and white-rot fungus (Trametes versicolor). The SCC extraction yields of J. virginiana, C. nootkatensis, and C. lawsoniana were 3.27%, 3.22%, and 3.29%, respectively. The SE yields of J. virginiana, C. nootkatensis, and C. lawsoniana were 0.80%, 0.71%, and 1.52%, respectively. The statistical analysis showed that SCC extracted cedar oils had higher antifungal activities than SE cedar oils against both fungi. In vitro studies showed that C. nootkatensis oils have the strongest antifungal activity, followed by C. lawsoniana, and J. virginiana oil.

Natural Wood Durability

The relationship between chemical composition and durability in wood was first reported by Hawley et al. (1924). Some heartwood has the inherent ability to resist biological degradation, often referred to as ‘‘natural durability’’ or ‘‘decay resistance’’ (Eaton and Hale 1993). Meanwhile, the relation between extractive content of heartwoods and their fungal tolerance is well established (see recent publications: Chedgy et al. 2007; Lim et al. 2007; Mburu et al. 2007; Kusuma and Tachibana 2008). Three North American important commercial wood species, Port-Orford cedar (Chamaecyparis lawsoniana), Alaska yellow cedar (Chamaecyparis nootkatensis), and Eastern red cedar (Juniperus virginiana) are known to have significant natural durability. Cedar species have been reported to have special bioactivity against termites and wood decay fungi (Liu 2004; Gao et al. 2008). Evaluations on antifungal properties (Gao et al. 2008), biocidal application (Dolan et al. 2007), and termiticidal activities (Liu 2004) of C. lawsoniana extracts have been reported. A chemical ecological study of the components of the essential oil of J. virginiana from different habitats was performed by Setzer et al. (1992). Volatile oil from J. virginiana, consisting primarily of cedrene (a terpene) and cedral has been used in perfumery (Heide et al. 1988; Semen and Hiziroglu 2005) and as an insect repellent. J. virginiana oil has been widely used in a very broad range of products owing to its unique properties, such as odor and repellency or toxicity to many pests.

Antibiotic Activity of Cedar Extractives

In addition, the antibiotic activities of C. nootkatensis have been studied extensively. For example, antimicrobial activity of essential oil from C. nootkatensis has been tested against anaerobic bacteria and yeast (Johnston et al. 2001). Heartwood extractives from C. nootkatensis have been tested for resistance to termites and fungi (Taylor et al. 2006). The composition of the leaf oil from C. nootkatensis has also been reported (Andersen and Syrdal 1970; Cheng and Von 1970). In most of these studies, conventional Soxhlet extraction (SE) was used, which is time consuming and requires organic solvents. Some bioactive components in cedar oils could be affected during SE. Supercritical CO2 (SCC) extraction has several advantages in extracting non-polar components of complex mixtures of natural products. The low viscosity and high diffusivity of SCC can result in higher extraction efficiencies and CO2 can be easily removed from the extract, leaving an extract that is uncontaminated by any solvent residue. However, SCC of these three cedar oils has been rarely reported (Eller and King 2000). The antifungal activities of these SCC-extracted oils has not been compared. The objectives of this research are to compare the extraction efficiency between hexane SE and SCC extraction, identify the main chemical components by GC-MS, compare the chemical composition of the extracts obtained by the two methods, and evaluate the antifungal activities of the SCC extracts of the three cedar woods.

Meet the Author

Dr. Todd Shupe is the President of Wood Science Consulting, LLC. He is a well-recognized expert on wood forensics, wood preservation, wood decay and degradation, and wood species identification. He has a broad background in new product development, quality management, and marketing and sales in both the public and private sectors. For more information please visit DrToddShupe.com.

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