Application of conductive polymer analysis for wood and woody plant identifications

An electronic aroma detection (EAD) technology known as conductive polymer analysis (CPA) was evaluated as a means of identifying and discriminating woody samples of angiosperms and gymnosperms using an analytical instrument (electronic nose) that characterizes the aroma profiles of volatiles released from excised wood into sampled headspace. The instrument measures electrical-resistance changes generated by adsorption of volatiles to the surface of electroactive, polymer-coated sensors. Unique digital electronic fingerprints of wood aromas, derived from multisensor-responses to distinct mixtures of wood volatiles, were obtained from woods of individual tree species. A reference library containing aroma signature patterns for 23 tree species was constructed for identifications of unknown samples using pattern-recognition algorithms. The 32-sensor array used with an Aromascan A32S instrument was sensitive to a wide diversity of organic compounds and produced outputs of distinct electronic aroma signature patterns in response to wood volatiles that effectively identified unknown samples from individual tree species included in the reference library. Some potential applications of CPA methods for research in ecology, forestry, plant taxonomy, and related disciplines were identified with some significant advantages and limitations. Other applications of this technology were discovered for the management of forested stands and ecosystems based on the identification of roles that wood-inhabiting organisms play in stand dynamics and long-term ecosystem functions. Results pertaining to tree systematics and phylogeny are discussed in the context of prevailing opinions of oak taxonomy.